BLM LIBRARY
88066249
Southwestern
Region
July 1997
Final Environmental
Impact Statement for
Carlota Copper
Project
Tonto National Forest
Volume II
Equal Employment Opportunity Statement
The United States Department of Agriculture (USDA) prohibits discrimination in its programs on the
basis of race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial
status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require
alternative means for communication of program information (Braille, large print, audio tape, etc.)
should contact the USDA Office of Communications at (202) 720-5881 (voice) or (202) 720-7808
To file a complaint, write the Secretary of Agriculture, U.S. Department of Agriculture, Washington,
D.C. 20250, or call (202) 720-7327 (voice) or (202)720-1127 (TDD). USDA is an equal employment
opportunity employer.
(TDD)
/. ' t -■
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if ^ ■ ■ '
Table of Contents
H ^
Volume I
Cover Sheet
Page
Summary xi
1 .0 INTRODUCTION AND PURPOSE AND NEED 1 -1
1.1 Introduction 1-1
1 .2 Project Location 1-1
1 .3 Purpose of and Need for Action 1 -1
1 .4 Authorizing Actions 1-3
1.5 Issues 1-3
1 .6 Interrelated Actions 1-3
1.6.1 Introduction 1-3
1.6.2 Past, Present, and Reasonably Foreseeable Future Actions 1-6
2.0 ALTERNATIVES INCLUDING THE PROPOSED ACTION 2-1
2.1 Proposed Action 2-1
2.1 .1 Overview of Proposed Carlota Copper Project 2-1
2.1.2 Mining Operations 2-11
2.1 .3 Heap-Leach Facilities 2-1 8
2.1 .4 Ore Processing Operations 2-29
2.1 .5 Project Support and Ancillary Facilities 2-34
2.1.6 Utilities, Equipment, Vehicles, and Supplies 2-43
2.1 .7 Site Access and Project Traffic 2-46
2.1 .8 Construction and Operational Considerations 2-48
2.1.9 Carlota’s Proposed Reclamation and Closure 2-49
2.2 Project Alternatives 2-58
2.2.1 Alternatives Considered in Detail 2-59
2.2.2 Alternatives Eliminated from Detailed Consideration 2-74
2.3 Comparative Analysis of Alternatives 2-89
2.4 Agency Preferred Alternative 2-89
Volume II
3.0 AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES 3-1
3.1 Air Resources 3-3
3.1.1 Affected Environment 3-3
3.1.2 Environmental Consequences 3-14
3.1.3 Cumulative Impacts 3-33
3.1.4 Monitoring and Mitigation Measures 3-35
3.2 Geology and Minerals 3-39
3.2.1 Affected Environment 3-39
3.2.2 Environmental Consequences 3-51
3.2.3 Cumulative Impacts 3-57
3.2.4 Monitoring and Mitigation Measures 3-58
3.3 Water Resources 3-61
3.3.1 Affected Environment 3-61
Carlota Copper Project Final EIS
I
Table of Contents
Page
3.3.2 Environmental Consequences 3-1 07
3.3.3 Cumulative Impacts 3-130
3.3.4 Monitoring and Mitigation Measures 3-1 34
3.4 Soils and Reclamation 3-145
3.4.1 Affected Environment 3-145
3.4.2 Environmental Consequences 3-1 53
3.4.3 Cumulative Impacts 3-168
3.4.4 Monitoring and Mitigation Measures 3-168
3.5 Biological Resources 3-175
3.5.1 Affected Environment 3-175
3.5.2 Environmental Consequences 3-201
3.5.3 Cumulative Impacts 3-218
3.5.4 Monitoring and Mitigation Measures 3-219
3.6 Cultural Resources 3-225
3.6.1 Affected Environment 3-225
3.6.2 Environmental Consequences 3-228
3.6.3 Cumulative Impacts 3-238
3.6.4 Monitoring and Mitigation Measures 3-239
3.7 Socioeconomics 3-241
3.7.1 Affected Environment 3-241
3.7.2 Environmental Consequences 3-254
3.7.3 Cumulative Impacts 3-268
3.7.4 Monitoring and Mitigation Measures 3-269
3.8 Land Use 3-271
3.8.1 Affected Environment 3-271
3.8.2 Environmental Consequences 3-275
3.8.3 Cumulative Impacts 3-279
3.8.4 Monitoring and Mitigation Measures 3-279
3.9 Recreation 3-281
3.9.1 Affected Environment 3-281
3.9.2 Environmental Consequences 3-282
3.9.3 Cumulative Impacts 3-285
3.9.4 Monitoring and Mitigation Measures 3-285
3.10 Wilderness and Wild and Scenic Rivers 3-287
3.10.1 Affected Environment 3-287
3.10.2 Environmental Consequences 3-288
3.10.3 Cumulative Impacts 3-291
3.10.4 Monitoring and Mitigation Measures 3-291
3.1 1 Visual Resources 3-293
3.1 1 .1 Affected Environment 3-293
3.1 1 .2 Environmental Consequences 3-294
3.1 1 .3 Cumulative Impacts 3-306
3.1 1 .4 Monitoring and Mitigation Measures 3-307
3.12 Noise 3-309
3.12.1 Affected Environment 3-309
3.12.2 Environmental Consequences 3-313
3.12.3 Cumulative Impacts 3-318
3.12.4 Monitoring and Mitigation Measures 3-319
3.13 Transportation 3-321
Carlota Copper Project Final EIS
Table of Contents
Page
3.13.1 Affected Environment 3-321
3.13.2 Environmental Consequences 3-323
3.13.3 Cumulative Impacts 3-325
3.13.4 Monitoring and Mitigation Measures 3-326
3.14 Hazardous Materials 3-327
3.14.1 Affected Environment 3-327
3.14.2 Environmental Consequences 3-327
3.14.3 Cumulative Impacts 3-334
3.14.4 Monitoring and Mitigation Measures 3-334
3.15 Summary of Monitoring and Mitigation Measures 3-335
3.16 Unavoidable Adverse Impacts 3-343
3.16.1 Air Resources 3-343
3.16.2 Geology and Minerals 3-343
3.16.3 Water Resources 3-343
3.16.4 Soils and Reclamation 3-343
3.16.5 Biological Resources 3-343
3.16.6 Cultural Resources 3-344
3.16.7 Land Use 3-344
3.16.8 Wilderness and Wild and Scenic Rivers 3-344
3.16.9 Visual Resources 3-344
3.16.10 Noise 3-344
3.16.1 1 Hazardous Materials 3-344
3.17 Relationship Between Short-Term Uses of Man's Environment and the
Maintenance and Enhancement of Long-Term Productivity 3-345
3.18 Irreversible and Irretrievable Commitment of Resources 3-349
Volume III
4.0 CONSULTATION AND COORDINATION 4-1
4.1 Public Participation and Scoping 4-1
4.2 List of Contacts 4-1
4.2.1 Federal Agencies 4-1
4.2.2 State Agencies/Universities 4-1
4.2.3 Tribal Governments 4-1
4.2.4 Local Agencies 4-2
4.2.5 Organizations 4-2
4.2.6 Private Entities 4-2
4.3 List of Agencies, Organizations, and Individuals to Whom Copies of this Final EIS
and the Record of Decision are Sent 4-2
4.3.1 Federal, State, and Local Agencies and Representatives 4-2
4.3.2 T ribal Agencies 4-3
4.3.3 Private Organizations 4-3
4.3.4 Individuals 4-3
4.4 List of Agencies, Organizations, and Individuals to Whom Copies of the
Record of Decision Only Are Sent 4-4
4.4.1 Federal, State, and Local Agencies 4-4
4.4.2 Private Organizations 4-4
iii
Carlota Copper Project Final EIS
Table of Contents
Page
4.4.3 Individuals 4-5
4.5 Public Review of the Draft EIS 4-6
5.0 LIST OF PREPARERS AND REVIEWERS 5-1
6.0 REFERENCES 6-1
7.0 ACRONYMS AND ABBREVIATIONS 7-1
8.0 GLOSSARY 8-1
9.0 INDEX 9-1
APPENDIX A Clean Water Act Section 404(b)(1) Alternatives Analysis A-1
APPENDIX B Air Ouality Analyses
B1 PLUVUE II Model Input Parameters B-1
B2 Summary of PLUVUE II Model Results B-1 1
APPENDIX C Water Resources Data
Cl Surface Water Quality Data C-1
C2 Water Supply Well and Spring Inventories C-5
C3 Aquifer Test and Water Level Data C-9
C4 Ground Water Quality Data C-1 1
C5 Water Quality Data Associated with Environmental Consequences C-1 7
C6 Monitoring and Mitigation Requirements C-24
APPENDIX D Acid Deposition and Ozone Analysis D-1
APPENDIX E Wellfield Mitigation Program E-1
APPENDIX F U.S. Fish and Wildlife Service Biological Opinion F-1
APPENDIX G Public Comments and Responses to the Draft EIS G-1
LIST OF TABLES
Volume I
Table No. Page
1 -1 Environmental Regulatory Requirements for the Carlota Copper Project 1 -4
1 -2 Potential Cumulative Impacts of Interrelated Actions on Environmental Resources 1-11
2-1 Summary of Mineable Reserves 2-3
2-2 Proposed Carlota Copper Project Acreages 2-7
2-3 Anticipated Mine Production Schedule 2-12
2-4 Typical Mine Rock Disposal Area Tonnages by Year 2-1 5
iv Carlota Copper Project Final EIS
Table of Contents
LIST OF TABLES (continued)
Volume II
Table No. Page
2-5 Locations and Approximate Capacities of Sewage Treatment Facilities 2-41
2-6 Estimated Water Requirements 2-43
2-7 Estimate of Major Mine Equipment Requirements 2-47
2-8 Anticipated Project Access Road Usage 2-48
2-9 Estimate of Construction Workforce Requirements 2-48
2-10 Anticipated Schedule of Project Activities 2-49
2-1 1 Proposed Soil Volumes for Salvage as Topsoil for Reclamation 2-51
2-12 Proposed Seed Mixtures for Reclamation Plan 2-52
2-13 Alternative Mine Rock Disposal Sites 2-61
2-14 Pit Backfill Alternatives 2-63
2-15 Physical Characteristics of Proposed Action and Eder Side-Hill Alternative 2-69
2- 16 Summary Comparison of Impacts Between the Proposed Action and Alternatives
Without Mitigation 2-91
3- 1 Selected Miami, Arizona, Meteorological Data 3-3
3-2 Mean Monthly Temperature Data (°F) for the Project Site (July 1 992 to June 1 993) 3-4
3-3 Frequency of Winds by Direction and Speed (July 1 992 to June 1 993) 3-7
3-4 Frequency of Winds by Direction and Stability Percent of Occurrence (July 1992 to June 1993) 3-7
3-5 National and State Ambient Air Quality Standards 3-1 0
3-6 PM,o Monitoring Summary for the Project Site 3-12
3-7 SOg Monitoring Summary for Miami, Arizona 3-12
3-8 Arizona Ambient Air Quality Guidelines 3-1 3
3-9 Photographic SVR Data for the Superstition Wilderness and the Sierra Ancha Wilderness 3-14
3-10 Air Emission Sources 3-17
3-1 1 Maximum Activity Rates (units in tons) 3-17
3-12 Control Technology and Efficiency 3-1 8
3-13 Summary of Maximum Hourly Controlled Emissions (in pounds) 3-19
3-14 Summary of Maximum Annual Controlled Emissions (in tons) 3-19
3-15 Summary of Maximum Hourly Controlled Emissions with the Implementation of Additional
Mitigation Measures (in pounds) 3-19
3-16 Summary of Maximum Annual Controlled Emissions with the Implementation of Additional
Mitigation Measures (in tons) 3-19
3-17 Maximum Estimated Impact at or Beyond the Limit of Public Access Plus
Background Concentrations (pg/m") 3-21
3-18 Estimated Impacts at Surrounding Class I Wilderness Areas and the Class II
Tonto National Monument (units in pg/m^) 3-22
3-1 9 Maximum Impacts of H^SQ^ and NQ (units in pg/m') 3-22
3-20 Ambient Metals Concentrations 3-23
3-21 Emissions Inventories for the Carlota Visibility Modeling Analysis 3-27
3-22 Visibility Impacts in the Superstition Wilderness 3-30
3-23 Summary of Alternatives - Emissions and Impacts 3-32
3-24 Seismic Events Affecting the Site Between 1776 and 1980 3-46
3-25 Descriptions of the 12 Levels of Earthquake Intensity on the Modified Mercalli Scale 3-49
3-26 Blasting Vibration Evaluation 3-55
3-27 Potential Geologic Considerations Associated with the Well Field Access Road Alternatives 3-57
3-28 Average Monthly and Annual Precipitation for Miami and Pinto Valley Mine 3-61
3-29 Pinto Valley Mine Annual Precipitation Data 3-61
Carlota Copper Project Final EIS
V
Table of Contents
LIST OF TABLES (continued)
Volume II
Table No. Page
3-30 Temperature Data for Miami 3-63
3-31 Estimated Monthly Evaporation Rates for Pinto Valley Area 3-64
3-32 Summary of Pinto Creek Basin Contributing Subwatershed Areas 3-64
3-33 Gaging Station Descriptions 3-69
3-34 Spatial and Temporal Distribution of Streamflows in the Upper Pinto Creek Watershed 3-70
3-35 Instantaneous Flow Measurements at 005 Gulch, Miller Spring, and Mule Spring 3-72
3-36 Estimates of 1 973 - 1 995 Annual Discharges at Pinto Valley Weir 3-75
3-37 Tonto National Forest Water Rights 3-78
3-38 Storm Rainfall Estimates for Pinto Creek and Powers Gulch Watersheds 3-78
3-39 Estimated Peak Discharges Under Existing Conditions at Key Concentration Points 3-79
3-40 PMP and 1/2 PMP Estimates for Pinto Creek and Powers Gulch Watersheds 3-81
3-41 Estimated 1/2 PMF Peaks and Volumes Under Existing Conditions at Key Concentration Points 3-81
3-42 Summary of Sediment Transport Rates 3-82
3-43 Summary of USLE Average Annual Sediment Yields for Existing Conditions 3-82
3-44 Surface and Ground Water Quality Standards for the Carlota Copper Project 3-84
3-45 Summary of Surface Water Quality for Affected Environment 3-85
3-46 Summary of Ground Water and Spring Water Quality for the Affected Environment 3-1 01
3-47 Anticipated Drawdown in the Alluvial Aquifer as a Result of Pumping Well TW-2 3-116
3-48 Comparison of Potential Postmining Water Resource Impacts Associated with the Proposed
Carlota/Cactus Pit and the Additional Backfill of the Carlota/Cactus Pit Alternative 3-128
3-49 BMP Copper's Pinto Valley Mine Production Wells 3-133
3-50 Typical Soil Characteristics 3-146
3-51 Soil Salvage Depth Summary 3-156
3-52 Estimated Erosion Losses by RUSLE for Representative Erodible Slopes on Selected
Project Components (in tons/acre/year) 3-159
3-53 Project-Specific Soil Salvage Criteria 3-169
3-54 Recommended Salvageable Topsoil Volumes 3-170
3-55 Special Status Plant and Wildlife Species Potentially Qccurring in the Carlota Project Area 3-176
3-56 Estimated Coverage by Major Vegetation Community Types in the Carlota Project Area 3-178
3-57 Summary of Habitat Characteristics at Study Sites in Pinto Creek and
Powers Gulch May 1993 and Haunted Canyon April 1994 3-192
3-58 Summary of Fish Species Identified in Pinto Creek and Haunted Canyon 3-192
3-59 Special Status Fish Species Potentially Qccurring or Historically Qccurring
in the Carlota Project Area 3-1 93
3-60 Species and Age Class of Fish Collected in Pinto Creek in May and September of 1993
and in Haunted Canyon in April of 1994 3-195
3-61 Summary of Shannon-Weaver Diversity, Evenness, DAT Index, and Number of Taxa in
Pinto Creek and Powers Gulch 3-1 98
3-62 Results of Aquatic Biota Tissue Analyses for Pinto Creek and Powers Gulch 3-1 99
3-63 Cultural Resource Impacts - Proposed Action 3-230
3-64 Cultural Resource Impacts - Project Alternatives 3-234
3-65 Study Area Population - 1 987 to 1 993 3-241
3-66 Labor Force and Unemployment - 1 992 3-242
3-67 Total Non-Agricultural Employment 3-244
3-68 Earnings by Industry 3-245
3-69 Inventory of Apartment and Mobile Home Units in Globe-Miami Area 3-246
vi Carlota Copper Project Final EIS
Table of Contents
LIST OF TABLES (continued)
Volume II
Table No. Page
3-70 Summary of Public Facilities and Services for the Globe-Miami and Superior Areas 3-248
3-71 Student Enrollment and School Capacities 3-250
3-72 Assessed Valuation by Jurisdiction 3-251
3-73 Gila County - Expenditures and Revenues 1989 to 1993 3-252
3-74 Pinal County - Expenditures and Revenues 1989 - 1993 3-253
3-75 1990 Minority and Low-Income Population 3-255
3-76 Projected Employment, Population, Housing, and School-Age Children
(Peak Construction Phase) 3-257
3-77 Projected Employment, Population, Housing, and School-Age Children
(Average Construction Phase) 3-258
3-78 Projected Employment, Population, Housing, and School-Age Children
(Operations Phase/Low- Impact [Larger Local Workforce] Scenario) 3-259
3-79 Projected Employment, Population, Housing, and School-Age Children
(Operations Phase/Low-Impact [Smaller Local Workforce] Scenario) 3-260
3-80 Summary of Land Ownership in Gila County 3-271
3-81 Summary of Land Ownership in Pinal County 3-271
3-82 Existing ROS Classification - Carlota Copper Project Area 3-281
3-83 Change in ROS Class Acreage - Proposed Action 3-284
3-84 Visual Resource Impact Summary for the Proposed Action 3-303
3-85 Summary of Visual Resource Impacts from Interrelated Actions 3-307
3-86 Noise Terminology and Symbols 3-310
3-87 Ambient Noise Survey Data 3-31 1
3-88 Weather Conditions During Noise Survey 3-31 1
3-89 Carlota Copper Project Equipment Roster 3-31 5
3-90 Project-Generated Noise Levels at Sensitive Receptors - Year 8 3-317
3-91 Project-Generated Noise Levels at Sensitive Receptors - Year 14 3-318
3-92 1991 Major Highway Traffic Volumes in the Carlota Copper Project Area 3-322
3-93 Hazardous Substances Approximate Daily Usage, Delivery Frequency, and On-Site Storage 3-327
3-94 Estimated Number of Spills Resulting from Truck Accidents (Rural Two-Lane) 3-328
3-95 Use and Storage Areas for Hazardous Materials 3-332
3-96 Summary of Monitoring and Mitigation Measures 3-335
3- 97 Irreversible, Irretrievable, Short-Term, and Long-Term Commitment of Resources -
Proposed Action 3-345
Volume III
4- 1 Commentors on the Draft EIS 4-7
A-1 Comparison of Carlota/Cactus Pit Parameters for the Small Project
Alternatives Versus the Proposed Action A-1 2
A-2 Mineable Reserve Summary for the Small Project Alternatives A-1 2
A-3 Summary of Project Economics for Small Project Alternatives A-1 7
B1-1 PLUVUE II Model Input Parameters B-1
B2-1 Summary of PLUVUE II Model Results B-1 1
C1-1 Pinto Creek Surface Water Quality Summary C-1
Cl -2 Powers Gulch and Haunted Canyon Surface Water Quality Summary C-3
C2-1 Water Supply Well Inventory C-5
Carlota Copper Project Final EIS vii
Table of Contents
LIST OF TABLES (continued)
Volume III
Table No. Page
C3-1 Summary of Aquifer Tests Conducted on the Carlota Copper Project Site
(Excluding Well Field) C-9
C3-2 Summary of Water Level Fluctuations in Monitoring Wells C-10
C4-1 Bedrock Ground Water Quality Summary C-1 1
C4-2 Alluvium Ground Water Quality Summary C-1 3
C4-3 Spring Water Quality Summary C-1 5
C5-1 Carlota/Cactus Pit Lake Water Chemistry MINTEQA2 Model Results at Water
Level Equilibrium (125 yrs) C-1 7
C5-2 Mine Rock Area Meteoric Water Mobility Test Results Tonnage Weighted to Rock Type C-1 8
C5-3 Pregnant Leachate Solution (PLS) Water Chemistry C-1 9
C5-4 Water Quality of Pinal Creek Alternative Water Supply, Miami Wash Area C-20
C5-5 Water Quality Data of Possible Mitigation Water Sources for Pinto Creek and Haunted Canyon C-21
C5-6 Comparison of Haunted Canyon Stream Water Quality and Well Field Bedrock Water Quality
with Arizona Stream Standard C-22
C6-1 Target Analytes for Suface Water and Ground Water Monitoring C-25
D-1 Qzone Concentrations and Calculated Sulfur and Nitrogen Deposition Affecting Terrestrial
Ecosystems in Class I Wilderness Areas D-3
D-2 Background Concentrations and Maximum Predicted Increases to Ambient Air
Concentrations of Selected Pollutants D-5
D-3 Qzone Concentrations and Calculated Sulfur and Nitrogen Deposition Affecting
Terrestrial Ecosystems in Non-Class I Areas D-6
D-4 Calculated Sulfur and Nitrogen Deposition Affecting Aquatic Ecosystems in Class I
Wilderness Areas D-10
D-5 Calculated Sulfur and Nitrogen Deposition Affecting Aquatic Ecosystems in Non-Class I Areas D-1 1
G-1 Summary of Non-Agency Comments and Response to Comments G-77
LIST OF FIGURES
Volume I
Figure No. Page
1-1 Location Map 1-2
1 -2 Location of Interrelated Actions and Proposed Carlota Copper Project 1 -7
1- 3 Areas of Existing Mine Disturbance, Superior-Miami-Globe Mining Districts 1-9
2- 1 a General Site Plan 2-4
2-1 b Detailed Site Plan 2-5
2-2 Well Field Location 2-9
2-3 Final Carlota/Cactus Pit Configuration 2-13
2-4 Pinto Creek Diversion Channel - Typical Cross Section 2-17
2-5 Heap-Leach Pad and Fluid Handling System 2-1 9
2-6 Leach Pad Liner System 2-23
2-7 Powers Gulch Inlet Control Structure 2-28
2-8 Powers Gulch Diversion Channel - Typical Cross Section 2-30
2-9 Process Block Diagram 2-31
2-1 0 Solvent Extraction/Electrowinning Plant Site Plan 2-35
2-1 1 General Arrangement of the Electrowinning Circuit 2-37
viii Carlota Copper Project Final EIS
Table of Contents
LIST OF FIGURES (continued)
Volume II
Figure No, Page
2-12 Mine Facilities and Warehouse Plan 2-39
2-1 3 Postclosure Topography 2-55
2-14 Alternative Mine Rock Disposal Sites 2-60
2-15 Additional Backfill of Carlota/Cactus Pit 2-62
2-16 Additional Backfill of Eder South Pit 2-64
2-17 Eder Side-Hill Leach Pad Alternative 2-67
2-1 8 Water Supply Alternative - Low-Quality Water 2-71
2-19 Alternative Access Roads to the Water Supply Well Field 2-73
2-20 Leach Pad Alternatives Considered but Eliminated 2-77
2- 21 Alternative Dam Sites and Associated Reservoir Footprints 2-85
3- 1 Air Quality Map 3-5
3-2 Wind Frequency Distribution 3-8
3-2a Carlota Visibility Modeling Qbserver Locations 3-29
3-3 General Geologic Map of the Project Vicinity 3-41
3-4 Geologic Map - Well Field Vicinity 3-43
3-5 Existing Mine Workings 3-47
3-6 General Precipitation Patterns in the Vicinity of the Project Study Area 3-62
3-7 Pinto Creek Basin Watershed Areas 3-65
3-8 Surface Water Monitoring Stations 3-68
3-9 Well, Spring, and Pond Inventory Map 3-73
3-10 Relationship Between 1986-1989 Annual Precipitation at Pinto Valley Rain Gage
and Discharge at Pinto Valley Weir 3-74
3-1 1 Comparison of Discharge and Runoff at Pinto Valley Weir to Monthly Precipitation for
Years 1986-1989 3-76
3-12 Concentration Points for Flood Peak Modeling 3-80
3-13 Ground Water Monitoring Wells 3-89
3-14 Ground Water Elevations - September 1993 3-91
3-15 Locations of Geologic Cross Sections 3-95
3-16 Geologic Cross Sections A-A’, B-B’, C-C’ for Leach Pad 3-97
3-17 Geologic Cross Sections D-D’, E-E’ for Main Mine Rock Area 3-99
3-18 Ground Water/Surface Water Trilinear Diagrams 3-104
3-19 AMW-21 Mean Water Table Elevation Versus HC-2 Streamflow 3-106
3-20 Water Level and Flow Response to the TW-2 Pump Test 3-114
3-21 BHP Copper Pinto Valley Mine Facilities and Production Wells 3-132
3-22 Proposed Ground Water and Surface Water Monitoring 3-1 35
3-23 Soil Map Units 3-151
3-24 Areas of Suitable Salvageable Soils 3-157
3-25 Locations of Major Vegetation Communities 3-1 79
3-26 Study Site Locations for Aquatic Biology Sampling 3-1 90
3-27 Number of Longfin Dace Collected at Pinto Creek Sites in 1993 by Age Class 3-194
3-28 Number of Desert Sucker Collected at Pinto Creek Sites in 1993 by Age Class 3-194
3-29 Fish Densities in Pinto Creek, May and September, 1993 3-196
3-30 Catch-Per-Effort from Electrofishing Surveys Conducted in Pinto Creek, May and
September, 1993 3-196
3-31 Macroinvertebrate Densities in Pinto Creek (Sites 1-5) and Powers Gulch (Site 6),
May and September, 1993 3-197
Carlota Copper Project Final EIS ix
Table of Contents
LIST OF FIGURES (continued)
Volume III
Figure No. Page
3-32 Location of Jurisdictional Wetlands and Waters of the U.S 3-203
3-33 Land Ownership and Use 3-273
3-34 Locations of Grazing Allotments 3-276
3-35 Section of Pinto Creek Inventoried for Potential Wild and Scenic River Designation 3-289
3-36a,b Views from U.S. Highway 60 KOP 3-295
3-37a,b Views from the KOP near Top-of-the-World 3-297
3-38a,b Views from the Superstition Wilderness KOP 3-299
3-39a,b Views of Reclamation Alternatives from the KOP near Top-of-the-World 3-301
3-40 Noise Monitoring Sites 3-31 2
3-41 Noise Emission Centroids 3-316
A-1 Oxide Copper Properties A-4
A-2 Carlota Project, Carlota/Cactus Pit Phase I A-1 3
D-1 Green and Red Line Values for Effects of Deposition on Fresh Water Systems D-10
X
Carlota Copper Project Final EIS
!
3.0 AFFECTED ENVIRONMENT
AND ENVIRONMENTAL
CONSEQUENCES
3.0 Affected Environment and Environmental
Consequences
This chapter describes the environment that would be
affected by the development of the proposed Carlota
Copper Project or the project alternatives. The
environmental baseline information summarized in
this chapter was obtained from field and laboratory
studies of the project area, published sources,
unpublished materials, and communication with
relevant government agencies and private individuals
with knowledge of the site. The affected environment
for individual resources was based on the area of
potential direct and indirect environmental impacts.
For some resources, such as geology, soils, and
vegetation, the affected area was determined to be
the physical location and immediate vicinity of the
areas to be disturbed by the project. For other
resources, such as water quantity and quality, air
quality, and social and economic values, the affected
environment comprised a larger area, i.e., watershed,
airshed, local counties, etc.
Chapter 3 also describes the anticipated direct,
indirect, and cumulative impacts of the proposed
action and the project alternatives, including the no
action alternative. Recommended monitoring and
mitigation measures developed in response to the
impacts are also identified for individual resources.
These measures are recommended by the Forest
Service and are not part of Carlota's Plan of
Operations for the proposed project. These measures
could be required by the Forest Service or other
regulatory agencies as conditions or stipulations of
approval and authorization of the Plan of Operations.
This chapter is organized by environmental resource
to provide the reader with a clear understanding of
the existing conditions and potential environmental
impacts associated with each resource. The
monitoring and mitigation measures recommended by
the Forest Service for all resources are summarized
in Section 3.15. Unavoidable adverse impacts are
identified in Section 3.16; short-term uses compared
to long-term productivity are discussed in Section
3.17; and irreversible or irretrievable commitments of
resources are presented in Section 3.18.
Carlota Copper Project Final EIS
3-1
3.0 Affected Environment and Environmental Consequences
3-2
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
3.1 Air Resources
3.1.1 Affected Environment
3. 1.1.1 Climatology
Regional Characterization and Influences
The climate of the Carlota Copper Project area is
marked by low to moderate precipitation, dry winds,
and warm temperatures. A mountainous region,
oriented southeast to northwest, separates the state
into a higher elevation plateau in the northeast and a
lower, desert-like region in the southwest. The project
area (elevation 3,700 ft-amsi) is located within the
mountainous region, resulting in highly localized
climatic conditions. A giant escarpment, the Mogollon
Rim, is located to the north of the project area and
represents a boundary for restricted air movement.
The area experiences a high percentage of sunshine
and low humidity. From late fall through early spring,
storm systems from the Pacific Ocean cross the
state. During these months, the area generally has
moderate daytime temperatures and cool nights. In
contrast, moisture-bearing winds from the southeast
(Gulf of Mexico) prevail during the hot summer
months through mid-September. Thunderstorms
occasionally develop, preceded by strong winds that
produce dust storms. The generally arid conditions, in
combination with these summer thunderstorms and
high winds, may contribute to airborne particulates in
the region. Typical annual precipitation of approx-
imately 1 9 to 20 inches is evenly distributed
throughout most of the year, except in the dry months
of April, May, and June.
The project area is located on the border of Gila and
Pinal Counties, with the closest town being Miami
(6 miles to the east). Meteorological data (1951 to
1980) from the National Oceanic and Atmospheric
Administration (NOAA) summarizing climatic condi-
tions for the Miami weather station are presented in
Table 3-1.
Project Meteorological Conditions
A meteorological monitoring program was initiated by
Carlota in July 1992. The monitoring site is located
approximately 5,000 feet west of the Cottonwood
tailings pond in Pinto Valley (elevation 3,800 ft-amsI;
Universal Transverse Mercator (UTM) coordinates
501,583 E, 3,693,714 N). At this station, temperature,
wind speed, wind direction, and sigma theta (standard
deviations of horizontal wind direction fluctuations)
are measured. Information on these parameters is
subsequently provided in this section. Information on
precipitation and evaporation is presented in Section
3.3, Water Resources. Figure 3-1 indicates the
locations of the meteorological and air quality
monitoring stations.
Temperature. The temperature data used in this
analysis (measured at the project site from July 1992
to June 1993) are presented in Table 3-2. The
average annual temperature during the sampling
period is 62°F. The maximum daily average for the
Carlota site is 88°F (June 1993), while the minimum
Table 3-1. Selected Miami, Arizona, Meteorological Data
Parameter i i.;: i
Miami
Elevation (ft-amsI)
3,560
Mean Annual Temperature (°F)
62.9
July Normal Daily Maximum Temperature (°F)
96.9
January Normal Daily Minimum Temperature (°F)
32.5
Mean Days Per Year >89°F
1.2
Mean Days Per Year <32°F
48
Mean Annual Rainfall (inches)
19.0
Mean Days Per Year >0.1 inch rain
37
Source: NOAA (1985)
Carlota Copper Project Final EIS
3-3
3.0 Affected Environment and Environmental Consequences - Air Resources
daily average at the site is 33°F (December 1992).
Temperature fluctuations on an hourly basis also are
recorded at the site. The highest maximum hourly
temperature during the data collection period was
103°F (June 26, 1993); the minimum hourly
temperature was 24°F (December 20, 1992).
Table 3-2. Mean Monthly Temperature Data (°F)
for the Project Site (July 1992 to June
1993)
MonUi
Monthly^
Maxlttium
Dally ,
Miniinuni
Daily
July
79
86
68
August
77
85
62
September
74
79
63
October
66
73
57
November
48
57
37
December
42
53
33
January
47
53
37
February
46
52
41
March
53
61
39
April
61
72
52
May
71
78
60
June
78
88
60
Source: Applied Environmental Consultants, Inc. (AEC)
(1992-1993)
The 1 year of on-site temperature data were
compared to long-term temperature data available
for the nearby Miami station (Ruffner 1985). The
annual average temperature measured at the
Carlota site during the 1992-1993 monitoring program
is approximately 1 degree less than the annual
average measured at the Miami station from 1951
through 1980. The major difference occurred in the
summer months of July and August. During these 2
months, average temperatures were 4 to 5 degrees
less at Carlota. This difference is likely caused by
the altitude of the on-site monitoring station (3,800 ft-
amsl), as compared to the Miami station (3,560 ft-
amsl).
The Carlota project area is located in a semi-arid
region with limited vegetative cover. Based on 30-
year (1951 to 1980) climatological data from Miami
(Ruffner 1985), temperatures occasionally drop below
the freezing point (32°F) from October through April,
potentially limiting the growing season. The number of
average annual heating degree days (below base
65°F) for this 30-year period is 2,846, and the number
of average annual cooling degree days (above base
65°F) is 2,104.
Winds. The wind information used in this analysis
was recorded at the project area from July 1992 to
June 1993 and is considered to be representative of
the long-term local wind patterns on the project site.
However, since the monitoring station is located
within Pinto Valley, the winds recorded at this station
likely represent the local drainage patterns of the
valley, rather than regional wind characteristics.
Winds measured at the site during this period are
summarized in Tables 3-3 and 3-4. Table 3-3 lists
frequency distributions of winds as a function of
speed and direction; Table 3-4 shows frequency
distributions of winds as a function of stability class
and direction.
The wind speed and direction data in Table 3-3 are
presented graphically in Figure 3-2 as a wind rose.
The mean wind speed is 2.6 meters per second
(m/s), with the winds predominating from the
upstream (south-southeast and southeast) directions.
The predominating winds from these two sectors
account for 48 percent of the wind direction
measurements. A secondary wind peak from the
downstream directions of northwest and north-
northwest accounts for 12 percent of the winds.
Seasonal wind data and wind roses are not presented
since there is minimal seasonal variance in wind
conditions (i.e., the annual wind data are considered
to be representative of conditions throughout the
year). The wind rose exhibits wind conditions that are
characteristic of valley drainage winds, (i.e., winds
blow predominately down the Pinto Creek valley, with
a secondary wind frequency peak in the up-valley
direction).
Table 3-4 presents the distribution of winds by
direction and stability. Stability is a measure of air
turbulence and the dispersive potential of the
atmosphere. It is related to radiative energy flux at the
surface, wind speed, and surface roughness. The six
stability classes range from A (the most unstable) to F
(the most stable). Stable air mixes the least, and it is
the most stratified. Stability class D is neutral, which
is normally associated with strong winds and
moderate turbulence.
3-4
Carlota Copper Project Final EIS
I
j
I
Riverside Technology, inc.
CARLOTA COPPER
PROJECT
Figure 3-1
Air Quality Map
3-5
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-3. Frequency of Winds by Direction and Speed (July 1992 to June 1993)
0.45-2.5
2.0-4.5
4.0-6.5
188 Intervals
6.6-S.5
(n»r»)
B.Ct" 1*1 «5
CmiJ-
N
3.1
0.7
0.1
0.0
0.0
0.0
3.9
2.0
NNE
1.0
0.2
0.0
0.0
0.0
0.0
1.2
1.7
NE
0.5
0.2
0.0
0.0
0.0
0.0
0.7
1.9
ENE
0.6
0.2
0.0
0.0
0.0
0.0
0.8
1.8
E
1.1
0.4
0.0
0.0
0.0
0.0
1.6
1.9
ESE
2.3
1.5
0.5
0.3
0.0
0.0
4.6
2.9
SE
13.4
2.6
0.7
0.6
0.3
0.0
17.6
2.3
SSE
23.8
5.5
1.0
0.3
0.0
0.0
30.6
2.3
S
1.8
2.2
1.0
0.1
0.0
0.0
5.0
3.3
SSW
1.1
2.3
1.0
0.2
0.1
0.0
4.7
3.8
WS
1.2
1.9
0.5
0.1
0.0
0.0
3.7
3.2
WSW
1.0
1.8
0.3
0.0
0.0
0.0
3.0
3.1
W
1.4
3.2
0.8
0.1
0.0
0.0
5.4
3.3
WNW
1.6
2.9
0.6
0.0
0.0
0.0
5.2
3.2
NW
2.4
0.9
0.3
0.0
0.0
0.0
3.7
2.5
NNW
5.5
2.2
0.2
0.0
0.0
0.0
7.9
2.1
All
62.3
28.5
7.0
1.7
0.4
0.0
100.0
2.6
Calm = 0.5%, Observations = 8,756, Missing data = 4, m/s = Meters per second
Source: AEC (1992-1993)
Table 3-4. Frequency of Winds by Direction and Stability Percent of Occurrence (July 1992 to
June 1993)
—
-xw—
Sta
C
bllitv Class
D
E
■
-
< ♦
N
1.5
0.4
0.9
0.4
0.1
0.7
4.0
NNE
0.6
0.1
0.0
0.0
0.0
0.4
1.1
NE
0.3
0.0
0.0
0.0
0.1
0.3
0.7
ENE
0.4
0.1
0.0
0.0
0.0
0.2
0.7
E
0.9
0.1
0.0
0.0
0.0
0.5
1.5
ESE
1.4
0.7
0.5
0.6
0.2
1.2
4.6
SE
1.4
0.5
0.8
6.3
3.4
5.2
17.6
SSE
1.2
0.6
1.0
9.0
15.4
3.5
30.7
S
0.8
0.8
0.8
1.3
0.3
1.1
5.1
SSW
0.7
0.9
1.1
1.0
0.3
0.7
4.7
SW
0.8
0.9
0.6
0.5
0.1
0.7
3.6
WSW
0.7
0.7
0.5
0.2
0.3
0.6
3.0
W
0.8
1.6
1.2
0.5
0.4
0.9
5.4
WNW
0.6
1.2
1.3
0.8
0.4
0.9
5.2
NW
1.4
0.4
0.4
0.6
0.2
0.8
3.8
NNW
2.6
1.4
1.9
0.9
0.2
0.9
7.9
All
16.1
10.4
11.0
22.1
21.3
18.6
99.6
Source: AEC (1992-1993)
Carlota Copper Project Final EIS
3-7
< 2.6 M/S
i 2.6 M/S
AVERAGE WIND SPEED = 2.6 M/S
CALMS ARE WINDS WITH
SPEEDS LESS THAN 0.5 M/S
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-2
Wind Frequency Distribution
Cariota Copper Project
Pinto Valley, Arizona
June 1992 - June 1993
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-4 characterizes wind stability by the following
frequency of occurrences: 40 percent are stable
winds (classes E and F), 38 percent are unstable
winds (classes A, B, and C), and 22 percent have
neutral stability. The stable winds are almost
exclusively from the southeast and south-southeast,
blowing in the down-valley direction. The unstable
winds are distributed over all directions, with north-
northeast to east being the least frequent. The
unstable winds (classes A, B, and C) occur during
daytime hours, while stable winds (classes E and F)
occur at night. Class D can occur either in the day-
time or nighttime. Given this information, nearly all
nighttime winds come from the southeast to south-
southeast; daytime winds are multi-directional.
Dispersion Conditions. The wind speed, direction,
and stability frequency information indicate how
pollutants would disperse in the air basin. Wind
direction determines where the pollutants would go.
Speed and stability determine the degree of dilution
that would take place with downwind distance.
Dispersion is directly related to wind speed.
Doubling the speed doubles dispersion potential
(and halves the pollutant concentration). Wind
directions of north-northwest through east usually
exhibit velocities that are well below mean speeds.
Although winds from these directions only occur
approximately 16 percent of the time, and 70
percent of these winds are classified as unstable,
the low-speed winds from these directions would
contribute to poor conditions for the dispersion of
pollutants.
The atmospheric stability classification also affects
dispersion potential. With increasing wind stability,
dispersion characteristics are reduced. The wind
direction during stable conditions significantly
influences the locations of highest pollutant impacts,
especially from surface-level sources such as those
associated with a heap-leach operation like the
proposed Carlota Copper Project. As shown in Table
3-4, the highest frequency of stable conditions is from
the southeast to south-southeast. In addition, winds
from these directions have a mean speed of 2.3 m/s
(below the mean speed of all winds) and occur nearly
50 percent of the time. This combination of stable,
low-speed, persistent winds spanning a narrow
direction range of 45 degrees indicates a strong
possibility that long-term, high pollutant impacts would
be modeled to occur northwest to north-northwest of
a surface-level source on the project site.
It is likely that the on-site meteorological data reflect
micro-scale wind conditions (i.e., wind conditions of
the Pinto Creek drainage patterns only), and that
emissions leaving the project site would actually be
affected by winds that are not so characteristically
homogeneous. Actual dispersion conditions beyond
the project site are likely to be more favorable to
dispersion than the conditions indicated by the data
collected on the site.
3.1. 1.2 Air Quality
Regional Characterization and Influences
In general, the complex terrain of the project area
should minimize air pollution impacts at or near the
project site caused by nearby sources of air pollution.
Mining is the major local industry and may contribute
to ambient concentrations of particulate matter,
sulfuric acid mist, and airborne metals. BHP Copper's
Pinto Valley Mine, which is located adjacent to the
proposed Carlota Copper Project, is the emission
source most likely to contribute to ambient
concentrations of these pollutants proximate to the
project site. Other significant sources are at least
several miles away and would have a relatively minor
contribution to Carlota's baseline levels of particulate
matter and hazardous air pollutants.
The town of Hayden, containing a smelter plant
(ASARCO) as a major industrial pollution source, lies
approximately 30 miles south of the project site and
may contribute a minor amount to ambient levels of
particulates and sulfur dioxide on the site. The town of
Miami is also the site of a smelter facility (Cyprus).
Phoenix (approximately 65 miles to the west) is the
closest major metropolitan area to the project site.
Phoenix is a potential source of significant quantities
of process and non-process (mobile source) emis-
sions, including carbon monoxide (CO), ozone (O3),
and particulate matter. Because of the mountainous
region and distance separating Phoenix and the
project site, emission sources in Phoenix are not
expected to contribute significantly to ambient
pollution levels near the project site, although the
regional transport of emissions from the Phoenix area
may influence visibility conditions and background
levels of ozone in the vicinity of the project.
Carlota Copper Project Final EIS
3-9
3.0 Affected Environment and Environmental Consequences - Air Resources
Air quality is frequently evaluated in terms of
concentrations of the six federally defined criteria
pollutants. These criteria pollutants are respirable
particulate matter less than 10 microns in
aerodynamic diameter (PM,o), sulfur dioxide (SOJ,
nitrogen dioxide (NOj), CO, O3, and lead (Pb). Health-
based ambient concentrations of these pollutants
(National Ambient Air Quality Standards, or NAAQS)
have been defined by the U.S. Environmental
Protection Agency (EPA) and adopted by the State of
Arizona. These standards are presented in Table 3-5.
Table 3-5. National and State Ambient Air
Quality Standards
■■V
Pollutant
Averaging |
Perfod'"'^ ■: ;
Standards
PM,o
24-hour
annual
150 pg/m^'^’
50 |ig/m^‘’*
SO,
3-hour
24-hour
annual
1 ,300 ^ig/m"‘"'
365 |ig/m'®
80 |ig/m^
NO,
annual
1 00 |ig/m^
CQ
1-hour
8-hour
40.000 |ig/m="">
10.000 pg/m"‘"’
O3
1-hour
0.12 ppm or
235 iLig/m"*"’
Pb
quarterly
1 .5 |ig/m^
'Not to exceed an average of once per year over
3 or more representative years of data.
^Not to be exceeded more than once per year.
Source: 40 CFR 50.4-12
Project Monitoring Station
Baseline conditions for particulates at the project site
were monitored using two volumetric, high-volume
PM,o samplers. Samples were collected for a 24-hour
period, with average ambient concentrations (in p
g/m^) of PM,o derived based on the quantity of
particulate collected and the volume of air drawn
through the sampler. PM,^ samples were collected
every 3 days by alternating samplers (i.e., each
sampler collects a sample every 6 days).
Carlota's PM,^ monitoring program began on
September 29, 1992, and was completed on
December 31 , 1993. The samplers were installed at a
site located northwest of the Cottonwood tailings
pond (BHP Copper's Pinto Valley Mine) in the Pinto
Creek drainage, just outside the Carlota property
boundary (elevation 3,700 ft-amsi; see Figure 3-1).
Because of a change in land use that has made the
samplers susceptible to localized road and windblown
fugitive dust emissions, monitoring was suspended
on March 20, 1 993. The station was relocated
southeast of the original site (elevation 3,825 ft-amsI),
restarted on May 7, 1993, and ran on an every-third-
day schedule until the study's completion. Air quality
instruments were audited quarterly by AEC. The
locations of both the original and current PM,^
monitoring sites, approved by the ADEQ, are
presented in Figure 3-1.
Air Quality Standards and Air Basin Attainment
Status
The NAAQS for PM,o, SO^, NQg^ CQ, Q3, and Pb are
shown in Table 3-5. The State of Arizona has adopted
the NAAQS as the state standards.
Particulate and SQg levels in the Hayden/Miami area
have been determined to exceed the federal (and
state) standards, likely because of SQ^ emissions
from the Miami smelters and particulate emissions
from all smelting operations in these areas.
Therefore, the EPA has designated this as a non-
attainment area for both particulates and SQ^. The
ambient air quality of the Hayden/Miami area is
considered to be within the federal and state ambient
air quality standards for all other criteria pollutants.
Furthermore, no exceedances of the PM,^ or SQ^
NAAQS were recorded in this area from 1990 through
1995.
The State of Arizona is mandated by EPA to develop
plans to bring ambient air quality in non-attainment
areas in the state to levels that are lower than the
NAAQS. Sources within the Hayden/Miami non-
attainment area are subject to the air pollution
reduction measures of these plans (also called State
Implementation Plans, or SIPs). At the time of this
writing, the PM,^ SlP for the Hayden/Miami non-
attainment area has not been approved by EPA.
Prevention of Significant Deterioration
Classification
The EPA has established a classification system for
the prevention of significant deterioration (PSD) of air
quality. This system applies to areas in attainment of
3-10
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
the NAAQS. Areas are categorized as Class I, Class
II, or Class III. Class I areas are typically areas with
pristine air quality, such as national parks, national
monuments, or wilderness areas. No areas in the
United States have been designated as Class III. All
other areas in the country are designated as Class II
areas, including the project area. Major stationary
sources are not permitted to cause expected
exceedance of the incremental ambient air quality
standards specified for Class I and Class II areas.
The proposed Carlota Copper Project would not be
considered a major stationary source, and therefore
PSD incremental standards would not need to be
addressed in terms of regulatory compliance.
However, expected impacts at nearby Class I areas
are compared to the PSD allowable increments as a
way to measure the significance of expected impacts
in these areas. The nearest PSD Class I areas are
the Superstition and Sierra Ancha wildernesses, 2 to
3 miles to the west and 25 miles to the north-
northeast, respectively. The Salt River Canyon and
Salome wildernesses, 12 miles to the northeast and
25 miles to the north-northwest, respectively, are not
designated Class I areas.
Measured Particulate Concentrations
The on-site particulate data used in this analysis
(both quarterly averages and maximum
concentrations) were collected during the last quarter
of 1992 and all four quarters of 1993 and are
presented in Table 3-6. The highest 24-hour PM,^
concentration (48.8 |ig/m^) occurred on October 18,
1992. Generally, the data indicate that exceedances
of the 24-hour NAAQS (150 pg/m^) are unlikely. Other
PM,o monitoring programs in Miami confirm this
conclusion (ADEQ 1990-1995). The average PM,^
concentration of 17.2 pg/m^ for the period from
October 1992 to December 1993 indicates that the
baseline annual average concentration would be well
below the annual NAAQS (50 pg/m®). The back-
ground concentration of PM,g for the project site is
assumed to be the average PM,^ concentration for the
monitoring period (17.2 pg/m®).
In the environmental consequences section, this
background concentration is added to maximum 24-
hour modeled PM,^ impacts and average annual
modeled PM,o impacts to estimate ambient levels of
PM,o (background plus impact). Maximum 24-hour
PM,o impacts from the project are expected to occur
under a consistent set of meteorological conditions
(many hours of low speed winds [1 to 2 m/s] in a
consistent direction [from the south-southeast] under
stable conditions [Stability Classes E-F]). Background
PM,o concentrations are not dependent upon such
specific meteorological conditions. A review of
meteorological data suggests that days during which
average background PM,^ concentrations occur,
meteorologic conditions are more similar to the
meteorology of the maximum PM,^ impact day than to
the meteorology of the maximum background day.
Other NAAQS Pollutant Concentrations
The ADEQ has monitored particulate matter and SOg
levels in the region of the Carlota project because of
the abundance of mining sources in the area.
However, no monitoring for the other NAAQS
pollutants (NOg, CO, O3, and Pb) has been conducted
in the area because of the lack of significant local
sources of these pollutants. As a result, no site-
specific background data are available for the project
site for these pollutants.
SO2 monitoring has been conducted and is currently
being performed at several locations near the town of
Miami. Results for the period from 1991 through 1995
indicate that there were no exceedances of the
annual, 24-hour, and 3-hour SO^ NAAQS {Table 3-7).
Ozone monitoring data are not available for the
project site. Background ozone levels are estimated
to be 0.040 ppm (40 ppb) for the project area. This
estimate represents the median of the range of daily
1-hour maximum background ozone concentrations
during the summertime in the United States (EPA
1996a). In addition, EPA’s PLUVUE II visibility model
(used in the visibility analysis for the Carlota project)
uses 0.040 ppm as its default background ozone
concentration for portraying clean areas in the
western United States. Consequently, the value of
0.040 ppm was chosen as representative for the
Carlota project area.
Background levels of NQ^ and NQg are estimated
to be 0.003 ppm each. Since no background NQj
monitoring has been conducted in the vicinity of the
proposed project site, these concentrations are
based on data reported for a similar rural site in
Springerville, Arizona, The reported value
represents the mean of maximum annual averages
Carlota Copper Project Final EIS
3-11
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-6. PM,^ Monitoring Summary for the Project Site
Quarter,
>|Year
Numbef
. of 1
^Siimpie^
Quaijter
Average
First . '^'^1
Cdncentrationl^
1 Second
|Maxinium
C4ncentration
Number
,,„of
Measured
Exceedances
(ng/Ai*)
S,(ng/in®)
ODater
OigAn*)*
Date
4^ 1992
29
21.7
48.8
10/18
41.9
11/17
0
r', 1993
22
14.4
36.6
02/06
27.5
03/11
0
2"", 1993
18
19.0
29.2
06/24
25.6
06/12
0
3^ 1993
29
18.3
26.7
08/11
24.8
09/10
0
4'^ 1993
25
12.7
28.8
10/04
26.3
10/01
0
Average for Monitoring Period = 17.2 ^ig/rn^
Source: AEC (1992-1993)
Table 3-7. SO^ Monitoring Summary for Miami, Arizona
Source: ADEQ (1991 - 1995b)
for six monitoring locations in Springerville for
the period from 1990 through 1995 (ADEQ 1990-
1995).
Air Toxins
In addition to the standards set for criteria pollutants,
the State of Arizona has established Ambient Air
Quality Guidelines (AQGs) for a large number of
toxins. The AQGs have been established to protect
human health. Small quantities of metals (contained
in the ore body and mine rock material), in addition to
sulfuric acid and octane (gasoline), are the toxic
emissions of interest associated with the proposed
Carlota Copper Project. A listing of the AQG values
for these toxins is presented in Table 3-8.
Background concentrations of air toxins are expected
to be negligible in the vicinity of the project. However,
because the background PM,o concentration is
assumed to be largely a result of dust emissions from
the nearby BHP Copper Pinto Valley Mine,
background concentrations of metals can be
estimated in the same way as the predicted maximum
concentrations. (This method is discussed more fully
in Section 3.1.2 - Environmental Consequences.) The
background metals concentrations, shown in Table
3-8, are calculated as the product of the background
PM,o concentration (17.2 pg/m^) and the average
metals concentrations as measured from soil samples
taken at the Carlota project site. The soil sample
analyses are discussed in more detail in AEC’s report
entitled Demonstration of Protection of Arizona Air
3-12
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-8. Arizona Ambient Air Quality Guidelines
♦k'
Substance
Background
^ Concentration - '
(pg/m“)
AQG(pg/m'>
1'Hour
,»:24-Hou^
Annual
Antimony (Sb)
8.60 X 10 '
15.0
4.0
Arsenic (As)
6.35 X 10 '
3.2 X 10 '
8.4 X 10'
2.3 X 10'
Barium (Ba)
1.34 X 10 '
15.0
4.0
...
Beryllium (Be)
2.03 X 10 '
6x 10'
1.6 X 10'
5.0 X 10 '
Boron (B)
4.00 X 10'^
23
7.5
...
Cadmium (Cd)
4.30 X 10 '
1.7
1.1 X 10'
2.9 X 10'
Chromium (Cr)
1.81 X 10^
11
3.8
...
Hexavalent Chromium (Cr VI)
1.81 X 10'
1.1 X 10'
2.9 X 10'
8.0 X 10 '
Lead (Pb)
2.28 X 10 '
...
9.0 X 10'
1.5*
Manganese (Mn)
6.81 X 10'
25
8.0
...
Mercury (Hg)
—
1.5
4.0 X 10 '
...
Nickel (Ni)
1.91 X 10'
5.7
1.5
4.0x10'
Octane (C FI )
...
1 1 ,000
2,900
...
Selenium (Se)
9.68 X 10 '
6.0
1.6
...
Silver (Ag)
6.54 X 10 '
3x 10'
7.9 X 10 '
...
Titanium (Ti)
5.59 X 10'
150
40
...
Vanadium (V)
4.15 X 10 '
1.5
4x 10'
...
Zinc (Zn)
7.16 X 10'
150
40
...
Sulfuric acid (FI,SOJ
...
22.5
7.5
—
‘Corresponds to lead NAAQS and is based on an average each calendar quarter.
Sources: ADEQ (1992a), AEC (1995d)
Quality Guideline Concentrations for Metals at the
Proposed Carlota Project (AEC 1 995d).
Air Quality Related Values
In addition to estimating the impacts of project
emissions on air quality, this EIS also evaluates the
impacts from air emissions on other resources on and
off the site. These air quality related values (AQRVs)
include the effects on biological resources (terrestrial
and aquatic) and visibility. Impacts of criteria
pollutants (NAAQS) and hazardous air pollutants
(especially sulfuric acid mist) emitted from the
proposed project are examined relative to the
baseline conditions of these resources. Baseline
conditions for these resources are described in
Section 3.5, Biological Resources, as well as the
following section on visibility.
Visibility
The federal Clean Air Act's PSD regulations mandate
that federal land managers protect visibility resources
within Class I areas (areas considered to have
pristine air quality). Visibility can be defined as the
degree to which ambient air pollutants obscure a
person's ability to see a given reference point through
the atmosphere. The federal government has chosen
to protect visibility in Class I areas because vistas are
a highly valued aspect of the experience of visiting
pristine and scenic areas, such as national parks,
monuments, and wilderness areas. The Forest
Service has requested an analysis of baseline
visibility conditions and of the project's impacts on
visibility in the nearby Class I areas.
Table 3-9 presents standard visual range (SVR) data
at the 10, 50, and 90 percent frequency values,
based on data collected from camera stations at the
Superstition Wilderness and Sierra Ancha Wilderness
from 1985 through 1992. The data are presented in
kilometers (km), and the frequency values represent
the percentage of all valid data points that were
analyzed to have an SVR less than or equal to the
specified distance. For example, 90 percent of the
valid samples collected in the Superstition Wilderness
Carlota Copper Project Final EIS
3-13
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-9. Photographic SVR Data for the Superstition Wilderness
and the Sierra Ancha Wilderness
A
Supf
^SVR (km)
10%
Tso^
^ -
li Anchi
^ 90%
3 ^
— qP
1985
68
145
293
137-154
113
183
298
179-187
1986
75
145
, 229
138-153
119
202
333
198-206
1987
86
172
332
166-179
120
206
341
202-210
1988
—
—
...
...
113
194
320
191-198
1989
—
—
...
...
119
202
320
199-205
1990
...
—
...
...
138
214
331
211-217
1991
—
...
...
—
151
232
331
229-235
1992
109^
209^
352^
192-22r
135
220
334
216-224
— Monitoring station inactive
’Confidence Interval; 90 percent confidence interval for the 50 percent SVR value
^New site location
Source: Air Resource Specialists (1993)
in 1985 showed a visibility of 293 km or less (or 10
percent showed a visibility greater than 293 km).
The results of camera data collected at the
Superstition Wilderness for the period 1985 through
1987 {Table 3-9) were used to estimate seasonal
background visual range values for the Carlota
visibility analysis. These values define baseline
visibility conditions for the visibility analysis.
A Best Estimate Annual 90"' Percentile Standard
Visual Range was defined as the 80'" percentile
cumulative frequency of camera data for all months of
the year, except December through March. This
definition most closely corresponds with SVR data
generated by collocated IMPROVE (interagency
Monitoring of PROtected Visual Environments)
samplers and camera sites at several eastern and
western locations and is consistent with Forest
Service precedent and guidance under Forest
Service Region 3 PSD application requirements. The
seasonal SVR values were calculated based on
scaling factors consistent with seasonal SVR patterns
at the Tonto and Chiricahua IMPROVE sites. The
seasonal background SVR values are 216 km -
Spring, 192 km - Summer, 240 km - Fall, and 264 km
- Winter. These values were used in the PLUVUE II
visibility modeling analysis conducted for the
proposed Carlota Copper Project. The results of this
modeling are discussed in Section 3.1.2.
3.1.2 Environmental Consequences
This section identifies the air quality impacts
associated with the air emissions from the proposed
Carlota Copper Project. The issues identified for air
quality included (1) impacts to health and safety and
visual resources caused by emissions from project
construction and operations, and (2) impacts to
AQRVs in Mandatory Class I areas from project air
emissions. The following evaluation criteria were used
in the air quality impact assessment:
• Project emissions and off-site concentrations of
all criteria pollutants; and comparison to federal,
state, and local ambient air quality standards and
guidelines
• Project emissions and off-site concentrations of
non-criteria pollutants listed in federal PSD
regulations
• Conformity with Hayden Area SIP and required
Reasonably Available Control Measures
(RACM)/Reasonably Available Control
Technologies (RACT)
• Project emissions and off-site concentration of
hazardous air pollutants (as listed in Title III of the
1 990 Clear Air Act Amendments or the State of
3-14
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Arizona AQG) and, when applicable, comparison
to AQGs 1-hour, 24-hour, and/or annual
standards
• Effects of the project emissions on AQRVs in
mandatory Class I areas through qualitative
and/or quantitative analyses
• On-site concentrations of the project's emissions
of criteria pollutants, hazardous pollutants
(including those listed in the Arizona AQG), and
non-criteria pollutants listed in the federal PSD
regulations as necessary for assessing air quality
impacts to biological resources and threatened
and endangered species
As a result of the findings of the Draft EIS public
comment process, several technical portions in this
Final EIS have been changed. The emissions
inventory used herein has now been fully approved
by the Forest Service and ADEQ. As a result, no
adjustments are necessary between the inventory
used in the Air Installation Permit (AlP) and that used
in the Final EIS. Because of the requirement for a
formal conformity determination, PM,^ and SO^
emissions have been remodeled. Modeling included
in this document is based on the approved inventory
and is consistent with the results presented in the
Conformity Determination (February 1996). Specific
changes incorporated in this Final EIS are discussed
below and are also detailed in the Conformity
Determination
During the visibility analysis process, Carlota agreed
to implement additional mitigation measures to
reduce the air quality impacts of the proposed project.
These additional measures included (1) equipping the
large haul trucks with new diesel engines to increase
horsepower and efficiency, (2) eliminating the haul
route from the secondary crusher to the leach pad by
using the overland conveyor after the second year of
production, and (3) increasing control of fugitive
particulate emissions from all unpaved haul roads
other than the plant entrance road and the leach pad
road.
Tailpipe emissions of PM,„, NO^, and CO were
reduced by recalculating the emission rates using
revised emission factors supplied by the
manufacturer for the newer diesel engines, as
compared to the AP-42 emission factors used in the
original emissions inventory. In addition, the revised
emission calculations incorporated the fact that the
newer engines will be able to meet production
requirements while operating at a lower average
engine load. This operational efficiency further
reduced tailpipe emissions of PM,^, NO^, and CO, and
lowered SO^ emissions, as well. Eliminating the haul
route from the secondary crusher to the leach pad
would eliminate fugitive particulate and tailpipe
emissions associated with haul truck traffic on this
route. There would also be a small decrease in
process emissions associated with the overland
conveyor since Carlota has reconfigured the
conveyor to have approximately one-half of the
conveyor drops assumed in the original inventory. An
increased rate of road watering over the previously
planned rate would further reduce PM,„ emissions
caused by trucks hauling ore and waste rock (AEC
1996a). These reduced emission rates were
incorporated into the visibility analysis, and additional
dispersion modeling was performed to reassess NO„
impacts (AEC 1996b). The results of this revised NO,
dispersion modeling are included in this section;
however, no additional dispersion modeling was
performed using the reduced PM,^, CO, and SO^
emission rates. Therefore, the PM,^, CO, and SO2
impacts discussed in this Final EIS are actually higher
than those that would likely occur with the proposed
project.
3.1. 2.1 Proposed Action
Description and Quantification of Emissions
The primary project emissions would be process dust
(e.g., dust from the crushing and conveying systems)
and non-process dust (e.g., dust from materials
handling, blasting, and the transport of ore and mine
rock along unpaved haul roads). Dust is quantified as
PM,o since this is the current format of the ambient
particulate standards. Emissions from the combustion
of fossil fuels in vehicles, the hot water heater, and
the backup diesel generators include PM,^, NO,, SO2,
CO, and volatile organic compounds (VOCs).
Emissions of VOCs from petroleum storage are also
quantified.
The proposed Carlota Copper Project would be a
source of sulfuric acid (H2SOJ mist emissions, an
Arizona listed air toxin. Potential sources of H2SO^
emissions include the tank house of the SX/EW plant.
Carlota Copper Project Final EIS
3-15
3.0 Affected Environment and Environmental Consequences - Air Resources
the ore preconditioning system, and the H^SOy
raffinate solution application on the leach pad.
Emissions of HjSO,, are based on the emission
estimates for the SX/EW plant that are presented in
the AlP application for the Carlota Copper Project.
The AlP process is a construction permitting process
coordinated by the ADEQ. Permits to construct new
facilities or modifications to existing facilities are
issued based upon ADEQ’s determination of a
proposed facility’s compliance with applicable state
and federal air regulations. This emission estimate is
based on a confidential empirical monitoring study of
emissions from an existing SX/EW plant that
represents the best source of information on HgSO,,
emissions currently available (AEC 1992). ADEQ has
reviewed the confidential study upon which the HgSO^
emission estimate is based. ADEQ has cited the
experimental approach as reasonable and has
characterized the emission estimate as conservative.
Given the emission rate and the ventilation rate of the
tank house, indoor concentrations of H^SO^ are
expected to be higher than the Qccupational Health
and Safety Administration (QSHA) “No Breathing
Apparatus” standard (1 mg/m^) and lower than the
QSHA Absolute Maximum standard (15 mg/m^).
ADEQ has commented that conditions related
specifically to HgSO,, emissions from the tank house
will be included in the AlP to ensure the direct
application of the emissions study to the Carlota
operation. HgSO,, emissions from the preconditioning
treatment and the leach pad are assumed in the AlP
to be negligible based on controls, solution appli-
cation methods, and on-site meteorology.
A number of metals that are also listed air toxins for
the State of Arizona may occur in trace amounts in
particulate emissions from both process and non-
process sources at the project. These include
antimony, arsenic, barium, beryllium, boron,
cadmium, chromium, lead, manganese, nickel,
selenium, silver, titanium, vanadium, and zinc. A
report prepared by AEC (1995d), presents the results
of metals analyses conducted on soil samples from
the project area and estimates metals concentrations
in airborne dust in the vicinity of the project. The
findings of this report are summarized later in this
section.
Qctane is also an Arizona-listed air toxin. Emissions
of VQCs resulting from fuel storage, combustion, and
evaporation at the raffinate pond are likely to contain
small quantities of octane. According to the EPA's
VOC/PM,g Speciation Data System (SPEC! ATE
Version 1.5), octane typically accounts for less than
0.4 percent of VQCs in these sources. VOC
emissions are estimated to be 1 ,202 tons per year.
This total incorporates a mass-balance approach to
estimate emissions from the raffinate pond. Based on
this estimate, emissions of octane are expected to be
less than 5 tons per year.
Maximum emission rates for two scenarios are
presented in the AlP application in order to represent
the case that results in maximum off-site impacts.
The first scenario corresponds to Year 8, the
operating year during which maximum hourly and
annual emissions would occur. Greater emissions in
Year 8 result from slightly greater combined ore and
mine rock haul truck distances. However, since
emissions are spread over a relatively large area in
Year 8, this scenario is less likely to produce
maximum off-site impacts.
The second scenario corresponds to Year 5, during
which the mining activities would be in closer
proximity to each other, and emissions from this
orientation would be more likely to result in maximum
off-site impacts. Another potential factor for higher off-
site emissions under this scenario is that more of the
haul road emissions would occur outside of the pits in
Year 5. Because emissions from the Year 5 scenario
result in the maximum case for off-site impacts. Year
5 emissions were used in this analysis to assess
impacts from the proposed action. A listing of Carlota
emission sources and associated pollutants is
presented in Table 3-10. Table 3-11 shows a list of
primary operations and their associated projected
activity levels for Year 5. (Note; A proposed
temporary crusher to be located at the Eder pits
would not become operational until Year 9 of the
project. Emissions from this crusher were included in
the analysis to determine the maximum emission
case but are correctly not included in the impact
analysis.)
Maximum hourly and annual emissions have been
calculated for all pollutants assuming maximum
daily ore and rock mining and processing rates
{Table 3-11). Hot water heater and backup generator
emissions are based on the maximum design fuel
rate, and generators have been assumed to run 5
3-16
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-10. Air Emission Sources
^ Source Oescriutiort
Source Type .
(point, fugitive, or
mobile)
Emission Species
Topsoil Removal in Carlota/Cactus Pit
F
PM,n/metals
Topsoil Unloading to Stockpiles
F
PM,ymetals
Drill Holes - Ore/Mine Rock
F
PM,ymetals
Blasting - Ore/Mine Rock
F
PM,ymetals
Load - Ore/Mine Rock
F
PM,ymetals
Mine Rock Unloading to Dump
F
PM,ymetals
Haul Truck Dumping to ROM Bin
F
PM,ymetals
Primary Crusher System
P
PM,ymetals
Conveyor Systems
P, F
PM,ymetals
Secondary Crusher System
P
PMJmetals
Unloading Ore to Leach Pad
F
PM,ymetals
Hauling on Unpaved Haul Roads
F
PM,ymetals
SX/EW Plant
P. F
H,SO„ VOCs
Stationary Combustion Sources (includes
boiler and backup generators)
P
PM,„, NO., CO, SO,, VOCs
Diesel/Gas Vehicles
F, M
PM,„, NO., CO. SO, VOCs
Diesel, Diluent, Organic Storage Tanks
F
VOCs
Table 3-11. Maximum Activity Rates (units in tons)
^ Activity
Ml Rate
Annual Copper Ore
7,500,000
Annual Mine Rock
20,500,000
Daily Ore and Rock Mining
125,000
Daily Ore Haul to Primary Crusher
70,000
Daily Ore Processing Rate
40,000
Daily Mine Rock Haul
100,000
Hourly Facility Process Rate
1,667
percent of the time (438 hours per year). Emission
factors used to calculate emissions were based on an
ERA document entitled AP-42, EPA’s Estimating Air
Toxics from Organic Liquid Storage Tanks and Air
Emission Species Manual, Volume I; the EPA's
VOC/PM,g Speciation Data System (SPECIATE
Version 1.5); the American Mining Congress report
entitled Report on Fugitive Dust Emission Factors for
the Mining Industries (1983); and an AEC study on
sulfuric acid emissions (1992).
Emissions from several sources at the proposed
Carlota Copper Project would be controlled by
implementing air pollution control measures.
Emissions of process and non-process particulates,
sulfuric acid, and VOCs would be controlled from a
variety of sources. These controls are presented in
Table 3- 12 along with the estimated control efficiency
for each measure. Control efficiencies are based on
information from AP-42.
Ore processing equipment for the proposed project
would include a primary crusher, vibrating screen,
secondary crusher, and conveying system. Each of
these facilities would be a source of PM,^ emissions.
Water sprays at the primary crusher and conveyor
transfer points would control emissions by 85 and
82.5 percent, respectively. In addition, chutes at the
conveyor transfer points would also reduce dust
emissions. The secondary crusher circuit would be
equipped with a baghouse. The filtration efficiency of
the baghouse is expected to exceed 99 percent with
a typical performance level of 0.01 grains/scf of
discharge air for the entire secondary crushing circuit.
Non-process mining activities that would have
controlled PM,;, emissions include ore hauling over
unpaved haul roads and drilling in the pit. Dust
emissions from haul roads would be controlled with
the routine application of water and dust palliatives. It
Carlota Copper Project Final EIS
3-17
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-12. Control Technology and Efficiency
Source
Pollutant
Control
Efficiencv. ■■
Drilling
PM,o
Filter/pneumatic
flushing
90 percent
Primary Crusher and Conveyor
Drop Points Material Handling'
PM,o
Water sprays
Chutes
Crusher = 85 percent
drop points = 82.5
percent
Secondary Crusher Circuit
PM,o
Baghouse
Control to 0.01
grains/scf
Haul Roads
PM,„
Water/chemical
application Gravel
roads
91 percent (access
and leach pad roads)
100 percent (other
interior haul roads)
Ore Conditioning
H,SO,
Shrouds
unknown
Extraction/Stripping Settlers
VOCs
Roofs
unknown
EW Tank House
H.SO,
Dispersion
balls/surfactants
unknown
'From primary crusher to loadout conveyor
is estimated that routine application of water or
biweekly application of chemical dust suppressants
(at an application intensity of 0.25 gallons per square
yard) would provide approximately 91 percent control
of dust emissions. (Carlota has committed to
increasing the application rate and volume of water
applied to haul roads to reach the equivalent of 0.01
inch of precipitation per day. This increase in watering
would further reduce fugitive particulate emissions.
This additional mitigation measure was incorporated
into the visibility analysis, but no additional dispersion
modeling was performed using the reduced
particulate emission rates.) Dust emissions from
drilling in the pit (in preparation for blasting) would be
controlled using a pneumatic flushing and filter
system with an estimated control efficiency of 90
percent.
Sulfuric acid would be used to condition the ore in
preparation for leaching and would be applied at
conveyor transfer points at three to four locations
immediately prior to or at the point of heap stacking
on the leach pad. Emissions of sulfuric acid from this
source would be reduced by conducting the ore
conditioning on a fully covered conveyor belt, which
should reduce wind effects to negligible levels. In
addition, a concentrated acid solution with low
pressure sprays would be used to minimize the
potential for acid mist escaping the ore conditioning
system. Sulfuric acid emissions at the leach pad
would be minimized by the use of wobblers or drip
lines to apply leaching solution instead of sprays.
Emissions of H2SO^ from the SX/EW plant would be
controlled using dispersion balls and surfactants to
reduce losses of acid mist.
Tables 3- 73 and 3-74 summarize the maximum
hourly and annual emissions from the proposed
Carlota Copper Project. These emission rates
match those presented in the Conformity
Determination (Air Sciences Inc. 1996c) and the
AlP (AEC 1995e). As indicated in these tables, PM,^
and NO^ are the pollutants that would be emitted in
the largest quantities. The majority of PM,^ emissions
would originate from non-process particulate sources,
and the majority of NO^ emissions would originate
from mobile sources. Detailed descriptions of
particulate and combustion emission calculations
are presented in the Conformity Determination and
AlP documents.
As stated previously, Carlota has agreed to
implement additional mitigation measures to reduce
the potential air quality impacts of the proposed
project. Tables 3-15 and 3-16 summarize the
maximum hourly and annual emissions from the
Carlota Copper Project based on the implementation
of the additional mitigation measures discussed at the
beginning of Section 3.1.2, Air Resources -
Environmental Consequences. These revised
3-18
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-13. Summary of Maximum Hourly Controlled Emissions (in pounds)
i Source Category
INO; :i
O
O
SO,
VOCs
H,SO,f
Process
11
82
18
1
9
—
Mobile
15
233
68
6
12
—
Non-Process
122
—
—
—
260
1
TOTAL
148
315
86
7
281
1
'Based on AEC (1996a)
Table 3-14. Summary of Maximum Annual Controlled Emissions (in tons)
Source Category -
s;NO,’
CO
^iSO, *
VOCs
H^o,r
Process
16
19
4
1
11
—
Mobile
65
1,022
296
25
51
—
Non-Process
322
—
—
—
1140
5
TOTAL
404
1,041
300
26
1202
5
'Based on AEC (1996a)
Table 3-15. Summary of Maximum Hourly Controlled Emissions with the
Implementation of Additional Mitigation Measures (in pounds)
Source Category p
r NO
f-ii-
^ CO
SO,*
VOCsl
H,SO, 1
Process
11
82
18
1
9
—
Mobile
3
79
14
2
12
—
Non-Process
16
—
—
—
260
1
TOTAL
30
161
32
3
281
1
Table 3-16. Summary of Maximum Annual Controlled Emissions with the
Implementation of Additional Mitigation Measures (in tons)
Source Category
NO.
“ CO g
•5.SO,
VOCs
H,SO,
Process
16
19
4
1
11
—
Mobile
13
348
62
9
51
—
Non-Process
49
—
—
—
1140
5
TOTAL
78
367
66
10
1202
5
Carlota Copper Project Final EIS
3-19
3.0 Affected Environment and Environmental Consequences - Air Resources
emission rates were incorporated into the visibility
modeling analysis and the NO, dispersion modeling
analysis. However, dispersion modeling for all other
pollutants was performed using the emission rates
listed in Tables 3-13 and 3-14. As a result, the PM,„,
CO, and SO^ impacts discussed in this EIS are higher
than those that would likely occur with the proposed
project given the additional mitigation measures now
committed to by Carlota.
Description of Modeling and Quantification of
Impacts
Long- and short-term impacts of all pollutants (except
PM,o) presented in the EIS are based upon the
BEEST-X model analyses included in the Revised
AlP (AEC 1995e). The PM,^ impacts are based upon
the ISCST3 model analyses presented in a separate
document (AEC 1995b) and are included in the
Conformity Determination. EPA’s ISCST3 model
conducts a refined evaluation in both simple and
complex terrain and incorporates a dry deposition
algorithm that EPA considers to be more accurate for
estimating deposition for particles less than 20
micrometers in diameter.
Impacts from criteria pollutants and HjSO^ have been
modeled using 3-km (1.8-mile) and 10-km (6-mile)
receptor grids that include receptors inside and
outside the project boundary (including the
Superstition Wilderness) and along the project
boundary. Additional receptors have been used to
estimate pollutant concentrations in the Sierra Ancha
Wilderness, Tonto National Monument, and two other
distant wilderness areas. Dispersion modeling of
project impacts was performed using the 1 full year of
on-site meteorological data (collected from July 1992
through June 1993 by AEC) summarized previously.
A more detailed discussion of particulate modeling is
presented in the Conformity Determination, and a
discussion of combustion pollutant modeling is
included in the Revised Technical Submittal
Application for a Class II Permit (AEC 1 995f).
Impacts from the project’s air emissions are esti-
mated for points outside of the limits of public access.
This limit is shown in Figure 3-1. The limit of public
access is approximately 600 meters distant of
locations of mining activity at the Carlota Copper
Project. This distance is an appropriate safety buffer
to protect the public from the hazards of blasting and
other mining activity and equipment. The limit of
public access would be demarcated by a combination
of natural and man-made barriers to convenient
access to the project site and would include the
following:
• Existing fence lines associated with Forest
Service grazing allotments in the project area
• New fences and/or gates along public access
roads
• Natural, steep terrain along the west side of the
project that prevents convenient access
• The BHP Copper tailings dam to the northeast of
the project
• Signs warning of the danger from blasting and
other hazards
Estimated maximum impacts for PM,^, NO,, CO,
and SOj are presented in Table 3-17. This table
also includes background concentrations and the
listing of federal standards. Based upon the air
quality impact analysis, emissions of PM,^, CO, NO,,
and SO2 from the proposed Carlota Copper Project
are not expected to exceed the NAAOS at or beyond
the limits of the project boundary. Impacts at the Top-
of-the-World subdivision are modeled to be less than
the values presented in Table 3-17, and therefore,
below the NAAOS.
The proposed conditions in the AlP for the project
include a requirement to monitor PM,g impacts in (or
near) the area of expected maximum impact (north of
the project in the direction of the Superstition
Wilderness) for the 5-year permit term. The purpose
of the PM,o monitoring requirement is to demonstrate
ongoing compliance with the PM,g NAAQS. The
program includes reporting measured levels above
120 |ig/m^ and allows ADEQ to work with Carlota to
reduce the frequency of occurrences of
measurements above this level, should they occur.
In addition to estimating impacts immediately
surrounding the project area, impacts are also
presented for the Superstition Wilderness, the Sierra
Ancha Wilderness, and the Class II Tonto National
Monument. Estimated impacts at the nearest Class I
area (the Superstition Wilderness), located
3-20
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-17. Maximum Estimated Impact at or Beyond the Limit of Public Access Plus
Background Concentrations (pg/m^)
■pollutani
Averaging
tnbirement
Maximum i
: Impacf ,
Maximum
Background^
Total
,^(^icentration
NAAQS.
PM,„
24-hour
94
17.2
111
150
annual
20
17.2
37
50
NO.
annual
22
6
28
100
CO
1-hour
468
2,280
2,748
40,000
8-hour
110
2,280
2,390
10,000
SO,
3-hour
15
875
890
1,300
24-hour
5
144
149
365
annual
1
10
11
80
CO, and SOj impact estimates are based on dispersion modeling that did not incorporate the
additional mitigation measures Carlota plans to implement, as described in AEC 1996a. Therefore, these
impact estimates can be considered conservative estimates, and the actual impacts would likely be lower.
'PM,;, background concentrations are based on 5 quarters of on-site monitoring data. For both 24-hour and
annual background concentrations, the average for the monitoring period is assumed. The NO, and CO
values represent the highest background concentrations at other similar rural locations. The measured
background SOj concentrations at Miami are influenced by a local smelter. SO^ concentrations in the
vicinity of the project should be much lower.
approximately 2 to 3 miles to the west, are expected
to be approximately an order of magnitude less than
impacts estimated at the project boundary.
Wilderness impacts for criteria pollutants are
presented in Table 3-18.
Based upon the air quality impact analysis, emissions
of CO, NO,, PM,o, and SO^ from the proposed Carlota
Copper Project are not expected to result in exceed-
ances of the NAAQS in the Class I Superstition
Wilderness and Sierra Ancha Wilderness or in the
Class II Tonto National Monument. In most cases,
expected impacts from the proposed project are a
fraction of the existing background concentrations.
Although the PSD increments are not strictly
applicable to the Carlota Copper Project (the
project is not a major source), the PSD
increments are presented here as a
measurement of the significance of particulate
impacts from the project.
HjSO,, emissions were calculated using a 3-km (1.8-
mile) grid and an additional 8 discrete receptors
located in sensitive vegetation areas. Table 3-19
shows the maximum impacts on or outside the project
area boundary. Impacts of NO from stationary
sources (i.e., the diesel hot water boiler and the two
backup generators) and AQG concentrations are also
presented in Table 3-19. Based upon the air quality
impact analysis, emissions of HjSO,, and NO from the
proposed Carlota Copper Project are not expected to
exceed the Arizona AQGs at the limits of the project
boundary.
HgSO,, impacts at the Top-of-the-World subdivision
(approximately 4 km south of the tank house) are
expected to be below the health-based AQG levels
(1-hour; 22.5 ^lg/m^ 24-hour: 7.5 pg/m^). The highest
expected 1-hour H^SO^ impact 4 km south of the tank
house is between 1.1 and 1.7 pg/m^. Twenty-four
hour average impacts are not expected to exceed 0.3
pg/m'.
Sulfuric acid and nitrogen oxide (NO assumed to be
equal to NO,) would be the two main pollutants
emitted from the facility for which there are Arizona
AQGs. Emissions of HgSO,, from the SX/EW plant
have been estimated based on a study conducted by
AEC (1 992) and modeled to determine the impacts of
this Arizona-listed toxin. Estimated impacts from
Although modeling of VOC emissions is impractical
because of the high complexity of VOC interactions
with other chemical species, ambient impacts of
octane are estimated herein using the results of
HjSO^ modeling. As shown in Table 3-14, the facility
will emit 5 tons per year of H^SO,,, resulting in 1-hour
and 24-hour maximum ambient concentrations of 21
Carlota Copper Project Final EIS
3-21
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-18. Estimated Impacts at Surrounding Class I Wilderness Areas and the Class II Tonto
National Monument (units in pg/m'^)
(2-X|iiies)
Tonto National
Monur^nt
(18 miles)
1 Sierra Ancha
tf Wilderness ,
(27 miles) 1
PSD
Increments
Class 1
1 1 Areas‘
PM,o
24-hour
6
1
1
8
annual
2
negligible
negligible
4
NO.
annual
3
negligible
negligible
N/A
CO
1-hour
, 85
84
4
N/A
8-hour
26
11
1
N/A
SO,
3-hour
4
2
negligible
25
24-hour
1
negligible
negligible
5
annual
negligible
negligible
negligible
2
^ PM,q, CO, and SO^ impact estimates are based on dispersion modeling that did not incorporate the additional
mitigation measures Carlota plans to implement, as described in AEC 1996a. Therefore, these impact
estimates can be considered conservative estimates, and the actual impacts would likely be lower.
^Although not a PSD source, this increment was used for comparison purposes.
Table 3-19. Maximum impacts of H^SO,, and NO
(units in pg/m")
Pollutant i
Concentrations
1: 1-Hour*^ 1 24-Hour:
H,SO.
Impact
21
2
AQG
22.5
7.5
NO’
Impact
559
74
AQG
690
230
’NO impact estimates are based on dispersion
modeling that did not incorporate the additional
mitigation measures Carlota plans to implement, as
described in AEC 1996a. Therefore, these impact
estimates can be considered conservative
estimates, and the actual impacts would likely be
lower.
pg/m^ and 2 pg/m^ respectively. Octane emissions
are estimated as 0.4 percent of total VOC emissions
from the facility (1 ,202 tons per year), are expected to
be less than 5 tons per year. Therefore, impacts of
octane will be similar in magnitude to those predicted
for HjSO^. The estimated 1-hour and 24-hour impacts
from octane emissions (approximately 21 pg/m^ and 2
pg/m®, respectively) are significantly below the
corresponding AQG values of 1 1 ,000 and 2,900
pg/m^ respectively.
Estimated ambient impacts of metals contained in the
soils at Carlota also have been quantified. The
maximum ambient concentrations of the metals for
each of three averaging periods (1-hour, 24-hour, and
annual) are estimated as the product of the predicted
maximum concentration of PM,o for the appropriate
averaging period (1,009.3 pg/m^ 93.6 pg/m^ and
19.7 pg/m^ respectively) and the average metals
concentrations. Table 3-20 provides a summary of
the average metals concentrations from the soils
analyses (in mg/kg), the background and maximum
expected metals concentrations for three time-
averaging periods, and the corresponding AQGs. The
predicted maximum concentrations, combined with
the background concentrations, do not exceed the
AQGs.
Regulations and Compliance
The proposed facility is classified as a minor source
based upori the annual level of process (point source)
emissions. In other words, emissions of criteria
pollutants (CO, NO^, PM,^, and SOJ from process
(point) sources are not expected to exceed major
source threshold levels (250 tons for CO and NO,,
100 tons for PM,^ and SO^, non-attainment pollutants
for the area). As a result of this classification, the
source is subject to the following regulations: (1)
NAAQS, (2) Article 6 (Emission from Existing and
New Non-Point Sources) of the Arizona Adminis-
3-22
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-20. Ambient Metals Concentrations
Average
Cone.
(mg/kg)
Background
Cone.
(pg/m*)
Estimated ^
1-hour
Ambient Concentration*
(uglrn*)
24-hour ' Annual
AQG Concentrations
1-hour 24-hour ^ Annual
Antimony
5.00
8.60 x 10 '
5.05 X 10'
4.68 X 10'
9.85 X 10 '
1.5 X 10’
4
...
Arsenic
3.69
6.35 x 10 '
3.72 X 10'
3.45 X 10 '
7.27 X 10 '
3.2 X 10 ’
8.4 X 10 '
2.3 X 10'
Barium
77.63
1.34 x 10 '
7.84 X 10 '
7.27 X 10 '
1.53 X 10 '
1.5 X 10’
4
...
Beryllium
1.18
2.03 X 10 '
1.19 X 10'
1.10 X 10'
2.32 X 10 '
6x 10'
1.6 X 10'
5x 10'
Boron
23.25
4.00 x 10 '
2.35 X 10 '
2.18 X 10'
4.58 X 10 '
2.3 X 10’
7.5
...
Cadmium
0.25
4.30 X 10 '
2.52 X 10 '
2.34 X 10 '
4.93 X 10 '
1.7
1.1 X 10’
2.9 X 10 '
Chromium
10.50
1.81 X 10'
1.06 X 10 '
9.83 X 10 '
2.07 X 10 '
1.1 X 10’
3.8
—
Lead
13.25
2.28 X 10 '
1.34 X 10 '
1.24 X 10 '
2.61 X 10'
—
—
1.5**
Manganese
396.00
6.81 X 10'
4.00 X 10 ’
3.71 X 10'
7.80 X 10 '
1.5 X 10'
4 X 10’
—
Nickel
11.13
1.91 X 10'
1.12 X 10'
1.04 X 10 '
2.19 X 10 '
5.7
1.5
4 X 10'
Selenium
5.63
9.68 X 10 '
5.68 X 10 '
5.27 X 10'
1.11 X 10'
6
1.6
—
Silver
0.38
6.54 X 10'
3.84 X 10 '
3.56 X 10 '
7.49 X 10 '
3x 10’
7.9 X 10'
—
Titanium
324.75
5.59 X 10'
3.28 X 10 ’
3.04 X 10'
6.40 X 10 '
1.5 X 10'
4x 10’
—
Vanadium
24.13
4.15 X 10 '
2.44 X 10 '
2.26 X 10'
4.75 X 10'
1.5
4 X 10’
—
Zinc
41.63
7.16 X 10 '
4.20 X 10 '
3.90 X 10'
8.20 X 10'
1.5 X 10'
4. X 10’
—
* Model-predicted PM,„ impact x metals concentration in soil.
** Corresponds to lead NAAQS and is based on an average each calendar quarter.
trative Code, (3) Arizona and federal New Source
Performance Standards (NSPS), (4) the Hayden PM,^
Non-Attainment Area SIP, and the Globe/Miami SO^
SIP. The AlP and this impact analysis assess
compliance with the NAAQS and compare the
predicted ambient air quality impacts of the project to
the AQGs.
Article 6 of the Arizona Administrative Code requires
the prevention of excessive emissions from material
handling, soil storage piles, and roadways. A
preventive maintenance schedule and a monthly
check would be developed for all water spray
systems used to reduce material handling emissions.
To prevent excessive emissions from storage piles,
water application would be used. Application of water
and/or chemical dust suppressants to all unpaved
roads would be used to achieve approximately 91
percent (up to 100 percent control on interior haul
roads) control efficiency of dust from these roads.
Compliance would be demonstrated by maintaining
records of chemical dust suppressant purchases and
water/chemical applications.
The Carlota crushers, screens, conveyor transfer
points, storage bins, and ore truck unloading station
are subject to the NSPS for Metallic Mineral
Processing Plants specified in 40 CFR 60, Subpart
LL. These standards require an opacity limit of 10
percent from process fugitive emission sources.
The mine would maintain a certified opacity observer
on the site to assess compliance with this
requirement.
The diesel, diluent, and organic storage tanks at
Carlota may be subject to Subpart Kb of the NSPS
regulations. If the vessels are assumed to be
larger than 40 cubic meters (approximately 10,000
gallons) and smaller than 75 cubic meters (approxi-
mately 20,000 gallons), NSPS only requires readily
accessible records of the tank dimensions and an
analysis showing the capacity of each storage
vessel.
The Carlota Copper Project would be subject to the
RACM prescribed by the Hayden/Miami area SIP.
These measures include the following;
Carlota Copper Project Final EIS
3-23
3.0 Affected Environment and Environmental Consequences - Air Resources
• Pave, vegetate, or chemically stabilize access
points where unpaved traffic surfaces adjoin
paved roads
• Develop traffic reduction plans for unpaved roads
(i.e., use low speed limits)
• Pave, vegetate, or chemically stabilize unpaved
parking areas
• Employ PACT for significant point sources (the
secondary crushing circuit would be subject to
this requirement)
To fulfill the intent of this plan, non-process particulate
emissions from Carlota would be reduced by water/
chemical applications to haul roads and storage piles.
A baghouse control on the secondary crusher fulfills
the PACT requirement.
SIP Conformity
A portion of the proposed Carlota Copper Project is to
be located within an area that has been designated
nonattainment for PM,q and SO^. Conformity with the
applicable SIP must be demonstrated for all pollutants
for which the area is designated nonattainment and
for which the project has the potential to emit total
emissions (both process and non-process) in an
amount exceeding the de minimis threshold of 100
tons per year.
Annual emissions of SO2 are estimated to be well
below the de minimis threshold (10 tons per year with
the implementation of additional mitigation
measures), while annual emissions of PM,^ are
estimated to be greater than the de minimis threshold.
Therefore, a demonstration of conformity with the SO^
SIP is not required, but a demonstration of conformity
with the PM,o SIP is required.
The determination that a project conforms with an
applicable SIP is made by ensuring that direct and
indirect emissions from the project will not:
• Cause or contribute to any new violation of any
standard in the area
• interfere with provisions in the applicable SIP for
maintenance of any standard
• Increase the frequency or severity of any existing
violation of any standard in any area
• Delay timely attainment of any standard or any
required interim emission reductions or other
milestones in the SIP for the following purposes:
(a) Demonstration of reasonably further
progress
(b) Demonstration of attainment
(c) Maintenance plan
The PM,o nonattainment designation for the
Hayden/Miami planning area is a result of expected
exceedances of the PM,g NAAQS proximate to the
copper smelting activities in the town of Hayden. As a
result, the predicted ambient level of PM,q upon which
the controls in the SIP are based pertains to
particulate levels in Hayden, as opposed to the
proposed project site. In November 1994, ADEQ
petitioned EPA to realign the Hayden/Miami PM,o
nonattainment area boundary to exclude the northern
portion of the area that contains the proposed Carlota
Copper Project site. Furthermore, monitoring of PM,^
concentrations in Miami does not indicate any
exceedances of the PM^g standard.
The particulate emission control measures in the SIP
pertain only to controlling PM,g emissions at two
specific copper smelters and associated activities,
located in Hayden, approximately 25 miles south of
the proposed project. The requirement that the
emissions not violate requirements or milestones in
the applicable SIP is automatically met because no
such requirements or milestones apply to sources
other than specifically identified smelter sources in
Hayden.
Compliance with the requirement to not cause or
contribute to any new violation of any standard or
increase the frequency or severity of any existing
violation of any standard in any area (i.e., any
NAAQS) is adequately demonstrated by a local air
quality analysis. This analysis is the only requirement
necessary to demonstrate conformity with the PM,g
SIP. This analysis must meet the applicable
requirements of 40 CFR 93.159, Procedures for
Conformity Determinations of General Federal
3-24
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Actions, including accuracy of emission estimation
techniques, applicability of air quality models, and
accuracy of emissions scenarios reflected in the
analysis.
The Globe Ranger District of the Tonto National
Forest has reviewed the air quality analysis
conducted for the Carlota Copper Project and has
determined that;
• The methods for estimating emissions from the
project meet the appropriate requirements.
• The local PM,^ emissions modeling methodology
is appropriate for determining whether emissions
from the project will cause or contribute to any
new violation of the PM,^ NAAQS.
• The results of the modeling analysis predict
maximum 24-hour ambient concentrations at the
process area boundary to be 1 1 0.8 pg/m^ (based
on a background concentration of 17.2 pg/m^),
which is below the ambient standard of 150
pg/m".
• The results of the modeling analysis predict the
maximum average annual ambient concentration
at the process area boundary to be 36.9 pg/m^
(based on a background concentration of 17.2
pg/m®), which is below the ambient standard of 50
pg/m".
• The action does not cause or contribute to any
new violation of any standard in any area.
• The action does not increase the frequency or
severity of any existing violation of any standard
in any area.
• The action does not violate any requirements or
milestones in the SIP.
Based on these determinations, the proposed
activities at the Carlota Copper Project are presumed
to conform with the applicable SIP for the project
area. The Conformity Determination document
(February 1996) provides additional details of the
analysis. To ensure the accuracy of the emissions
inventories used in this analysis, the AlP will include
conditions and voluntary requirements that meet
federal enforceability requirements.
Analysis of Air Quality Related Values
As part of the NEPA process, the federal land
manager (in this case, the Forest Service) is
assessing the potential impact from proposed
projects on AQRVs. AQRVs were established for
designated Class I areas by the PSD program under
the Clean Air Act and represent resources that could
be adversely affected by changes in air quality. There
are two Class I areas within 50 miles of the proposed
Carlota Copper Project: the Superstition Wilderness
and the Sierra Ancha Wilderness. Visibility has been
identified as a specific AQRV for these wilderness
areas. Potential impacts to visibility are discussed
below. It has also been recommended that certain
terrestrial and aquatic resources be considered
AQRVs for these wilderness areas (Blankenship
1991). Potential impacts to terrestrial and aquatic
AQRVs are addressed in Appendix D, Acid
Deposition and Ozone Analysis. In addition to the
Class I areas, the Forest Service requested that
potential air quality-related impacts to terrestrial and
aquatic resources be evaluated at the Class II Tonto
National Monument and the Carlota Copper Project
site (not Class I areas). The terrestrial and aquatic
resources evaluated for these areas were considered
to be the same as the AQRVs identified for the Class
I wilderness areas.
Visibility Analysis
Baseline visibility information has been presented in
Section 3.1.1, Air Resources - Affected Environment.
This section describes the results of a comprehensive
visibility modeling analysis. The technical report
entitled Carlota Copper Project Emissions and
Potential Impact on Visibility Resources in the
Superstition Wilderness (USDA Forest Service
1997b) contains a complete discussion of the
comprehensive visibility modeling analysis. The
purpose of this analysis was to determine if there
would be potential impacts from the proposed Carlota
Copper Project on the nearby Superstition Wilderness
and to assess the magnitude and frequency of
potential impacts. Visibility modeling was performed
using EPA’s PLUVUE II visibility model. PLUVUE II
Carlota Copper Project Final EIS
3-25
3.0 Affected Environment and Environmental Consequences - Air Resources
predicts the transport, atmospheric diffusion,
chemical conversion, surface deposition, and
optical effects of emissions from sources. The
model estimates visual range reduction, changes
in scene contrast, and atmospheric discoloration
caused by plumes composed of PM,q, N0„, and SO2
emissions. For the Carlota visibility analysis,
potential visibility impacts were quantified based
on PLUVUE II model results for three parameters:
visual range reduction, plume contrast, and color
difference.
Reduction in SVR is the percent reduction in the
farthest distance one can see a large black object
(e.g., mountain peak) caused by atmospheric
contaminants. This parameter can be interpreted to
indicate the haziness or loss of contrast of viewed
landscape features caused by these contaminants.
Plume contrast (PC) is the relative brightness of a
plume compared to a viewing background. Color
difference (AE) is an indicator of the perceptibility of a
plume due to both its contrast and its color compared
to a viewing background.
Modeling Inputs and Assumptions. PLUVUE II
modeling was performed in accordance with a
detailed modeling protocol (USDA Forest Service
1996e). The protocol development included a peer
review process that involved representatives from
the Forest Service, the Forest Service's technical
air quality consultants (Air Sciences Inc. and
CH2M HILL), the National Park Service, Carlota
Copper Company, Carlota Copper Company’s
technical air quality consultant (AEC), and EPA
Region IX. This protocol specified values for all
model input parameters.
Meteorological data collected at the project site over
an 18-month period were analyzed and used to
develop two worst-case meteorological conditions
(i.e., first percentile and fifth percentile worst-case
meteorological conditions) according to EPA
guidance. These two meteorological conditions
represent combinations of wind speed and stability
class along a 120 degree wind direction for each
season of the year. Wind speeds and stability classes
were selected according to their potential to produce
visibility impacts. The 120 degree wind direction
(winds from the east-southeast) was selected since
such winds occur along the Pinto Valley drainage and
blow in a direction from the project toward the
Superstition Wilderness over the shortest possible
distance.
Background pollutant concentrations for NO„, NOj,
SO2, and O3 and the background visual range data,
as presented in Section 3.1.1, Affected Environment,
were also used in the PLUVUE II modeling.
The visibility modeling analysis considered six
alternative emissions inventories that included
emission rates for NO„, PM,^, and SO2. Inventories 1,
2, and 3 represent the most likely maximum
unmitigated emissions, the maximum allowable
unmitigated emissions, and the average unmitigated
emissions, respectively. The inventories for these
three alternatives were based on data contained in
the AlP and the Final Air Impact Analyses for the
Environmental Impact Statement for the Carlota
Copper Project {AEC 1996c), as well as technical
data provided by Carlota during the process of
refining the visibility modeling protocol (AEC 1996d).
The mitigated emission inventories (Emission
Inventories 4, 5, and 6) were based on emissions
information provided in the report Revised Emissions
Inventory for Mitigation Measures Planned for the
Carlota Copper Project (AEC 1 996a) and the data
sources for the first three emissions inventories.
These three alternative emissions inventories
incorporate additional mitigation measures committed
to by Carlota that reduce fugitive particulate
emissions and tailpipe emissions of PM,^, SO^, and
NO„. These measures are needed to reduce potential
visibility impacts in the Superstition Wilderness. Table
3-21 summarizes the six alternative emissions
inventories used in the Carlota visibility analysis.
The Forest Service has assessed the relative
importance of the six alternative emission inventories
considered in the visibility modeling analysis. The
Forest Service has determined that mitigated
emission inventories 4 (maximum daily emissions
without emergency generators) and 5 (maximum daily
emissions with emergency generators) are more
significant than mitigated emission inventory 6
(average daily emissions). The Forest Service
considered EPA guidance (EPA 1996b) on modeling
maximum emission cases and the lack of federal
enforceability (through conditions in the ADEQ Draft
Air Installation Permit) associated with the average
operating conditions in emission inventory 6 in
arriving at this weighting decision.
3-26
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-21. Emissions Inventories for the Carlota Visibility Modeling Analysis
|S{o“
Name
Description
Comments
1*
Maximum
24-hour
emissions
without
emergency
generators
Emission rates based on maximum 24-hour
emission rates, excluding emergency
generators, including particulate process
emissions from ore processing sources
(crushers and conveyors).
Line power available.
Cannot occur simultaneously with
emissions inventory 2.
Most likely maximum emission
inventory.^
2
Maximum
24-hour
emissions
with
emergency
generators
Maximum 24-hour emissions, including
emergency generators, excluding particulate
process emissions from ore processing
sources (crushers and conveyors).
Line power interrupted.
Can’t occur simultaneously with
Emission Inventory 1.
Limited by ADEQ AlP condition to 438
hours/year. Consistent with EPA
modeling guidance.”'*
3
Average
emissions
scenario
Emissions based on maximum annual
emission rates divided by 365 days,
excluding emergency generators, including
ore processing sources (crushers and
conveyors).
Annual emissions divided by 365.
Carlota represents this inventory as
being typical for the operation.
No enforceable limits in AlP conditions
at these operating rates.’
4
Mitigated
maximum
24-hour
emissions
without
emergency
generators
Emission rates based on maximum 24-hour
emissions rates, excluding emergency
generators, including particulate process
emissions from ore processing sources
(crushers and conveyors). Additional
mitigation measures employed.
Line power available.
Cannot occur simultaneously with
Emission Inventory 5.
Most likely maximum mitigated
emission inventory.’ ®
5
Mitigated
maximum
24-hour
emissions
with
emergency
generators
Maximum 24-hour emissions, including
emergency generators, excluding particulate
process emissions from ore processing
sources (crushers and conveyors). Additional
mitigation measures employed.
Line power interrupted.
Cannot occur simultaneously with
Emission Inventory 4.
Limited by AlP condition to 438
hours/year.
Consistent with EPA modeling
guidance.”'’®
6
Mitigated
average
emissions
scenario
Emissions based on maximum annual
emission rates divided by 365 days,
excluding emergency generators, including
ore processing sources (crushers and
conveyors). Additional mitigation measures
employed.
Annual mitigated emission rate divided
by 365.
Carlota represents this inventory as
being typical for the operation.
No enforceable limits in AlP conditions
at these operating rates.’ ®
*The numbering system used to present model results in this report is as follows: for each emission scenario, the percentile
meteorological condition was modeled and designated with a “-1” (for example, “1-1” for emission scenario 1), and the S'" percentile
meteorological condition was modeled and designated with a “-5” (for example, “2-5” for emission scenario 2).
Sources:
' AEC 1996d
' AEC 1996c
"EPA 1996b
^ 40 CFR Chapter 1 , Part 51 , Appendix W
*AEC 1996a
Carlota Copper Project Final EIS
3-27
3.0 Affected Environment and Environmental Consequences - Air Resources
Four observer locations were chosen at high points in
order to provide the best vantage point for looking out
over the complex terrain. Figure 3-2a shows the
location of each observer point (Iron Mountain,
Mound Mountain, Government Hill, and Grizzly
Mountain) with respect to the Superstition Wilderness
and the Carlota project site. All of these observer
locations are accessible by hikers.
A complete description of all the values used for the
model input parameters is presented in Table B1-1 oi
Appendix B1.
Modeling Approach. PLUVUE II modeling was
conducted for 12 modeling scenarios and 4 observer
locations. The 12 modeling scenarios were created
from a pool of 6 emission scenarios and 2
meteorological conditions. Specific dates and times of
year were chosen to represent the range of possible
sun paths across the sky. As a result, each modeling
scenario required 48 model runs (one model run for
each observer location [4], season [4], and time of
day [3], 4x4x3 = 48). Therefore, a total of 576 (12 x
48 = 576) model runs were produced and examined
for this visibility modeling analysis.
Model Results. The PLUVUE II model results were
compared to perceptibility threshold values as defined
by the Forest Service Region 3 (Air Sciences, Inc.
1996d) for each of the three visibility perception
parameters (PC, AE, and SVR). The perceptibility
thresholds of PC, AE, and SVR are established
according to Region 3’s definition of Limits of
Acceptable Change for visibility as being a “just
noticeable change.” If the impacts are above any one
of these three thresholds, the plume’s effect on
visibility conditions is interpreted to be a “just
noticeable change.” Table 3-22 presents a summary
of the predicted plume visual impacts in the
Superstition Wilderness for each of the 12 modeling
scenarios. Note that the “% of Samples Above
Threshold” does not reflect the amount of time that
the Forest Service Region 3 perceptibility thresholds
are predicted to be exceeded. Rather, this
percentage value reflects the percentage of all valid
samples that are predicted to exceed the Forest
Service Region 3 perceptibility threshold for the
particular model scenario. For example, a value of 35
percent means that 35 percent of the valid samples
are predicted to exceed the Forest Service Region 3
perceptibility thresholds for the particular model
scenario, and not that the Forest Service Region 3
perceptibility thresholds are predicted to be exceeded
35 percent of the time.
The Forest Service has characterized its best
estimate of the frequency of occurrence of impacts as
at least 4 daylight hours per year for any exceedance
at the first percentile meteorological condition and at
least 22 daylight hours per year for any exceedance
at the fifth percentile meteorological condition (USDA
Forest Service 1997a). Also note that the “Median %
Above Threshold” reflects the severity of visibility
impacts. For example, a value of 50 percent would
represent a more severe visibility impact than a value
of 5 percent.
The modeling scenarios containing the unmitigated
emission inventories (i.e., modeling scenarios 1-1,
1-5, 2-1, 2-5, 3-1, and 3-5) were modeled first.
Modeling scenario 2-1 produced the greatest number
of exceedances of the Forest Service Region 3
perceptibility thresholds with 22 percent of the
modeled samples (421 samples) predicted to exceed
the threshold. For this modeling scenario, the Forest
Service Region 3 perceptibility thresholds were
exceeded by a median of 107 percent for PC and 80
percent for AE. Modeling scenarios 1-5 and 3-5
produced the least number of exceedances with 2
percent of the valid modeled samples predicted to
exceed the thresholds for each of these scenarios (47
and 45 samples for 1-5 and 3-5, respectively). For all
6 unmitigated scenarios, the Forest Service Region 3
perceptibility threshold was exceeded by a median
ranging from 53 to 107 percent for PC, and from 44 to
80 percent for AE. There were no exceedances of the
SVR perceptibility threshold for the six unmitigated
emission inventories.
The implementation of additional mitigation measures
resulted in a substantial reduction in predicted plume
impacts in the Superstition Wilderness. The results of
the mitigated model runs are presented in Table 3-22
in modeling scenarios 4-1, 4-5, 5-1, 5-5, 6-1, and 6-5.
Modeling scenario 5-1 produced the greatest number
of exceedances of the perceptibility thresholds, with 8
percent of the modeled samples (160 samples)
(compared to 22 percent [421 samples] for the
unmitigated scenario 2-1). For this modeling scenario,
the Region 3 perceptibility thresholds were exceeded
by a median of 36 percent for PC and 35 percent for
AE (compared with 107 and 80 for PC and AE,
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3.0 Affected Environment and Environmental Consequences - Air Resources
Table 3-22. Visibility Impacts in the Superstition Wilderness
I Scenarios
Maximum 24-hour Emissions without Emergency Generators
1% Meteorological Condition
5% Meteorological Condition
Unmitigated
Mitigated
Unmitigated
Mitigated
Model Scenario
1-1
4-1
1-5
4-5
% of Samples Above Threshold
17%
1%
2%
<1%
Median % Over Threshold
SVR
0%
0%
0%
0%
Median % Over Threshold
PC
81%
22%
74%
0%
Median % Over Threshold
AE
60%
12%
44%
21%
Maximum 24-hour Emissions with Emergency Generators
1 % Meteorological Condition
5% Meteorological Condition
Unmitigated
Mitigated
Unmitigated
Mitigated
Model Scenario
2-1
5-1
2-5
5-5
% of Samples Above Threshold
22%
8%
4%
1%
Median % Over Threshold
SVR
0%
0%
0%
0%
Median % Over Threshold
PC
107%
36%
88%
55%
Median % Over Threshold
AE
80%
35%
45%
33%
Average 24-hour Emissions without Emergency Generators
1% Meteorological Condition
5% Meteorological Condition
Unmitigated
Mitigated
Unmitigated
Mitigated
Model Scenario
3-1
6-1
3-5
6-5
% of Samples Above Threshold
16%
1%
2%
<1%
Median % Over Threshold
SVR
0%
0%
0%
0%
Median % Over Threshold
PC
66%
31%
53%
0%
Median % Over Threshold
AE
59%
10%
45%
21%
respectively, for scenario 2-1). Modeling scenarios
4-5 and 6-5 produced the least number of exceed-
ances with less than 1 percent of the modeled
samples predicted to exceed the thresholds for each
of these scenarios (5 samples) (compared with 2
percent for both unmitigated scenarios 1-5 and 3-5).
For modeling scenarios 4-5 and 6-5, the perceptibility
threshold was exceeded by a median of 21 percent
for AE. There were no exceedances of the Forest
Service Region 3 perceptibility threshold for SVR
for the six mitigated emission inventories and no
exceedances of the Forest Service Region 3
perceptibility threshold for PC for mitigated scenarios
4-5 and 6-5.
Assessment of PLUVUE II Model Results . The
PLUVUE II model results for the mitigated emission
inventories show a significant decrease in the number
of cases in which modeled values of PC or AE are
greater than the perceptibility thresholds and in the
magnitude of the modeled values of PC and AE when
compared to the PLUVUE II model results for the
unmitigated emission inventories. However, the
results of the PLUVUE II modeling indicate a potential
for perceptible plume impacts to occur in the
Superstition Wilderness because of emissions from
the Carlota Copper Project. Any perceptible plume
impacts would exceed the Tonto National Forest’s
visibility objective of zero daylight hours per year of
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences • Air Resources
perceptible plume impacts in Class I wilderness
areas. This is based on language in Subpart 2,
Section 169A(a)(1) of the Clean Air Act Amendments
of 1977 (Visibility Protection Goal, Clean Air Act).
Although the model results for the mitigated emission
inventories show fewer cases of modeled values of
PC or AE that are greater than the perceptibility
thresholds and a lower magnitude of impacts than the
results for the unmitigated emission inventories, the
model results indicate the potential for perceptible
visibility impacts for each of the observer locations,
each viewing background, each of the three time
periods, and each of the four seasons. Appendix B2
contains tables that summarize the PLUVUE II model
results by season, observer location, viewing
background and color, and time of day.
The Superstition Wilderness is one of the most
frequently visited wilderness areas in the National
Forest System. Seasonal use information is limited
but is reported by the Forest Service as being year-
round with summer receiving the least use (USDA
Forest Service 1990). Visitor use is most intense in
the western half of the Superstition Wilderness,
although visitor use in the eastern half of the
Superstition Wilderness is increasing (USDA Forest
Service 1996d; Hansen 1997). This information is an
important basis for the Forest Service’s decision to
evaluate the potential for plume visibility impacts from
the Carlota Copper Project in the Superstition
Wilderness and in developing its conclusions about
the potential impacts.
The Forest Service has also considered the mitigation
measures committed to by Carlota in an evaluation of
the potential for plume visibility impacts. The Forest
Service and Carlota worked together to evaluate and
select mitigation measures to be employed to reduce
emissions in order to reduce (or eliminate) the
number and magnitude of predicted visibility impacts.
Based on an assessment of the effectiveness and
economic cost of each of the mitigation measures,
Carlota agreed to implement three of the mitigation
measures that were evaluated: (1) using newer
engines in the large haul trucks, (2) eliminating the
haul from the crusher to the leach pad, and
(3) augmenting water application rates on the main
unpaved haul roads (AEC 1996e). (Other mitigation
measures were considered and evaluated to be
infeasible for the project.) The implementation of the
mitigation measures committed to by Carlota would
result in a substantial reduction in the number and
magnitude of potential visibility impacts associated
with the project, as reflected in the model results
{Table 3-22).
Conclusions and Strategy - Superstition
Wilderness. The Forest Service is aware of the
technical limits, uncertainties, and conservative
nature of this visibility modeling analysis. The
PLUVUE II model does not adequately capture
complex terrain effects, and it was not specifically
designed to address the variety of source types
associated with a surface mine. There is also
uncertainty associated with the emission factors,
control efficiency factors, and the daily operational
rates of all activities at the mine. The Forest Service
Region 3 Limits of Acceptable Change and the Forest
Service visibility objective used in the analysis are
conservative. The Tonto National Forest acknow-
ledges that there are a number of factors that are
assumed to occur simultaneously in predicting
potential visibility impacts in the Superstition Wilder-
ness (e.g., maximum emission rates, specific
meteorological conditions, background SVR). The
assumption that such factors occur simultaneously
leads to a conservative estimate of the frequency of
visibility impacts in the Superstition Wilderness.
Based on the results of this visibility analysis and
given the technical limits, conservative nature, and
uncertainties associated with visibility modeling, the
Forest Service developed a monitoring strategy
designed to ensure visibility within the Superstition
Wilderness is protected from the Carlota Copper
Project. The purpose of this monitoring program is to
verify that emissions from the Carlota Copper Project
do not adversely affect visibility resources within the
Superstition Wilderness. A complete description of
the monitoring plan is contained in Section 3.1.4, Air
Resources - Monitoring and Mitigation Measures.
Conclusions - Sierra Ancha Wilderness/Tonto
National Monument. A high ridge, which is the
boundary between the Tonto Basin Ranger District (to
the north) and the Globe Ranger District (to the
south) separates the proposed Carlota Copper
Project site (in the Globe Ranger District) from the
Sierra Ancha Wilderness and the Class II Tonto
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3.0 Affected Environment and Environmental Consequences - Air Resources
National Monument (in the Tonto Basin Ranger
District). This ridge not only interrupts the flow of the
plume, but acts as a visual barrier along every line of
sight from the Sierra Ancha Wilderness and the Tonto
National Monument toward the Carlota Copper
Project site. Furthermore, these two areas are
sufficiently distant from the project site that sustained,
uninterrupted, unidirectional winds over the large
distance are unlikely. The Sierra Ancha Wilderness
and the Tonto National Monument are, therefore,
physically protected from visibility impacts caused by
the project’s emissions.
3. 1.2.2 Alternatives
The alternatives associated with mine rock disposal
and leach pad sites have the potential to result in
different air emissions than the proposed action. The
air quality emissions and impacts of these
alternatives are summarized in Table 3-23. The other
types of alternatives would result in insignificant
changes in air emissions.
Mine Rock Disposal Alternatives
The Cactus South and Cactus Central mine rock
disposal areas (south and southeast of the mine,
respectively) would create an alternative storage
capacity for 7.6 million tons of mine rock. Because
the mining processes associated with the additional
disposal sites would be identical to those in the
proposed action, the total storage capacity for mine
rock would not increase, and fugitive emissions from
mine rock disposal activities of the project would not
be expected to increase. Each of the two alternative
disposal sites covers approximately 22 acres;
therefore, the addition of these two sites would
increase the total disturbed area of the project by
approximately 5 percent. Because of the availability of
the additional disposal sites, the disturbed area of the
Main and Cactus Southwest mine rock disposal areas
would decrease. This decrease would tend to
counteract the effect of the 5 percent increase in
disturbed surface areas. As a result, emissions
increases resulting from implementing this alternative
are expected to be zero.
Approximately 88 million tons of mine rock would be
required to backfill the Carlota/Cactus pit to the
existing elevation of Pinto Creek. Because of the
configuration of the pit, this additional backfilling
cannot be done during mining of the Carlota/Cactus
pit. The entire backfilling process would therefore
take place for 3 to 4 years, beginning at completion of
the proposed project. Backfilling would occur at a rate
of approximately 26 million tons per year. The
predicted project emissions are based on the
maximum annual production rate. Therefore, because
the additional backfilling rate is equal to the highest
predicted processing rate for the proposed project,
the emissions from the project should not increase
but should simply continue for an additional 3 to 4
years. Emissions during any given year are not
expected to be greater than the already estimated
maximum annual emissions. Furthermore, as a result
of backfilling, an additional 110 acres of the
Carlota/Cactus pit and an additional 43 acres of the
Main mine rock disposal area would be reclaimed,
decreasing post-project emissions that are caused by
erosion.
Table 3-23. Summary of Alternatives - Emissions and Impacts
Alternative
EffS^Btisslons
Additional Mine Rock
Disposal Sites
0 percent to 5 percent increase
0 percent to 5 percent
increase
Backfill of
Carlota/Cactus Pit
No increase in short term; extend life of
project; decrease emissions in long term
Same as maximum modeled
case
Backfill of Eder
South Pit
No increase in short term; decrease in
long term
Same as maximum modeled
case
Eder Side-Hill Leach
Pad
Minor increase in fugitive emissions from
increased hauling distances
Same as maximum modeled
case
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
The total amount of mine rock used for backfilling the
Eder South pit would be approximately 5 million tons.
This process would be completed during and
subsequent to Year 14, when emissions are expected
to be substantially lower than peak emissions. The
emissions from the additional backfilling combined
with emissions from regular processes would still be
lower than emissions during the year with the highest
activity rate. Furthermore, a total of 49 additional
acres would be reclaimed as a result of this alter-
native, reducing post-project emissions that are
caused by erosion. Therefore, the total impact
resulting from the additional emissions related to
backfilling the Eder South pit would be lower than the
estimated maximum impacts expected from the
proposed project.
Eder Side-Hill Leach Pad Alternative
The relocation of the Eder mine rock area would
result in an increase in mine rock hauling distance
from the Eder North pit (and back to the pit for
backfilling) and either no change or a slight decrease
in hauling distance of mine rock from the Eder South
pit. The net change in overall fugitive emissions from
these activities in the southern area of the project is
expected to be insignificant since haul road dust
controls have 91 percent efficiency (up to 100 percent
control on interior haul roads), and the increase in
emissions would be minor. The smaller capacity of
the leach pad (75 million tons) might result in as much
as a 25 percent decrease in emissions due to
hauling/ conveying of ore over the life of the project. It
is also possible that sulfuric acid emissions from the
SX/EW tank house could decrease since less ore
would be processed, and therefore, less sulfuric acid
would be used over the life of the process. It is likely
that overall mining activity rates during the maximum
year would not be significantly affected by this
change in the heap configuration, so short-term and
annual impact estimates presented in the EIS are
representative of impacts from this proposed
alternative.
No Action Alternative
The no action alternative serves as the baseline
condition for evaluating the environmental
consequences of the proposed action and the project
alternatives. Selection of the no action alternative
would preclude the development of the Carlota
Copper Project. The baseline levels of pollutants in
the area of the proposed action, as presented in the
affected environment section of the EIS, represent
the air quality resulting from the no action alternative.
Existing nearby sources (principally, BMP Copper's
Pinto Valley Mine) and regional influences on air
quality (long-range transport of mobile source
emissions from the metropolitan Phoenix area) would
remain the primary sources of emissions impacting
the air quality of the project site.
3.1.3 Cumulative Impacts
The cumulative impacts associated with the Carlota
Copper Project include estimated impacts from the
project and impacts associated with other past,
present, and reasonably foreseeable future actions
that would have an impact on the air resources
affected by the proposed project's emissions. These
other actions include mining projects, private land
development, and highway development. The
topography of the area surrounding the proposed
project is complex, with steep mountain ranges and
narrow valleys (drainages).
These characteristics serve to define reasonably
distinct, small air basins that are likely to only be
affected by emission sources that are located within
the air basin. The location of the Carlota Copper
Project fits this description. Therefore, only other
emission sources that are in, or expected to be in, the
immediate vicinity of the project area (within or
adjacent to the valleys defined by Pinto Creek and
Powers Gulch) are considered in this cumulative
analysis.
As described in the emissions portion of the
environmental consequences section, the principal
emission of concern for a surface copper mine is dust
emissions. As a result, Carlota collected ambient
particulate data (PM,^) for 15 months (see Section
3.1.1, Air Resources - Affected Environment). These
data, although presented in terms of representing
background particulate levels, actually represent
particulate levels resulting from existing emission
sources in the area. In other words, when estimated
impacts from the Carlota Copper Project are added to
background concentrations (see Table 3-18), the
resulting total PM,^ concentration represents the
cumulative impact of the proposed project and all
existing sources.
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3.0 Affected Environment and Environmental Consequences - Air Resources
The most important existing source that has been
accounted for in the PM,^ monitoring data is the BHP
Copper Pinto Valley Mine that is located on the
eastern side of Pinto Valley, adjacent to the proposed
project site. This project has been operational for 20
years, and background levels of PM,^ emissions in
the Pinto Valley include impacts from the BHP
Copper project. Obviously, any other particulate
emissions associated with other recreational or small-
scale mining (such as the nearby placer mine) or
other developments (nearby highways and
commercial and residential developments) are also
included in the background particulate concentrations
of 17.2 pg/m® (24-hour average and annual average).
With the addition of the Carlota Copper Project,
maximum cumulative impacts of PM,^ emissions from
the project and all existing PM,(, emission sources are
modeled to be 1 1 1 pg/m^ (24-hour average) and 37
pg/m® (annual average) in a small area to the north of
the operation.
The other pollutant of concern with respect to BHP
Copper's Pinto Valley Mine is HgSO^ mist. BHP
Copper's ore processing methods are similar to the
proposed project's methods, and emissions of H2SO4
mist from each facility's SX/EW plant are assumed to
be proportional to the production rate of the mine.
Because the Carlota Copper Project's forecasted
annual maximum ore processing rate is expected to
be comparable to BHP Copper's current process
rates, the emission rate of H2SO4 mist from the Pinto
Valley Mine is assumed to be approximately equal to
that from the proposed project facility (as estimated in
the Carlota AlP and presented earlier in this analysis).
Because emission rates are similar and meteoro-
logical conditions at these two operations are also
similar (they are located in the same valley), it is
assumed that ambient impacts from H2SO^ mist
emissions from BHP Copper's SX/EW plant are
similar to the modeled impacts of the proposed
Carlota Copper Project SX/EW plant. In other words,
the distribution of impacts caused by emissions from
the Carlota SX/EW plant is expected to be very
similar to the distribution of impacts resulting from
emissions from BHP Copper's SX/EW plant.
To assess the cumulative impact of HjSO, emissions
from both projects, maximum off-site H2SO, impacts
from the Carlota Copper Project can be summed with
estimated impacts from the BHP Copper project for
each receptor of interest. The maximum 1-hour off-
site impact from the Carlota Copper Project is
predicted to be 20.8 pg/m" at a location approximately
2,500 meters north of the proposed SX/EW plant.
This location is approximately 1 ,500 meters west of
the BHP Copper SX/EW facility. The maximum 1-hour
impact would occur with light, southerly winds. These
meteorological conditions are not likely to produce
any additional impact at this same location due to
emissions from the BHP Copper SX/EW facility. The
maximum cumulative impact is represented by the
maximum impact from the Carlota SX/EW plant (20.8
pg/m"). This concentration is below the 1-hour AQG of
22.5 pg/ml
The maximum 24-hour off-site impact from the
Carlota Copper Project is 1.9 pg/m" at a location
approximately 1 ,750 meters south-southeast of the
proposed SX/EW plant. This location is approximately
4,100 meters south-southwest of the BHP Copper
SX/EW facility. The maximum 24-hour impact at this
location caused by HjSO, emissions from the BHP
Copper SX/EW facility is expected to be less than 0.1
pg/m". Therefore, the maximum cumulative 24-hour
concentration resulting from both projects is likely to
be 2 pg/m", below the 24-hour H2SO, AQG of 7.5
pg/ml
Background concentrations of CO, NO^, and SO^ are
assumed to include current impacts from existing
sources (including the Pinto Valley Mine operation).
Therefore, the impacts from the proposed Carlota
operation plus background are assumed to represent
cumulative impacts for CO, NO,, and SO^.
Ozone is a pollutant formed by interaction of ozone
precursors (NO, and hydrocarbons) and sunlight and
occurs after downwind transport of ozone precursors
and sufficient residence time in the atmosphere. Near
site levels of ozone are not expected to be affected
by sources of precursor emissions at Carlota or Pinto
Valley Mine. Again, background concentration of
ozone (used in the AQRV analysis) are assumed to
represent impacts from existing sources.
The Carlota visibility modeling analysis used
estimates of background pollutant concentrations and
visual range data obtained from nearby monitoring
stations and other technical literature. The visibility
modeling analysis incorporated these data along with
estimated emissions from the Carlota Copper Project
and used them to determine potential plume impacts.
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Air Resources
Therefore, the results of the visibility modeling
analysis are assumed to portray the cumulative
visibility impact of the proposed project and the
existing sources in the project area. Mitigation
measures and monitoring are being required to
ensure that the potential visibility impacts meet the
Forest Service Region 3 Limits of Acceptable Change
and the Tonto National Forest visibility objective. Data
from the visibility monitoring program could indicate
impacts from new emission sources in the project
area. If visibility monitoring indicates impacts from
new sources, the Forest Service could decide to
augment the data collection program and/or to
investigate emissions and controls of new sources.
BMP Copper has proposed a 1,200-acre expansion of
the Pinto Valley Mine. This expansion would provide
land for mine rock disposal sites, tailings facilities,
and miscellaneous operations. If approved,
construction of the facilities would occur in 1997. This
expansion would result in increased land disturbance
and increased fugitive emissions. However, it is
unlikely that the proposed expansion, if approved,
would significantly alter the cumulative impacts of the
Carlota Copper Project and BHP Copper's Pinto
Valley Mine as described above. No other new or
expanded mining operations are proposed for the
immediate area of the proposed project, although
Cyprus Mining has proposed expanding its current
leach pad (approximately 3 miles east of the
proposed project) by 1,300 acres of disturbance.
Other future developments that are reasonably
foreseeable and have the potential to affect the
project area include private land development
projects (in the form of development of a limited
number of lots at Top-of-the World) and several
small-scale highway improvements along the U.S.
Highway 60-70 system. Private land development at
Top-of-the-World has the potential for localized and
short-term increases in dust emissions during
construction. Because of the limited availability of lots
that could be developed, air quality impacts from this
development are expected to be insignificant.
Planned highway projects are to take place over the
next 3 years and will primarily address safety and
flow concerns (as opposed to adding lanes to
accommodate increases in traffic volume). Small-
scale highway projects of this nature are likely to be
sources of dust emissions that have the potential to
cause localized dust impacts during construction. It is
unlikely that any of these projects would result in
long-term increases in vehicular emissions that would
have any impact on the project area.
The one private land development that has the
potential to cause an increase in mobile emissions in
the area of the project is the casino that is currently
operating on the San Carlos Indian Reservation
(approximately 8 miles east of Globe). It is likely that
traffic volume along the U.S. Highway 60-70 system
will increase since this is a primary corridor between
the Phoenix metropolitan area and the San Carlos
Indian Reservation. Increases in CO, NO,, and VOCs
could cause increases in ambient concentrations of
CO, NO,, and ozone in the project area, and may
contribute to visibility degradation in the Superstition
Wilderness (which is 5 miles north of U.S. Highway
60 at its closest point, near Superior). Highway
projects, such as widening climbing lanes, improving
intersections, and widening shoulders, should
enhance traffic flow along the corridor and ameliorate
emission impacts associated with heavy congestion
(i.e., stop-and-go traffic).
Overall, future developments other than the Carlota
Copper Project can be expected to result in ambient
air quality impacts that only marginally affect the air
quality of the project area. The Carlota Copper
Project and BHP Copper's Pinto Valley Mine would be
the primary sources of the emissions that affect the
area. Lastly, tourism in the Globe/Miami area is being
encouraged and Highway 88 is being improved. Both
of these factors have the potential to increase traffic
flow in the future.
3.1.4 Monitoring and Mitigation Measures
AQ-1: The design of the ventilation system for the
tank house would facilitate deposition of H2SO^
emissions as close to the tank house as possible.
AQ-2: The Forest Service has considered the
implementation of the mitigation measures, the
technical limits and uncertainties in the visibility
modeling analysis, and the results of the PLUVUE II
model runs based on the mitigated emission
inventories to evaluate potential perceptible visibility
impacts and to formulate a strategy to ensure the
protection of visibility within the Superstition
Wilderness. Specifically, the Forest Service has
developed a monitoring strategy designed to protect
Carlota Copper Project Final EIS
3-35
3.0 Affected Environment and Environmental Consequences - Air Resources
visibility of the Carlota Copper Project in the
Superstition Wilderness. It would be maintained until
1 year after the Carlota Copper Project reaches its
maximum production rate.
The monitoring plan employs a three-tiered approach.
The first tier would be to determine the existence of
perceptible plume impacts in the Superstition
Wilderness and to determine if emissions from the
Carlota Copper Project cause or contribute to
perceptible impacts in the Superstition Wilderness. If
the findings of the Tier 1 monitoring program indicate
that a perceptible impact in the Superstition
Wilderness exists and that emissions from the Carlota
Copper Project may be the cause of or may
contribute to those impacts, then Tier 2 would be
invoked to further characterize the impacts and to
more accurately attribute impacts to emissions from
the Carlota Copper Project. A Tier 2 program could
include continuous particulate and NO, monitoring at
locations upwind and downwind from the Carlota
Copper Project and/or increased frequency or
additional sampling and chemical analysis of
particulate matter at the wilderness boundary. The
specific configuration of a Tier 2 monitoring program
would be determined based on the information
gathered in the Tier 1 program. In Tier 3, the data
from Tier 1 and Tier 2 would be considered by the
Forest Service in consultation with Carlota to identify
and implement additional mitigation measures
necessary to rectify the impact. The implementation
of this monitoring strategy would meet the Forest
Service’s objectives, existing guidance, and legal
responsibilities as they pertain to protecting the
visibility of mandatory Class I wilderness areas.
The requirements of the Tier 1 program would be
included as a component of the final Plan of
Operations for the Carlota Copper Project. The Tier 1
monitoring program would include the following
items'':
^ The Forest Service has decided not to require aerosol
monitoring as part of the Tier 1 monitoring program for the Carlota
Copper Project. However, the Forest Service believes that aerosol
monitoring is a useful component for characterizing visibility
impacts. Aerosol monitoring could be accomplished through a joint
effort among the Forest Service, Carlota Copper Company, and
other sources that potentially contribute to visibility impacts in the
Superstition Wilderness.
• Meteorological Monitoring. Continuous
meteorological monitoring collected at three
locations (on-site, at the Superstition Wilderness
boundary, and at a location [to be determined]
between the project and the Superstition
Wilderness) at the 10-meter level. Parameters to
be monitored would include wind speed, wind
direction, relative humidity (on-site location only),
and precipitation (on-site location only).
Purpose/Use of Monitoring Element: Continuous
meteorological monitoring would provide one line
of evidence needed to appropriately attribute to
the Carlota Copper Project measured visibility
impacts (if any) in the Superstition Wilderness.
For perceptible plume impacts in the Superstition
Wilderness to be attributed to emissions from the
Carlota Copper Project, the wind direction data at
the Carlota site must indicate the potential for
emissions from the Carlota Copper Project to
cause impacts in the Superstition Wilderness.
Because of the complex nature of the terrain in
the area, data collected at three appropriately
sited locations would be necessary to avoid
monitoring only micro-scale meteorological
conditions. Other meteorological data, such as
wind speed and Pasquill-Gifford stability class,
would be needed to further characterize the
meteorological conditions during the periods of
perceptible plume impacts.
• Scene. Video camera site (if line power is
available). (If line power is not available, an 8-
millimeter [mm] camera site would be substi-
tuted.) The site would be located at a point with
an appropriate view for determining impacts to
the Superstition Wilderness. The site would be
operated continuously during daylight hours and
would be equipped with one or two cameras,
depending on siting constraints, in order to
capture the view looking into the Superstition
Wilderness and a view back toward the Carlota
Copper Project.
Purpose/Use of Monitoring Element: The video
camera would be used as a surrogate for the
human eye. The camera would be situated to
monitor the presence of a visible plume leaving
the Carlota site and entering the Superstition
Wilderness.
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Scene. A photographic camera site. The
site would be located at a point with an
appropriate view looking into the Super-
stition Wilderness and aimed at a critical
target within the Superstition Wilderness.
The site would be operated with three
pictures taken per day. The photographic
camera site would be operated by the Forest
Service.
Purpose/Use of Monitoring Element: The
35-mm camera site would further document
the scene quality for public presentation
purposes. The images would be used to capture
visual characteristics within the Superstition
Wilderness on the “cleanest” days of the year.
The images would be processed, digitized, and
modified to show estimated changes in visibility
conditions (AE and contrast) based on the
monitoring data collected adjacent to the
Superstition Wilderness.
• Optical. Continuously operating transmissometer
site located near the Superstition Wilderness. A
nephelometer may be substituted depending on
siting considerations.
Purpose/Use of Monitoring Element: The trans-
missometer would be used to document hourly
average integrated values of the light-extinction
coefficient (a measure of light attenuation) within the
Superstition Wilderness. The transmissometer data
would serve as the primary measure of visibility
impairment within the wilderness. Transmissometers
are capable of measuring the total extinction of light,
which is influenced by light-scattering fine particles
and light-absorbing elemental carbon (soot) and
nitrogen dioxide.
Carlota Copper Project Final EIS
3-37
3.0 Affected Environment and Environmental Consequences - Air Resources
3-38
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
3.2 Geology and Minerals
3.2.1 Affected Environment
This section addresses the topography, regional
geology, bedrock geology, surficial deposits,
seismicity, geologic hazards, and mineral resources
for the Carlota Copper Project. The regional and local
geology summary also provides background
information for predicting ground water flow path-
ways, evaluating potential impact on ground water
resources, and designing a ground water monitoring
program (see Section 3.3, Water Resources).
3.2. 1. 1 Topography and Physiographic Setting
The proposed project area is situated within a broad
chain of northwest-trending ranges from the Pinal
Mountains to the southeast, the Dripping Springs
Mountains to the south, and the Superstition
Mountains to the west. The topography of the project
area, presented in Figure 2-1 b, is characterized by
irregular and varied topographic features that
developed in response to erosion across complex
fault structures and diverse rock formations. The
elevation across the site ranges from approximately
5,000 ft-amsi along the ridge line adjacent to the Eder
South pit in the southeast to approximately 3,200 ft-
amsl in Pinto Creek in the well field area. Natural
slopes flanking the ridges are steep, with gradients
typically ranging from 1.5:1 to 2.5:1 (H:V).
The main portion of the project area is drained by two
northwest-flowing streams, Pinto Creek and Powers
Gulch, that are separated by a broad, northwest-
trending ridge. Pinto Creek is the larger of the two
and flows along a sinuous course in the eastern
portion of the project area and through the site of the
proposed Carlota/Cactus pit. Powers Gulch is a small
tributary to Haunted Canyon that flows through the
western portion of the project area and through the
proposed heap-leach pad site; its headwaters are
immediately south of the project near U.S. Highway
60. Powers Gulch flows into Haunted Canyon approx-
imately 1 mile downstream from the heap-leach pad
site. Haunted Canyon originates in the Superstition
Wilderness located west of the project area. The
proposed well field would consist of several wells
located along the lower reach of Haunted Canyon and
along Pinto Creek immediately downstream of the
Haunted Canyon-Pinto Creek confluence.
3.2. 1.2 Geologic Setting
The project is located within the Globe-Miami Mining
District. The rocks exposed within the district are
igneous, metamorphic, and sedimentary rocks that
range from Precambrian to Tertiary in age. These
rocks record a complex structural and depositional
history that has included repeated episodes of
tectonic uplift, faulting, erosion, and deposition of
sedimentary and volcanic materials.
Basement rock throughout the district consists of the
Precambrian Pinal Schist that is intruded with
Precambrian granite and diabase. Locally, upper
Precambrian sedimentary rocks of the Apache Group
rest unconformably on the eroded surface of the Pinal
Schist. The Apache Group is, in turn, separated from
Paleozoic limestones and quartzites by another ero-
sional surface. These older rocks were intruded by
bodies of granite porphyry (named the Schultze
Granite) during mountain building in the Late
Cretaceous to Early Cenozoic eras. A thick sequence
of dacitic volcanic and volcaniclastic rocks of Miocene
age, and the Gila Conglomerate of Miocene to
Pliocene age, mantle the older rock units and fault
structures. Erosion during the last several million
years in this area has removed portions of these
deposits, exposing the older formation.
The distribution of the major rock types in the
vicinity of the proposed project, along with their
respective ages, are presented in Figures 3-3 and
3-4. Representative geologic cross sections
through the leach pad, the Carlota/Cactus pit,
and the Main mine rock disposal area are presented
in Section 3.3, Water Resources (Figures 3-16,
3-17 and 3-18). The primary rock units in the vicinity
of the project are described below, from oldest to
youngest.
Bedrock Units
The Pinal Schist and massive bodies of Precambrian
diabase intruded into the Pinal Schist comprise the
oldest rocks exposed in the area. These rocks
underlie large portions of the heap-leach facility and
mine rock disposal sites, and would be exposed in
the open pits. The Pinal Schist is the main host rock
for mineralization at the Eder South deposit and one
of several host rocks for mineralization in the
Carlota/Cactus pit.
Carlota Copper Project Final EIS
3-39
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
The “Granite on Manitou Hill” (Peterson 1962) is a
Precambrian age, weakly foliated granitic intrusion
that occurs in Manitou Hill and between Pinto Creek
and Powers Gulch in the vicinity of the Cactus
Southwest mine rock area.
Rocks of the upper Precambrian Apache Group
include three conformable units: the Pioneer Forma-
tion (which includes the Pioneer shale and Pioneer
Quartzite), Dripping Springs Quartzite, and Mescal
Limestone. These units occur beneath portions of the
heap-leach facility. Main mine rock disposal area, and
well field area. The Dripping Springs and the Pioneer
Quartzite locally contain abundant open fractures that
readily store and transmit ground water. These
fractured quartzites are two of the primary water-
yielding rock units encountered in the well field.
Pioneer Quartzite is typically a fine- to medium-
grained arkosic quartzite that has been extensively
intruded by diabase sills and dikes (Peterson 1962).
The Dripping Springs Quartzite formation is charac-
terized as a fine- to medium-grained white to vari-
colored quartzite with occasional thin shale interbeds.
Paleozoic rocks exposed at the surface near project
facilities or in the well field area include the Cambrian
Troy Quartzite, the Devonian Martin Limestone, the
Mississippian Escabrosa Limestone, and the Permian
Naco Group. The Cambrian Troy Quartzite is
encountered at depth in the well field. Peterson
(1962) describes the Troy Quartzite as having a
distinct conglomeratic basal unit that grades upward
into dark reddish-brown pebbly sandstone and slabby
argillaceous sandstone. In the well field, the Troy
Quartzite is a significant water-yielding unit. The
limestone units are exposed in the northwest portion
of the Main mine rock disposal area, locally along the
Kelly fault zone, and in the well field area.
The Tertiary Schultze Granite is exposed over
extensive areas south of the proposed Carlota/Cactus
and Eder South pits, including the area traversed by
U.S. Highway 60 and the Top-of-the-World commu-
nity. The Schultze Granite is considered to be the
mineralizer in the Globe-Miami Mining District and
hosts ore in many of the deposits. However, the
granite is not mineralized on the project site, and its
genetic significance to the copper mineralization
within the Carlota Copper Project area has not been
established.
The Whitetail Conglomerate is preserved locally in the
Carlota Copper Project area. The Whitetail is up to
several hundred feet thick in the area and is com-
posed predominantly of poorly stratified sand-to-
cobble-sized diabase and limestone fragments. A
thick volcanic ash unit near the top of the Whitetail
Conglomerate has been dated at approximately 30
million years ago. The Whitetail does not appear to be
mineralized in the project area.
The Tertiary Cactus Breccia is the most important ore
host rock in the Carlota/Cactus pit in terms of volume.
The breccia is composed of variably altered Quartz-
Muscovite Schist clasts derived from the Pinal Schist.
Other fragments in the breccia appear to be derived
from the Schultze Granite, quartzite units of the
Apache Group, and other intrusive rocks. The breccia
is typically chaotic and unsorted, with clasts generally
quite angular and ranging from house-size boulders
down to sand-size fragments. Limonite coating on
clasts, as well as limonite disseminated within clay
matrixes, impart a characteristic red color to the
breccia. The preserved thickness of the breccia
exceeds 600 feet, and vague layering preserved in
the deposit dips moderately northeast. The breccia
appears to be of sedimentary origin and likely
represents an ancient subaerial landslide deposit.
The Cactus Breccia would be exposed in the walls of
the final Carlota/Cactus and Eder North pits.
Stratigraphically, the Cactus Breccia is overlain
by the Apache Leap Tuff. The tuff is dacitic in
composition, generally welded, and often exhibits
a crude subhorizontal layering. An approximately
10-foot-thick black vitrophyric (glassy) zone
commonly occurs near the base of the tuff. A thin
ash layer is also present locally near the base of the
tuff. The tuff is a significant ore host in the Carlota
project area and would comprise portions of the
upper zones in the walls of the final Carlota/Cactus
and Eder pits.
The Gila Conglomerate is present in the northeastern
part of the area and locally appears to be weakly
mineralized. The Gila consists of poorly sorted alluvial
fan deposits that record a period of erosion, deposi-
tion, and uplift that predates the current period of
tectonic activity. Regionally, the Gila is a major
ground water aquifer, as discussed in Section 3.3.1 .3,
Water Resources - Ground Water,
3-40
Carlota Copper Project Final EIS
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CARLOTA COPPER PROJECT
Figure 3-4
Geologic Map -
Well Field Vicinity
3-43
3.0 Affected Environment and Environmental Consequences • Geology and Minerals
Bedrock Structure
The rocks within the mineral district have been
extensively faulted. Some of the faults appear
to have contributed to, or controlled, the occurrence
of the mineralization. Most of the recognized
faults occur along two primary trends: a north
to northwestern trend and a northeastern trend.
The northeastern faults are associated with mineral-
ization throughout the district and are presumably
deep-seated. In addition, these structures appear
to be the overall controlling structure for the
mineral district; all of the productive mineral
deposits in the district are located within a
6-mile-wide northeast-trending band (Peterson
1962).
Major fault block structures have developed in the
project area as a result of Tertiary extensional
tectonics that affected the region. The north-trending
Castle Dome Horst, hosting the Pinto Valley Mine,
and the northwest-trending Cactus Graben, hosting
the Carlota/Cactus deposit, are the two most
significant structural features in the area.
The Cactus Graben consists of a 1 ,200- to 1 ,500-
foot-wide block that is bound by two northwest-
trending parallel faults: the Kelly fault (forms the
southern boundary) and the North fault (forms the
northern boundary). Movement along the Kelly
fault zone was initiated after the emplacement
of the breccia in this area. Based largely upon the
absence of both breccia and dacite to the south
of the fault, the Kelly fault is postulated to have
been responsible for several thousand feet of
oblique-slip movement. Less movement appears
to have occurred on the North fault. In general, the
Kelly fault. North fault, and Cactus fault (described
below) define the boundaries of the Carlota/Cactus
ore body.
The Cactus Breccia is separated from the
underlying Precambrian rocks in the Cactus
Graben by a 4- to 10-foot-wide, gently dipping
fault zone that is referred to as the Cactus fault.
This structure may be a remnant of the basal
slide plane of the Cactus Breccia, or it may be a
thrust fault that developed after the breccia was
deposited.
Surficial Deposits
Surficial deposits identified on or near the project
facilities and in the well field area include alluvium and
undifferentiated slope deposits {Figures 3-3 and 3-4).
Alluvium occurs in the floodplain adjacent to Pinto
Creek, Powers Gulch, and Haunted Canyon, as well
as along several tributary washes in the project area.
The alluvium consists of unconsolidated silt, sand,
gravel, and boulders. Alluvial deposits are most
extensive along Pinto Creek, where the deposits
range from 80 to 500 feet in width and up to 30 feet
deep (Montgomery & Associates, Inc. 1992).
Undifferentiated slope deposits cover extensive areas
adjacent to Powers Gulch, particularly between the
Eder North and Eder South pits, in the southern
portion of the proposed heap-leach area, and locally
along the slopes adjacent to Pinto Creek. These
deposits are composed of talus, colluvium, and
landslide debris. Talus consists of accumulations of
rock fragments of any size or shape that have been
heterogeneously deposited by nature at the base of
steep slopes. Colluvium develops from the downslope
movement of soil and weathered rock caused by
slope wash and soil creep processes. Landslide
debris generally consists of chaotic mixtures of soil
and rock fragments that were deposited by the
downslope gravitational movement of these materials
(Transportation Research Board 1978). The actual
existence, as well as the depth and age, of specific
landslide deposits has not been determined.
3.2.1. 3 Historic Mine Workings
The locations of known historic mine workings in
relation to the proposed mine facilities are shown in
Figure 3-5. These workings include shafts, shallow
prospect pits, side-hill cuts, and adits (drifts) located
in Pinto Creek valley and Powers Gulch. Minor
amounts of fill typically occur in the vicinity of these
prospects and along access roads. These deposits
consist of loose soil and rock material. Because of
their limited extent, these deposits are not
distinguished on the surficial geologic map. However,
the general location of these deposits can be inferred
from the locations shown on the map of existing mine
workings {Figure 3-5).
Carlota Copper Project Final EIS
3-45
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
3.2. 1.4 Faulting and Seismicity
An active fault is one that shows evidence of dis-
placement during the Holocene (last 10,000 years),
and a potentially active fault is a fault that shows
evidence of surface displacement during the Pleisto-
cene (last 2,000,000 years). Recent mapping
conducted by the Arizona Bureau of Geology and
Mineral Technology indicates that there are no known
active or potentially active faults in the vicinity of the
project site. The nearest potentially active fault in the
region is located near the southern shore of
Roosevelt Lake, approximately 20 miles north of the
project site (Scarborough et al. 1 986, Peartree and
Scarborough 1984).
The project site is located within a moderately active
seismic region. As indicated in Table 3-24, four
significant earthquakes have affected the area in
recent historic times. The largest earthquake was an
estimated 7+ Richter magnitude event centered in
northern Mexico in 1887. This earthquake was
reportedly felt throughout the southwest. The other
three seismic events that affected the area were
moderate earthquakes centered in the region near
Globe, Miami, and San Carlos (30 miles east of the
project site).
All four earthquakes produced an estimated modified
Mercalli intensity of VI in the project vicinity (DuBois
et al. 1982). Intensity VI corresponds to moderate
ground-shaking and minor damage, as detailed on
the Modified Mercalli Intensity Scale presented in
Table 3-25.
3.2.1. 5 Mineralization
The information on mineralization presented below is
based on the visual examination of surface
exposures, drill core and cuttings, and associated
petrographic work, as presented in the Update to the
Plan of Operations (Carlota 1993a).
The Cactus Breccia is the primary host rock for
mineralization in the Carlota/Cactus and Eder North
deposits. Important mineralization also occurs in the
dacite overlying the Cactus Breccia, in the Carlota
deposit, and along approximately 3,300 feet of the
Kelly fault, which bounds the Cactus and Carlota
deposits to the south. Mineralization along the Kelly
fault is hosted in brecciated diabase (northwest
segment) and Pinal Schist (southeast segment).
Mineralization in the Eder South deposit is hosted
within fractured and brecciated Pinal Schist.
Chrysocolla (hydrous copper silicate) is the dominant
ore mineral in all of the deposits; however, significant
amounts of chalcocite (copper sulfide) and malachite
(copper carbonate) also occur locally. Black copper
pitch and/or neotocite (copper, magnesium, and iron
oxide) occur(s) locally with chrysocolla. Iron oxides
and pyrite (iron sulfide) occurs within local zones in
the Cactus Breccia. Clays and iron oxides (hematite)
can locally contain significant amounts of copper.
Chalcocite, the only copper sulfide mineral identified,
is restricted to isolated zones within the lower parts of
the Cactus deposit. The Chalcocite occurs as rim-
mings or partial to total replacements of pyrite (iron
sulfide). Pyrite occurs as both veinlets or dissemi-
nated grains within individual breccia fragments.
Carlota/Cactus Deposits
The extent and grade of mineralization at the Carlota
Copper Project has been determined from extensive
drilling, sampling, and assaying. The results of the
drilling are presented on cross sections in the Plan of
Table 3-24. Seismic Events Affecting the Site Between 1776 and 1980
Dflto
Location
Approximate .
Distance from
Site (miles)
VO. V
® Richter
Magnitude
, Modified Mercaiii
3 Jntensity in
flcinityolSito
May 3, 1887
Batepito, Mexico
150
7.25±’
VI
June 17, 1922
Miami, Arizona
10
unknown
VI
September 11, 1963
Globe, Arizona
15
4.1
VI
December 25, 1969
San Carlos, Arizona
30
4.4
VI
’Estimated from historic data
Source: DuBois et al. (1982)
3-46
Carlota Copper Project Final EIS
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-5
Existing Mine Workings
r ^
.
V ■ .. ■-
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
Table 3-25. Descriptions of the 12 Levels of Earthquake Intensity on the Modified Mercalli Scale
I. Not felt.
II. Felt by persons at rest, on upper floors, or favorably placed.
III. Felt indoors. Hanging objects swing. Vibration like passing of light trucks. Duration estimated. May not be
recognized as an earthquake.
IV. Hanging objects swing. Vibration like passing of heavy trucks, or sensation of a jolt like a heavy ball
striking the walls. Standing automobiles rock. Windows, dishes, doors rattle. Wooden walls and frame may
creak.
V. Felt outdoors; direction estimated. Sleepers waken. Liquids disturbed, some spilled. Small unstable
objects displaced or upset. Doors swing. Shutters, pictures move. Pendulum clocks stop, start, change
rate.
VI. Felt by all. Many frightened and run outdoors. Persons walk unsteadily. Windows, dishes, glassware
broken. Knickknacks, books, etc. off shelves. Pictures off walls. Furniture moved or overturned. Weak
plaster and masonry D cracked.
VII. Difficult to stand. Noticed by drivers of automobiles. Hanging objects quiver. Furniture broken. Weak
chimneys broken at roof line. Damage to masonry D, including cracks; plaster, loose bricks, stones, tiles,
and unbraced parapets fall. Small slides and caving in and along sand or gravel banks. Large bells ring.
VIII. Steering of automobiles affected. Damage to masonry C; partial collapse. Some damage to masonry B;
none to masonry A. Stucco and some masonry walls fall. Chimneys, factory stacks, monuments, towers,
elevated tanks twist and/or fall. Frame houses moved on foundations if not bolted down; loose panel walls
thrown out. Decayed piling breaks off. Branches break from trees. Changes in flow or temperature of
springs and wells. Cracks in wet ground and on steep slopes.
IX. General panic. Masonry D destroyed; masonry C heavily damaged, sometimes with complete collapse;
masonry B seriously damaged. General damage to foundations. Frame structures, if not bolted, shift off
foundations. Frames racked. Serious damage to reservoirs. Underground pipes break. Conspicuous
cracks in ground and liquefaction.
X. Most masonry and frame structures destroyed with their foundations. Some well-built wooden structures
and bridges destroyed. Serious damage to dams, dikes, embankments. Large landslides. Water thrown on
banks of canals, rivers, lakes, etc. Sand and mud shift horizontally on beaches and flat land. Rails bend
slightly.
XI. Rails bend greatly. Underground pipelines completely out of service.
XII. Damage nearly total. Large rock masses displaced. Lines of sight and level distorted. Objects thrown in
the air.
Masonry A:
Masonry B:
Masonry C:
Masonry D:
Good workmanship and mortar, reinforced designed to resist lateral force.
Good workmanship and mortar, reinforced.
Good workmanship and mortar, unreinforced.
Poor workmanship and mortar and weak materials, like adobe.
Source: Blair and Spangle (1979)
Carlota Copper Project Final EIS
3-49
3.0 Affected Environment and Environmental Consequences • Geology and Minerals
Operations (Carlota 1992). The Carlota and Cactus
deposits are adjacent to each other and would be
mined together in the Carlota/Cactus pit. The Cactus
deposit is defined as being east of Pinto Creek; the
Carlota deposit is defined as being west of Pinto
Creek. Significant mineralization is noted for roughly
3,600 feet along the length of the two deposits, as
well as in the Cactus Breccia and the Kelly fault, and
locally within the dacite. This zone of mineralization
extends to a depth of up to 600 feet in the Carlota
deposit and 400 feet in the Cactus deposit.
Within the Cactus deposit, only oxide-type mineral-
ization is found in outcrops, while a mixed oxide-
sulfide mineralization occurs at depth. The Kelly fault
defines the southern and western limit of mineraliza-
tion in both the Carlota and Cactus deposits and
contains oxide mineralization over widths of 10 to 70
feet, with typical grades of 0.6 to 1 .0 percent copper.
Mineralization in both deposits is generally floored by
the low-angle Cactus fault, which separates the
overlying mineralized Cactus Breccia from underlying,
generally barren Pinal Schist. Mineralization in both
deposits appears to be strongest (greater than 0.50
percent total copper) adjacent to or in close proximity
to the Kelly fault, with diminishing intensity farther
away from the fault. However, significant mineraliza-
tion is present up to 1 ,000 feet away from the fault
toward the east.
Mineralization in the Carlota deposit is entirely of the
oxide type, while mixed oxide-sulfide type ore would
be mined in the Cactus deposit. Over much of the
Cactus deposit, the oxide-sulfide boundary, defined
as where the ratio of nonsulfide copper to total copper
is less than 50 percent, mimics the current ground
water table and is as close as 50 feet to the surface.
Where sulfide mineralization (chalcocite) is present, it
is generally quite uniform and consistent, often
grading approximately 0.7 percent copper, but with
multipercent grades often present immediately below
the oxide-sulfide boundary. Surface mineralization in
the Cactus deposit is generally present as
chrysocolla, which appears to have formed after
preexisting malachite. Malachite is the most common
oxide mineral that occurs between the surface and
the oxide-sulfide boundary.
Essentially all of the ore in the bottom of the Cactus
deposit, including the mixed sulfide-oxide ore, would
be mined. As a result, little, if any, sulfide material
would remain in the bottom or sides of the pit at the
conclusion of mining. In the Carlota deposit, and in
the segment of the pit between the Carlota and
Cactus deposits, some ore would remain below the
final pit floor. Although this ore meets the 0.15
percent copper cutoff grade, it is not economically
feasible to mine because of the increased stripping
required to enlarge the pit to extract the ore and the
relatively low grade of the material.
Eder North and South Deposits
Mineralization in the Eder North deposit is hosted
within the Cactus Breccia, which apparently infills a
northeast-southwest trending depression into the
underlying Pinal Schist and Whitetail Conglomerate.
The north and south limits of the deposit are poorly
defined, but the deposit is known to extend roughly
1 ,000 feet across the axis of the channel. The eastern
limit is defined by erosion, while the western limit,
although poorly defined, is known to extend for over
1 ,300 feet downward from the surface exposure,
under the overlying, essentially barren Apache Leap
Dacite. However, an economic limit is imposed in this
direction because of the westwardly dip of the breccia
into the steep, dacite-capped ridge.
Mineralization in the Eder South and Eder Middle pits
occurs mainly as chrysocolla along fractures within
the Pinal Schist. The mineralization in these pits con-
sists of copper oxide; no sulfide mineralization has
been found. Significant (greater than 0.15 percent)
near-surface copper mineralization in the Eder South
pit is present over an area measuring roughly 2,400
feet (north-south) by 1,000 feet (east-west). Mineral-
ization often extends from the surface to depths of
roughly 200 to 300 feet; the base of the mineralization
is at approximately 4,200 ft-amsi. The western portion
of the deposit is overlain by essentially barren
Apache Leap Dacite, and the eastern edge of the
mineralization is defined by erosion. As with the Eder
North pit, mineralization is known to extend at least
1 ,000 feet west of the outcropping zone under the
dacite cap that forms a steep ridge; however,
because of the depth to this segment of the ore body,
as well as the ore grades, mining this portion of the
ore body is not considered economically viable. The
mineralization to the north and south of these pits
appears to diminish gradually, perhaps related to a
lack of faulting and ground preparation. Near the
south end of the deposit, the mineralization appears
3-50
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
to increase along the east-west-trending structural/
intrusive boundary of the Schultze Granite and then
diminish within the granite further to the south.
Mineral Reserves
The mineral reserve is defined as the in-place mineral
inventory without the imposition of economic
constraints. The mineral reserve was estimated from
the computer block model of the deposits and was
based on data from all of the exploration drill holes
(Carlota 1993a). The reserve estimates are based on
an ore cutoff grade of 0.15 percent total copper. The
resulting geologic resource for the three-pit area
totals approximately 140 million tons (Carlota/Cactus,
95 million tons; Eder South, 31 million tons; and Eder
North, 14 million tons).
The mineable reserve is defined as the portion that
can be economically recovered and has been
determined for the Carlota/Cactus, Eder South, and
Eder North deposits. The mineable portion of these
deposits is calculated based on the pit geometry,
which is determined using a computer-generated
floating cone. The floating-cone computer algorithm
uses the computer block model of the ore body,
current economics, and operating costs to estimate
the break-even economic limits of a pit. The
estimated production costs were based on previous
studies and actual costs from similar-size mines and
SX/EW plants. The copper recoveries are based on
column tests run on the various ore types.
The mineable reserves are summarized in Table 2-1.
The reserves presented in this report are the sum of
proven and probable reserves. The current mine plan
would recover approximately 72 percent of the
available resource (approximately 100 million tons of
mineable ore out of the estimated 140-million ton
mineral reserve). Remaining mineral reserves would
include approximately 14 million tons within the
Carlota/Cactus deposit and approximately 25 million
tons within the Eder deposits. These reserves are not
considered economically recoverable at this time.
Other Mineral Deposits
Drilling conducted by Carlota during the exploration
phase of the project has thoroughly defined the
economic-grade copper mineralization (grading
greater than 0.15 percent copper) within the area of
the planned Carlota/ Cactus, Eder North, and Eder
South pits. The initial geological investigations also
delineated areas within the project site that were
determined to be economically unfavorable for the
development of mineral deposits. Other drill holes,
including bedrock monitoring wells, geotechnical
holes, and ground water test wells, were routinely
assayed for copper. Additional condemnation drilling
was conducted to determine if any possible economic
copper or other mineralization existed in areas
planned for the mine rock areas, heap-leach pile, and
processing facilities. The results of these combined
geological investigations indicate that no mineralized
areas exist within the project site other than the
Carlota/Cactus and Eder orebodies.
3.2.2 Environmental Consequences
Issues related to geology and minerals for the
proposed Carlota Copper Project include (1) impacts
to potential future development of mineral resources,
and (2) creation or exacerbation of geologic hazards
from project operations that affect project facilities.
The evaluation criteria used to analyze the impacts of
the proposed action and alternatives on geology and
minerals are given below:
• Results of condemnation drilling within the project
area and the identification of non-leachable ores
• Local and regional geologic characteristics
• Geological instability associated with project
facilities (slope stability analysis of mine rock
areas, pits, and leach pad) and with mining
activities (adits and shafts)
3.2.2. 1 Proposed Action
The direct impacts of the proposed action on geologic
and mineral resources would include (1) the genera-
tion of approximately 21 1 million tons of mine rock to
be left on the site in reclaimed mine rock areas and
as partial backfill for the Carlota/Cactus pit and the
Eder North and Eder South pits, (2) the generation of
approximately 100 million tons of spent ore to be left
in the closed and reclaimed heap-leach facility, and
(3) the extraction of 900 million pounds of copper
from the geologic resource. Under the proposed
action, these direct impacts would not be mitigated.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Geology and Minerals
Additional direct impacts could include the effects of
ground vibration on nearby residences caused by
blasting, as discussed below. Potential water quality
impacts caused by the heap-leach and mine rock
facilities are discussed in Section 3.3, Water
Resources.
Indirect impacts from the proposed action could
include subsidence around pre-existing mine
workings and induced slope instability and seismic
ground shaking, as discussed below. Surficial
materials would be altered over approximately 1,428
acres. Land disturbance could potentially increase
erosion and sedimentation; the potential impacts from
increased erosion and sedimentation are addressed
in Section 3.3, Water Resources, and Section 3.4,
Soils and Reclamation.
Ground Subsidence
Ground subsidence over existing historic mine
openings is a potential hazard on the project site.
Mineral exploration and mine development activities
occurred on the site intermittently between 1908
and 1929 (Peterson 1962). The locations of the
known mine workings and prospects are shown in
Figure 3-5. The major underground workings are
located within the footprint area of the Carlota/Cactus
pit and the heap-leach pad. These included the 400-
foot-deep Carlota Shaft, the 500-foot-deep Hamilton
Shaft, the 300-foot-deep Arizona National Shaft, and
6,500 feet of lateral workings on three levels driven
off the Hamilton Shaft. These workings are
inaccessible and partially filled in or buried. The
proposed Carlota/Cactus pit would remove most of
the buried mine workings and shallow surface
openings in this area. Six additional shallow shafts,
with openings ranging from 5 to 30 feet deep, and
several other shallow workings have been identified
within the footprint of the leach pad. There is little, if
any, information on the original depth, lateral extent,
or amount of backfill already present in these work-
ings. If not properly backfilled, the potential exists for
settling and/or subsidence to occur beneath the heap,
resulting in a tear or puncture in the leach pad liner. A
break in the liner material could result in process
solutions entering into the ground water system.
Carlota has provided a plan and conceptual drawings
for backfilling and sealing existing mine workings
(Carlota 1994a). This plan has been incorporated into
the proposed action. Under the proposed action, all
shafts would be decommissioned by backfilling them
with rock to within 5 feet of the surface. The walls
would be excavated to a 1:1 (H:V) slope. The remain-
ing opening of the shaft would be sealed with mass
concrete. Adits that are 6 feet or greater in diameter
would be cleaned to their full extent and backfilled
with mass rock fill to within 15 feet of the portal. The
outer 15 feet of the adit would be sealed as a cast-in-
place concrete bulkhead. Adits that are less than 6
feet in diameter would be backfilled from the back of
the adit forward using the tremie method and capped
at the surface with a cast-in-place concrete bulkhead.
Other adits or near horizontal workings located in
areas where minor subsidence is unlikely to damage
any of the project facilities would be backfilled with
rock and sealed at the surface with a concrete bulk-
head. Additional mitigations for sealing the mine
workings are provided in Section 3.2.4, Geology and
Minerals - Monitoring and Mitigation Measures. If
properly executed, these procedures should mitigate
potential subsidence or the potential for infiltration of
fugitive process solutions.
Landslides and Slope Stability
Landslides are a potential hazard in mountainous
terrain and could potentially damage any facility
located within the landslide pathway. Landslides can
also be induced by placing mine rock piles or heap-
leach facilities on potentially unstable slopes. Adverse
geologic structures and ground water conditions
encountered in the pit can result in failure of the pit
walls, endangering workers and facilities in the pit or
on the rim of the pit.
Based on concerns regarding slope stability in some
key areas of the project (USDA Forest Service 1994)
the Forest Service requested the U.S. Geological
Survey (USGS) Branch of Earthquake and Landslide
Hazards to perform a field reconnaissance and
review of geologic data to evaluate the potential risk
associated with the project from slope instability. In
the area of the Eder slope west of Powers Gulch, the
USGS observed little evidence of large-scale
landslide deposits, identifying only small rock-fall,
debris-flow, and possible debris-avalanche deposits
estimated to be relatively shallow (generally 0 to 15
feet thick, locally up to a maximum of 15 to 30 feet
thick) (Ellis and Baum 1995). In addition, no evidence
was found of large-scale block slides in the ridge area
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
between the Carlota/Cactus pit and the Cactus
Southwest mine rock disposal area. The rocks
appeared to be competent and maintaining steep
slopes. The USGS concluded that careful
investigation, design, and implementation practices
should prevent any potential problems from becoming
a serious threat to mining operations or to permanent
post-mining features, such as the pits, diversion
systems, or leach pad. Following the USGS study,
Carlota conducted a geological investigation that
included a subsurface investigation in the western
portion of Powers Gulch in the vicinity of the Eder pits
and Eder mine rock disposal area (Womack &
Associates 1996a). The results of this investigation
generally agreed with those of the USGS and
indicated that large-scale slumping or other forms of
landsliding have not occurred in this area. However,
an apparent shallow slip surface was observed in a
test trench located near the toe of the proposed Eder
mine rock disposal area that could potentially result in
instabilities in the Eder mine rock disposal area.
Therefore, mitigation is proposed in Section 3.2.4,
Geology and Minerals - Monitoring and Mitigation
Measures, for site-specific slope improvement
measures to be developed prior to construction.
The potential for landslides, slope failure in or
beneath the mine rock piles, or failure of the pit walls
has been evaluated by Call and Nicholas, Inc. (1992,
1993). Along an east-west section in the northern part
of the Main mine rock disposal area, the factor of
safety under the most favorable conditions was 1.13.
Assuming that less than ideal seismic and drainage
conditions are likely to exist during the life of the
project (including the reclamation phase), there may
be inadequate protection against mass failure in this
area. Small localized rock slides along the face of the
dumps and rock avalanche-type failures are not
uncommon on rock dumps. These types of failures
are generally unavoidable and could affect the
immediate area downslope from the dumps.
Slope stability problems in the Carlota/Cactus pit
could occur because of the presence of the basal ash
layer associated with the Apache Leap Tuff unit.
Additional drilling is necessary to determine the
continuity and orientation of the ash layer in the
northeastern segment of the pit. If the ash layer is
continuous and adversely oriented, it could create a
weak zone in the pit wall and could potentially cause
a slope stability problem. Although the risk appears to
be relatively low, a large failure in the north segment
of the pit wall could potentially damage the Pinto
Creek diversion channel. In any of the pits where the
rocks exhibit near-vertical fractures, rock toppling
could occur. Several proposed facilities are situated
within proximity to the final pit rim, including the SK-
EW plant, the stockpile and secondary crushing area,
and the mine shop/warehouse area. Depending on
the location and extent of slope failure, there is some
potential for future slope instability of the pit wall to
damage facilities.
Portions of the original pit walls would remain in the
Carlota/Cactus pit and the Eder North and Eder South
pits following project reclamation and closure. After
some period of weathering, it is likely that portions of
the pit walls would eventually experience some
degree of slope failure. Typical slope failures that
occur in steep rock cuts of this nature include rock
falls, toppling, and localized block slides. Mitigation
measures for postclosure pit wall instability are
addressed in Section 3.2. 4.2, Geology and Minerals -
Slope Stability.
Stability analyses were also conducted by Knight
Piesold and Company (1995a) on the proposed heap-
leach pad and the process solution ponds. Based on
these analyses, the leach pad and the pond
embankment designs were determined to be
structurally stable under static and seismic loading
conditions (Knight Piesold 1995a).
The proposed Powers Gulch diversion channel
traverses the lower portion of the western valley
slope that flanks Powers Gulch. Existing access
roads in the vicinity of the alignment suggest most
of the diversion would be constructed in intact
bedrock. However, the alignment crosses swale
areas and shallow ravines that are covered by slope
deposits. These slope deposits probably include
talus, colluvium, and shallow landslide deposits.
Since these deposits occur on a relatively gentle
slope, and appear to be relatively thin, major slope
stability problems along the alignment are not
anticipated. Although the risk appears low, there is
some potential for small failures (i.e., debris slides,
debris flows) to impact or damage the diversion
during operation and postclosure. Failure of the
diversion could damage the heap-leach pad. Impacts
from this type of failure are addressed in Section 3.3,
Water Resources.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Geology and Minerals
Debris flows are rapidly moving landslides initiated
after prolonged and intense rainfall in relatively steep
areas covered by granular soils. Debris flows typically
originate near the head of a steep ravine, travel down
the ravine channel, and are deposited where the
slope flattens or opens into a valley. Since the Pinto
Creek diversion is located in a relatively broad valley
with a moderate gradient, the risk of debris flows
impacting the diversion is considered to be low.
The water pipeline between the well field and the
processing facilities and the transmission line
traverse areas of bedrock exposure or shallow soils
over bedrock. Based on the known conditions,
significant landslide or slope stability problems are not
anticipated.
The proposed water supply access road from the Iron
Bridge to the well sites would follow along the lower
portion of the western side of the Pinto Creek valley.
Based on the available maps, the road would be
constructed on relatively steep sideslopes with
gradients that range from approximately 1 .5:1 to 2:1
(H:V). The road in this area would be located outside
and above the alluvial valley floor. Because of the
steep terrain, the road would require grading to cut
the bedrock slopes and to fill the swales and gullies.
The distance the cut and fill slopes would extend
upslope and downslope from the roadway would
depend on the design cutslope and fill slope angle.
Although there are no known landslides in this area,
there is always some risk of inducing slope failures
when cutting along the toe of a steep slope. In
addition, considering the steep terrain, both the cut
slopes and fill slopes would be susceptible to
accelerated erosion. Given the close proximity of the
road to Pinto Creek, it is likely that even with standard
erosion control measures in place, there may be
some increase in sedimentation into Pinto Creek from
the road construction. If the grading activity induced a
major slope failure (landslide), the failure could
contribute a large influx of material into Pinto Creek.
Seismicity
The Uniform Building Code places the site within
Seismic Zone 2, which corresponds to a 5.6 Richter
magnitude event and a maximum intensity of
VII. Based on the historic seismicity outlined in
Table 3-24, moderate seismic events could potentially
affect the site during the life of the project. Deforma-
tion analyses performed by Knight Piesold and
Company (1993b) on the leach pad and PLS ponds
concluded that during seismic shaking, significant
permanent deformation of the designed structures
would be highly unlikely. Design and construction
procedures for the mine facilities, heap-leach pad,
mine rock disposal areas, and mine pit slopes are
expected to adequately minimize the potential for
seismic damage or seismically induced slope stability
problems.
Blasting
Mining would be conducted using conventional bench
highwall techniques with benches created as part of
ore and mine rock extraction. Benches would be
drilled and shot with ammonium nitrate and fuel oil
(ANFO) as the blasting agent. A major concern with
blasting is the potential effects of ground vibration on
nearby residences. The Office of Surface Mining
Reclamation and Enforcement (OSMRE 1987) has
developed regulations designed to protect the general
public from the potential effects of blasting. These
regulations are based on extensive research
conducted by the U.S. Bureau of Mines (USBM) to
quantify ground vibration and air blasts and their
effects on structures. The potential impacts of
blasting-induced ground vibration to residential
structures in the vicinity of the Carlota Copper Project
were evaluated based on these regulations using (1)
the maximum charge weight per 8 millisecond delay
(provided by Carlota 1995f), (2) the minimum
distance between existing residential structures and
the blast point (scaled distance between the nearest
Top-of-the-World residence and the Eder South Pit),
and (3) calculated peak particle velocity and scaled-
distance factors as defined by OSMRE (1987). The
calculated peak particle velocity and scaled-distance
factors were then compared with the maximum
allowable peak particle velocity and scaled-distance
factors established by OSMRE to protect residential
structures.
The results of this evaluation are summarized in
Table 3-26. These results indicate that the maximum
charge weights and generated peak particle velocities
are below the maximum values allowed using either
the USBM criteria or OSMRE regulations. The USBM
criteria for peak particle velocity are sufficiently
conservative as “to provide essentially 100 percent
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
Table 3-26. Blasting Vibration Evaluation
Calculated
Values'
USBM
Criteria
^tUSBM1980)
OSMRE Maximumr
t Allowable Values ^
(OSMRE 1987) t
Explosive Weight Per
8 Millisecond Delay
3,660
—
5,831"
Peak Particle Velocity
(inches per second)
0.27"
0.5 to 2.0
1.0
'Based on blasting design information provided by Carlota assuming a maximum charge weight of 3,660
pounds per delay (915 pounds per blast hole multiplied by 4 blast holes) and a minimum distance of 4,200
feet between the Eder South Pit and Top-of-the- World.
^Estimated maximum horizontal particle velocity based on the minimum scaled distance between the Eder
South Pit and Top-of-the- World and a conservative two standard deviations from the mean regressions value
for measured vibrations at a large variety of sites (USBM 1980).
®Based on the recommended scaled distance factor of 55 (Page 23, OSMRE 1987) and scaled distance of
4,200 feet.
protection of such structures, regardless of repair”
(Siskind 1994). Since the maximum allowable criteria
established by the USBM and OSMRE would not be
exceeded and were established to protect residential
structures, blasting as proposed by Carlota is not
anticipated to result in damage to structures or
property in the vicinity of the project.
Research conducted by the USBM (Siskind and Kopp
1987), which included monitoring numerous
residential wells near blasting sites, concluded that no
significant impacts to water wells were observed from
vibration levels at or below the levels established to
protect residential structures (Siskind 1994). Based
on the proposed blasting design, no adverse impacts
to water wells from blasting are anticipated.
3.2.2.2 Alternatives
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. The
alternative Cactus South and Cactus Central mine
rock disposal areas would increase the total disturbed
area of the project by approximately 44 acres. Since
there are no known mineral deposits in the footprint
area of these alternative mine rock disposal sites, this
alternative would have no impact on the mineral
resource. In addition, there are no known geologic
hazards, such as landslides, in the vicinity of these
alternative mine rock and disposal sites.
Additional Backfill of the Carlota/Cactus Pit. The
placement of backfill in the Carlota/Cactus pit to the
approximately 3,520 ft-amsi elevation of Pinto Creek
would decrease the overall slope height and thereby
increase the long-term stability of the pit walls. The
backfill would also eliminate the potential for a failure
of the north margin of the pit wall to adversely affect
the Pinto Creek diversion channel.
Approximately 14 million tons of mineral resource
(greater than 0.15 percent copper) would remain
beneath the floor of the western and central portion of
the pit after mining ceases. Since the market for
copper is volatile, there is some possibility that this
remaining mineralization may become economically
viable in the future. However, by placing the
additional backfill into the pit, these mineral reserves
would be essentially rendered uneconomic to recover
in the future.
Additional Backfill of the Eder South Pit. Decreas-
ing the overall slope height in the Eder South pit from
710 to 570 feet by placing additional backfill would
tend to incrementally increase the long-term stability
of the pit wall. However, slope failures may still occur
over time because of the weathering of the over-
steepened bedrock. Use of the material from the Eder
mine rock disposal area for both backfill and capping
material for the heap leach pad at closure would
remove all of the material in the disposal area.
Removal of the disposal area would increase long-
Carlota Copper Project Final EIS
3-55
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
term stability of the Eder slope and Powers Gulch
areas and reduce threats to the diversion system and
leach pad. Approximately 25 million tons of mineral
resource (greater than 0.15 percent copper) would
remain at the conclusion of mining. Since the
remainder of the mineral reserve is located at a
greater depth in a southwest direction from the pits,
the location of the additional backfill should not inhibit
any future attempt to recover these deposits.
Leach Pad Alternative
Eder Side-Hill Leach Pad Alternative. A portion of
the alternative heap-leach site is located on an east-
facing slope that descends from below the ridge that
hosts the Eder ore deposits to Powers Gulch. The
slope has an approximate average gradient of 3:1
(H:V). As shown on the geologic map {Figure 3-3),
large portions of this slope area are covered by slope
deposits that include talus, colluvium, and possibly
small, localized landslide deposits. Exploration roads
constructed in this area have typically encountered
bedrock at shallow depths. The subsurface conditions
inferred from condemnation drill holes, monitor wells,
and geotechnical boreholes and test pits completed in
this area indicate that these slope deposits are up to
20 to 30 feet thick. Some of these deeper slope
deposits may include intact weathered bedrock.
Present data indicate that there is no subsurface
evidence to support the existence of any large or
deep-seated landslides in the vicinity of the
alternative heap-leach site; however, evidence does
indicate the possibility that there may be smaller
isolated landslide deposits within the slope deposit
material. Depending on the location and physical
characteristics of these materials, they could
potentially pose a risk to the short- and long-term
stability of this alternative heap-leach site.
The overall slope stability of the side-hill leach
pad alternative is marginal and requires special
features, such as a large toe berm (ranging from
approximately 40 to 50 feet in height), to maintain a
minimum factor of safety. Knight Piesold and
Company’s (Carlota 1994b) preliminary analyses
indicate the minimum factors of safety for this
scenario were 1 .3 for static and 1 .0 for pseudostatic.
These factors of safety are less than the minimum
factors of safety (1.5 static and 1.1 pseudostatic)
used for dam design. Based on both the uncertainty
regarding the subsurface conditions underlying the
alternative site, and relatively low factors of safety for
the design, there appears to be some risk regarding
the short- and long-term stability of this heap-leach
alternative. As a result, there appears to be a greater
risk of slope failure impacting the heap during both
operation and closure for this alternative compared to
the proposed heap-leach location.
Water Supply Alternative
Low-Quality Water, Water Supply Wells, and
Dewatering Wells. This alternative would require the
construction and maintenance of several miles of
pipeline through mountainous terrain. The engi-
neering geologic and geotechnical conditions have
not been assessed along the pipeline alignment. For
any pipeline traversing moderately steep slopes, the
potential exists for the pipeline to be damaged by land
slides or rockfall. These risks could be reduced by
adjusting the alignment during final design based on
the results of engineering geologic analysis.
Alternative Water Supply Well Field Access
Roads
A summary of the potential impacts of the well field
access road alternatives is presented in Table 3-27
and is discussed below. Evaluations listed in Table
3-27 would reflect potential conditions until BMPs are
implemented.
Access Road Alternative A. This alternative access
would restrict the amount of new disturbance to the
alluvium in the valley floor of Pinto Creek. Sections of
this access road would flood and become inaccess-
ible during periods of high flow in Pinto Creek. The
flooding and movement of coarse material down the
drainage could require periodic regrading and road
maintenance. Disturbed soils could be susceptible to
erosion and could cause increased sedimentation in
Pinto Creek. These potential effects would be mini-
mized by implementation of adequate road drainage
and erosion and sedimentation controls similar to
those described in the proposed action.
Access Road Alternative B. This alternative
access road alignment would require the construction
of a new road from existing Forest Service Road
287A down a moderate gradient along the Fifty
Dollar Spring drainage to the existing well field access
road.
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
Table 3-27. Potential Geologic Considerations Associated with the Well Field Access Road
Alternatives
Proposed
Alternative A
l*:Altematlve:B;-'^''9''
Slopes
steep
gentle
moderate
Cuts and Fills Required
many
few, if any
some
Estimated Risk of Induced Slope
Instability (landslides)
moderate to
high
low
low to moderate
Potential for Accelerated Erosion'
high
moderate
low to moderate
Potential for Increased
Sedimentation in Pinto Creek'
high
moderate to high
moderate
Potential for Damage during
Flooding'
low
very high (probably
unavoidable)
low to moderate
’The potential for significant impacts from these considerations would be minimized
by erosion and sedimentation
controls and implementation of the Storm Water Protection Plan to which Carlota is
committed as part of the proposed action. The relative level of involvement necessary to implement
such measures on the alternatives may be inferred from this table.
Based on the map presented in Figure 2-19, the
alignment should require only minor cuts and fills.
Since the amount of hillside grading would be limited,
the risk of induced slope failure would be low. Without
BMPs to control erosion, sedimentation, and
drainage, the amount of erosion and sediment yield
could be anticipated to increase because the road
would disturb the soil and bedrock within or
immediately adjacent to the stream channel.
However, similar to the proposed action, road
drainage features and erosion and sedimentation
controls would be implemented to minimize the
potential for these effects.
No Action Alternative
The no action alternative would eliminate the recovery
of approximately 900 million pounds of copper. The
proposed action indicates a 20-year mine life and an
average yearly production of approximately 60 million
pounds of copper. This production rate represents
approximately 1 percent of the current annual copper
consumption in the United States, based on statistics
provided by the U.S. Bureau of Mines (Edelstein
1994). The mineral resource would still be available
for future mining.
3.2.3 Cumulative Impacts
Surface mining activity affects the geology and
mineral resources through excavating, modifying, or
covering natural topographic and geomorphic
features and by removing mineral deposits. The study
area for the cumulative impact analysis for geology
and mineral resources was restricted to the Globe-
Miami-Superior mineral belt. The existence of
disturbed mining areas within the mineral belt was
determined by interpreting recent black and white
aerial photographs. The boundary of each identified
disturbed area was planimetered to determine the
affected acreages.
Mining disturbance has included open-pit and
underground mining, waste rock disposal, heap
leaching, ore milling and processing, tailings disposal,
and exploration (road construction, drill pads, and
bulk sample areas). Mining projects within the study
area include BHP Copper’s Pinto Valley Mine, Old
Carlota Mine, Gibson Underground Mine, Copper
Cities Mine, Miami Unit, Cyprus Miami Mine, Ray
Mine, and Superior BHP Copper’s Underground Mine.
The location of the disturbed mining areas and the
corresponding estimated acreages of disturbed land
are presented in Figure 1-3. The estimated
cumulative area affected by past mining activity
includes 59 identified disturbed sites and a total of
approximately 16,525 acres.
The project would create approximately 1,428 acres
of additional disturbance. Assuming that acreages
of past disturbance are reasonable estimates,
implementation of the proposed action would increase
the total disturbed acreage in the mining district by
approximately 8 percent. Because copper mining is a
major activity in the district, it is reasonable to
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Geology and Minerals
assume that large-scale mining will continue and will
result in the creation or expansion of other open pits,
mine rock disposal areas, heap-leach pads, and
tailings facilities in the foreseeable future. Considering
the current level of activity in the district, it is reason-
ably foreseeable that in addition to the proposed
Carlota and other projects, the district could expand
the acreage of disturbance by another 5 to 10 percent
in the next decade.
3.2.4 Monitoring and Mitigation
Measures
Potential impacts to geology and minerals would be
minimized by the following mitigation measures.
These measures apply to the proposed action and,
where noted, to specific alternatives.
3.2.4. 1 Ground Subsidence
GM-1: The following mitigations for abandonment of
shafts, adits, and other workings are intended to
supplement the measures provided by Carlota
(1994a) and incorporated into the proposed action:
(1 ) All wood, garbage, or other debris or loose
material would be removed from the
openings prior to backfilling.
(2) All rock backfill for shafts would consist of
large rocks at least 1 foot across their
largest dimension.
(3) A grout or cement that is designed to
function or exist in an acidic environment
would be used for all mass concrete work
to fill openings within the footprint of the
leach pad.
GM-2: All existing drill holes (exploration,
geotechnical, monitoring, etc.) within the leach pad
footprint would be plugged and abandoned with grout
or cement that is designed to function or exist in an
acidic environment. Well abandonment would be in
accordance with all applicable Arizona regulations.
3.2.4.2 Slope Stability
GM-3: Potential slope stability problems in the
Carlota/Cactus pit and the Eder pits would be
effectively mitigated by the recommendations
proposed by Call and Nicholas, Inc. (1993) and the
USGS (1995). These recommendations include (1)
engineering geologic mapping as mining progresses
to identify any potentially adverse geologic conditions
in the pit walls, (2) rock-coring to further define the
existence and orientation of the basal ash layer or
other potential failure planes that may be suspected,
(3) slope dewatering, (4) slope monitoring to detect
initial signs of instability, and (5) contingency planning
to anticipate or react to potential slope instabilities.
Options to preclude impacts to facilities from future pit
slope failures include modifying the final pit rim
location or adjusting a facility location to provide an
adequate setback distance. If potentially adverse
geologic conditions are exposed in the pit wall as
mining progresses, the final setback distance of any
potentially affected facility would be modified as
necessary to reduce the potential for damage.
At closure, the stability of the pit walls would be
assessed from operational information, and berms
and fences would be placed beyond the projected
limits of any potential mass failures. Monitoring for
such occurrences would continue for a number of
years after closure. The length of monitoring would be
determined by the Forest Service and other agencies,
as appropriate. If additional geologic or geotechnical
investigations related to pit wall stability are
determined to be necessary during operations or the
postclosure monitoring period, they would be
conducted according to appropriate agency
recommendations.
GM-4: Road design and alignment for the water
supply access road would be approved by the Forest
Service. The potential for induced slope instability and
increased erosion resulting from project construction
can be effectively reduced by designing the road
based on the results of a geotechnical investigation to
determine existing slope conditions and appropriate
grading design and erosion control measures.
Erosion could be effectively minimized by building the
portion of road that traverses the hillslope entirely in
cut bedrock and hauling generated fill material to
relatively flat areas where the material would not be
subjected to accelerated erosion.
GM-5: Site-specific mitigation measures for potential
slope stability problems associated with the Powers
Gulch diversion and embankment, Eder mine rock
disposal area Eder side-hill leach pad alternative, and
3-58
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
low-quality water pipeline associated with the low
quality water supply alternative would depend upon
the actual geologic and slope conditions and
development plans in specific areas. The site-specific
mitigation measures would be developed after a
thorough (design-level) geotechnical investigation and
analysis of the slope conditions. Appropriate design
and slope improvement measures would be deve-
loped as needed to minimize the potential for slope
failure during operation and postclosure. If other pre-
ferred closure technologies for the heap leach pad
are identified during the life of the project which do
not require the use material from the Eder mine rock
disposal area for a water balance cover, all remaining
material in the Eder mine rock disposal area will still
be removed and placed on the heap leach pad or
other areas for revegetation purposes. Final design of
the Powers Gulch diversion, Eder mine rock disposal
area, Eder side-hill leach pad alternative, and low-
quality water pipeline would be approved by the
Forest Service.
GM-6: There may be some potential for unstable
slope conditions to develop during seismic loading or
if local saturated conditions develop in any of the
mine rock disposal areas (Proposed Action and
alternative mine rock disposal sites). Therefore, the
final design for the mine rock areas would be
approved by the Forest Service. The approval would
depend on demonstration, through geotechnical
analysis, that the mine rock facilities would be stable
during both the operational and postclosure periods.
Geotechnical considerations to be addressed include
foundation stability and stability of the mine rock
facilities under static, seismic loading, and local
saturation conditions. Other issues to be considered
for the final design that could affect stability include
long-term drainage and erosion control.
Carlota Copper Project Final EIS
3-59
3.0 Affected Environment and Environmental Consequences - Geology and Minerals
3-60
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
3.3 Water Resources
3.3.1 Affected Environment
3.3.1. 1 Hydrometeorology
Precipitation
elevation. Data for Miami, Arizona, and the Pinto
Valley Mine comprise the most recent and complete
precipitation records for the area {Table 3-28). From
1973 through 1995, the Pinto Valley Mine, at an
elevation of 4,000 ft-amsi, averaged approximately
23.8 inches of precipitation annually {Tables 3-28 and
3-29).
The proposed project is located in the Central
Highland physiographic province of Arizona, in a
transition zone between the forested plateaus to the
north and east and the arid desert to the southwest.
Significant precipitation variations occur over short
distances because of the effects of mountainous
topography (GWRC 1994). The regional climate is
characterized by semiarid conditions with two seasons
of maximum precipitation. Most warm-season rainfall
occurs during July and August, usually as intense,
short-duration thunderstorms over a limited area.
Winter precipitation occurs primarily during December,
January, February, and March. Winter precipitation is
typically gentler, more widespread, and of longer
duration than summer rainfall. From year to year, cool-
season precipitation is considerably more variable
than that of the warm season. High accumulations of
precipitation may occur over several days during the
winter months (Sellers and Hill 1974). In any given
year, the total amount of precipitation may differ
considerably from the long-term average {Figure 3-6).
Records indicate that mean annual precipitation varies
from locale to locale and typically increases with
Table 3-28. Average Monthly and Annual
Precipitation for Miami and Pinto
Valley Mine
Pmcipitation Means (i
nchesV ^
Month *
f Miami ^
Pinto Valley
January
2.52
2.92
February
2.16
2.59
March
2.57
3.04
April
0.58
0.69
May
0.54
0.72
June
0.23
0.21
July
2.32
2.60
August
2.72
3.14
September
1.69
1.92
October
1.40
1.57
November
1.67
1.87
December
2.13
2.52
Total
20.56
23.81
’Monthly means from 1973-1995
Source: Earthinfo, Inc. (1996) and GWRC (1994, 1995b,
1996)
Table 3-29. Pinto Valley Mine Annual Precipitation Data
YMr
A Annual Precipitation i
> Annual Precipitation
' (irtches)
1973
17.95
1985
30.36
1974
18.79
1986
29.94
1975
16.75
1987
13.62
1976
17.85
1988
15.28
1977
13.23
1989
10.15
1978
38.73
1990
20.24
1979
21.27
1991
23.71
1980
20.70
1992
30.92
1981
23.67
1993
30.44
1982
35.31
1994
19.69
1983
41.24
1995
17.71
1984
40.15
Average annual precipitation = 23.81 inches
Source: GWRC (1994, 1995b, 1996)
Carlota Copper Project Final EIS
3-61
D:\A210\CDR\FIG3-6.CDR REVISION: 2/13/97
3.0 Affected Environment and Environmental Consequences - Water Resources
Miami, at 3,560 ft-amsl, had an annual mean of
approximately 20.6 inches of precipitation for the same
period (Earthinfo, Inc. 1996, GWRC 1994, 1995b,
1996). The weather station at the Pinto Valley Mine is
located within approximately 2 miles of the project
area and is probably the most representative of project
area conditions (GWRC 1994). Regionally, the total
annual precipitation varies widely between given
years, as shown in Figure 3-6. This is typical of arid
and semiarid environments. For example, at Miami the
recorded total annual precipitation ranges from
approximately 12.9 to 36.4 inches. At the Pinto Valley
Mine, the recorded range is approximately 10.2 to 41.2
inches. Total annual precipitation at the project area
probably varies similarly to the Pinto Valley Mine site.
Temperature
The temperature station at Miami is the closest known
long-term recording station to the site. Temperature
data for Miami indicate a mean daily maximum of 55°F
and a mean daily minimum of 32.7°F for January. For
Miami during July, the mean daily maximum is
97°F, and the mean daily minimum is 70.3°F
{Table 3-30). The freeze-free period (32°F) is typically
from March 22 through November 22, and the period
between killing frosts (28°F) is typically February 12
through December 9 (Sellers and Hill 1974). The
location of this station may reasonably represent
long-term temperature and frost-free conditions in the
region. Since portions of the project site are at a
slightly higher elevation, temperatures in the project
area itself may be cooler, with shorter frost-free
seasons. Additional regional and site-specific
temperature information is presented in Section 3.1,
Air Resources.
Evaporation
National Weather Service (NWS) information (NOAA
1982) indicates free water surface evaporation in the
project locale is estimated to average approximately
65 inches per year. This figure closely represents the
potential evaporation from a shallow lake, watered
vegetation, or very wet soil. Monthly estimates of
evaporation rates are shown for the Pinto Valley area
in Table 3-31 (GWRC 1994). These figures total 66.65
inches per year and are in close agreement with NWS
estimates.
3.3.1. 2 Surface Water
General Watershed Characteristics
Three major drainages, Pinto Creek, Powers Gulch,
and Haunted Canyon, occur in the project area. The
Powers Gulch and Haunted Canyon subwatersheds
form part of the overall Pinto Creek watershed. Pinto
Creek drains into Roosevelt Lake (located on the Salt
River) approximately 18 miles downstream from the
project area. The watershed, major subwatersheds,
and streamcourses are shown in Figure 3-7. The
proposed mining operation is located in the upper
portion of the overall Pinto Creek watershed.
Upstream of the project area, the watershed extends
in a southeasterly direction up to the ponderosa pine
Table 3-30, Temperature Data for Miami
—I
Temperatun
■isft •
Maximuii^
»{°F) Means e-
BaSy
Minimum
. ^
Monthly
January
55.0
32.7
43.9
February
60.4
35.4
47.9
March
65.1
39.5
52.3
April
74.7
47.3
61.0
May
84.5
55.7
70.1
June
93.7
64.2
79.0
July
97.0
70.3
83.7
August
93.9
67.9
80.9
September
89.7
62.9
76.3
October
78.8
52.0
65.4
November
65.4
40.5
53.0
December
56.6
34.2
45.4
Source: Sellers and Hill (1974)
Carlota Copper Project Final EIS
3-63
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-31. Estimated Monthly Evaporation Rates
for Pinto Valley Area
Average Monthly Evaporation ^
.1 Month
r Rate (Inches) V
January
2.03
February
2.85
March
4.60
April
6.07
May
8.30
June
9.12
July
9.11
August
8.29
September
6.36
October
4.88
November
3.03
December
2.01
Average annual evaporation = 66.65 inches
Source: GWRC (1994)
Table 3-32. Summary of Pinto Creek Basin Contributing Subwatershed Areas'
Pinto Creek SubwaitHahed
I : Area
V Square Miles
4cre$
Incremental Mean
Discharge^
Powers Gulch
5.5
3,520
769
Haunted Canyon
12.3
7,872
1,719
West Fork of Pinto Creek
27.2
17,408
3,801
Horrell Creek
11.8
7,552
1,649
Willow Spring Creek
5.0
3,200
699
Pinto Valley
20.1
12,864
2,809
Upper Pinto Creek
15.1
9,664
2,110
Lower Pinto Creek
78.4
50,176
N/A^
Existing Non-Contributing Mining
Operation Area
2.8
1,792
0
TOTALS
178.2
114,048
N/A^
For locations, see Figure 3-7.
^In acre feet/year per subwatershed as a general estimate; actual values may vary from those
shown. Values are derived from a relationship explained under “Mean Annual Runoff.”
^No gaging data are available below the Pinto Valley weir.
zone in the Pinal Mountains. Runoff through the
project area is affected by upstream contributions as
well as by conditions in the project area itself. The
overall area of the Pinto Creek watershed (178.2
square miles) can be divided into several smaller
drainages. The area for each contributing
subwatershed is summarized in Table 3-32.
Approximately 2.8 square miles of area within the
overall watershed are occupied by existing mining
operations that totally contain precipitation falling
within that area and do not contribute to surface runoff.
Several major tributaries to Pinto Creek occur
downstream from the proposed mine facilities. These
tributaries provide a significant source of water to
Pinto Creek, both in the form of surface flow and
ground water recharge to alluvium. These tributaries,
as shown in Figure 3-7, include Haunted Canyon, the
West Fork of Pinto Creek, and Horrell Creek.
The Pinto Creek watershed is mountainous, with
steeper, more rugged topography in the project area
transitioning to flatter, less rugged terrain nearer the
Salt River. Surface conditions in the project area are
dominated by dense interior chaparral, which
comprises approximately half of the vegetative cover
in the area. Approximately 1 5 percent of the project
area vegetation is made up of rubbleland chaparral,
which is similar in species composition to the interior
3-64
Carlota Copper Project Final EIS
:? If . rS.
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m&'X
•JOooA_J4ig^f
VA Si' ^
/^ i !&?’■'
(<Ciy
(nQ-O^-;
Qj'liA''
CARLOTA COPPER PROJECT
Figure 3-7
Pinto Creek Basin
Watershed Areas
jit>>v>>,»' j;-
3.0 Affected Environment and Environmental Consequences - Water Resources
chaparral type but includes significant areas of rock
outcrops and boulder fields.
Approximately 25 percent of the vegetation in the
project area is made up of dry slope desert brush,
which typically occurs on dry, south-facing slopes.
Smaller percentages of the vegetation in the project
area and surrounding region are made up of juniper-
grassland and riparian types. Further descriptions of
vegetation in the region are presented in Section 3.5,
Biological Resources.
Within the project area and surrounding region, large
nonvegetated areas are covered with rock as outcrops
or as individual particles ranging from gravels to
boulders. Finer-grained soils complete the remainder
of the watershed surface and are typically shallow
over bedrock (Cedar Creek Associates, Inc. 1994).
Soils in the project area typically are in Hydrologic Soil
Group D (high runoff potential). High rates of runoff
occur on these soils primarily because of their
shallowness over bedrock. Deeper soils occur in
isolated areas along toeslopes and in alluvial valleys.
Soils in these small areas are in Hydrologic Soil
Groups A and B (low to moderate runoff potential). For
the overall watershed, total erosion rates are limited by
large areas of dense vegetation, rock outcrops and
other erosion-resistant surfaces.
Channel gradients along Pinto Creek are 80 to 120
feet per mile in the proposed pit area and approx-
imately 50 feet per mile downstream near the
confluence with Haunted Canyon. Farther down-
stream, near the confluence with Horrell Creek, the
gradient is approximately 35 feet per mile. Short
reaches of steeper or flatter gradients exist along the
streamcourse.
Being in close proximity to Pinto Creek, the Powers
Gulch and Haunted Canyon watersheds and channel
characteristics are similar. The channels are mountain
streams with relatively steep slopes and coarse bed
material. Channel morphology is often controlled by
exposed bedrock. Existing channel gradients in
Powers Gulch are approximately 225 feet per mile in
the vicinity of the proposed leach pad, and range from
approximately 530 feet per mile in the headwaters
south of the proposed leach pad to approximately 95
feet per mile at the confluence with Haunted Canyon.
The existing channel gradient in Haunted Canyon is
approximately 150 feet per mile upstream of Powers
Gulch, 130 feet per mile just below the confluence with
Powers Gulch, and approximately 50 feet per mile
at the confluence with Pinto Creek. Short reaches of
steeper or flatter gradients exist along these stream-
courses.
Streamflows. A stream gaging station known as the
Pinto Valley weir has operated for several years on
Pinto Creek, approximately 7.5 miles downstream of
the Carlota Copper Project (GWRC 1994). The
drainage area for Pinto Creek at the Pinto Valley weir
is composed of the following subwatersheds: Powers
Gulch, Haunted Canyon, the West Fork of Pinto
Creek, Horrell Creek, Willow Spring Creek, Upper
Pinto Creek, and Pinto Valley. The watershed gaged
by this station is approximately 97 square miles. The
Pinto Valley weir was established in the early 1980s
by Magma Copper Company. The USGS assumed
operating responsibility for this station in October
1994. Daily stream discharge records are available for
periods of several weeks or months, ranging from mid-
July 1985 through the present. These partial records
comprise the most recent, closest, and most
continuous discharge data for the Pinto Creek
watershed area.
Carlota Copper Company implemented a surface
water and ground water monitoring program in the
project area and nearby locale during 1992 and
1993 (Montgomery & Associates 1993; GWRC
1994). Surface water monitoring stations associated
with this program are shown in Figure 3-8. At locations
identified as M & A in Figure 3-8, discharge estimates
were made on a quarterly basis from May through
December 1992 by Montgomery & Associates. The
remaining stations were gaged approximately biweekly
by GWRC during April, May, June, August, and
October 1993 (GWRC 1994). Carlota has
subsequently continued to collect surface water data
at many of the sites established in the 1992-1993
program (GWRC 1995d, 1996b). In March 1996,
Carlota installed and began operating three
continuous-recording stream gaging stations on
Haunted Canyon (HC-2, HC-3, and HC-4).
Additionally, the USGS recently installed and began
operating a continuous-recording stream gaging
station on Pinto Creek (PC-7) downstream from the
Haunted Canyon confluence. A description of each
gaging station location, including information on
watershed areas contributing to each station, is
presented in Table 3-33.
Carlota Copper Project Final EIS
3-67
3-68
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-33. Gaging Station Descriptions
p
Isyuo'lt
-
Description
Approximate
Watershed ’
Area (square
miles)
Proportion of
Pinto Creek
above
PC-10’ .
Proportion of
above Roosevelt
PC-1
Pinto Creek above 005 Gulch
7.9
8.1%
4.5%
PC-2
Pinto Creek below 005 Gulch
10.0
10.3%
5.7%
PC-3
Pinto Creek above Carlota/Cactus pit
11.0
1 1 .3%
6.3%
PC-4
Pinto Creek below Cactus well 126
14.0
14.4%
8.0%
PC-5
Pinto Creek below BHP Copper domestic
well 37
14.8
15.3%
8.5%
PC-6
Pinto Creek above Haunted Canyon
15.1
15.6%
8.6%
PG-1
Powers Gulch above proposed leach pad
0.6
0.6%
0.3%
PG-2
Powers Gulch @ well cluster PG-2/PG-2A
1.9
2.0%
1.1%
PG-3
Powers Gulch @ west end of Kelly fault
5.0
5.2%
2.9%
PG-4
Powers Gulch above confluence with
Haunted Canyon
5.5
5.7%
3.1%
HC-1
Haunted Canyon above Powers Gulch
11.4
1 1 .8%
6.5%
HC-2
Haunted Canyon below Powers Gulch
17.1
17.6%
9.8%
HC-3
Haunted Canyon between Powers Gulch and
Pinto Creek
17.2
17.7%
9.8%
HC-4
Haunted Canyon above confluence with Pinto
Creek
17.6
18.1%
10.1%
PC-7
Pinto Creek below Haunted Canyon
34.3
35.4%
19.6%
PC-8
Pinto Creek above W. Pinto Creek
47.6
49.1%
27.2%
PC-9
Pinto Creek below Horrell Creek
94.2
97.1%
53.8%
PC-10
Pinto Creek @ BHP Copper Weir
97.0
100%
55.4%
L-1
Limited station between PC-2 and PC-3
10.1
10.4%
5.8%
L-2
Limited station on Powers Gulch near monitor
well PG-5
1.6
1 .6%
0.9%
L-3
Limited station on Powers Gulch west of
proposed mine rock disposal area
13.9
14.3%
7.9%
'The contributing Pinto Creek watershed area above PC-10 (Pinto Valley Weir) is approximately 97 square miles.
^The contributing Pinto Creek watershed area above Roosevelt Lake is approximately 175 square miles.
Although the baseline monitoring program has been
relatively limited in duration and does not approach
the historical range of flow conditions, it enables
some general inferences about the nature of flows in
the watershed. Data from the Pinto Valley Mine
precipitation station for 1992 indicate that total annual
precipitation levels were approximately 28 percent
higher than the 20-year historical average at that
station, and approximately 37 percent higher than the
20-year historical average at Miami, Arizona. As a
result, the initial monitoring program generally reflects
surface runoff conditions higher than typical for the
site.
The spatial and temporal distribution of streamflows
during the monitoring period is presented in Table
3-34. The major source of the perennial baseflow at
the Pinto Valley weir is near-surface ground water
flow surfacing from alluvial deposits. On the basis of
site investigations during years of above-average
Carlota Copper Project Final EIS
3-69
3.0 Affected Environment and Environmental Consequences - Water Resources
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3-70
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
precipitation and recent site investigations during a
period of below-average precipitation (fall 1995
through fall 1996), Pinto Creek is intermittent over
much of its course above the Pinto Valley weir
{Figure 3-7).
In general, reaches of Pinto Creek having perennial
flow during the monitoring program were associated
with bedrock-lined channel conditions (GWRC 1994).
This is the case for the stream reach at station PC-4,
the portions of the reach between stations PC-5 and
PC-6, and the stream reach at station PC-7, all
locations where the creek is generally incised into
bedrock. High specific conductivities in surface water
samples may indicate that a percentage of the low
flow in the reach between PC-5 and PC-6 originates
from existing tailings pond seepage from the adjacent
Pinto Valley Mine.
Most tributaries to Pinto Creek within the project
study area are intermittent; on-site observations of
the smaller tributaries indicate that most are
ephemeral, flowing only in direct response to precipi-
tation events. Cottonwood Gulch was noted to carry
surface flows during part of the year (Cedar Creek
Associates, Inc. 1993c). In addition, the 005 Gulch
tributary exhibited flow throughout the monitoring
program {Table 3-35), but this location is an NPDES
discharge point for the existing Pinto Valley Mine.
Ephemeral surface flow was observed in Gold Gulch.
Flows in Powers Gulch are intermittent. The only
significant tributary flow to Powers Gulch originates
from Mule Spring. This spring did not go dry during
the monitoring period, but flows were less than 0.002
cfs (1 gpm) by late June {Table 3-35).
Flows in Haunted Canyon were intermittent above the
Powers Gulch confluence and perennial over most of
its length from below Powers Gulch to its confluence
with Pinto Creek. Streamflow, ground water, and
water quality data collected in Haunted Canyon
suggest that perennial reaches are sustained during
baseflow periods by the discharge of ground water
from the confined bedrock system into the alluvium
and the stream.
Ponds. Small ponds occur as man-caused features
at the Yo Tambien Mine in the southeastern part of
the project area and at a stock pond in the northern
part of the project area, as shown in Figure 3-9
(Cedar Creek Associates, Inc. 1993b). The volume
and surface area of these ponds fluctuate seasonally.
Typically, the pool at Yo Tambien is less than 0.05
acre in size, and the stock pond ranges from dry
conditions to a pool size of approximately 0.3 acre.
Mean Annual Runoff
An extrapolation of site-specific rainfall and runoff
data was used to estimate mean annual runoff for the
project area. Although errors may be introduced by
extrapolating relationships based on this short period
of record, these data are the most accurate
information available for the project area, and are
useful for comparative purposes in impact analysis.
The impact analysis considered daily flow data for the
Pinto Valley weir (approximately 200 feet downstream
of PC-10, Figure 3-8) and annual precipitation
records for the Pinto Valley rain gage as collected by
Magma Copper Company. A statistical relationship
based on linear regression (R'=0. 99998) was
developed between precipitation and streamflow for
the Pinto Valley gages {Figure 3-10). The period used
to estimate this relationship included both wet and dry
years, and provided a basis for comparisons using
data collected in the vicinity. The mean annual
discharge at the Pinto Valley weir, as calculated by
this method, was approximately 13,570 acre-feet from
1973 through 1995 {Table 3-36). The available data
indicate that the average annual areal runoff per
square mile from the watersheds above the Pinto
Valley weir is approximately 2.62 inches per year for
the 23-year period of precipitation recorded. This
estimate is intended for comparative purposes. The
actual annual yield will vary from this estimate
according to the accuracy of the extrapolated
precipitation runoff relationship and specific
precipitation and watershed characteristics. The
estimated mean annual discharges for key Pinto
Creek subwatersheds are shown in Table 3-32.
As shown in Figure 3-11, little precipitation runs off to
become streamflow. Precipitation contributions to flow
are greatest in the winter and early spring. Over the
examined historical record, relatively heavy
precipitation contributed to mean annual flow peaks
ranging from 23 cfs to approximately 3,230 cfs.
Runoff and streamflows decrease quickly as
precipitation declines in late spring. Throughout the
summer and fall, the effects of high evapo-
transpiration and soil moisture deficits can be seen in
Carlota Copper Project Final EIS
3-71
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-35. Instantaneous Flow Measurements at 005 Gulch, Miller Spring, and
Mule Spring
Date
005 Gulch
Miller Spring @
Pinto Creek
Mule Spring
SPm
cfs
Qm
cfs
gpm
cfs
1993
Apr. 27
110
0.243
12
0.027
May 07
6.8
0.0152
130
0.285
12
0.027
May 17-19
18.9
0.0422
68
0.152
6.8
0.0152
Jun. 02-04
4.8
0.0106
32
0.0713
6.8
0.0152
Jun. 16-18
4.8
0.0106
31
0.0688
4.8
0.0106
Jun. 28-30
0.0
0.005
0.0
0
0.41
0.000918
Aug. 03-04
0.7
0.00163
7.2
0.016
0.73
0.00163
Oct. 28-29
17
0.0368
17
0.0372
Nov. 30
0.0
0
8.1
0.018
1994
Jan. 09
37
0.0827
0.0
0
7.3
0.0163
Feb. 21
0.0
0
190
0.422
Mar. 22
92
0.204
0.0
0
97
0.217
Apr. 12-14
27
0.0608
0.0
0
8.1
0.018
May 13-21
3.1
0.0068
0.0
0
13
0.0291
Jun. 14-21
0.0
0
0.0
0
4.4
0.0098
Jul. 14
0.0
0
8.0
0.0179
Aug. 09
0.0
0
0.0
0
1.0
~ 0.002228
Sep. 14-15
7.7
0.0172
81
0.18
5.5
0.0123
Oct. 24
6.6
0.0147
0.0
0
5.4
0.012
Nov. 21-22
9.3
0.0207
0.0
0
1.8
0.004
Dec. 27-28
120
0.27
110
0.25
900
2.00
1995
Jan. 09
Feb. 01-02
560
1.24
170
0.37
230
0.52
Feb. 27-01
350
0.78
130
0.29
110
0.24
Mar. 28-29
67
0.15
99
0.22
45
0.10
Apr. 27-28
43
0.0949
81
0.18
4.5
0.01
May 31-02
6.8
0.0152
27
0.06
4.8
0.0106
Jun. 26-31
1.0
~ 0.002228
0.0
0
2.0
~ 0.004456
Jul. 14-26
0.0
0
0.0
0
5.0
~ 0.01114
Aug. 28-30
4.6
0.0102
0.0
0
0.40
0.0009
Sep. 25-26
0.99
0.0022
0.0
0
2.0
0.0044
Oct. 24
9.0
0.02
0.0
0
1.5
0.0033
Nov. 29
4.6
0.0102
0.0
0
6.0
0.0133
Dec. 27-28
3.4
0.0075
0.0
0
6.0
0.0133
~ indicates the measured flow was approximated.
Source; GWRC 1996b
3-72
Carlota Copper Project Final EIS
IJdb COON SPRING
V, STOCK PONO
\ #31660 CDX-4
,3666 GRIZZLY BEAR SPRING NORTH
3666 GRIZZLY BEAR SPRINGl
3l6dd DOMESTIC |2
316dc MIUER SPRING fZ
SSdd SPRING
I 36coO^
^ SPRING (
36d6 CACTUS 126
35eo MULE SPRING0^
• 32ed6 MILLER SPRING |3
^ 036dd CACTUS ADIT SPRING
y '-'N «3ibde MILLER SPRING #2
.06a6 1. 2.3.4 O .
0166 EDER-NORTH AOlf>
06o6 YO TAMBIEN ADIT and PONO
• 02dco
04ee COYOTE
12o6 SPRING
Top-of-the-World
PRIVATE WELLS !
(Sae Notes) I
D:\A2 HMN»gt21l>il»SPG.I>WC
IlSdec PEAK 26
«
\'o
• 23ood PEAK 29
j 22od FIFTY DOLLAR SPRING
236c SEEPp.,. 0'
(?^36e SEEP 23oo f3 SEEP CAISSON
/ \
\
o\
EiH
ME
Legend
Proposed Pit
•
Active Water Supply Well
O'
\j
Mine Rock Area
O
Inactive Water Supply Well
Leach Pad
?
Spring
Diversion Channel
©
Carlota Water Supply Wells
County Line
□
Stock Pond
I jQ23d6 SEEP
N
Top-of-the-Worid Boundary
— ~ Stream
•'*'V
2560 PV-SX V
\
Notes: (1 ) As presented in the well and spring inventory table,
the AOVI/R records Indicate that 83 private wells are
located within the Top-of-the-World area. Wells within
the Top-of-the-World area are too numerous to be
accurately shown on this map. (2) Carlota monitoring
. wells are also not shown on this map.
TIN
TiS
25co SEEP "V
25d6c PEAK 37
V#2Sde |1 SEEP CAISSON
30ccc DOMESTIC |1 •
30dd SHOPJJTE #1
• • 30ddc SHOP SITE #2
INVENTORY
BOUNDARY
Seal* in F««t
0 1000 2000
Riverside Technology, inc.
CARLOTA COPPER
PROJECT
Figure 3-9
Well, Spring, and Pond
Inventory Map
3-73
D \A210\CDR\FIG3-10 CDR REVISION: 11/19/96
(y-oe) 96jbl|os!q lenuuv
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-10
Relationship Between 1986 - 1989
Annual Precipitation at Pinto
Valley Rain Gage and Discharge
at Pinto Valiev Weir
3-74
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-36. Estimates of 1973 - 1995 Annual Discharges at Pinto Valley Weir
Vpnr
(Inches)
Annual Discharge
Annual Discharge
(acre-feet)
1973
17.95
1.52
7,854
1974
18.79
1.68
8,674
1975
16.75
1.29
6,684
1976
17.85
1.50
7,757
1977
13.23
0.63
3,250
1978
38.73
5.44
28,124
1979
21.27
2.14
1 1 ,093
1980
20.70
2.04
10,537
1981
23.67
2.60
13,434
1982
35.31
4.79
24,788
1983
41,24
5.91
30,672
1984
40.15
5.70
29,509
1985
30.36
3.86
19,959
1986
29.94
3.78
19,550
1987
13.62
0.70
3,631
1988
15.28
1.01
5,250
1989
10.15
UvUo
246
1990
20.24
1.95
10,088
1991
23.71
2.60
13,473
1992
30.92
3.96
20,506
1993
30.44
3.87
20,038
1994
19.69
1.85
9,552
1995
17.71
1.47
7,620
MEAN
23.81
2.62
13,573
Note; Years of highest (1983) and lowest (1989) total precipitation and discharge are shaded. All precipitation
values were measured at Pinto Valley Mine near the site. Discharge values for 1986-1989 were measured at
Pinto Valley weir. Discharge values for all other years were estimated using equation in Figure 3-10. The
contributing watershed area above the weir is approximately 97 square miles.
the general lack of streamflow response to the normal
range of precipitation.
During the late fall and winter, precipitation generates
increasing runoff in response to cooler air
temperature, increasing soil moisture content, and
reduced evapotranspiration. In general, this effect
reaches its maximum between December and the
end of March.
Most streamflow occurs as a result of winter to early
spring precipitation events. Generally, only minor
increases in flow result from precipitation later in the
year, and flows typically recede throughout the late
spring, summer, and fall. Most of the annual
streamflow volume is generated by surface runoff and
shallow alluvial flow that surfaces during winter and
early spring.
Water Rights
Rights to use surface waters in Arizona are generally
administered under the state's surface water code,
which is based on the doctrine of prior appropriation.
This doctrine allocates water rights on a priority basis
with the highest priority going to the first appropriator
to apply water to a beneficial use (the senior
appropriator). Subsequent appropriators would have
rights junior to those who appropriate water before
them. In times of water shortage, junior appropriators
may have to forego their appropriations to satisfy the
rights of senior appropriators.
Carlota Copper Project Final EIS
3-75
D:\A210\CDR\FIG3-11.CDR
REVISION: 3/1 9/97 (Title block only)
j Total Monthly Precipitation (in) [ | Total Monthly Runoff (in)
Total Monthly Precipitation (In) | | Total Monthly Runoft (in)
5
5
4,
S4,
0 3.5
1 3.0
c
° 2.5
ra
5.2.0
o
2 1.5
1.0
0.5
0.0
Annuul Runoff = .\,63 i ac'-fL Annual Precipilauon = 1 3 62 m
lL I La 1^1 1^
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Total Monthly
Precipitation (in) j " j Total Monthly Runoff (in)
I Total Monthly Precipitation (in)
□
Total Monthly Runoff (in)
Riverside Technology, inc
CARLOTA COPPER PROJECT
Figure 3-11
Comparison of Discharge and Runoff
at Pinto Valley Weir to Monthly
Precipitation for Years 1986 - 1989
3-76
3.0 Affected Environment and Environmental Consequences - Water Resources
Several water rights exist within and downstream of
the project area. The Salt River Valley Water Users'
Association owns and operates a number of
reservoirs downstream of the project area and claims
rights to most of the water upstream of these
reservoirs. Salt River Project’s rights were
adjudicated in the Kent Decree in 1910. Ultimate
quantification of its rights (and those of all other
claimants in the upper Salt River watershed) will be
determined in the Upper Salt River adjudication,
which is currently in progress. The Tonto National
Forest has claims and certificates of water rights for
springs, stock tanks, instream flow uses, and
diversions both within and downstream of the project
area. Tonto National Forest water rights claims are
identified in Table 3-37.
The Tonto National Forest also has a water right
permit (33-89109) that begins near the Pinto Valley
weir (PC-10) for maintenance of instream flows in
Pinto Creek. The purpose of this appropriation is to
protect water-dependent resources, such as wildlife
and fish, by requiring that certain water flows be
maintained within the creek. This right varies by
month and ranges from 1 .0 to 2.69 cfs. Other water
rights also allow for withdrawal of water from Pinto
Creek downstream of the project area. These water
rights are associated with private lands bordering
Pinto Creek and include claims to 32 acre-feet per
year for stock watering at the Barnes Property private
lands (36-29478.0001) in T2NR13E Sec 24 and
claims for 17 acre-feet per year for irrigation and
stock watering at the Henderson Ranch private lands
in T2NR13E Sec 1 . Numerous wells owned and
operated by BHP Copper (Pinto Valley Mine) are also
located near Pinto Creek downstream of the project
area. The water rights status of these wells will be
determined with the completion of the Upper Salt
River adjudication.
Flood Flows
Storm runoff events were modeled at important points
of concentration within the project area. The Pima
County Department of Transportation and Flood
Control District (PCDOT&FCD) procedure
(PCDOT&FCD 1972) was used to estimate flood
peaks associated with storm recurrences of 2 years
to 500 years (SLA 1993). The Corps of Engineers
HEC-1 flood hydrograph procedure (COE 1990) was
used to estimate flood peaks and volumes associated
with 1/2 PMP events (Knight Piesold 1996e and
1996).
The procedure developed for Pima County is based
on determining watershed characteristics such as
area, length and mean slope of the longest
watercourse, vegetation, soils, and land surface
types. Empirical relationships between these factors
are used to calculate the peak flow resulting from
selected precipitation events. Precipitation estimates
for various durations and recurrence intervals are
shown in Table 3-38; these estimates were
developed primarily from the Rainfall Frequency Atlas
for Arizona (SLA 1993, NOAA 1973).
The 500-year, 1-hour precipitation estimates were
developed by SLA using a logarithmic extrapolation
based on the 2-year, 1-hour and 100-year, 1-hour
precipitation values identified from NOAA maps (SLA
1991). These values were used as inputs to the flood
peak and sediment transport rate estimation
procedures.
Flood peaks associated with the selected rainfall
events are shown in Table 3-39, as determined by
the PCDOT&FCD procedure. These peak flow
analyses were conducted for Pinto Creek and
Powers Gulch at major points of interest (Figure
3-12), and for smaller tributary watersheds in the
immediate vicinity of the Carlota Copper Project.
Figure 3-12 shows the locations of several of the
watershed outlets where flood hydrology was
modeled (SLA 1993). Flood peaks were simulated
along Pinto Creek, Powers Gulch, and Haunted
Canyon. Concentration points used for hydrologic
and hydraulic simulations are denoted by an “S” in
their alphanumeric identifiers. The locations of these
points may differ from surface water field monitoring
stations which lack the "S." As shown in Table 3-39,
the magnitude of simulated flood peaks are not
directly proportional to watershed area. This is
because of the varying effects of different watershed
and channel characteristics.
Estimates of general and local storm PMP were
computed by Knight Piesold (Knight Piesold 1996e)
using the method presented in "Hydrometeorological
Report No. 49, Probable Maximum Precipitation
Estimates, Colorado River and Great Basin Drainage"
(NOAA and COE 1984). PMP and 1/2 PMP estimates
are presented in Table 3-40. The 1/2 PMP peak flow
Carlota Copper Project Final EIS
3-77
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-37. Tonto National Forest Water Rights
Name
Water Right No.
Location
(acre-feeVyear)
Mule Spring
36-18874
T1NR13E Sec 35
.11
Indian Spring
36-103383
T1NR13ESec 35NENW
.11
Horse Shoe Spring
36-103165
T1NR13E Sec 26
.26
Haunted Spring
36-103028
T1NR13E Sec 26
.26
Grizzly Bear Spring
36-14670
T1nR13E Sec 36
.15
Yo Tambien Spring
36-14794
T1NR13E Sec 6
.15
Frenchy Spring
36-103117
T1NR13E Sec 23
.26
Grizzly Mtn. Tank
38-14617
T1NR13E Sec 26
.32
Pinto Creek Diversion
36-24007
T1NR13E Sec 23
16.2
Pinto Creek Instream Use
Certificate 2326.001
T1 NR1 3E Sec 1 4 through
T2NR13E Sec 23
6.27
Haunted Canyon Instream Use
Certificate 2305.001
T1NR13E Sec 28
through T1NR13E Sec 14
.92
Table 3-38. Storm Rainfall Estimates for Pinto Creek and Powers Gulch Watersheds
*
twration
Areal ;
i^l^uction
^iFactor’
Point Rainfall (i
nches) i)
1
2-year i
Ss-year
10-year
Ss-yeai
s6-year ■
100-year
SOO-year’
1-hour
0.930
1.24
1.63
1.89
2.22
2.52
2.81
3.50
2-hour
0.945
1.50
1.97
2.27
2.67
3.03
3.39
4.20
3-hour
0.965
1.67
2.19
2.53
2.98
3.38
3.77
4.60
6-hour
0.973
2.00
2.62
3.02
3.55
4.03
4.50
5.50
24-hour
0.982
3.00
3.89
4.47
5.24
5.92
6.60
8.20
'Because of its larger size, areal-reduction factors only apply to the Pinto Creek watershed.
^Note; Five-hundred-year rainfall values were logarithmically extrapolated from NOAA 1973.
Source: SLA (1993)
and volume analyses were conducted for Powers
Gulch.
One-half the probable maximum flood (1/2 PMF)
peaks and volumes associated with seasonally
representative 1/2 PMP events, as determined using
the HEC-1 flood hydrograph procedure (Knight
Piesold 1996e, 1996f, 1996g), are presented in Table
3-41.
The magnitude of recorded peaks varies widely in
response to precipitation. For isolated runoff events
identified in recent records (1986-1989) at the Pinto
Valley weir, average daily high flows ranged from 6.5
cfs to 3,239 cfs. These mean daily flows corre-
sponded to a daily precipitation at Miami of 0.34
inch and 1.09 inches, respectively. The smaller event
occurred during a period of no preceding rain,
whereas the larger event was preceded by 1 .79
inches of rain in the previous week. Some periods of
missing data occur in the weir records for these
years, but they primarily occur during continued low
flow periods and do not appear to significantly affect
annual yield projections.
In general, streamflows respond rapidly to intense
precipitation, with runoff creating flashy events that
sharply rise and recede. Streamflows from major
flood events will respond similarly. Peak discharges
are significantly higher than typical flows in the
channels, and provide high-energy conditions for
sediment transport. These conditions are generally
3-78
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-39. Estimated Peak Discharges Under Existing Conditions at Key Concentration Points’
Point
—
Description
Area
(square miles)
Q2
(cfs)
as
(C<8)
Q10
(cfs)
■
Q25
(cfs)
(cfs)
Q100
(cfs)
Q500
(cfs)
SPG-1
Powers Gulch at
downstream limit
of the proposed
diversion channel
2.28
246
801
1,287
2,051
2,822
3,660
5,682
SPG-3
Powers Gulch at
downstream limit
of the project
study area
5.52
500
1,601
2,618
4,203
5,895
7,630
N/A
SHC-2
Haunted Canyon
immediately
downstream of
Powers Gulch
confluence
17.86
594
2,242
3,840
6,313
8,920
11,697
N/A
SPC-1A
Pinto Creek at
upstream limit of
the project study
area
13.18
316
1,192
2,009
3,367
4,829
6,396
10,100
SPC-2
Pinto Creek at
downstream limit
of the project
study area
14.45
335
1,269
2,123
3,532
5,044
6,729
N/A
SPC-4^
Pinto Creek
immediately
downstream of
Haunted Canyon
confluence
35.97
882
3,296
5,246
8,217
11,281
14,554
N/A
’Concentration points used for hydrologic and hydraulic simulations are denoted by an “S” in their identifiers (See Figure 3-12).
The locations of these points may differ from surface water field monitoring locations. “Q” signifies discharge (e.g., Q100
signifies the estimated peak discharge from a storm that has a 1 in 100 chance of occurring in any given year). Values reflect a
1 -hour thunderstorm event unless otherwise indicated.
^Values reflect a 24-hour storm event.
Source: SLA (1993)
capable of flushing fine sediments through and out of
the headwater channel systems in the vicinity of the
project area.
Erosion and Sedimentation
t
The Pinto Creek basin watersheds may be described
as relatively mountainous with steep channels in the
upstream areas transitioning into flatter and wider
valleys further downstream. Large portions of the
upper watersheds (including the project area) are
densely vegetated, and significant portions of
nonvegetated areas are covered with rock, either as
outcroppings or gravel- to boulder-sized material. Past
and current mining operations are located in the Pinto
Creek watershed in the general vicinity of the
proposed project. Because of the vegetative and rock
cover, the existing watershed is reasonably stable with
respect to erosion. Although significant hillslope
erosion occurs in some areas that have a soil mantle,
sediment supply from the overall watershed is limited.
Sediment transport rates were calculated using the
Zeller-Fullerton equation (SLA 1993). Transport rates
for selected cross sections of upper Pinto Creek and
Powers Gulch were ranked low, medium, and high.
Carlota Copper Project Final EIS
3-79
3-80
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-40. PMP and 1/2 PMP Estimates for Pinto Creek and Powers Gulch Watersheds’
Time of Year s.
1 Storm Type
PMP (inches) i
1/2 PMP (Inches)
January
72-hour general
23.1
11.6
February
72-hour general
22.8
11.4
March
72-hour general
22.1
11.1
April
72-hour general
20.2
10.1
May
72-hour general
18.6
9.3
June
72-hour general
18.9
9.5
July
72-hour general
25.6
12.8
August
72-hour general
29.8
14.9
September
72-hour general
29.7
14.9
October
72-hour general
28.9
14.5
November
72-hour general
25.3
12.7
December
72-hour general
23.6
11.8
Summer
6-hour local
14.1
7.1
'PMP estimates derived from
HMR49 (NOAA and COE 1984)
Source: Knight Piesold (1996e)
Table 3-41. Estimated 1/2 PMF Peaks and Volumes Under Existing Conditions at Key Concentration Points
Concentration
Point
Description
Flood Peak
Mr Volume
6^hr
LocalatoiiM
ml/2 PMF
72-hr August
General Storm
1/2 PMF
72-hr October
General Storm t
1/2 PMF ^
72-hr February
General Stomi
* 1/2 PMF
PG-Inlet
Powers Gulch
at upstream
limit of the
proposed
diversion
channel
Peak (cfs)
Volume (cf)
Volume (ac-ft)
Volume (gal)
4,861
11,952,000
274
89,412,912
499
25,961,760
596
194,219,926
456
25,177,680
578
188,354,223
321
19,732,680
453
147,620,179
SPG-1
Powers Gulch
at
downstream
limit of the
proposed
diversion
channel
Peak (cfs)
Volume (cf)
Volume (ac-ft)
Volume (gal)
12,838
36,532,800
838
273,301,877
1,474
76,970,520
1,767
575,816,458
1,348
74,574,720
1,712
557,893,478
950
58,413,960
1,341
436,994,833
Source: Knight Piesold 1996g
The average medium sediment transport rates for the
cross sections were increased statistically to
represent the upper 95 percent confidence limit of the
medium values. The results are shown in Table 3-42.
This table shows reasonable estimates of sediment
transport rates associated with streamflows for the
runoff events listed.
SLA also modeled average annual sediment yields
using the Universal Soil Loss Equation (USLE) and a
sediment delivery ratio. The results for selected
points of interest are shown in Table 3-43 for existing
conditions. The results show that, on a unit area
basis, relatively higher sediment yields originate from
the Powers Gulch/Haunted Canyon area, and
relatively lower yields originate from the upper Pinto
Creek watershed.
Pinto Creek Mainstem Watershed. Channel
geometry and bed material characteristics were
documented in reports prepared for Carlota (SLA
1993) and in a report of on-site observations (Simons
Carlota Copper Project Final EIS
3-81
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-42. Summary of Sediment Transport Rates
Watercourse
Sediment Transport Rates (in cfs) by
Return interval
10-yr
50»yr
100-yr
500-yr
Pinto Creek
18
59
89
136
Powers Gulch
44
100
141
234
Source: SLA (1993)
Table 3-43. Summary of USLE Average Annual Sediment
Yields for Existing Conditions
Concentration
Point
Drainage Area
(acres)
Existing Conditions
(acre*feet/yr)
SPG1
1,457
0.49
SPG3
3,534
1.09
SHC2
1 1 ,422
4.50
SPC2
9,246
2.03
SPC4
23,012
6.05
Source: SLA (1993)
& Associates 1993). The bed of Pinto Creek in the
project area is stable, consisting primarily of cobble-
sized material but containing material ranging from
sand size up to boulder size. The stream banks are
vegetated and, in general, appear to be stable. At the
time of the site visit, the moderate flow in the channel
was clear with virtually no sediment transport.
Some tailings deposits are evident on floodplains
along reaches of Pinto Creek located downstream
from BHP Copper's Pinto Valley Mine. Some of these
materials were released from tailings facilities located
adjacent to Pinto Creek during the winter of 1992-
1993. Other deposits accumulated from tailings
releases that occurred prior to the 1992-1993 winter.
Some of the deposited tailings were removed from
the drainage during cleanup activities under the
direction of the EPA, Arizona Game and Fish, and the
Forest Service in 1993.
Observations made during high discharges at other
times of the year indicate that a substantial amount of
fine-grained material is carried by higher flows. As
sand- and silt-sized material is washed from
sideslopes into the channel during heavy
precipitation, it contributes to higher turbidity levels.
Short-duration, high-intensity rainfall and relatively
steep channel slopes in the project area contribute to
flashy flow events with considerable sediment
transport capacity. Most of the fine-grained material is
washed downstream.
As previously described, the overall watershed is
either densely vegetated or occupied by non-erodible
rock surfaces. This, in effect, limits sediment supply.
High transport capacities accompanied by limited
sediment supplies typically lead to channel
degradation, bank erosion, and lateral channel
migration. In the project area, however, this
tendency is typically overcome by the presence of
large sediment sizes (e.g., coarse gravels and
cobbles) and bedrock-lined channel sections. These
factors restrict the scour of finer sediments and
provide geomorphic controls, respectively. The result
is that for a large range of discharges, the Pinto
Creek channel is stable or in a state of dynamic
equilibrium with the watershed.
Powers Gulch and Haunted Canyon Watersheds.
The watershed and channel characteristics in both of
these tributaries are similar to Pinto Creek. The
channels are mountain streams with relatively steep
slopes and coarse bed material. Much of the Powers
Gulch and Haunted Canyon watershed area is
armored against erosion because of dense chaparral
vegetation and exposed bedrock or other large-sized
rock materials. In addition, the Powers Gulch and
Haunted Canyon channels are relatively stable.
3-82
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Similar to Pinto Creek, the sediment transport
capacity of these streams significantly exceeds the
natural sediment supply produced by the watershed,
particularly at higher flows.
Surface Water Quality
Water quality requirements for surface waters in the
project area are defined in Arizona's surface water
quality rules (Arizona Administrative Code R18-11-
101 through R1 8-1 1-205). These rules identify that
water quality in Pinto Creek and its tributaries is for
protection of the following designated uses: Warm
Water Fishery (A&Ww), Full Body Contact Recreation
(FBC), Fish Consumption (FC), Agricultural Irrigation
(Al), and Agricultural Livestock Watering (AgL).
Narrative water quality standards (adopted as of April
24, 1996) are based on the EPA's list of “free-from”
pollutants in amounts or combinations that settle to
form significant bottom deposits; cause objectionable
odors; cause off-flavor in aquatic organisms (e.g.,
fish) or waterfowl; are toxic to humans, animals, or
plants; cause noxious aquatic plant growth; or cause
or contribute to a violation of an aquifer water quality
standard. "Free from" refers to a narrative
requirement for waters to be free from individual or
mixtures of toxic substances in toxic amounts.
Numeric water quality standards include levels not to
be exceeded for bacteria, physical properties (e.g.,
temperature and turbidity), inorganic nonmetal (e.g.,
pH, dissolved oxygen, fluoride, sulfide, nitrate, and
phosphate), and total recoverable and dissolved
metals. Numeric water quality standards for Pinto
Creek and its tributaries are listed in Table 3-44.
General Surface Water Quality. The water quality
data used to evaluate surface water conditions
included data collected from 1992 through 1995
(Montgomery & Associates 1993, GWRC 1996b,
Miller & Associates 1994). Data were available for
Pinto Creek, Powers Gulch, and Haunted Canyon.
Pinto Creek was divided into three reaches for
summarization: upstream and downstream of the
proposed Carlota/Cactus Pit and from below the
Haunted Canyon confluence to above the confluence
with the Salt River {Table C1-1 in Appendix C, Water
Resources Data). Available historical water quality
data from Pinto Creek (Central Arizona Association of
Governments 1981 and 1983) support the general
water quality conditions described in the summary.
Powers Gulch was also divided into two reaches for
summarization: upstream and downstream of the
proposed heap leach pad and mine rock disposal
areas (Table Cl -2 in Appendix C, Water Resources
Data). Haunted Canyon was summarized separately
as one reach {Table C 7-2 in Appendix C, Water
Resources Data). The quality control data provided
for field duplicates and blanks, although not supplied
with all results, generally met the established criteria
or were determined to be acceptable on a case-by-
case basis.
A condensed list of water quality constituents was
selected from the detailed summary tables in
Appendix C, Water Resources Data, to characterize
and compare the water quality of Pinto Creek,
Powers Gulch, and Haunted Canyon {Table 3-45).
The water type of all three monitored reaches of Pinto
Creek is predominantly calcium-sulfate. The
upstream reach of Powers Gulch is a sodium,
calcium-bicarbonate, sulfate water type, while the
downstream reach of Powers Gulch is a calcium,
sodium-bicarbonate water type. The Haunted Canyon
water type is calcium-bicarbonate. TDS concen-
trations were higher in the Pinto Creek reach
downstream of the proposed Carlota/Cactus Pit than
in the upstream reach of Pinto Creek or in Powers
Gulch or Haunted Canyon.
Flows varied greatly throughout the system. Sporadic
fluctuations in chemistry most likely relate to timing
with major storm events. TDS concentrations roughly
increased with decreasing flows, while stream
temperatures seemed to be more independent of
flows and varied more with season (GWRC 1996).
Measurements of pH were always within standard
limits. Metals concentrations were generally low and
below water quality standards, with a few exceptions.
These exceptions included copper within Pinto Creek
above and below the proposed Carlota/Cactus pit and
lead in Powers Gulch downstream of the proposed
heap-leach pad and mine rock disposal areas.
Above normal precipitation during the months of
December 1992 and January 1993 resulted in an
accidental release of mine tailings and PLS from
existing Pinto Valley Mine operations into Pinto Creek
(Hargis and Associates 1993). Water quality data are
available for Pinto Creek within and below the project
area shortly after these releases (Hargis and
Associates 1993, Montgomery & Associates 1993,
Carlota Copper Project Final EIS
3-83
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-44. Surface and Ground Water Quality Standards for the Carlota Copper Project
ConsMtuent
Aifeona
IFederall:
MCL
Nimerle Water Oualitv Criterion
Acute { Chronic I IPBC I FC 1 Aol 1 AgL
Physical and Aqqreqate P
roperties
Total Dissolved Solids
mq/L @ 180“C
—
500'
—
—
—
...
...
...
Turbidity
NTU
5
—
50
50
50
...
...
...
Water Temperature
Deq. Celsius
—
...
3.0'
3.0'
...
....
...
...
Major Cations
Calcium
mq/L as Ca
—
—
—
—
—
...
...
...
Magnesium
mq/L as Mq
...
—
—
...
...
...
...
Potassium
mq/L as K
...
...
—
...
...
...
...
...
Sodium
mg/L as Na
—
...
—
...
...
...
Major Anions
Bicarbonate
mg/L as CaCO,
...
...
...
...
...
...
...
...
Chloride
mq/L as Cl
—
250'
...
...
...
...
...
Sulfate
mq/L as SO,
—
250'
—
—
—
—
...
—
Inorganic Nonmetallics
Boron
mq/L as B
...
...
...
...
12.6‘
...
1.0 TR
...
Cyanide
mq/L as CN
0.2
0.2'
0.041 TR
0.0097 TR
2.8 TR‘
210 TR
...
0.2 TR
Dissolved Oxygen
mg/L as O,
...
—
6.0
—
...
...
...
...
Fluoride
mq/L as F
4.0
4.0'/2.0'
...
...
8.4'
...
...
...
Nitrate
mq/L as N
10
10'
...
...
224‘
...
...
...
Nitrate + Nitrite
mq/L as N
10
10'
...
—
...
...
...
Nitrite
mq/L as N
1
1'
...
...
14.0*
...
...
...
Orthosphosphate
mg/L as P
...
...
...
...
...
—
—
...
pH
standard units
...
6.5-8.5'
6.5-9.0
6.5-9.0
6.5-9.0
—
4.5-9.0
6.5-9.0
Sulfide
mq/L as S
...
...
0.1
...
...
...
...
...
Total Ammonia
mg/L as N
...
...
8
...
...
...
...
...
Total Nitrogen
mq/L as N
...
...
2.00
0.60
—
...
...
...
Total Phosphorus
mq/L as P
...
...
1.00
0.12
—
...
—
Metals
Aluminum
mq/L as Al
...
0.05-0.2’
...
...
...
...
...
...
Antimony
mq/L as Sb
0.006
0.006'
0.088 D
0.030 D
0.056 TR
0.14 TR
—
...
Arsenic
mq/L as As
0.05
0.05'
0.360 D
0.190 D
0.05 TR
1.45 TR'
2.0 TR
0.2 TR
Barium
mq/L as Ba
2
2'
...
...
9.8 D‘
...
—
...
Beryllium
mq/L as Be
0.004
0.004'
0.065 D
0.0053 D
0.004 TR‘
0.00021 TR
...
...
Cadmium
mq/L as Cd
0.005
0.005'
0.053 D
0.002 D
0.07 TR
0.041 TR'
0.05 TR
0.05 TR
Chromium (III)
mq/L as Cr
...
...
3.1 D
0.37 D
140.0 TR'
67.0 TR'
—
...
Chromium (VI)
mq/L as Cr
...
...
0.016D
0.01 ID
0.7 TR'
3.4 TR'
—
—
Chromium (total)
mq/L as Cr
0.1
0.1'
...
...
...
—
1 TR
1 TR
Cobalt
mq/L as Co
...
...
...
...
...
—
—
—
Copper
mq/L as Cu
...
1.3"/1.0'
0.034 D
0.021 D
5.2 D
—
5.0 TR
0.5 TR
Iron
mq/L as Fe
...
0.3'
...
—
...
—
—
—
Lead
mq/L as Pb
0.05
0.015"
0.197 D
0.008 D
...
—
10.0 TR
0.1 TR
Manganese
mq/L as Mn
...
0.05'
...
...
19.6 TR'
...
10.0
—
Mercury
mq/L as Hq
0.002
0.002'
0.0024 D
0.00001 D
0.042TR
0.0006 TR
—
0.01 TR
Molybdenum
mq/L as Mo
...
...
...
...
...
...
—
—
Nickel
mq/L as Ni
0.1
0.1'
2.5491 D
0.2834 D
2.8 TR
0.73 TR'
—
—
Selenium
mq/L as Se
0.05
0.05'
0.02 TR
0.002 TR
0.7 TR'
9.0 TR
0.02 TR
0.05 TR
Silver
mq/L as Aq
...
0.1'
0.013 D
...
...
...
—
—
Strontium
mq/L as Sr
...
...
...
...
...
—
—
...
Thallium
mq/L as Tl
0.002
0.002'
0.70 D
0.15 D
0.012 TR'
0.041 TR'
—
—
Zinc
mq/L as Zn
...
5.0’
0.21 D
0.19 D
42.0 TR'
22.0 TR'
10.0 TR
25.0 TR
Radionuclides
Gross Alpha Activity
pCi/L
15
15'
...
...
...
—
—
—
Gross Beta Activity
mrem/yr
4
4 (50 pCi/L)
...
...
—
...
—
—
Radium 226 + 228
pCi/L
5
5'
...
...
...
...
...
...
'Arizona Aquifer Water Quality Standard (1996)
'Federal Primary maximum contaminant level (MCL) for drinking \A(ater
'Federal Secondary MCL for drinking water
'A concentration of 200 mg/L as CaCO, was used for calculating water quality criteria
that are hardness dependent (Cd, Cu, Pb, Ni, Ag, Zn)
'Temperature criteria are given as increases from ambient levels
‘Arizona-adopted (as of April 24, 1996) water quality criterion under review by EPA
'Action level for treatment technique requirement
*Total ammonia criterion is based on field measurements of pH and water
temperature
D = Dissolved fraction
TR = Total recoverable fraction
A&Ww = Aquatic and wildlife (warm water fishery)
FBC = Full body contact
FC = Fish consumption
Agl = Agricultural irrigation
AgL = Agricultural livestock watering
3-84
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-45. Summary of Surface Water Quality for Affected Environment
13^!, ,1-' ■
. Suifaca Water
Water
Type
pH
(s.u.)
u
Water
Temperature
f C)
ean ± 1 Stand
% Oiseplved .r
Oxygen
(mg/Laebj
«TDS
^(mg/L
;180*C)
atton
TSS^
(mg/L
103*0
Sulfate-
iliiilP
t
(ct
Water Quality
CrRerion
Exceedances*
Pinto Creek
Upstream of
Proposed
Carlota/Cactus
Pit
Ca -
SO,
in
± e.4
15.3
±3.92
8.1
±2.3
384
±111
6
±4
169
± 73.1
1.4
±2.7
DO, Cu
Downstream of
Proposed
Carlota/Cactus
Pit
Ca-
se,
7.7
± e.4
15.4
±4.3
7.4
±1.2
932
± 343
0.8
± 0.8
463
± 184
1.66
± 2.68
DO, Cu
Below Haunted
Canyon
Confluence to
above Salt River
Confluence
Ca-
se,
7.5
± e.3
19.1
±3.2
8.1
± 2.3
840
±449
3.6
± 2.7
347
± 275
1.2
± 1.25
DO
Powers Gulch
Upstream of
Proposed Heap
Leach Pad and
Mine Rock
Disposal Areas
Na,
Ca-
HCO,.
SO,
7.8
±e.e
9
±0
8.85
±0.00
110
±0
144
±0
16.7
±0.0
0.16
±0.00
No
Exceedances
Downstream of
Proposed Heap
Leach Pad and
Mine Rock
Disposal Areas
Ca,
Na-
Hce,
7.3
±0.0
5.5
±0.0
9.86
±0.00
124
±0
5
±0
21.3
±0.0
2.35
±0.00
Pb
Haunted Canyon
Ca-
Hce,
7.5
±0.3
17
±4
4.7
±0.0
326
± 59
2.4
±2.7
52.1
±20.3
0.21
± 0.18
DO
'During water quality sampling.
^Constituents with values that exceeded a water quality criterion in at least one sample.
Magma Copper Corporation 1993). These values
might not be indicative of naturally-occurring baseline
conditions and, therefore, were not included in the
concentration ranges and calculations of average
baseline copper concentrations presented in Table 3-
45 and Table C1-1 of Appendix C, Water Resources
Data. Copper concentrations in samples affected by
the accidental release of tailings and PLS ranged
from 0.018 mg/L to 0.193 mg/L dissolved copper and
from 0.025 mg/L to 1 .83 mg/L total recoverable
copper (Hargis and Associates 1993, Montgomery &
Associates 1993, Magma Copper Corporation 1993).
Samples collected since the release (GWRC 1996)
did not reflect the same elevated copper
concentrations.
Pinto Creek Water Quality. Pinto Creek surface
water quality data were summarized for three reaches
upstream and downstream of the proposed
Carlota/Cactus pit and below the Haunted Canyon
confluence to above the Salt River confluence
(Figure 3-8) (PC-3, PC-5, PC-7, PC-7.5, PC-8, and
PC-10).
Pinto Creek surface water is a calcium-sulfate type.
Table 3-45 summarizes the pH, water temperature,
dissolved oxygen, TDS, TSS, sulfate, and flow for
Pinto Creek. Analyses of samples collected in Pinto
Creek both upstream and downstream of the
Carlota/Cactus pit and below the Haunted Canyon
confluence met applicable stream standards for all
Carlota Copper Project Final EIS
3-85
3.0 Affected Environment and Environmental Consequences - Water Resources
constituents except dissolved oxygen and copper
(Pinto Creek above and below the Carlota/Cactus pit
only) {Table C1-1 /n Appendix C, Water Resources
Data). Laboratory analytical detection levels were not
sufficiently sensitive to evaluate ambient water quality
with respect to applicable water quality standards for
the following constituents: cyanide, total phosphorus,
antimony, beryllium, cadmium, copper (Pinto Creek
station below Haunted Canyon confluence only),
mercury, selenium, and thallium. Copper is common
in pyrite ores found throughout the region, and
potential sources to surface waters include natural
oxidation processes and historic mining operations.
ADEQ's Water Quality Assessment Report for 1996
(ADEQ 1996) identifies that the reach of Pinto Creek
from its headwaters to the confluence with Spring
Creek does not support its designated uses because
of a violation of the dissolved copper standard for
warm water fisheries recorded below the Gibson Mine
in 1992 and for a violation of the state's narrative
standards as a result of a tailings spill from the Pinto
Valley Mine in 1991. The assessment also reports
that the dissolved copper standard was violated in
1993 as a result of a major leach solution and tailings
spill from this same mine.
Powers Gulch Water Quality. Powers Gulch
surface water quality data were summarized for two
reaches upstream and downstream of the proposed
heap-leach pad and mine rock disposal areas
(PG-1 and PG-4). Table 3-45 summarizes pH,
water temperature, dissolved oxygen, TDS, TSS,
sulfate, and flow. Analyses of water samples
collected upstream of the proposed heap-leach pad
and mine rock disposal areas indicated no water
quality standard exceedances, while at the
downstream site only lead exceeded water quality
standards {Table C1-2 in Appendix C, Water
Resources Data).
The single exceedance (0.094 mg/L as Pb) of
a lead standard (0.008 mg/L as Pb for chronic
aquatic wildlife) may be a result of sampling or
analytical error considering that the dissolved
lead concentration is more than an order of
magnitude greater than the total recoverable
concentration, and because lead solubility is
relatively low (less than 0.05 mg/L as Pb) in oxidizing
waters of neutral pH. Provided the reported lead
concentration is credible, possible sources of lead
include the localized geology or resuspension of
sediment deposits originating in upstream reaches.
Laboratory analytical detection levels were not
sufficiently sensitive to evaluate ambient water quality
with respect to applicable water quality standards for
the following constituents: cyanide, beryllium,
cadmium, mercury, selenium, and thallium. In
addition, total phosphorous analyses were not
available for either reach.
Haunted Canyon Water Quality. Haunted Canyon
surface water (HC-2) is generally a calcium-
bicarbonate type. The pH, water temperature,
dissolved oxygen, TDS, TSS, sulfate, and flow
are summarized in Table 3-45. Analyses of water
quality samples collected from Haunted Canyon
consistently met applicable Arizona Surface Water
Quality Standards for all constituents tested
except dissolved oxygen {Tables C1 -2 In Appendix C,
Water Resources Data). Laboratory analytical
detection levels were not sufficiently sensitive to
evaluate ambient water quality with respect to
applicable water quality standards for the following
constituents: cyanide, total phosphorus, antimony,
beryllium, cadmium, copper, mercury, selenium, and
thallium.
Well Field Area Water Quality. The well field area
for the Carlota Copper Project lies adjacent to Pinto
Creek and Haunted Canyon in the area of their
confluence. Surface water quality data were available
from upstream and downstream of the well field.
Upstream water quality in Haunted Canyon is
described in the previous paragraph. The water
chemistry in Haunted Canyon was a very dominant
calcium bicarbonate water type, while at a sampling
location in Pinto Creek (PC-5) located upstream from
the Haunted Canyon confluence, the water chemistry
was a very dominant calcium sulfate water type
(GWRC 1996). At a sampling point downstream of the
Haunted Canyon-Pinto Creek confluence and well
field (PC-7), the water type was a calcium-
bicarbonate type, indicating that Haunted Canyon
streamflows exert an influence on the water chemistry
of Pinto Creek below the confluence of these two
streams. This change in water type is limited because
further downstream in Pinto Creek (PC-7.5) the water
type reverts back to the calcium sulfate type (GWRC
1996b). TDS appears to behave similarly, exhibiting a
mixing of the two streams (GWRC 1994).
3-86
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
3.3.1. 3 Ground Water
Several hydrogeologic investigations have been
conducted for the project to provide the necessary
background information for this EIS and to support
the Aquifer Protection Permit application
(Montgomery & Associates 1992, 1993, GWRC
1994). These investigations have focused on defining
the hydrogeologic conditions in the project area and
in the vicinity of the well field. These investigations
have included monitoring well installation, aquifer
testing and analysis, water quality monitoring, and
drawdown analysis. Ground water monitoring
included measuring water levels monthly in up to 32
wells located in the project vicinity. Quarterly water
quality samples were collected in up to 18 wells.
Regional Hydrogeology and Ground Water Use
The general lithologic and structural conditions in the
region are discussed in Section 3.2, Geology and
Minerals. Three principal hydrostratigraphic units
have been recognized in the region: (1) bedrock
complex, (2) Gila Conglomerate, and (3) alluvium.
The bedrock complex is composed of sedimentary,
volcanic, and metamorphic rocks that range from the
Precambrian to the Tertiary age. Yields from wells in
the bedrock complex are generally low (less than 50
gpm), although fractured sections of Precambrian
Quartzite and Paleozoic Limestone can locally yield
up to several hundred gpm. The Schultze Granite and
Apache Leap Dacite, which underlie areas just south
of the project facilities, yield small quantities of water
to domestic wells in the Top-of-the-World community.
The Gila Conglomerate is the principal aquifer in
Pinto Valley and in the Globe-Miami area. The
conglomerate aquifer provides ground water to
several mining projects within the Globe-Miami Mining
District, including the adjacent Pinto Valley Mine.
Wells drilled 500 to 800 feet deep typically yield 50 to
150 gpm. Qverdraft has depleted the quantity of
water available in the Gila Conglomerate (Peterson
1962). Although the Gila Conglomerate is present on
the project site, it is not considered an aquifer since it
occurs above the general water table elevation for the
area.
Alluvium occurs as a thin, discontinuous ribbon that
veneers portions of valley bottoms along Pinto Creek
and its tributaries. This material consists of porous
unconsolidated sand, silt, gravel, and boulders
transported by surface runoff and deposited in stream
channels and floodplains. From the headwaters to the
Pinto Valley weir, the width of the alluvium ranges
from approximately 0 to 1 ,200 feet, with an estimated
average of 100 to 200 feet. The alluvium has an
estimated maximum thickness of approximately 50
feet. However, the average thickness of the alluvium
between the project site and BHP Copper's Pinto
Valley weir is probably on the order of 10 to 20 feet.
Because of the alluvium's limited extent, the volume
of water it stores is limited.
The static water level elevations in the unconfined
and poorly confined units are generally lower in down-
stream areas of the drainages as compared to
upstream areas. These water level data indicate that,
where unimpeded by ground water barriers, ground
water throughout the area generally moves from
higher elevation areas toward the axis of major
valleys and then down the axis of the valleys.
Ground water in the region is withdrawn primarily
for mining and domestic use. According to the
Arizona Department of Water Resources (ADWR)
records, a total of 99 water supply wells have been
permitted in the project vicinity. All permitted wells,
excluding monitoring wells, are summarized in Table
C2-1 in Appendix C, Water Resources Data; the well
locations, except for wells at Top-of-the-World, are
shown in Figure 3-9. Uncertainty regarding precise
locations, coupled with the large number of wells,
precluded presenting the private wells at Top-of-the-
World in Figure 3-9. However, the general location of
these wells is indicated by the well number code’ in
Table C2-1 in Appendix C, Water Resources Data.
BHP Copper owns 1 1 water supply wells with
reported yields^ that range from 10 to 445 gpm within
the inventory boundary. These wells are located east
and north of the Carlota/Cactus pit area. BHP Copper
’ The well number includes the a-b-c-d well location
system of the ADWR in accordance with the BLM's
system of land subdivision that identifies the township,
range, section, quarter section, and quarter-quarter
section.
® The reported yields are based on information provided
on driller's logs submitted to the ADWR. These yields
are typically based on short-term pump tests and may be
greater than the actual long-term sustainable yield for
the well.
Carlota Copper Project Final EIS
3-87
3.0 Affected Environment and Environmental Consequences - Water Resources
also has two large-diameter, caisson-type wells that
are apparently used to capture seepage from the
tailings facilities.
In the area outlined as Top-of-the-World in Figure 3-9,
there are 83 known wells — 78 private wells and 5
wells owned by ASARCO. The private wells within the
Top-of-the-World area have reported yields that
average 12 gpm and range from less than 1 gpm to
40 gpm. The total depth of the private wells at Top-of-
the-World ranges from 8 to 1,002 feet. These existing
data do not indicate any apparent trends regarding
yield versus depth.
Hydrogeology of the Project Area
Knowledge of the hydrogeologic conditions in the
project area is based on detailed geologic mapping
and exploration drilling and on information obtained
from monitoring wells. The locations of the monitoring
wells are shown in Figure 3-13. The wells are
clustered in three primary areas: (1) Pinto Creek in
the vicinity of the Carlota/ Cactus pit, (2) Powers
Gulch in the vicinity of the heap-leach pad and Eder
pits, and (3) the well field area. Ground water occurs
in the bedrock complex that underlies the area and in
the alluvium that veneers bedrock along major
drainage courses.
Bedrock. In the bedrock complex, the recharge,
storage, flow, and discharge of ground water is
controlled by the porosity, permeability, and structure
(i.e., fault and fracture zones) of the geologic
materials. As presented in Section 3.2, Geology and
Minerals, the lithology and structural conditions within
the project area are complex. For example, through
detailed geologic mapping in the immediate project
area and in the vicinity of the well field, Carlota has
identified over 30 different rock units and numerous
fault zones that range from Precambrian (greater than
600 million years before present [mybp]) to late
Tertiary (5 mybp). Ground water in these bedrock
units is stored and transmitted through a system of
interconnected fractures, or fracture networks.
Because of the broad variation of rock types and the
complex pattern of fracturing present in the project
area, the concentration and interconnection of
fractures is envisioned to be highly variable across
the area.
Ground water flow pathways in the bedrock
complex are further complicated by major faults
(i.e., Kelly fault. North fault. Cactus fault, Bundy
fault, and Eder fault system, as shown on the
geologic map in Figure 3-3) that offset and displace
various rock units. Faulting commonly forms zones
of crushed and pulverized rock that may behave
as barriers to ground water movement. Depending
on the physical properties of the rock mass and
the amount of movement, faulting can also create
conduits along the fault trace, resulting in zones
of relatively high ground water flow and storage
capacity compared to the unfaulted surrounding
rock.
The results of pump tests conducted in selected
bedrock monitoring wells (excluding the water supply
test wells) are presented in Table C3-1 in Appendix
C, Water Resources Data. During short-term pump
tests (several hours), most wells exhibited rapid
drawdown at low pumping rates (1 to 94 gpm). In fact,
most monitoring wells could sustain pumping of only a
few gpm. The transmissivity computed from analyzing
water level drawdown data is low, ranging from less
than 1 to 380 gallons per day (gpd) per foot of aquifer;
hydraulic conductivity is also low, ranging from less
than 0.005 to 9.5 gpd per square foot of aquifer. It is
important to note that these values represent the bulk
hydraulic properties of the entire saturated thickness
of bedrock tested. This saturated test interval typically
includes several rock types and is up to 580 feet long.
Considering that the hydraulic conductivity is
controlled by fractures, and that the quantity, size,
interconnection, and orientation of these fractures are
not uniform within individual rock units or between
different rock units, the hydraulic properties within
each monitoring well are undoubtedly heterogeneous
(different from one segment of the well to another)
and strongly anisotropic (different in different
directions).
The principal source of recharge to the bedrock
complex is from infiltration of rainfall and snowmelt
to fractures in bedrock outcrops. In addition, the
bedrock probably receives some recharge seasonally
from the alluvial aquifer. Locally, where the stream
channel is incised into bedrock, the bedrock complex
is probably also seasonally recharged directly by
streamflow.
3-88
Carlota Copper Project Final EIS
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Proposed Pit
Mine Rock Area
Leach Pad
Diversion Channel
Proposed Pipeline Route
Proposed Power Line Route
County Line
Top-of-the- World Boundary
- — - Stream
• Ground Water Monitoring Well
© Well Field Production Well
Monitoring Well Designations
AMW Alluvial
BMW Bedrock
MW Bedrock (Carlota/Cactus Pit)
Bedrock (Powers Gulch)
Piezometric
BMW-4
Source: GWRC1994
Seal* In Feet
0 1000 2000
Riverside Technology, inc.
CARLOTA COPPER
PROJECT
Figure 3-13
Ground Water
Monitoring Wells
3-89
3.0 Affected Environment and Environmental Consequences - Water Resources
Alluvium. Ground water also occurs in the alluvium
that veneers bedrock in the bottom of the Pinto
Creek, Powers Gulch, and Haunted Canyon
drainages. Ground water in the alluvium is stored and
transmitted through interconnected pores; porosity of
the alluvium is estimated to range from 30 to 40
percent (Montgomery & Associates 1992). The
volume of water flowing through the alluvium is
dependent on the areal extent and saturated
thickness of the alluvium. The mapped areal
distribution of the alluvium in the vicinity of the project
facilities and well field is shown on the geologic maps
{Figures 3-3 and 3-4). In Pinto Creek, in the vicinity of
the Carlota/Cactus pit, the alluvium ranges from 80 to
500 feet wide and is up to 30 feet deep. In Powers
Gulch, the alluvium occurs along a discontinuous
ribbon that is up to 500 feet wide and is generally less
than 20 feet thick. In the reach of Haunted Canyon
between Powers Gulch and Pinto Creek, the alluvium
ranges from approximately 150 to 400 feet wide. The
thickness of the alluvium was investigated by
conducting three seismic refraction survey lines
across the valley floor (perpendicular to the stream
channel). Based on the results of these seismic
refraction surveys (hdyroGEOPHYSICS, Inc. and
BIRD Seismic Services, Inc. 1995), the thickness of
alluvium is inferred to be very thin (generally less than
10 feet).
The alluvial aquifer in Pinto Creek receives recharge
from the infiltration of streamflows, particularly during
periods of high runoff. Locally, the alluvium may
receive some recharge from the bedrock complex
(see the discussion under the heading "Ground
Water/Surface Water Interactions" for additional
details).
Water Levels and Ground Water Flow. Existing
bedrock monitoring wells are of variable construction.
For this reason, it is not possible to define the
variations in potentiometric (head) conditions in
the bedrock complex at depth, between major
lithologic units, or on either side of major structures.
Water level contours based on water level
measurements in the monitoring wells are presented
in Figure 3-14. The contour map indicates that the
hydraulic potential exists for ground water to flow
from the higher elevation ridges toward, and down
the axis of, the principal drainage features (Pinto
Creek and Powers Gulch). This implies, however,
that the bedrock unit behaves as a single
hydrogeologic unit, which may or may not be the
case. The fluctuation of water levels recorded for
each monitoring well is summarized in Table C3-2
in Appendix C, Water Resources Data. The data
suggest that some wells tap into different blocks
of fractured rock that have poor hydraulic
communication with each other.
Observations during drilling also provide evidence
that ground water conditions in the bedrock complex
may be variable, and the bedrock may not behave as
a single continuous bedrock aquifer. Montgomery &
Associates (1992) indicates that during exploration
drilling, a large hydraulic head difference was
encountered on either side of the Kelly fault. Also,
exploration drilling data indicate that the Kelly and
Cactus faults contain large amounts of clay. These
observations suggest that both the Kelly and Cactus
fault zones probably impede the movement of ground
water. Other subsurface data in the vicinity of the
Bundy fault indicate that this structure probably
behaves as a conduit for ground water flow
(Montgomery & Associates 1992). The calculated
hydraulic conductivity values for the bedrock complex
are highly variable, spanning five orders of
magnitude; this wide range of hydraulic conductivity
indicates the bedrock complex is heterogeneous and
anisotropic.
In addition, as described later in this section, the
chemical composition of the ground water sampled is
highly variable between different bedrock wells. This
variation is noted even where wells are completed in
the same primary geologic formations. The
composition of the ground water is dependent on the
time of contact between the water and the host rock
and reactivity of the host rock. The variation in ground
water composition presumably reflects that water
within the bedrock complex is evolving through
different flow pathways and lithologies and that there
is poor mixing (or interconnection) between different
hydrochemical water types.
The water level data, pump test and recovery data,
drilling observations, and chemical composition of the
ground water all provide evidence that, with respect
to hydraulic characteristics, there may be some
degree of partitioning within the bedrock complex.
Although poorly defined and presumably highly
complex, this partitioning is likely to control ground
water flow pathways, recharge and discharge, and
3-90
Carlota Copper Project Final EIS
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CARLOTA COPPER PROJECT
Figure 3-14
Ground Water Elevations
September 1993
3-91
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3.0 Affected Environment and Environmental Consequences - Water Resources
drawdown patterns resulting from ground water
withdrawal.
Heap-Leach Pad and Rock Disposal Areas. The
interpreted hydrogeologic conditions in the vicinity of
the heap leach and Main mine rock disposal facilities
are illustrated on a set of cross sections. The location
of the cross sections are shown in Figure 3-1 5\ cross
sections through the heap-leach pad and Main mine
rock disposal area are presented in Figures 3-16 and
3-17, respectively, and are discussed below. Ground
water flow in the vicinity of the proposed heap-leach
pad is controlled by movement through fractured
bedrock units and along prominent faults. Also, minor
amounts of ground water move through the thin
alluvium present along the Powers Gulch drainage
channel. The depth to ground water and distribution
of bedrock units, faults, and alluvium in the vicinity of
the heap-leach facility are illustrated on the geologic
map {Figure 3-3) and cross sections {Figure 3-16).
The primary bedrock units beneath the leach pad
area consist of Pinal Schist, Precambrian Diabase,
and Apache Group. The major structural discontinuity
trends northeast-southwest. Water level data from
monitoring wells in the leach pad area indicate the
potentiometric surface for the bedrock complex
ranges from a few feet above land surface to greater
than 30 feet below land surface. Monitoring wells
installed in the bedrock adjacent to the creek in
Powers Gulch (BMW-8, PG-2, PG-5,) record
potentiometric conditions that seasonally are near
(less than 5 feet below the surface) or above the
existing ground surface. Seasonal water levels in the
shallow wells completed in the alluvium (AMW-18,
PG-2A) are within a few feet of the surface (less than
5 feet below the ground surface). In the late winter
and early spring, an upward hydraulic gradient exists
in the vicinity of PG-2, located in the creek channel in
the southern half of the heap-leach pad. This upward
hydraulic gradient caused this monitoring well to
discharge at the surface in the spring of 1992.
Ground water gradients range from approximately
200 feet per mile in the valley bottom to 800 feet per
mile along the side slopes of Powers Gulch. Pump
tests of the bedrock monitoring wells located in the
southern portion of the leach pad indicate that the
bulk permeability of the bedrock is low with hydraulic
conductivities ranging from 0.03 to 1.3 gpd per
square foot.
Subsurface conditions in the vicinity of the Main mine
rock disposal area are illustrated in the cross sections
in Figure 3-17. The principal rock unit types beneath
the Main mine rock disposal area are the Tertiary
Apache Leap volcanics and Paleozoic limestone. The
Cactus Southwest mine rock area would be placed on
the Precambrian Pinal Schist and Granite on Manitou
Hill. The depth to ground water beneath these
facilities is not known. However, the elevations of
these sites suggest that, in general, the potentio-
metric surface of the bedrock is probably several tens
of feet beneath the surface. One possible exception is
Grizzly Bear Springs located in the southeast portion
of the Main mine rock disposal area (see Figure 3-9
for location). When these springs are flowing, the
potentiometric surface of the bedrock is inferred to be
above the ground surface. The Eder mine rock area
would be constructed on slope deposits overlying
Pinal Schist. Projecting water level data from the
monitoring wells located immediately downslope of
the Eder North and Eder South pits suggests that the
potentiometric surface for the bedrock is probably 30
to 40 feet or more beneath the surface.
Springs. Major springs in the locale include Miller
Spring, Mule Spring, Fifty Dollar Spring, and Coon
Spring {Figure 3-9). Water quality analyses are
summarized for selected springs in Table C4-3 of
Appendix C, Water Resources Data. The first two
springs are within the project area. Numerous other
springs, adit flows, and seeps occur farther up the
tributaries of Pinto Creek. Miller Spring and Mule
Spring were monitored at approximately monthly
intervals from the spring of 1993 through 1995
(GWRC 1996b). As shown in Table 3-35, the maxi-
mum measured flow at Miller Spring was 0.37 cfs
(approximately 166 gpm); the spring was reported dry
on 19 of the 33 monitoring dates. Mule Spring flowed
throughout the monitoring period. Measured flows
ranged from 2 cfs (approximately 898 gpm) to less
than 1 gpm (GWRC 1996b).
The Grizzly Bear Spring (see Figure 3-9 for location)
consist of two small springs or seeps. On June 21 ,
1993, the reported discharge at each spring was less
than 1 gpm (GWRC 1994). No other flow data are
available for these springs.
Several springs, including 23db, 25ca, and 36ab
(Miller Spring), are located near to and downgradient
Carlota Copper Project Final EIS
3-93
3.0 Affected Environment and Environmental Consequences - Water Resources
from an existing tailings facility owned by BHP
Copper. The proximity of these springs and their
relatively high electrical conductivity values indicate
possible contamination of the spring water quality, but
there is no substantiating evidence that the tailings
facility is the contaminant source. However, Miller
Spring was formerly used as an NPDES discharge
point for the Pinto Valley Mine.
Ground Water Quality
Ground Water Quality Standards. Ground water
quality standards for state aquifers have been
established by the State of Arizona under Arizona
Administrative Code, Title 18, Environmental Quality,
Chapter 1 1, Water Quality Boundaries and
Standards, Article 4, Aquifer Water Quality Standards.
All aquifers in the state are classified for drinking
water protected use except for aquifers that are
reclassified to a non-drinking water protected use
pursuant to A.R.S. § 49-224 and A.A.C. R1 8-1 1 -503
Petition for Reclassification. The term “drinking water
protected use” is defined in Section R1 8-1 1-401 to
mean the protection and maintenance of aquifer
water quality for human consumption. The term “non-
drinking water protected use” is defined in Section
R1 8-1 1-401 to mean the protection and maintenance
of aquifer water quality for a use other than human
consumption.
The bedrock and alluvial aquifers identified in the
project area are classified for drinking water protected
use. Water quality criteria to protect a drinking water
protected use classification are prescribed in Section
R1 8-1 1-405 (Narrative Aquifer Water Quality
Standards) and Section R1 8-1 1-406 (Numeric Aquifer
Water Quality Standards: Drinking Water Protected
Use).
Narrative aquifer water quality standards restrict
discharges that (1) cause a pollutant to be present in
an aquifer classified for a drinking water protected
use in a concentration that endangers human health,
(2) shall cause or contribute to a violation of a water
quality standard established for a navigable water of
the state, and (3) shall cause a pollutant to be present
in an aquifer that impairs existing or reasonably
foreseeable uses of water in an aquifer.
Numeric aquifer water quality standards are based on
federal primary MCLs. federal MCLs include primary
MCLs (health-based) and secondary MCLs (public
welfare-based). Because Arizona aquifer standards
are promulgated after federal primary MCL
promulgation and because Arizona Aquifer Water
Quality Standards do not include all federal primary or
secondary MCLs, water quality criteria to protect
drinking water protected aquifers in the Carlota
Copper Project area will be based not only on Arizona
Aquifer Water Quality Standards but on federal
primary and secondary MCLs as well. Numeric water
quality standards for aquifers in the project area are
listed previously in Table 3-44.
General Ground Water Quality. The water quality
data used to evaluate ground water conditions
included data collected during 1992 (Montgomery and
Associates, Inc. 1993) and 1993 to 1995 (GWRC
1994, 1996b). Data were available for areas in the
Pinto Creek, Powers Gulch, and Haunted Canyon
drainages. Bedrock and alluvial ground water quality
were summarized separately for Pinto Creek, Powers
Gulch, the well field area, springs, and private wells
{Tables C4-1, C4-2, and C4-3 in Appendix C, Water
Resources Data). A condensed list of water quality
constituents was selected from the detailed summary
tables in Appendix C, Water Resources Data, to
characterize and compare bedrock, alluvial, and
spring water quality {Table 3-46).
Data from bedrock wells in each area were combined
to summarize the water quality of the bedrock
system. Water quality in individual rock types was not
evaluated since few wells isolate specific rock types.
The monitoring wells are designated as either
bedrock or alluvial monitoring wells. The bedrock
monitoring wells are designed to prevent the
interception of ground water contained in the
overlying surficial material, such as alluvium or
colluvium. Several of the alluvial monitoring wells,
however, were designed to intercept ground water in
both alluvium and shallow bedrock. This type of
completion makes it difficult to characterize the
background alluvial water quality. For this EIS, only
alluvial wells that contained a minimum of 75 percent
(by depth) of the open portion of the well in alluvium
were considered in the water quality summary tables.
The selection of the 75 percent cut-off was arbitrary.
However, since the alluvium is typically several
orders of magnitude greater in hydraulic conductivity
than the bedrock, it seems reasonable to assume that
3-94
Carlota Copper Project Final EIS
<S w
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CARLOTA COPPER PROJECT
Figure 3-15
Locations of Geologic
Cross Sections
' ^' ■■'^.;!/ ■ V > >V- -■' ••
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3-97
D
Cross Section D—D'; Looking N1 1°E
D'
LEGEND
— Geological Contact
— ^ — Fault, Showing Direction
of Movement
0-^ Thrust Fault (Sawteeth
In Upper Plate)
— X — Water Table Elevation
(Approximate)
V.E. = 0
200
400
Feet
1" = 500’
600 800
E
Cross Section E—E'; Looking N83°W
E’
Source: Carlota Copper Company 1994
EXPLANATION OF GEOLOGIC UNITS
Qal Alluvium (Quaternary)
Qt Slope Deposits - Undifferentiated (Quaternary)
TIv Apache Leap Volcanics (Tertiary)
TIv, Apache Leap Volcanics - Vitrophyre (Tertiary)
Cbx Cactus Breccia (Tertiary)
Tw Whitetail Conglomerate (Tertiary)
Fh Limestone (Paleozoic)
Me Escabrosa Limestone (Mississippian)
Dm Martin Limestone (Devonian)
€t Troy Quartzite (Cambrian)
Pcdb Diabase (Precambrian)
Peps Apache Group (Precambrian)
Pepi Pinai Schist ( Precambrian)
See Figure 3-15 for Locations of Geoiogic Cross Sections
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-17
Geologic Cross Sections
D-D’, E-E’ for Main
Mine Rock Area
3-99
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3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-46. Summary of Ground Water and Spring Water Quality for the Affected Environment
'Constituents with values that exceeded a water quality criterion in at least one sample
the water quality of a well that contains 75 percent of
its open interval in alluvium will be dominated by
ground water input from the alluvium. The quality
control data provided for field duplicates and blanks,
generally near or below the applicable water quality
standards.
Pinto Creek Drainage Ground Water Quality.
Among the bedrock wells developed in the Pinto
Creek drainage for water quality monitoring, BMW-1 ,
BMW-2, BMW-4, and BMW-5 (GWRC 1996b) meet
the selection criteria and were used in the analysis
(well locations shown in Figure 3-13). Ground water
from these wells is generally a calcium/sodium-
bicarbonate/sulfate type. The pH, water temperature,
TDS, sulfate, fluoride, dissolved iron, and dissolved
manganese are summarized in Table 3-46. Spatial
variation in the water type of bedrock well samples
was observed throughout the Pinto Creek drainage.
Analyses of water quality samples collected
consistently met applicable Arizona Aquifer Protection
Standards and federal primary and secondary MCLs
for all constituents tested except TDS, fluoride, iron,
and manganese {Tables C4-1 /n Appendix C, Water
Resources Data). Laboratory analytical detection
levels were not sufficiently sensitive to evaluate
ambient water quality with respect to applicable water
quality standards for the following constituents:
beryllium and thallium.
Two alluvial water quality monitoring wells were
isolated within the Pinto Creek drainage; one in
the Pinto Creek alluvium (AMW-15) and the other in
the alluvium of Cottonwood Gulch (AMW-12) {Figure
3-13). Ground water from these wells is generally a
calcium-sulfate type. The pH, water temperature,
TDS, sulfate, fluoride, dissolved iron, and dissolved
manganese are summarized in Table 3-46. A large
variation in sulfate and TDS concentrations from
these wells (GWRC 1994 and 1996b) and the close
proximity of the wells suggest possible influences
from mineralized areas and/or existing mining
Carlota Copper Project Final EIS
3-101
3.0 Affected Environment and Environmental Consequences - Water Resources
disturbance in the area. Analyses of water quality
samples collected consistently met applicable Arizona
Aquifer Protection Standards and federal primary and
secondary MCLs for all constituents tested except
TDS, sulfate, cadmium, iron, and manganese {Table
C4-2 in Appendix C, Water Resources Data).
Laboratory analytical detection levels were not
sufficiently sensitive to evaluate ambient water quality
with respect to applicable water quality standards for
the following constituents; antimony, beryllium, and
thallium.
Powers Gulch Drainage Ground Water Quality.
Among the bedrock wells developed in the Powers
Gulch drainage for water quality monitoring, only
BMW-6, BMW-7, BMW-8, BMW-9 and BMW-11
(GWRC 1996b) meet the selection criteria and were
used in the analysis {Figure 3-13). Ground water from
these wells is generally a calcium/magne-
sium/sodium-bicarbonate type. The pH, water
temperature, TDS, sulfate, fluoride, dissolved iron,
and dissolved manganese are summarized in Table
3-46. Analyses of water quality samples collected
consistently met applicable Arizona Aquifer Protection
Standards and federal primary and secondary MCLs
for all constituents tested except pH, TDS, sulfate,
cyanide, iron, lead, and manganese {Table C4-1 in
Appendix C, Water Resources Data). Laboratory
analytical detection levels were not sufficiently
sensitive to evaluate ambient water quality with
respect to applicable water quality standards for the
following constituents: beryllium and thallium.
One well was isolated in the Powers Gulch alluvium
(AMW-17) {Figure 3-13). Ground water from this well
is generally a calcium/magnesium/sodium-sulfate
type. The pH, water temperature, TDS, sulfate,
fluoride, dissolved iron, and dissolved manganese are
summarized in Table 3-46. The high TDS and sulfate
concentrations displayed by samples from this well
may not be representative of the entire alluvium in
this reach of Powers Gulch. Summaries of other
surface water {Table 3-45) and bedrock ground water
{Table 3-46) samples within Powers Gulch do not
reflect the same relative TDS and sulfate
concentrations. Analyses of water quality samples
collected consistently met applicable Arizona Aquifer
Protection Standards and federal primary and
secondary MCLs for all constituents tested except
TDS, chloride, sulfate, fluoride, antimony, cadmium,
and manganese {Table C4-2 in Appendix C, Water
Resources Data). Reported detection levels were too
high to evaluate water quality standard exceedances
for the following constituents: beryllium and thallium.
Well Field Area Ground Water Quality. Three
bedrock test production wells (TW-1 , TW-2, and TW-
3) in the well field area were sampled for water quality
{Figure 3-13). Ground water from these wells is
generally a calcium-bicarbonate type. The pH, water
temperature, TDS, sulfate, fluoride, dissolved iron,
and dissolved manganese are summarized in Table
3-46. Analyses of water quality samples collected
consistently met applicable Arizona Aquifer Protection
Standards and federal primary and secondary MCLs
for all constituents tested except iron, manganese,
and gross alpha activity {Table C4-1 in Appendix C,
Water Resources Data). Laboratory analytical
detection levels were not sufficiently sensitive to
evaluate ambient water quality with respect to
applicable water quality standards for the following
constituents: antimony, beryllium, and thallium.
Two water quality monitoring wells (AMW-21 and
AMW-23) were isolated in the alluvium within the well
field area {Figure 3-13). A third monitoring well
(AMW-22) did not isolate the alluvium, and therefore
water quality sample results from this well were not
included in the alluvial water quality summary.
Ground water from these wells is generally a calcium-
bicarbonate type. The pH, water temperature, TDS,
sulfate, fluoride, dissolved iron, and dissolved
manganese are summarized in Table 3-46. Analyses
of water quality samples collected consistently met
applicable Arizona Aquifer Protection Standards and
federal primary and secondary MCLs for all
constituents tested except TDS, antimony, lead, and
manganese {Table C4-2 in Appendix C, Water
Resources Data). Laboratory analytical detection
levels were not sufficiently sensitive to evaluate
ambient water quality with respect to applicable water
quality standards for the following constituents:
beryllium and thallium.
Spring Water Quality. Two springs (Grizzly Bear and
Mule springs) within the project area were sampled
for water quality (Montgomery & Associates 1993
and GWRC 1996). Water samples from these springs
are generally a calcium-bicarbonate type. The pH,
water temperature, TDS, sulfate, fluoride, dissolved
iron, and dissolved manganese are summarized in
Table 3-46. Analyses of water quality samples
3-102
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
collected for Grizzly Bear Spring showed no water
quality standard exceedances, while Mule Spring only
exceeded the manganese water quality standard
{Table C4-3 in Appendix C, Water Resources Data).
Laboratory analytical detection levels were not
sufficiently sensitive to evaluate ambient water quality
with respect to applicable water quality standards for
the following constituents: antimony (Mule Spring
only), beryllium, and thallium (Mule Spring only).
Private Well Water Quality. Data were available
from 4 private wells (Montgomery & Associates 1993)
in the upper reaches of the Powers Gulch drainage
(Top-of-the-World). Ground water from these wells is
generally a calcium-bicarbonate type. The pH, water
temperature, TDS, sulfate, fluoride, dissolved iron,
and dissolved manganese are summarized in Table
3-46. Analyses of water quality samples collected
consistently met applicable Arizona Aquifer Protection
Standards and federal primary and secondary MCLs
for all constituents tested except TDS, and zinc
{Table C4-1 in Appendix C, Water Resources Data).
Ground Water/Surface Water Interactions
Interpretations regarding ground water/surface water
interactions are based on measurements of surface
flow at surface stations, ground water levels in
bedrock and alluvial wells, and comparison of the
chemical character of the surface water and ground
water. In the project area, possible ground
water/surface water interactions include (1) infiltration
of streamflow as recharge to the alluvial and bedrock
aquifers, (2) discharge of ground water stored in the
alluvium to streams and bedrock aquifer, (3)
discharge of ground water from the bedrock aquifers
into the alluvial aquifer, and (4) discharge of bedrock
ground water directly into streams (where the stream
channel is incised into bedrock).
Pinto Creek. During periods of high streamflow, the
porous alluvium is recharged by the infiltration of
streamflow. As the streamflow declines, water drains
from the alluvium into the stream. This process prob-
ably plays a significant role in sustaining baseflow
along some reaches of Pinto Creek (based on the
distribution of alluvium along the Pinto Creek
drainage), particularly in the perennial reach
extending downstream from PC-10 and the
discontinuous flowing reaches that occur between
PC-5 and the Haunted Canyon confluence. As the dry
season progresses, the water level in the alluvium
may drop to the point where it falls below the bottom
of the stream channel. At this point, the streamflow in
the channel reach ceases. However, some flow is still
moving downstream beneath the channel as alluvial
underflow. Where the saturated alluvium pinches out
in a downstream direction, this alluvial underflow will
re-emerge for some distance as surface flow through
a bedrock channel. As a result, during baseflow,
stream segments with intermittent alluvium and
bedrock reaches are typically characterized by
discontinuous dry (alluvium) and flowing (bedrock)
reaches. These processes are probably responsible,
at least in part, for the discontinuous flow reported
(GWRC 1996b) between PC-3 and PC-6, and
downstream from PC-7 along Pinto Creek. Discharge
of ground water from the bedrock complex into the
stream channel or into the alluvium and then into the
stream channel could contribute to or control the
location of flowing reaches between PC-5 to PC-7.
However, there are insufficient data to quantify the
contribution from these different sources. A portion of
the flows in Pinto Creek downstream of the Haunted
Canyon confluence appear to be controlled by
discharge from the bedrock complex in Haunted
Canyon (see Haunted Canyon Area well field
discussion below).
In the vicinity of the Carlota/Cactus pit, Pinto
Creek flows through a reach that is mantled with
alluvium. The water chemistry data, as illustrated in
Figure 3-18, indicate that surface water and ground
water in the alluvium are very similar calcium-sulfate
type waters with moderate to high TDS (see Table
3-45 and 3-46). The similarity between these two
waters suggests that there is interaction between the
surface flows and ground water in the alluvium. Water
level data from monitoring wells in the vicinity of the
Carlota/Cactus pit indicate that there is a potential for
ground water flow between the alluvium and bedrock.
This potential, measured as a difference in head
between the two aquifers, varies seasonally and from
location to location. As shown in Figure 3-18, water
quality data from numerous bedrock wells in the
Carlota/Cactus pit area reflect a wide variation in
ground water chemistry, being dominated by
combinations of calcium, sodium, bicarbonate, and
sulfate. The major influence of sodium and
bicarbonate in the bedrock ground water (not seen in
Carlota Copper Project Final EIS
3-103
Pinto Creek Area
Haunted Canyon
and Well Field
Calcium (Ca)
CATIONS
%meq/L
Chloride (Cl)
ANIONS
Legend
Bedrock Wells
(Test Production Wells)
Alluvial Well in
Haunted Canyon (AMW-21)
Alluvial Well in
Pinto Creek (AMW-23)
Surface Water Station,
Haunted Canyon (HC-2)
Surface Water Station,
Pinto Creek (PC-7)
Riverside Technology, inc.
Notes: Data plotted was restricted to represent water quality data
collected at the selected monitoring points during low stream
flow (or baseflow) periods. The composition of the alluvial
and surface water would vary at higher stream flows as the
contribution from runoff increases.
CARLOTA COPPER PROJECT
Figure 3-18
Ground Water/Surface Water
Trilinear Diagrams
3-104
3.0 Affected Environment and Environmental Consequences - Water Resources
the calcium-sulfate dominated alluvial and surface
waters of the area, as shown in Figure 3-18) suggests
that the chemical composition of the bedrock and
alluvial waters are dissimilar. This dissimilarity
suggests that there is only minor interaction between
the two aquifers, and that flow from the bedrock
complex is relatively small and may not contribute
significantly to the alluvial or surface flows in Pinto
Creek in the vicinity of the proposed Carlota/Cactus
pit.
Water quality data collected during low flow from
station PC-7, located 3,000 to 4,000 feet downstream
from the Haunted Canyon confluence, are presented
in Figure 3-18. This sample was collected at a time
when no surface water flow was observed upstream
from Haunted Canyon at surface water stations PC-1,
PC-2, PC-3, PC-4, PC-5, and PC-6. These water
quality data indicate that at low flows, the flow in Pinto
Creek below the well field (PC-7) is distinct from
water quality in Haunted Canyon (HC-2) and
upstream in Pinto Creek (PC-3 and PC-5). On the
Trilinear plot {Figure 3-18), the PC-7 sample falls
between the Haunted Canyon and the upstream Pinto
Creek water samples. Therefore, the water at PC-7
during low flow is interpreted as a mixture of these
two distinct water types. One possible explanation is
that baseflow in Pinto Creek, below Haunted Canyon,
is a mixture of discharge from Haunted Canyon and
underflow in Pinto Creek that is not visible at the
surface at PC-6, located upstream from Haunted
Canyon.
Powers Gulch. Water level data from wells in the
Powers Gulch area indicate that at certain times of
the year, there is a potential for flow from the
bedrock to the surface; at other times there is a
potential for flow from the surface into the bedrock.
A bedrock monitoring well, located in the creek bed
in Powers Gulch (PG-2) within the footprint of the
proposed heap-leach pad, had recorded water levels
above the ground surface in April and May 1992,
March 1993, and March through May 1995. Other
bedrock monitoring wells indicate that at times the
depth to the potentiometric surface for the bedrock
complex is very near the surface (PG-1 , PG-2, and
PG-5) over a portion of the heap-leach site
(particularly adjacent to the stream channel). Mule
Spring, located in a tributary to Powers Gulch west of
the heap-leach pad, apparently represents discharge
of ground water from the bedrock complex.
Haunted Canyon Area. In the well field area,
recorded water levels for the three alluvial monitoring
wells range from a few feet beneath the surface to
approximately 12 feet beneath the surface. Pressure
measured in the shut-in water supply wells indicates
that the potentiometric surface for the water supply
wells ranges from approximately 40 to 65 feet above
the surface. These head differences indicate that the
bedrock aquifer is confined, and there is a large
vertical hydraulic gradient between the bedrock
aquifer system and the alluvial/surface water system.
Monthly water level data from AMW-21 indicate that
the alluvial water levels fluctuate up to approximately
3 feet per year. The water table fluctuation
corresponds to recharge (rise) from the stream during
periods of increasing runoff and discharge (drop) as
streamflows decrease. However, because of the
limited extent of saturated alluvium in Haunted
Canyon, the contribution of alluvial discharge to
streamflow is estimated to be very small. The results
of the seismic surveys support the assumption that
the baseflow component of the hydrograph for
streamflow (or low flow) in Haunted Canyon is
sustained by water leaking upward from the bedrock
complex.
As illustrated in Figure 3-19, there is a correlation
between the flows in Haunted Canyon (at HC-2) and
alluvial water levels (at monitor well AMW-21, located
near HC-2). The correlation between the streamflows
and alluvial water levels indicates that there is a close
interconnection between the streamflow and alluvial
water levels. This correlation is also supported by a
diurnal study conducted to evaluate daily fluctuations
in streamflow and alluvial water levels (GWRC
1995b). During the diurnal study, flows at station HC-
2a varied from 2 gpm to 56 gpm, and the water level
in the nearby alluvial well (AMW-21) varied 0.64 foot
over the 24-hour observation period. Again, the
maximum and minimum flows correlated with the
maximum and minimum water levels in the alluvium,
although the response in the alluvium lagged behind
the stream fluctuations by approximately 2 hours. The
streamflow and alluvial fluctuations recorded during
the diurnal study suggest close interconnection
between the stream and alluvial systems. In addition,
the diurnal study indicates that evapotranspiration
can result in significant daily streamflow and alluvial
water level fluctuations, particularly in the late spring,
summer, and early fall. The chemical data, as shown
in Figure 3-18, indicate that during low-flow periods.
Carlota Copper Project Final EIS
3-105
c:\projects\a2 1 0\fig3-19.doc 3/6/97
Streamflow (gpm)
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-19
AMW-21 Mean Water Table
Elevation Versus HC-2 Streamflow
3.0 Affected Environment and Environmental Consequences - Water Resources
the general composition of water in the bedrock test
production wells, in the alluvium, and in the stream in
Haunted Canyon are similar. These data suggest that
the perennial flow in Haunted Canyon and the water
level in the alluvium are sustained during baseflow
periods by the discharge of ground water from the
confined bedrock system.
3.3.2 Environmental Consequences
The primary water resource issues include the
following; (1) reduction in surface and ground water
for current users and water-dependent resources
upstream, within and downstream of the project area,
(2) impacts to ground water and surface water
quality, (3) physical or chemical impacts caused by
discharging dredged or fill material, (4) impacts to
floodplains within and downstream of the project area,
(5) changes in channel dynamics caused by diverting
Pinto Creek and Powers Gulch, and (6) impacts
related to the water quality and elevation of the
postmining Carlota/Cactus pit lake. Potential impacts
to waters of the U.S., wetlands, and riparian areas
are addressed in Section 3.5, Biological Resources.
Evaluation criteria that were used to analyze water
resource impacts included the following:
Surface Water
• Alteration of streamflow quantities
• Degradation of surface water quality constituents
based on Arizona standards for designated
beneficial uses
• Acres of floodplains affected
• Alteration of channel geometry or gradients
sufficient to produce increased aggradation,
degradation, sidecutting, channel migration, or
sedimentation as measured by flow velocity and
sediment transport
• Water quality of postmining Carlota/Cactus pit
lake
Ground Water
>
• Change in water supply available to existing wells
in the area because of project operations
• Change in elevation of ground water level in
streamside alluvium and bedrock aquifer system
• Degradation of water quality within a given
aquifer caused by the introduction of foreign
substances based on the Arizona Aquifer
Protection Standards.
3.3.2.1 Proposed Action
Pit Construction and Dewatering Impacts
Permanent withdrawal of the Carlota/Cactus pit area
would result in a reduction of approximately 0.4
square mile of contributing watershed area. This
would equal roughly 1 percent of the watershed area
at the confluence of Haunted Canyon and Pinto
Creek and would reduce mean annual runoff
downstream by approximately 56 acre-feet based on
average annual watershed runoff above the Pinto
Valley weir of 2.62 inches. This reduction represents
approximately 1 percent of the mean annual runoff at
the PC-7 gage site.
The Eder pits would occupy a combined area of
approximately 83 acres (0.1 square mile) of the
Powers Gulch watershed area (5.5 square miles).
During mining operations, this part of Powers Gulch
would be withdrawn from the area contributing
surface runoff to the watershed, which would reduce
surface runoff by approximately 18-acre feet per year.
This volume represents approximately 2 percent of
the runoff from the Powers Gulch watershed and less
than 0.4 percent of the runoff at the PC-7 gage site.
This impact would occur primarily during storm
events. The impact would end after reclamation and
closure since the Eder Pits would be returned to an
area that contributes surface runoff to the watershed.
Reclamation would be accomplished by partially
backfilling the Eder pits with mine rock and
recontouring the backfilled surface so that
Carlota Copper Project Final EIS
3-107
3.0 Affected Environment and Environmental Consequences - Water Resources
precipitation falling over the reclaimed area would be
free to exit the area as stormwater runoff.
The results of ground water monitoring and pump
tests indicate that water-bearing rocks in the vicinity
of the Carlota/Cactus, Eder North, and Eder South
pits contain fractures that would likely yield ground
water to the pits during the mining operation. As a
result, dewatering would be required to limit the
amount of inflow into the pits and to maintain pit wall
stability. Dewatering would be designed to maintain
water levels below the floor of the pit as mining
progresses. Pit dewatering activities would result in
the drawdown of water levels in the bedrock complex
during operation. The maximum drawdown, which
corresponds to the ultimate pit depth, would be
approximately 750 feet in the immediate vicinity of the
Carlota/Cactus pit, 230 feet in the Eder South pit
area, and 200 feet in the Eder North pit area. After
dewatering ceases, the water level in the
Carlota/Cactus pit would rise, responding in part to
ground water inflow. The Eder pits would be backfilled
to above the premining water level to prevent
postclosure ponding.
Ground water in the bedrock complex is stored and
transmitted along interconnected fracture networks
within the rock mass. Since the rock mass is actually
composed of several different rock types of different
ages, it is suspected that the orientation and
interconnection of fractures is not uniform within the
bedrock complex. This variability in fracture
characteristics from one arealo the next is indicated
by the broad range in hydraulic conductivity (less than
0.005 to 9.5 gpd per square foot of aquifer [gpd/ff])
for pump tests conducted in the monitoring wells
{Table C3-1 in Appendix C, Water Resources Data).
The geologic characterization data and pump test
results indicate that the hydraulic properties of the
rock mass are generally heterogeneous (different
from one location to another) and at least locally
anisotropic (different in different directions).
Considering the complexity of the hydrogeologic
setting, it is not possible to predict the precise
boundaries of the area that will be affected by
drawdown resulting from the mine dewatering
activities.
The general dewatering requirement and the area of
influence have been evaluated using MODFLOW,
a finite difference numerical model ( GWRC 1994).
The bedrock complex aquifer was modeled as a
single, continuous, homogenous and isotropic
aquifer with a hydraulic conductivity of 0.1 gpd/ft".
Sensitivity analyses were performed by varying
the hydraulic conductivity from 0.05 to 0.2 gpd/fT.
The alluvial aquifers were not considered in
construction of the layering and zonation within
the model. In addition, no attempt was made to
calibrate the model to steady state conditions.
These assumptions and model procedures limit the
usefulness of the model to predict maximum
drawdown from pit dewatering.
Using the numerical model MODFLOW (GWRC
1994) and the assumptions stated previously, the
maximum computed rates of ground water inflow/pit
dewatering requirements predicted by the model
ranged from 85 to 280 gpm for the Carlota/Cactus pit,
1 5 to 47 gpm for the Eder North pit, and 33 to 1 02
gpm for the Eder South pit, depending on the
hydraulic conductivity value used for the bedrock
complex.
The low transmissivity for the bedrock complex
indicates that the amount of drawdown would
decrease rapidly away from the pit. However, the
extent of the cone of depression in any direction
depends on the hydraulic properties of the water-
bearing rocks. For example, the drawdown effects
would be much greater along transmissive fracture
zones and would be limited in the directions of low-
permeability bedrock. For the purposes of analyses,
the maximum extent of the 10-foot drawdown contour
(predicted using MODFLOW) was selected as the
general area of drawdown impacts. Although some
drawdown could occur outside of the 10-foot
drawdown contour, these changes would probably be
indistinguishable from natural fluctuations in the
ground water levels that occur seasonally and from
year to year. Based on the hydrogeologic conditions,
as well as pump test data, it appears that the impacts
from drawdown would generally be restricted to areas
immediately surrounding the pits. The drawdown
associated with the Carlota/Cactus pit would affect a
considerably larger area than the drawdown from the
Eder pits. Based on available hydrogeologic data,
pump test data, analytical modeling, and numerical
modeling, it appears that the drawdown impacts
(defined as greater than 10 feet of drawdown) would
not extend farther than 1 to 2 miles from the perimeter
of the Carlota/Cactus pit. Locally, drawdown could
3-108
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
affect water supply wells, spring or seep discharge,
and streamflows.
As stated previously, there is uncertainty regarding
the configuration and aerial distribution of the
maximum extent of the 10-foot drawdown contour
resulting from mine dewatering efforts. A
comprehensive ground water and surface water
monitoring program is proposed as part of the
monitoring and mitigation measures (Section 3.3.4,
Water Resources - Monitoring and Mitigation
Measures). Under this program, the monitoring data
would be used to track the extent and rate of
expansion of the cones of depression resulting from
mine dewatering. The results of the MODFLOW
modeling was used to select the boundary of the
initial area to be included within the monitoring area.
The monitoring would be used to trigger the
implementation of mitigation measures for individual
wells, springs, and streams on National Forest
System lands and to make information available to
the public with regard to changes in environmental
conditions.
Impacts on Wells. The drawdown of water levels in
the bedrock complex caused by dewatering activities
could potentially affect some wells located in the
vicinity of the project. Water supply wells located
within the drawdown area could experience a
noticeable drop in their pumping water levels. Where
alterations in directions of ground water flow are
experienced, changes in well water quality are also
possible. The magnitude of the water level decline
and degree of water quality variation would depend
on the location of the well and the actual
hydrogeologic conditions. Impacts to wells from
lowering the water level could increase pumping
costs and possibly decrease production. In addition,
individual wells could become unusable if the water
level was lowered to below the pump setting or below
the bottom of the well. Given the complex
hydrogeologic conditions, it is not possible to
determine with certainty which wells (if any) will be
affected by the mine dewatering efforts. However,
using conservative estimates, any well located within
the 10-foot drawdown contour, which is estimated to
extend no further than 1 to 2 miles from the
Carlota/Cactus Pit could potentially be affected.
The Top-of -the- World community is dependent on
ground water derived from pumping private water
supply wells. Most of the wells are constructed in
fractured bedrock consisting of the Schultze Granite
and Apache Leap Dacite units, and reported yields
range from less than 1 gpm to 40 gpm. Apparently
in recent years some of these wells have had
problems with declining water levels and decreased
yields (scoping comment letters). These problems
may be the combined result of (1) decreased
recharge of the bedrock aquifer during periods of
below-normal precipitation, (2) depletion of the
aquifer by overpumpage, and/or (3) well interference
between adjacent wells. Based on the
aquifer characteristics and the distance to active
mining projects, it is unlikely that any wells in the
community have been affected by existing dewatering
at currently operating mines in the area.
The northern margin of the Top-of-the- World
community is located approximately 10,000 feet south
of the Carlota/Cactus pit and 4,500 feet south of the
Eder South pit. Since the northern portion
of the Top-of-the-World wells are located within
2 miles of the open pits, there is some potential for
dewatering to affect these wells. Because of the
hydrogeologic conditions found in this area, these
effects are not anticipated to include water quality
impacts. Results from pump tests indicate that, in
general, the bedrock complex has a low transmitting
and storage capacity. In addition, water quality,
water level, and pump test data also suggest that
there is some partitioning within the bedrock aquifer.
These factors would tend to limit the maximum
extent of the cone of depression caused by pit
dewatering. However, there is uncertainty regarding
actual hydraulic communication between fractures
in the vicinity of the pits and the Top-of-the-World
community. Considering these uncertainties and
the importance of ground water as the sole source
of water to the Top-of-the-World community,
monitoring is proposed in Section 3.3.4, Water
Resources - Monitoring and Mitigation Measures.
The Pinto Valley Mine has several water supply wells
located within a 1 - to 2-mile radius of the Carlota/
Cactus pit. Little information exists to evaluate the
potential for interaction between the ground water on
the project site and the Pinto Valley Mine. However,
because of the level of uncertainty involved, the Pinto
Valley Mine wells, may potentially be affected and are
also addressed in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures.
Carlota Copper Project Final EIS
3-109
3.0 Affected Environment and Environmental Consequences - Water Resources
Impacts on Seeps and Springs. Drawdown from
mine dewatering could potentially affect natural
springs in the project vicinity. The magnitude of the
impact would depend on the relationship between the
spring location and the zone of influence (or cone of
depression) caused by dewatering. Potential impacts
could range from a minor reduction to a complete
elimination of flow. Depending on the origin of the
ground water that discharges at the surface as a
spring, a reduction in flow could be accompanied by a
change in water quality. However, where the source
of the spring discharge is a single hydrostratigraphic
unit (or aquifer) with relatively constant water quality,
lowering the water level within the unit, and thereby
reducing spring discharge rates, should not result in a
significant change in water quality. It is likely that
flows and water quality conditions in affected springs
would return to premining conditions once ground
water levels recover after the cessation of mining.
Identified springs within a 2-mile radius of the Carlota/
Cactus pit include (1) natural springs (developed and
undeveloped), (2) springs created by discharge from
abandoned mine workings (adits), and (3) springs
from existing tailings facilities. Mule Spring, located
approximately 2,000 feet from the Eder North pit and
4,000 feet from the Carlota/Cactus pit, and spring
35dd, located approximately 2,500 feet from the
Carlota/Cactus pit, could potentially be affected. The
Grizzly Bear Springs and two small springs with
reported discharge rates of less than 1 gpm (GWRC
1994) located within the Main mine rock disposal area
are anticipated to be affected by pit dewatering and
the placement of mine rock material. Springs that
discharge from caved mine adits or near other mine
workings within or near the pits would either be
eliminated by mining (36ca, 36dd) or affected by
dewatering (06ab, 01 bb, 12ab). Miller Spring and
other springs with high specific conductance that
appear to be controlled by seepage from existing
tailings facilities (25ca) should not be affected by pit
dewatering since these springs are not related to or
controlled by discharge from the bedrock complex
ground water system. Yo Tambien spring flows out of
an adit above Pinto Creek approximately 2,000 feet
south of the Carlota/Cactus Pit. Based on the
proximity of the spring to the pit, it is possible that the
flows could be reduced. Therefore, monitoring and
mitigation for reduced spring flow are addressed in
Section 3.3.4, Water Resources - Monitoring and
Mitigation.
Impacts on Shallow (Alluvial) Ground Water and
Streamflows. Dewatering the Carlota/Cactus
pit could potentially deplete some ground water
stored in the alluvium in both the upstream and
downstream reach of Pinto Creek adjacent to the
Carlota/Cactus pit. The length of the reach that would
be affected could potentially extend up to a few
thousand feet from the perimeter of the pit.
Montgomery & Associates (1993) estimated that the
length of reach affected would probably be on the
order of 2,000 feet upstream and downstream from
the pit. Assuming an average alluvial width of 300
feet, a saturated thickness of 10 feet, hydraulic
conductivity of 50 feet per day, and an approximate
gradient of 100 feet per mile, the estimated rate of
flow through the alluvium in this reach is on the order
of 16 gpm.
Following the Montgomery & Associates report
(1993), alluvial and bedrock monitoring well nests
were established in Pinto Creek upstream and
downstream from the Carlota/Cactus Pit (AMW15,
BMW4, AMW13, BMW5; see Figure 3-13). One
purpose of these wells was to provide information on
the interactions between the bedrock and alluvial
aquifer systems. Monthly water levels recorded from
mid-1993 through 1995 indicate that the water levels
in the alluvium are generally several feet higher than
water levels in the bedrock. This indicates that at
these locations there is separation between the
alluvial and bedrock aquifer systems. The water
quality data for these wells (GWRC 1996b) indicates
that the alluvial water contains high sulfate (205-491
mg/L) and high TDS concentrations (508-934 mg/L)
compared to the bedrock water quality (sulfate 11-
157 mg-L, TDS 288-504 mg/L). Therefore, the alluvial
and bedrock waters are chemically distinct. Under the
existing condition, there is a potential for some
seepage from the alluvium into the bedrock aquifer.
Furthermore, these data suggest that at these
locations, the streamflows in Pinto Creek are not
sustained by or controlled by discharge from the
bedrock system. Based on these monitoring data, pit
dewatering is not anticipated to significantly affect the
alluvial flows or streamflows in Pinto Creek. However,
interaction between the bedrock and alluvial system
may vary further upstream or downstream from the pit
within the area that may be affected by drawdown of
the bedrock system. Therefore, there may be some
potential for pit dewatering to capture alluvial flows
above and below the existing well nests.
3-110
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Excavation of the Carlota/Cactus Pit would expose
the Pinto Creek alluvium in the north and south walls
of the pit upstream and downstream of the proposed
diversion channel. As part of the proposed action, the
potential removal of water from the alluvial system
would be reduced by constructing an alluvial cutoff
wall upstream from the pit. Because of the reversal of
gradients near the pit, there may also be the potential
for some of the ground water in the alluvium
downstream from the pit to flow into the pit, where the
alluvium would be daylighted in the north pit wall.
However, as estimated above, these flows are
anticipated to be on the order of 16 gpm or less.
Daylighting the alluvium in the North pit wall could
result in capturing some alluvial interflow in Pinto
Creek. Therefore, monitoring and mitigation for
potential inflow into the pit are addressed in Section
3.3.4, Water Resources - Monitoring and Mitigation.
Alluvial water quality in Pinto Creek near the pro-
posed Carlota/Cactus pit is variable, possibly
because of previous mining activities or other natural
mineralization. Depending on the specific alluvial
flows intercepted and the extent of dewatering,
impacts to remaining alluvial flows are possible. Cap-
turing water in the alluvium would reduce alluvial flow
and could reduce surface flows in Pinto Creek up-
stream and downstream from the Carlota/Cactus pit.
Pit Water Recovery Impacts
There are three proposed pits for the Carlota Copper
Project: two Eder pits (North and South, including the
small Eder Middle pit) and the Carlota/Cactus pit. The
Eder pits would be located on the west hillside of
Powers Gulch and would be partially backfilled with
mine rock material. The pit bottom elevations prior to
backfilling would be 3,880 ft-amsi for the Eder North
pit and 4,080 ft-amsI for the Eder South pit. The final
backfilled pit elevations would range from approxi-
mately 4,000 to 4,200 ft-amsI. Approximately 4 million
tons of mine rock would be placed in the Eder pits.
The backfilled material would be contoured so that no
ponding of water would occur within the pits; any
precipitation captured by the pit highv/alls and fill
areas would exit the pit as stormwater runoff. This
situation would be similar to premining conditions;
therefore, long-term impacts to surface or ground
water are not anticipated in the Eder area.
The Carlota/ Cactus pit would be partially backfilled.
Water balance calculations have determined that
water would be impounded in the pit after the
cessation of mining (and pumping); the backfill
material would only be partially submerged by the
final pit lake. Surface water runoff, direct precipitation
to the lake, and ground water seepage would
contribute as inflow to the pit lake. The following
discussion refers to pit water recovery impacts for the
Carlota/Cactus pit.
A water balance approach was used to determine
the final pit lake elevation once mining operations
cease. The water level in the lake would depend
on the amount of water entering the pit through
ground water inflow, surface runoff from the pit walls,
direct precipitation onto the lake surface, and the
amount of water lost from the lake surface through
evaporation. The pit lake water balance for the EIS
analysis used conservative (high) estimates for initial
ground water inflow and conservative (high)
estimates for surface water runoff, both of which
increase the predicted final lake level. Even using
these conservative assumptions, the relatively high
evaporation rates result in a final pit lake level that is
estimated to stabilize at approximately 3,345 ft-amsI,
which is approximately 150 feet below the premining
ground water level in the alluvium beneath Pinto
Creek, and several hundred feet below the premining
water level in the bedrock slopes adjacent to Pinto
Creek. Since the elevation of the lake surface is
predicted to be considerably below the surrounding
water levels in the bedrock and alluvial systems, the
pit lake is anticipated to behave as a sink whereby
the ground water gradient in all directions would be
toward the pit. Ground water gradients sloping down
toward the pit in all directions should effectively
prohibit any significant ground water outflow from the
pit lake.
From the water balance calculations, it is estimated
that the equilibrium water level (defined as less than
0.1 percent change in water level annually) in the
Carlota/Cactus pit would be achieved approximately
125 years after the pumping stops and would be
approximately 505 feet above the pit floor (3,345 ft-
amsl). At this level, the pit lake surface would be 135
feet below the Pinto Creek diversion’s lowest point
(3,480 ft-amsI) and would hold approximately 17,100
Carlota Copper Project Final EIS
3-111
3.0 Affected Environment and Environmental Consequences - Water Resources
acre-feet of water. After the lake fills, an estimated
480 acre-feet per year (300 gpm) would be lost
through evaporation off the lake surface.
Water quality standards prescribed by the ADEQ for
surface water do not apply to open pits associated
with the mining of metallic ores (Title 18, Section R18-
11-102). Since water balance modeling indicates that
the pit should behave as a sink, outflow from the pit
lake to ground water is not anticipated. Therefore,
Arizona Aquifer Protection Standards would also not
be applicable to pit water quality.
Dissolved and suspended materials would be
transported to the pit lake by ground water inflow, by
direct precipitation and runoff, and through natural
leaching of the wall rock exposed in the pit; the pit
water would then be concentrated by evaporation.
The contribution of TDS from ground water was
estimated by averaging water quality data from
bedrock wells near or in the Carlota/Cactus pit that
were determined to be representative of rock types
and ground water flows present at closure (BMW-1,
BMW-2, MW-4, MW-5, MW-6, MW-9, MW-10). An
average precipitation rate of 20.37 inches per year
was used (GWRC 1994). Available precipitation
chemistry data from Graham County, Arizona
(National Atmospheric Deposition Program 1994) was
used to estimate the dissolved solids contribution to
the pit lake from precipitation. It was assumed that 50
percent of all precipitation that fell on soils and rock
within the pit watershed would end up in the pit lake,
and that 100 percent of the precipitation that fell
directly on the pit lake surface would be added to the
lake volume. Total evaporation from the pit lake was
proportional to the lake surface area at a rate of 5.554
feet per year (GWRC 1994).
In addition, meteoric water mobility test results and
acid generation/neutralization test results were used
to estimate wall rock and backfill contributions to the
pit lake final water chemistry. Wall rock and backfill
materials were predicted to be non-acid generating
and therefore the meteoric water mobility test results
were assumed to be an accurate estimation of
dissolved constituent contributions from these
materials. It was assumed that precipitation runoff
and water in the pit lake would leach metals, sulfate,
and other major ions from pit wall rock and backfill,
increasing the TDS load to the pit lake.
Mass balance calculations were performed on the pit
water to determine the concentrations of constituents
of interest when the water level reaches equilibrium.
Processes such as precipitation and adsorption slow
the concentration process by diluting dissolved
constituents from the water when thermodynamic
conditions are favorable. The EPA computer model
MINTEQA2 is designed to predict these processes.
The MINTEQA2 model was applied to the equilibrium
pit water chemistry to predict the anticipated water
quality. The geochemistry of the pit wall rocks and
partial backfill material were included in this analysis.
The MINTEQA2 model predicted that a pit water TDS
concentration of 687 mg/L {Table C5-1 in Appendix C,
Water Resources Data) would occur 125 years after
the cessation of pumping. The predicted pH of the pit
water would be 8.4 standard units, within the full body
contact and agricultural livestock water quality
standard range of 6.5 to 9.0 standard units. No data
were available for predicted concentrations of
beryllium, but significant levels of this constituent
would not be expected because of the high pH and
oxidizing nature of the pit lake water chemistry. The
inflow data for constituents reported as below the
minimum reportable level were not included in the
mass balance calculations or modeled for final pit
water quality. As shown in Table C5-1, the
concentrations of metals for the inflow data were low
and either remained unchanged or decreased in
concentration over the 125-year model period.
Although mass balance calculations and modeling
were performed for 125 years after the cessation of
mining (predicted time for the water level to reach
equilibrium), the pit water chemistry would not be
anticipated to be at equilibrium at this point in time.
The predicted zero outflow scenario means that the
concentrations of most constituents would continue to
increase. Natural systems provide sinks (sources of
removal) for many dissolved constituents, but many
of the major ions (sodium, chloride, sulfate) and TDS
would continue to increase in concentration to levels
many times greater than those modeled at 125 years.
Regardless of the final pit lake water quality, no
impacts to other surface or ground water resources
surrounding the pit would be expected, since no
outflow of water from the pit lake is predicted to
occur. Potential impacts to wildlife are discussed in
Section 3.5, Biological Resources.
3-112
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Well Field Impacts
The location of the proposed water supply well field
would tap into the bedrock aquifer in the vicinity of the
confluence of Haunted Canyon and Pinto Creek.
GWRC (1994) conducted a series of pump tests to
determine the long-term sustainable yield of a well
field located in this area. Three bedrock wells (TW-1,
TW-2, and TW-3) were drilled, and a series of
pumping and recovery tests were conducted between
October 1993 and January 1994. The locations of
these three bedrock wells (proposed water supply
wells) and the geology of the area are shown in
Figure 3-4. The pumping periods of the tests ranged
from 5 days (TW-1 and TW-3) to 24 days (TW-2). The
pump tests indicated that production wells located in
this area could supply the general water requirements
of the mine (GWRC 1994) (see Section 2. 1.6.1).
To evaluate the potential impacts to surface water
flows and shallow alluvial ground water from the well
field development, several streamflow stations, and
three shallow wells were monitored during the
pumping and recovery tests. The location of the
streamflow stations (HC-2, PC-7, and PC-7A) and
alluvial wells (AMW-21, AMW-22, and AMW-23)
located near the well field and included in the pump
testing are shown in Figure 3-4. Since TW-2 was
pumped at the highest rate (604 gpm) for the longest
time (24 days) and showed the largest impact on
alluvial water levels and surface flows in Haunted
Canyon, the results from this pump test provide the
primary information to evaluate potential impacts to
streams and ground water resources. Additional data
collected during the 5-day pump tests of TW-1 and
TW-3 provide supplemental information to predict
impacts.
The results of the TW-2 pump test are presented in
Figure 3-20. During the pump test, there was a slight
decrease in pressure recorded in bedrock
observation well TW-1 located 1,700 feet south of
TW-2, but no response in TW-3 located 2,300 feet
northwest of TW-2. The pressure in TW-1 recovered
to near prepumping conditions after the TW-2 pump
test was completed. The response in these wells
indicates that the bedrock aquifers tapped by TW-1
and TW-2 are interconnected. The several-day pump
test in TW-1 and TW-3 did not affect water levels or
pressure conditions in the other bedrock wells. From
these results, it appears that the cone of depression
in the bedrock complex caused by well field extraction
would extend out in some irregular fashion up to a
distance of a few thousand feet from the well field.
The water level in the alluvium also declined during
the TW-2 pump test. AMW-22 (located 200 feet from
TW-2) appeared to decline approximately 2.0 feet;
AMW-21, located in Haunted Canyon (1,550 feet
south of TW-2), declined 1 .0 feet; and AMW-23,
located along Pinto Creek (2,200 feet northwest of
TW-2), was not affected by the pumping. It is
important to note that drawdown in the alluvial wells
appeared to reach equilibrium during the TW-2
aquifer test (i.e., the water levels did not lower further)
after approximately 14 days in AMW-22 and 21 days
in AMW-21. Water levels in these wells recovered
slowly after the pumps were shut off.
During the TW-2 pump test, streamflows were
monitored in Haunted Canyon at station HC-2,
located approximately 3,200 feet south of TW-2, and
in Pinto Creek at station PC-7A, located
approximately 2,300 feet north of TW-2. The
measured flows at the Haunted Canyon (HC-2)
station during the pump test are presented in Figure
3-20. During the pump test, the Haunted Canyon flow
decreased from approximately 45 gpm at the start of
the test to 5 gpm at the end of the test. The flow
progressively increased to approximately 27 gpm
within a few days of shutting off the pump. The
decrease in flow recorded in Haunted Canyon during
the TW-2 pump test suggests that pumping the TW-2
well would reduce the flow in Haunted Canyon. No
decrease in flow was observed during the TW-2
pump test at the PC-7A station in Pinto Creek.
The pump tests of TW-1 and TW-3 did not appear
to affect streamflow in Haunted Canyon. However,
while pumping TW-3, the streamflow in Pinto Creek at
station PC-7, located 1 ,400 feet downstream from the
pumping well, decreased from approximately 350
gpm to 250 gpm. After the pump was shut off, the
flow at this station increased steadily over the next
several days to approximately 290 gpm. These data
suggest that pumping the TW-3 production well would
reduce the flows in Pinto Creek.
The pump and recovery tests indicated that there is a
hydraulic connection between water pumped from the
bedrock complex, water stored in the alluvium, and
surface flows. This connection is also supported by
the fact that the chemistries of the surface water.
Carlota Copper Project Final EIS
3-113
D:\A21CACDR\FIG3-20.CDR REVISION: 2/26/97
Pump On
i
Pump OW~|
A
TW-1 Observation Well
I Pump On I
A
|| Pump
A
AMW-21 Observation Well
50 -]
•TJ
0 ■
3
z
c
•50 ■
8>
C
-100 ■
£
u
■150 ■
-200 ■
TW-2 Pumping Well
Surface Flow at HC-2
AMW-22 Observation Well
Surface Flow at PC-7A
Date
Date
Riverside Technology, inc
CARLOTA COPPER PROJECT
Figure 3-20
Water Level and Flow
Response to the TW-2
Pump Test
3-114
3.0 Affected Environment and Environmental Consequences - Water Resources
ground water in the alluvial wells, and ground water in
the bedrock test wells in the well field area were
similar (see discussion under Ground Water/Surface
Water Interactions in Section 3.3.1). This chemical
similarity suggests that during low-flow conditions, the
surface flows and water levels in the alluvium are
sustained primarily by discharge from the bedrock
system. Pumping the bedrock wells would reduce the
amount of discharge from the bedrock into the
alluvium and creek bed.
Impacts on Wells. Based on the localized drawdown
pattern observed in the bedrock during the three
pump tests, it appears unlikely that wells located
more than 1 mile from the well field production wells
would be affected by long-term pumping. There are
four BHP Copper wells located within a 1-mile radius
of the well field: Peak 26, Peak 29, #3 Seep Caisson,
and well PV-SX. However, only Peak 26, Peak 29,
and PV-SX are completed into the bedrock aquifer.
Water levels in these wells would be lowered if (1) the
bedrock aquifers tapped by Carlota’s well field
production wells were hydraulically interconnected
with the bedrock aquifers intercepted by these three
bedrock wells, and (2) if the cone of depression
caused by pumping the Carlota production wells
overlaps with the cone of depression caused by
pumping any of these three BHP Copper bedrock
water wells. Given the complex hydrogeologic
conditions, it is not possible to determine if the BHP
Copper wells would be affected. Possible impacts
include a noticeable change in pumping water levels.
Impacts on Seeps and Springs. There was no
measurable decrease in discharge in either of the two
springs (Fifty Dollar Spring and Mule Spring, see
Figure 3-9 for location) monitored during the pump
tests. Although no impacts were observed during the
pump tests, it is conceivable that long-term pumping
of multiple wells in this area could affect natural
spring discharge in the vicinity of the well field. The
magnitude of the impact would depend on the
relationship between the spring location and zone of
influence (or cone of depression) caused by the well
field extraction. Based on the localized drawdown
pattern observed in the bedrock during the three
pump tests, it appears unlikely that springs located
more than 1 mile from the well field production wells
would be affected by long-term pumping.
Five springs and seeps have been identified within a
1-mile radius of the well field {Figure 3-9). These
include Fifty Dollar Spring, Coon Spring, and three
unnamed springs. The flow rate in June, 1993, was 2
gpm at Fifty Dollar Spring, and 1 gpm or less at the
other four springs. Most of these springs discharge in
areas where bedrock is located, or very near the
surface. Therefore, ground water extraction could
potentially reduce the discharge at any or all of these
springs. It is unlikely that other springs located
outside this area would be affected by the well field.
Monitoring and mitigation measures are proposed to
minimize impacts to springs in Section 3.3.4-Water
Resources, Monitoring and Mitigation Measures.
Impacts on Shallow (Alluvial) Ground Water and
Streamflows. The distance-drawdown relationships,
as well as the establishment of static water levels in
the alluvium after pumping in TW-2, were used
to estimate the decline in alluvial water levels that
may occur as a result of pumping from the well field.
The estimates, presented in Table 3-47, suggest
that at a distance of 1 ,000 feet from the pumping
well, the drawdown is anticipated to range from 1 to 3
feet, depending on the pumping rate. However, it
should be noted that because of the complex
structure of the bedrock in this area, as well as the
uncertainties regarding the combined effects of
several wells pumping in this area, the actual
drawdown in the alluvium may be more or less than
estimated.
As stated previously, water quality data provided from
the well field suggest a similar water chemistry in
Haunted Canyon surface waters and the local alluvial
and bedrock ground water. The water chemistry of
Pinto Creek, however, is significantly different from
the Haunted Canyon water chemistry (see Figure
3- 19). The water chemistry of Pinto Creek below the
Haunted Canyon confluence suggests a mixing effect
of upper Pinto Creek and Haunted Canyon water
chemistries. Therefore, decreasing the contribution of
Haunted Canyon flows would have the potential to
alter the downstream water quality of Pinto Creek.
In summary, based on the TW-2 pump test, pumping
the well field would have a direct impact on
streamflows in Haunted Canyon and water levels in
the alluvium in Haunted Canyon and Pinto Creek
Carlota Copper Project Final EIS
3-115
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-47. Anticipated Drawdown in the Alluvial Aquifer as a Result of Pumping Well TW-2
Production Rate
Estimated Drawdown in the Alluvia
VaHous Distances from the Pump
i Aquifer' at
ingWeli(s)
too feet
1,000 feet
5,000 feet
600
2.3
1.3
0.7
800
3.0
1.8
1.0
1,000
3.8
2.3
1.2
1,200
4.6
2.7
1.4
'Based on extrapolating measured drawdown in AMW-21 and AMW-22 during 24-day pump test of
TW-2 at 604 gpm.
immediately downstream of the confluence of
Haunted Canyon and Pinto Creek. These impacts
would be most noticeable during periods when
streamflow consists primarily of baseflow. Although
these data indicate that the streamflows and water
stored in the alluvium would be affected by the
proposed well field, it is not possible to determine with
certainty the magnitude and areal extent of the
impacts. It appears that most or all of the perennial
reach in Haunted Canyon (between Powers Gulch
and Pinto Creek) would be affected to some extent.
Streamflows and water stored in the alluvium in Pinto
Creek could also be directly affected for several
thousand feet up and downstream from the water
supply wells. A direct reduction in flow in the vicinity
of the Pinto Creek and Haunted Canyon confluence
would incrementally reduce flow for some distance
downstream in Pinto Creek. See Section 3.10 for a
discussion of impacts to the downstream section of
Pinto Creek that is eligible for Wild and Scenic River
designation. The Pinto Creek water quality
downstream from the Haunted Canyon confluence
could also be affected. Reductions in flow for Haunted
Canyon would increase the TDS concentration in
Pinto Creek below the confluence of these streams
because Haunted Canyon has a lower TDS
concentration, which acts to dilute the relatively
higher TDS of Pinto Creek. Additional pump testing
and monitoring, as recommended in the mitigation
section (Section 3.3.4), would be required to further
refine the boundaries of the affected area and the
magnitude of the impacts. Mitigation is proposed in
Section 3.3.4 (Water Resources, Monitoring and
Mitigation Measures) to mitigate potential flow
reductions in Haunted Canyon and Pinto Creek
resulting from well field pumpage.
Impacts from Well Field Access Roads. The
construction of the well field service road from the
south and the main access road from the north would
create cut and fill slopes that would be susceptible to
erosion if BMPs are not employed. However, Carlota
has committed to implementing BMPs to minimize
erosion and sedimentation. The potential for erosion
and sedimentation and the effectiveness of BMPs are
analyzed in more detail in Section 3.2, Geology and
Minerals, and Section 3.4, Soils and Reclamation.
The proposed undeveloped service road crossing of
Haunted Canyon (Carlota 1994c) would create
channel and bank instability because of traffic on
unprotected surfaces. This would contribute to sedi-
ment yield, an adverse impact for which additional
monitoring and mitigation measures are
recommended (Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures).
Heap-Leach Impacts
The heap-leach pad, ponds, and process plant area
would occupy approximately 342 acres (0.5 square
mile) of the Powers Gulch watershed area (5.5
square miles). During mining operations, this part
of Powers Gulch would be withdrawn from the
contributing watershed area. Based on a mean
annual watershed runoff of 2.62 inches above the
Pinto Valley weir, removal of this contributing
watershed area would reduce surface water runoff
by approximately 75 acre-feet per year. This volume
represents approximately 10 percent of the runoff
from the Powers Gulch watershed and less than 2
percent of the runoff at the PC-7 gage site down-
stream of the confluence of Haunted Canyon and
Pinto Creek. This impact would occur primarily during
storm events and would end after reclamation and
closure of the heap facilities since the area would be
returned to the area that contributes surface runoff to
the watershed. Reclamation would be accomplished
3-116
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
by creating a low-permeability recontoured heap
surface that would continue off the pad and into the
diversion channels. Final grading v>/ould ensure that
all surface runoff would be diverted efficiently to the
Powers Gulch and east diversion channels and
conveyed downstream to Powers Gulch.
A substantial amount of water consumption would
be associated with the heap-leach process. However,
Carlota proposes to minimize the consumptive use
of water by designing dominantly in-pad ponds to
reduce evaporation and by using pit water to fulfill a
portion of the project water needs. Some consump-
tive use of water would occur as a result of evapo-
ration on the pad surface, adsorption by the ore, and
the use of water in dust suppression. Mitigation has
been proposed to maximize water conservation
(Section 3.3.4 - Water Resources Monitoring and
Mitigation Measures).
The proposed process water management system,
including the main and north PLS embankments
and ponds and the raffinate and plant PLS/SX ponds,
would be designed to contain the maximum oper-
ational water storage requirement occurring during
a wet month in a wet year, in addition to runoff from
a 1/2 PMF event occurring on the pad, plant, and
contributing watershed area. All pond pump systems
would include emergency backup pumps and
diesel-powered electrical generators. Water balance
and flood hydrology analyses have been conducted
by Carlota and its consultants (Knight Piesold 1995a,
1995e, 1996e, 1996f, 1996g, 1996h) to determine
the volumes of water to be contained under these
conditions. Scenarios that produced the largest
combined volume (the maximum operational
volume plus the 1/2 PMF stormwater volume)
were analyzed for each month of the year. The
main heap-leach embankment/PLS pond, the
north heap-leach embankment/PLS pond, and the
raffinate and plant PLS/SX ponds were evaluated
separately to determine the scenario for each
individual component within the heap-leach facility.
Hydrologic modeling to estimate 1/2 PMF peaks
and volumes assumed that heavy rainfall had
occurred the 5 days previous to the given storm
event (antecedent moisture condition [AMC] III),
and that soils were nearly saturated. Therefore,
these estimates were considered to be very
conservative. Additionally, the heap water balance
conservatively estimated the monthly maximum
operational volumes.
The maximum combined operating and stormwater
volume for the main heap-leach embankment and
pond occurs from the 72-hour February 1/2 PMF
stormwater volume (80.1 million gallons) and an
operating base pool of 82.2 million gallons (Knight
Piesold 1997). The main heap-leach facility, operating
in conjunction with the Powers Gulch inlet control
structure and diversions, would receive approximately
80.1 million gallons of the total direct precipitation and
flood runoff volume of 367.4 million gallons from the
pad, the upper watershed, and the west side of
Powers Gulch (Eder area) (Knight Piesold 1997). The
remaining 287.3 million gallons would be routed
through the Powers Gulch Diversion around the
facility. This facility, as designed (main embankment
crest height of 3,830 ft-amsi), would completely
contain the combined volume of 162.3 million gallons
without decanting any solutions to the north heap-
leach pad or any other location, since the facility has
approximately a 190.2-million-gallon solution storage
capacity (or 170.2 million gallons with 3 feet of
freeboard). To better accommodate a situation where
back-to-back heavy precipitation events might occur,
mitigation has been specified that would require this
component facility to have the capability of pumping,
within a 10-day or less period, the entire volume of
solution generated by the 100-year, 24-hour storm
out of the main heap-leach PLS pond into a suitable
location available for emergency containment
(Section 3.3.4, Water Resources - Monitoring and
Mitigation Measures).
The maximum combined operating and stormwater
volume for the north heap-leach embankment and
pond (35 million gallons) occurs from the 72-hour
October 1/2 PMP volume (direct precipitation on the
north pad with zero runon) with a base pool operating
volume of 14.8 million gallons. Not only would this
facility, as designed, contain the 1/2 PMP volume
(20.2 million gallons) on top of the maximum October
operating base pool, it would also contain the entire
PMP volume of approximately 40.5 million gallons
(combined containment volume of 55.3 million
gallons) without overtopping (Knight Piesold 1997),
since the solution capacity of the north embankment
and PLS pond at the top of the embankment is
approximately 58.4 million gallons.
Carlota Copper Project Final EIS
3-117
3.0 Affected Environment and Environmental Consequences • Water Resources
The maximum combined operating and stormwater
volume for the raffinate and plant PLS/SX ponds
coincides with the 72-hour August 1/2 PMP
(maximum base pool operating volumes of
approximately 1.79 million gallons and 1.59 million
gallons, respectively). The maximum combined
stormwater and operating volume for the raffinate
pond is approximately 3.46 million gallons as
compared to a total solution capacity of approximately
4.54 million gallons at the embankment crest
elevation of 3,900.5 ft-amsi (or approximately 3.46
millions gallons with 3 feet of remaining freeboard)
(Knight Piesold 1997). The maximum combined
stormwater and operating volume for the plant
PLS/SX pond is approximately 2.31 million gallons as
compared to a total solution capacity of approximately
3.18 million gallons at the embankment crest
elevation of 3,925 ft-amsI (or approximately 2.31
million gallons with 3 feet of freeboard). Under these
conditions, the potential for impacts from process
water overflow is considered minimal.
The 1/2 PMP has a very low probability of occur-
rence. Since the flood hydrology and water balance
analyses considered other conservative variables
(AMC III conditions, operational data based on the
wettest year on record, and the availability of addi-
tional storage capacity within the 3 feet of embank-
ment freeboard), the estimated solution volumes are
conservative, and would tend to decrease the
probability of occurrence even further. Additionally,
the heap-leach facility embankments would be
designed to adequate safety standards for opera-
tional and closure conditions, and would be con-
structed and lined to prevent instability from seepage.
In the postmining configuration, process water
impoundments would be recontoured and related
embankment locations would be incorporated into the
postmining topography. Therefore, the potential for
overtopping or failure of process water embankments
is considered minimal. Mitigation is proposed in
Section 3.3.4 (Water Resources - Monitoring and
Mitigation Measures) specifying that, at a minimum,
the above-referenced pond volume capacities must
be maintained in the final facility design.
The quality of surface water and/or ground water
would be impacted if process solutions seeped or
were accidentally released from the heap-leach
facility. Although Powers Gulch would be permanently
diverted around the heap, process solutions that seep
or are accidentally released from the facility could
enter Powers Gulch immediately downstream from
the facility. Ground water in the vicinity of the heap is
controlled by movement through fractured bedrock
units and along prominent faults. Also, minor amounts
of ground water move through the thin alluvium
present along the Powers Gulch drainage bottom.
Depending on the time of year, the elevation of the
ground water potentiometric surface under the heap-
leach pad varies from a few feet above land surface
to more than 30 feet below land surface. This
indicated that, in the absence of engineering controls,
a high potential exists for intercommunication
between process solution and ground water from
seepage or release of process water.
The potential for uncontained seepage or the release
of process water would be minimized during
operations because of Carlota's proposed facility
design (see Section 2.1, Proposed Action, for design
details). The heap would be constructed as a valley
fill with internal solution storage. A single synthetic
liner would be installed in heap areas where no
solution storage is planned. In areas where perpetual
solution storage would occur during operation, a
double-lined system with an internal LCRS would be
constructed to detect leaks and provide for the
collection and recovery of solution should seepage
occur through the primary liner. Near-surface ground
water beneath the pad would be collected and
transmitted away from the heap base via a central
spine drain located in the topographic low of Powers
Gulch augmented by dedicated finger drains. This
underdrain system would minimize the potential for
hydrostatic uplift in the heap-leach pad area and
would facilitate the isolation of ground water from
process solutions. The heap would be designed as a
zero-discharge facility. As summarized in Section
2. 1.3.1, during operation, surface runoff would be
diverted around the heap, and direct precipitation
would infiltrate and be contained within the heap.
Although an accidental release of process solutions
from the heap-leach facility is unlikely during
operations, any release to the environment would
result in significant impacts to localized surface water
and ground water quality. The ore would be leached
with a dilute sulfuric acid solution that would result in
process water with low pH and high heavy metals
concentrations. The process water chemistry was
estimated (Knight Piesold 1993a) to have a pH of 1 .4,
3-118
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
a TDS of 29,600 mg/L, and elevated levels of heavy
metals (e.g., 2,190 mg/L copper, 44.8 mg/L
manganese, 3,560 mg/L iron, and 16.5 mg/L zinc).
The severity of any water quality impacts resulting
from a release of process water from the heap would
depend upon the size and timing of the release, the
time required to detect the release, and the measures
implemented to remedy the situation.
Local surface waters and bedrock ground waters in
Powers Gulch and Haunted Canyon (well field area)
are generally low in TDS (less than 500 mg/L) and
are of a calcium, sodium-bicarbonate water type.
Metals concentrations in the surface waters and
ground waters are mostly low or below detection
limits. Although the local waters would be expected to
provide a certain amount of buffering capacity due to
moderate concentrations of carbonate and excess
acid-neutralizing potential in underlying rock, the low
pH process solution would be expected to lower
surface water pH values to below levels set by
Arizona to protect designated uses if released in
amounts significant to flow. Releasing high TDS, high
metals concentrations, and sulfate-dominated
process solution could potentially impact the quality of
the local surface and ground waters. Potential
impacts to Powers Gulch and Haunted Canyon would
include exceedances of stream water quality
standards and would change the overall stream water
chemistry.
Downstream water quality impacts are influenced by
the intermittent nature of the regional surface waters.
A surface release of process solutions would most
likely be transported downstream from the project
area by ephemeral flows. Pinto Creek below the
project area has a sulfate water chemistry with most
metals concentrations low or below detection limits
and TDS concentrations of approximately 500 mg/L.
Potential impacts would include exceeding stream
water quality standards or changing the overall
stream water chemistry. Potential impacts to ground
water downgradient of the project area would depend
on the specific area geology, ground water flow, and
hydraulic conductivity.
Carlota has proposed a monitoring, spill protection,
and spill containment program (SCHMM Plan) to
minimize the probability of releasing process solutions
into the environment during operations, and to
provide for the rapid detection and control of process
solution seepage or accidental spills. The ground
water and surface water monitoring plan (GWRC
1996a) includes several alluvial and bedrock
monitoring wells and surface water sampling stations
located downstream from the heap leach/PLS pond
facility as part of a comprehensive monitoring
network. Regular sampling of water collected in the
underdrain collection pond is also included in the
plan. The monitoring locations and sampling
frequency included in the plan are summarized in
Section 3.3.4, Water Resources - Monitoring and
Mitigation Measures. The monitoring network would
provide for early detection of a release to ground
water or surface water. In addition, the monitoring
plan has been accepted by the ADEQ and required
as part of the State of Arizona Aquifer Protection
Permit (ADEQ 1996).
The SCHMM Plan proposed by Carlota (1996a)
considers the potential flow paths of accidental
process solution spills; these flow paths would
provide locations for water monitoring and sampling,
rapid detection, and treatment or capture of
accidental process water discharges before they
migrate into the Powers Gulch surface and ground
water system. Automatic pumps with standby diesel
power and electronic metering, monitoring, and
control systems would be provided. Dedicated
backup pumps are included in the process solution
pond designs (Knight Piesold 1995a).
The primary focus of the SCHMM would be to prevent
process water discharges. Should a discharge occur,
the emergency response objectives of the plan would
be to minimize and address potential immediate
health or safety hazards, to limit potential spill impacts
to the smallest possible area, and to facilitate
subsequent cleanup and disposal activities. If an
accidental process water discharge or spill were to
reach surface or ground waters, the plan emphasizes
methods to quickly contain and remove contaminants
from the water to minimize water quality impacts,
avoid downstream transport of contaminants, and
minimize damage to aquatic life (Carlota 1996a).
However, because of the quantity and hazardous
nature of the PLS and raffinate solution, a release
would have the potential to degrade surface and
ground water quality. Therefore, monitoring and
mitigation measures are proposed in Section 3.3.4
(Water Resources - Monitoring and Mitigation
Measures).
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3.0 Affected Environment and Environmental Consequences - Water Resources
Carlota has proposed a heap closure plan (Carlota
1994a) that would drain as much process solution as
possible from the heap, and would recontour and
reclaim the heap to minimize infiltration, enhance
surface runoff and evapotranspiration, and prevent
the build-up of water at topographic lows within the
heap. The postclosure water balance for the heap
was estimated using the Hydrologic Evaluation of
Landfill Performance (HELP) model (Carlota 1994a).
The results of the modeling do not indicate a
significant change in moisture content in the heap
over the 20-year model period.
The Powers Gulch diversion channel would be
reshaped as necessary to convey large flood events
without impacting the stability of the heap or allowing
flood waters to infiltrate. Ground water would remain
separated from the heap by the permanent spine and
finger drain system under the liner. Several years
before closing the main leach pad area, Carlota would
begin closure of the stand-alone north pad area to
conduct full-scale testing of closure and reclamation
options.
Leaching characteristics and the static and kinetic
behavior of the leached ore from the proposed project
were determined using metallurgical tests (PINTAIL
Systems, Inc. 1994). An Acid-Base Accounting (ABA)
test was conducted to define the balance between
potential acid-producing minerals and acid-consuming
minerals. Results of the ABA test indicated that the
oxide spent ore, representing approximately 80
percent of the total ore body, did not possess the
potential to produce acid. The mixed-zone spent ore,
representing approximately 20 percent of the total ore
body, produced results falling in an intermediate
range (ANP [Acid Neutralization Potential]:APP [Acid
Producing Potential] ratios between approximately 1
and 3), indicating a limited potential for acid
generation. Kinetic humidity column testing was used
to model the processes of geochemical weathering of
the spent ore. Results indicated that leachate from
the oxide spent ore type and the mixed zone spent
ore would have pHs of less than 6 and less than 3,
respectively. Both would contain elevated metal
concentrations — conditions expected from an acid
leached ore. The Meteoric Water Mobility Test
(MWMT), which was used to evaluate the spent ore
for its potential to release contaminants into meteoric
water, indicated that concentrations of regulated
metals from the oxide ore were below the standards
and that concentrations of regulated metals from the
mixed-zone ore exceeded the standards for copper,
iron, and magnesium. Metals exceeded Arizona
surface water quality standards for Powers Gulch and
downstream receiving waters, Arizona aquifer
standards, and Federal Primary and Secondary
MCLs. The Toxicity Characteristic Leaching
Procedure (TCLP) was used to test for leaching of
eight TCLP-specific toxic metals from the spent ore
rock matrix. All metals analyzed from the TCLP-
leached oxide and mixed-zone ores were below the
regulated standards. Based on these test results, a
release from the heap to surface waters following
closure would potentially impact stream water quality,
which could impair the stream's resident aquatic life,
including habitat for the desert sucker, long fin dace,
and the potential Pinto Creek Scenic River segment
(see Sections 3.5, Biological Resources, and 3.10,
Wilderness and Wild and Scenic Rivers).
Although the spent ore would be primarily non-acid-
generating because the acid leaching would have
occurred for approximately 20 years, the current
proposed closure plan recognizes the possible
presence of acid in the spent ore. The plan is
designed to minimize any release of water originating
from the internal portion of the leach pad by retarding
infiltration into the spent ore. At closure, Carlota
would consider the most current technology to
improve upon heap closure options already identified
(see Section 3.4, Soils and Reclamation), including
but not limited to, injecting milk lime directly into the
heap to chemically and physically fix residual acidity,
applying various soil compaction techniques, and
using sealants, such as clay or lime, to reduce
permeability. Water monitoring would continue
following heap closure until the success of heap
closure could be verified by the ADEQ and the Forest
Service. As improved closure technologies are
identified throughout the life of the project, the
reclamation bond required by the Forest Service
would be adjusted accordingly.
The severity of water quality impacts would depend
on the size and timing of the release, the rapidity of
detection, and the remediation measures. Although, a
release from the heap after closure is not anticipated
due to the proposed draindown and capping
processes at closure, any possible release would
have the potential to degrade surface and ground
water quality because of the quantity and hazardous
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3.0 Affected Environment and Environmental Consequences - Water Resources
nature of the spent ore; therefore, monitoring and
mitigation measures are proposed in Section 3.3.4
(Water Resources - Monitoring and Mitigation
Measures).
There are several state and federal water quality
permits that would be secured by Carlota before
project construction. These permits would require that
the heap leach be built, operated, and closed to
comply with BADCT with regard to environmental
protection. An Aquifer Protection Permit would be
required by the ADEQ to protect ground water quality.
A CWA Section 402 Permit would be required by
the EPA to protect surface water quality from storm
water runoff from the heap-leach facility. A CWA
Section 404 Permit would be required by the COE to
protect and mitigate losses of waters of the U.S.,
including wetlands; the ADEQ would require Section
401 certifications for both of the CWA Section 404
and 402 permitting process. The water monitoring
and compliance requirements in these permits would
be designed to protect surface and ground water
quality.
A discussion of potential impacts to riparian areas
and wetlands is presented in Section 3.5.1, Biological
Resources - Affected Environment.
Stream Diversion Impacts
Permanent diversions would be planned around the
Carlota/Cactus pit in Pinto Creek and the heap-leach
facility in Powers Gulch. The following sections
describe the anticipated changes to the respective
watersheds and channels.
Pinto Creek Diversion. For the proposed action, the
Pinto Creek diversion would be constructed along the
edge of the Carlota/Cactus pit. The alignment of the
Pinto Creek diversion in the pit area during operations
is shown in Figure 2-3. The proposed operational
design would, at a minimum, provide conveyance for
all flows up to the 500-year flood peak (approximately
10,100 cfs). The proposed diversion channel
alignment would be similar to the existing channel
and would not cause a major change in the slope of
the channel. The hydraulics of the diversion channel
were determined over a range of potential channel
widths in order to select a preliminary cross-sectional
geometry that would provide acceptable sediment
transport conditions (SLA 1993). At the end of
operations, the diversion would be reconfigured as
necessary for long-term postclosure functioning
(Carlota 1994a).
With adequate hydraulic design and implementation,
the diversion hydraulics would remain similar to
existing conditions as would the sediment transport
capacity (SLA 1993). In this case, which has been
shown to be feasible in preliminary design, the
channel dynamics would remain relatively unaffected
by the proposed diversion on Pinto Creek both
upstream, downstream, and within the diverted reach
(SLA 1993). Bed material size distributions and
channel cross sections would not be significantly
affected by the project either upstream or
downstream of the diversion channel. Detailed
diversion designs and maintenance during operations
would ensure that channel depths would be adequate
to contain flows, and that the stability of upstream and
downstream channels and banks would be
maintained.
With BMPs to control erosion and sediment as
proposed, the increase in sediment produced by
the project would be negligible. Any small increase
in sediment supplied by the watershed to Pinto
Creek would be transported by the channel, since
the sediment transport capacity of Pinto Creek,
including the diverted section, is much greater than
the supply (SLA 1993). Watersheds similar to Powers
Gulch and the upper reaches of Pinto Creek often
have sediment transport capacities larger than the
actual quantity of sediment supplied. This is caused
by such characteristics as steep channel gradients,
hillslopes protected by dense vegetation, and a lack
of erodible material under normal runoff conditions. In
some areas, this would encourage streambed
degradation: however, in the project area, the
processes of sediment sorting and bedrock exposure
have naturally armored many channel reaches
against further degradation. Consequently, diversion
designs can be conceptually oriented to sediment
supply, rather than attempting to match future
sediment transport capacities to existing capacities.
Although overtopping of a properly designed diversion
is unlikely, overtopping could occur if flows greater
than the 500-year flood were experienced. However,
the probability of the 500-year flood occurring is 0.2
percent during any year of the operation. Diversion
overtopping would create minor adverse impacts to
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3.0 Affected Environment and Environmental Consequences - Water Resources
the environment if it occurred during operations and
damage to the diversion was rapidly repaired. For the
postmining configuration, the diversion would be
stabilized by a large bench with a backfill berm in the
upstream area where flow momentum is toward the
pit. These features would add considerable long-term
protection and stability to the diversion area. In
addition, the flow path and meander configuration of
the proposed diversion around the remainder of the
pit would encourage flow momentum away from the
pit and onto channel sections reinforced by bedrock.
When these attributes are considered and a
postmining design for an adequate recurrence
interval is implemented, diversion overtopping and
subsequent failure would be highly unlikely. Mitigation
is proposed that would require the postclosure
channel design to accommodate an event of the
magnitude prescribed by the appropriate agencies.
Powers Gulch Inlet Control Structure and
Diversion. For the proposed action. Powers Gulch is
to be diverted around the heap-leach pad and
associated facilities. In addition, an inlet control
structure would be constructed to attenuate storm
runoff flows before they entered the main diversion.
Storm runoff from the hillside to the east of the leach
pad would be collected by the east diversion channel
and routed through the inlet control structure. The
channel alignments for this action is shown in Figures
2-1 a and 2-1 b. The bed of the diverted channel would
follow a flatter gradient than the natural channel in a
longer path around the heap-leach pad on the
watershed sideslope; once it passes the north end of
the heap-leach pad, it would be directed back to the
existing Powers Gulch channel by constructing a
flume drop.
The primary purpose of the inlet control structure is to
operate in conjunction with the heap-leach facility and
the Powers Gulch and east diversions to attenuate
flood peaks, thereby reducing the size and associated
disturbance required for the Powers Gulch diversion.
As an example of this effect, the 6-hour 1/2 PMF
peak in Powers Gulch immediately downstream from
the location at which the Powers Gulch diversion re-
enters Powers Gulch would be approximately 12,838
cfs without the inlet control structure and heap-leach
facility in place. During the operational phase of the
project with these facilities in place, the peak would
be attenuated to approximately 3,047 cfs (Knight
Piesold 1996h). The Powers Gulch and east
diversions would be sized to pass the peak flows from
the 6-hour 1/2 PMF.
At mine closure the inlet control structure would be
removed and the peak flows entering the Powers
Gulch diversion would no longer be attenuated. Since
the natural runoff hydrograph would be passed
directly through the diversion, no long-term impact
would occur to the quantity of downstream flow in
Powers Gulch, Flaunted Canyon, and Pinto Creek.
Although Carlota has proposed to reshape the
Powers Gulch and east diversion channels to convey
large flood events without impacting the stability of
the heap or allowing flood waters to infiltrate the leach
pad, the magnitude of “large flood events” has not
been defined. Therefore, monitoring and mitigation
are proposed that would require the monitoring and
postclosure channel design to accommodate the full
PMF event or an event as otherwise specified by the
Forest Service (Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures).
The existing slope of Powers Gulch in the vicinity
of the proposed heap-leach pad is approximately
4.3 percent, while the flatter portion of the diverted
channel is approximately 1 .5 percent, and the slope
of the steeper flume drop portion is approximately
22.2 percent in the upper section and 11.8 percent
in the lower section. With the proposed change in
alignment and gradient through the diverted reach.
Powers Gulch would flow at a lower velocity in
the flatter section and at a higher velocity in the
steeper section. In the section with reduced gradient
and velocity, the sediment transport capacity of
the channel would be reduced below the existing
transport capacity, decreasing the ability of the
channel to transport the sediment load. In the
section with the increased gradient and velocity,
there is an increased potential for scour. Flowever,
bedrock controls in the channel bed would minimize
this scour potential in the steep gradient reach.
Some high energy flow effects could occur on the
flatter reach of Powers Gulch immediately down-
stream of the steep gradient depending on the
channel characteristics, flow state, and the nature
of flow transitions. Potential impacts would include
local scour and bank erosion, with subsequent
sedimentation in the Powers Gulch and Haunted
Canyon reaches immediately downstream. These
would be adverse impacts requiring monitoring and
mitigation.
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Regarding the reach with the flatter gradient, SLA
(1993) states that “lesser slopes than the long-term
slope would be adequate (from both a hydraulic and
sediment-transport standpoint), provided the channel
is periodically maintained to remove any accumulated
sediments.” Much of the sediment produced by the
watershed is composed of finer-sized particles that
would continue to be transported through the
diversion channel. However, the coarser fraction of
sediment, primarily consisting of bedload, may
deposit on the bed of this portion of the diversion
channel. While some accounting for sediment
deposition was included in the freeboard calculation
in the form of bed waves, no direct analysis of
bedload deposition was conducted. It is unknown if
the freeboard for sediment would adequately
compensate for the actual deposition that may occur.
To account for this uncertainty, SLA (1993)
recommends observing hydraulic conditions and
sediment deposition during the life of the project
before developing and constructing a final
postclosure design for the diversion channel.
Therefore, monitoring and mitigation are proposed in
Section 3.3.4 (Water Resources - Monitoring and
Mitigation Measures).
Overtopping of the Powers Gulch and east diversions
would be very unlikely since the diversions, operating
in conjunction with the inlet control structure and the
heap-leach facility, would be designed to convey the
1/2 PM F event. Although overtopping of a properly
designed and constructed diversion is unlikely, the
possibility of overtopping would remain if flow
exceeded the design capacity or if there were
inadequate inspection and maintenance activities.
Overtopping could also result from landslides or
debris flows affecting the integrity of the diversion,
particularly with the additional loading and slope
steepening associated with the Eder mine rock
disposal area. Overtopping could create adverse
impacts to the environment even with rapid repair
of the diversion. During operations, diversion
overtopping would cause water quality impacts if
the stormwater storage capacity of the heap-leach
facility was exceeded and process solution escaped
over the main PLS embankment. Overtopping could
also increase the potential for erosion of the toe of the
heap adjacent to the Powers Gulch diversion
channel. Therefore, mitigation is proposed in Section
3.3.4 (Water Resources - Monitoring and Mitigation
Measures).
The inlet control structure is designed to attenuate
peak storm flows and is not designed to retain water
for future use. The structure would be dry except
during or immediately following storm events.
Therefore, the potential for water temporarily detained
by the inlet control structure to seep into the bedrock
system and significantly affect or increase the
hydrostatic heads in the bedrock system beneath the
heap leach pad should be minimal.
Water quality impacts to Powers Gulch, Haunted
Canyon, and Pinto Creek from a potential surface
release of process solution have been outlined in the
discussion of heap-leach impacts earlier in this
section. Overtopping of the Powers Gulch diversion
and erosion of the heap-leach pad would have similar
impacts on surface water quality. Eventually, the
excess transport capacity in the system would likely
disperse the deposited material downstream.
However, the leach pad would remain exposed to
channel flows and accelerated erosion. This major
adverse impact would be avoided by Carlota’s
commitment to ensuring long-term diversion
functions, as identified in the proposed action.
Downstream of the proposed heap-leach pad, a short
section of steep gradient would occur along the
diversion alignment. Channel slopes in this area
would be on the order of 15 to 20 percent. The higher
flow velocities in this downstream reach may require
some form of energy dissipation if it is determined
that the natural channel section cannot withstand the
associated hydraulic forces. Although the natural
Powers Gulch channel contains exposed bedrock and
is armored by coarse gravel and boulders for much of
its length, an unacceptable amount of local scour and
site instability may occur in the area immediately
downstream of the steep reach, creating an adverse
impact. Therefore, mitigations are proposed in
Section 3.3.4 (Water Resources - Monitoring and
Mitigation Measures).
Erosion and Sedimentation Impacts
With regard to the overall project effect on erosion
and sedimentation, the predicted changes in
sediment yields from the Pinto Creek and Powers
Gulch watersheds would be expected to be minimal.
The results of modeling by SLA (1993) indicate that,
without BMPs, disturbances related to mining
operations would result in an increase of
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3.0 Affected Environment and Environmental Consequences - Water Resources
approximately 0.12 acre-foot in the average annual
amount of sediment volume delivered to point SPC4
(see Table 3-43), which is located immediately
downstream of the Pinto Creek/Haunted Canyon
confluence (SLA 1993). At that point, the increase in
sediment yield would be approximately 2 percent. It
should be noted that these estimates refer to
sediment yielded on a watershed basis, and are not
directly related to site-specific erosion rates
discussed in Section 3.4, Soils and Reclamation. As
indicated in Section 3.4, localized increases would be
more significant. Not all eroded material ends up as
streamborne sediment. Upstream of the Pinto
Creek/Haunted Canyon confluence, the sediment
yield would be increased approximately 2.5 percent.
Thus, even without BMPs, the overall increase in
sediment yield as a result of the project would be
minimal. As part of the proposed action, the
incorporation of BMPs at key locations during and
after operations would minimize long-term sediment
yield impacts. However, temporary impacts to aquatic
habitat may occur until fine sediments are flushed
through the channel system. These effects are
discussed in Section 3.4, Soils and Reclamation, and
Section 3.5, Biological Resources.
Floodplain Impacts
Under the proposed action, the mine components
would directly affect approximately 39 acres of alluvial
deposits by earthmoving. Of this area, an estimated
35 to 50 percent (approximately 14 to 20 acres)
would be composed of alluvial soils on terraces along
Pinto Creek and lower Powers Gulch. The remaining
area would be composed of gravel- to boulder-sized
alluvial deposits in channels and bars. A small stock
pond would be removed by constructing project
components. Additional acreage would be disturbed
by road and pipeline crossings and well pads
associated with water supply and power facilities for
the project. This area would be small relative to the
overall extent of floodplains and channels in the Pinto
Valley watershed, and would not constrict flow areas
to the point where flood flow hydraulics would be
adversely affected. BMPs, including controlling
erosion and sedimentation, would be combined with
hydraulic design and construction of diversions and
sediment controls to minimize the potential for
additional impacts in floodplain areas. A discussion of
wetlands and waters of the U.S. is presented in
Section 3.5, Biological Resources.
Other Project Components
Impacts from the Mine Rock Disposal Areas. Five
separate areas for the disposal of mine rock have
been proposed: the Main, Cactus Southwest, and
Eder rock disposal areas; Carlota/Cactus pit backfill;
and backfill of the Eder pits {Figures 2-1 a and 2-1 b).
Potential impacts from the Carlota/Cactus pit and
Eder pits backfill are addressed previously in the
section on pit water recovery impacts.
Construction of the Main mine rock disposal area
would eliminate Grizzly Mountain Tank (a small stock
pond).
Surface runoff from the Cactus Southwest mine rock
disposal area would be permanently directed toward
the Carlota/Cactus pit during mining and after mine
closure. Therefore, approximately 74 acres of
watershed would be permanently removed from the
watershed contributing runoff to Pinto Creek. Average
annual runoff would be reduced by approximately 16
acre-feet, based on a mean annual watershed runoff
of 2.62 inches above the Pinto Valley weir. This
volume represents less than 0.4 percent of the runoff
at the PC-7 gage site downstream of the confluence
of Haunted Canyon and Pinto Creek. This impact
would occur primarily during storm events
Based on conclusions and recommendations from
previous investigations (Knight Piesold 1993a), mine
rock for the proposed project would be disposed of
without special treatment. Mine rock would be
deposited directly upon untreated soils and rock and
would be exposed to precipitation events. Carlota
proposes to prepare the mine rock disposal areas to
minimize surface water runoff, erosion, and
sedimentation from the disposal sites (CWA Section
402 Permit Application 1994). As described in the
SWPP plan and the NPDES permit application, the
mine rock disposal areas would have upgradient
interceptor ditches to convey runoff from undisturbed
areas to natural drainages. The tops of the mine rock
disposal areas would be graded away from the
embankment crests to prevent surface runoff from
flowing down the rock face. Storm runoff from the
tops of the mine rock disposal areas would be
temporarily detained on the tops of the disposal
areas. Sediment basins and/or the sediment-control
BMPs constructed downgradient of the mine rock
disposal areas would control excess sediment runoff
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3.0 Affected Environment and Environmental Consequences - Water Resources
originating on the disposal areas. An NPDES permit
would be required for any water discharged from the
sediment basins as a result of precipitation events
less than the 100-year, 24-hour recurrence. The
permit application would require approval by the EPA
and ADEQ via a 401 certification. Discharge from the
basins would be required to comply with the water
quality limits set in the NPDES permit, and therefore
would not violate any water quality standards in Pinto
Creek or Powers Gulch.
MWMT results (Knight Piesold 1993a) on rock types
to be deposited in the mine rock areas reflect TDS
concentrations below or comparable with present
ground and surface water concentrations (less than
250 mg/L). In general, most metals analyzed were
low in concentration or not detectable. Reportable
lower detection values for most metals were near or
below applicable surface water quality standards.
For weight percent adjusted MWMT results {Table
C5-2 in Appendix C, Water Resources Data), the
Cactus Southwest mine rock area copper value was
0.0514 mg/L (exceeding the aquatic and wildlife
[warm water fishery] acute and chronic stream
standards of 0.034 mg/L and 0.021 mg/L,
respectively); the Eder mine rock area manganese
value was 0.08 mg/L (exceeding the federal
secondary drinking water standard of 0.05 mg/L),
and the aluminum values of all three rock areas
exceeded the federal secondary drinking water
standard for aluminum (0.005-0.2 mg/L). The
potential impact associated with these results would
still be low since MWMT results are not normally
compared one-to-one with water quality standards (a
typical comparison is 10 to 1). Stream water quality
standards exist for thallium, but analyses for thallium
on the MWMT were not performed. All metals
analyzed were below Arizona aquifer protection
standards.
Increased leaching and contaminant mobility could
occur if surface or ground water pH were lowered
because of runoff from the mine rock areas. The
results of acid-neutralizing potential and acid-
producing potential indicate that even under the most
conservative estimates, composite waste rock
material would have an excess of acid-neutralizing
potential (Knight Piesold 1993a). Under these
circumstances, the potential to lower present pH
values below standard levels (6.5 standard units) in
surface or ground water is low. Since the source of
the acid-neutralizing potential is generally believed to
be carbonate (Knight Piesold 1993a), the potential for
increased pH values above standard levels (8.5
standard units) would also be low.
The proposed action reduces the potential for impacts
to surface and ground water quality under normal
circumstances. Although the leaching of metals from
mine rock is anticipated to be low, the variability of
rock material being mined creates the potential for
acid-generating conditions to exist in some materials.
Acid generation generally increases the mobility of
metals and would produce a source of contamination
for surface and ground water degradation. As part of
the ADEQ's Aquifer Protection Permit, Carlota has
committed to continual characterization during active
mining as specified by ADEQ (Carlota 1995a). The
waste rock from mining activities would be sampled
and analyzed at a frequency of 1 sample for every 1
million tons of waste rock using the EPA's Method
1312. Synthetic Precipitation Leaching Procedure.
Provided that these measures are followed, potential
impacts to surface or ground water quality are not
anticipated. In addition, as part of the Aquifer
Protection Permit, if geochemical testing indicates
that some of the material has the potential to
generate acid or leach metals. Carlota would develop
a materials handling plan to prevent impacts to
surface or ground water and submit it to ADEQ for
approval.
Impacts from SX/EW Plant and Associated
Facilities. The SX/EW plant would be upgradient
of the proposed plant PLS/SX and raffinate ponds,
and any spills or leaks from the plant would flow to
the pond. The plant PLS/SX and raffinate ponds
would be upgradient of the heap and PLS ponds.
Raffinate pond overflows or other releases would
be retained in downgradient project components,
which have been sized to contain extreme events.
Spills infiltrating into the ground would likely be
captured by the dewatering wells. Under normal
operating conditions, potential impacts to water
quality from the SX/EW plant and associated facilities
would be minimal because of the procedures to be
followed in the Stormwater Pollution Prevention plan
(CWA Section 402 Permit Application 1994) and
the SCHMM (Carlota 1996a). If deviations from these
plans occurred, the potential for affecting both
ground and surface water quality would increase.
As presented in Table C5-3 in Appendix C, Water
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3.0 Affected Environment and Environmental Consequences - Water Resources
Resources Data, the PLS and raffinate solutions
would be maintained at pH values below 2 and
would contain TDS, sulfate, and metals con-
centrations at orders of magnitude above any
applicable ground or surface water quality standards.
In the event of an operational deviation (i.e., spill,
leak, or procedural error), potential impacts to
water quality could be greatly reduced by having
response teams and procedures, cleanup and
remediation teams and procedures, and secondary
containment structures in place before they are
needed. However, because of the quantity and
hazardous nature of the PLS and raffinate solution,
any possible release would have the potential to
degrade surface and ground water quality. Measures
for spill control, cleanup, and remediation are
directly associated with the potential to affect ground
waters. The low pH of the solution would minimize
metals attenuation capabilities of soil material.
Although potential contaminant loads would generally
be localized, the process solutions would provide
an extremely mobile source of dissolved constituents
to ground water. Therefore, monitoring and mitigation
measures are proposed in Section 3.3.4 (Water
Resources - Monitoring and Mitigation Measures).
Impacts from Support Facilities. Construction and
operating conditions for supporting operations have
been outlined in the CWA Section 402 Storm Water
Pollution Prevention Permit Application (1994), the
COE CWA Section 404 Permit Application (1994), the
Arizona Aquifer Protection Permit Application (1994),
and the SCHMM (1996). Supporting operations would
include the maintenance shop and warehouse
facilities: the crushing, conveying, and stacking
operations: and access and haul roads. Other
proposed disturbances would include storage
facilities, power distribution lines, pipelines, and the
administration building. Potential impacts to water
quality, surface water quantity, and erosion and
sedimentation from supporting operations would not
be anticipated if BMPs and plans for spill prevention,
control, and remediation were appropriately applied.
However, because of the quantity and hazardous
nature of the materials used at the maintenance shop
and warehouse (oils, lubricants, solvents), any
possible release would have the potential to degrade
surface and ground water quality. In addition, the
effects from erosion and sedimentation from access
roads and haul roads after initiating the proposed final
reclamation and closure practices would have the
potential to degrade surface water quality. Therefore,
monitoring and mitigation measures are proposed in
Section 3.3.4 (Water Resources - Monitoring and
Mitigation Measures).
3.3.2.2 Alternatives
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. Two
additional sites (Cactus South and Cactus Central)
have been identified for mine rock disposal {Figure 2-
12). Potential water resource impacts from the Cactus
Central site are generally similar to those for the
proposed mine rock disposal sites. However, the
Cactus South site lies in the drainage area of
Cottonwood Gulch. Analyses of surface water from
Cottonwood Gulch {Tables C1-1 and C1-2 \r\
Appendix C, Water Resources Data) indicate
elevated levels of TDS (2,380 mg/L) compared to
Pinto Creek (360 mg/L). Associated with the higher
TDS concentration is a concentration of dissolved
copper (0.40 mg/L) that exceeds the Pinto Creek
surface water quality standard for aquatic and warm
water fisheries. Total iron and manganese
concentrations of 0.45 mg/L and 0.09 mg/L,
respectively, exceed federal secondary MCLs.
Although increased leaching from mine rock caused
by low pH would not be expected (surface water
pH=7.5), the quality of the surface water that would
come in contact with the Cactus South disposal site
would be dramatically different than that seen at the
other mine rock disposal sites. Since the rock would
essentially fill the drainage, the potential exists for this
relatively low-quality surface water to move through
and discharge from the rock disposal facility. Because
of the background water quality of the surface water,
it is likely that the discharge from the mine rock would
violate water quality standards.
Surface water quantity impacts would be minimal
since both alternative sites would likely consist of
relatively free-draining rock materials. However, if
restricted drainage were to occur within the rock
materials over the long term, the potential exists for
ponding to occur behind the Cactus South alternative.
In addition, buildup of a saturated zone would
compromise slope stability in either rock disposal
area, but this is unlikely given the coarse nature of
mine rock on the site. Ponding would necessarily be
avoided during operations at the Cactus South
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
location because of the need for access to an existing
well.
After closure, if ponding were to be built up behind the
Cactus South location, poor water quality could
present a seasonal hazard to wildlife. In addition, if
ponding occurred, approximately 42 acres would be
withdrawn from the contributing watershed area.
Using estimates derived from Pinto Valley weir data,
this withdrawal would represent a surface water loss
of approximately 9 acre-feet per year. Most of the
water probably would be lost through evaporation
during the year. Overall, this would be a negligible
effect on surface water yields. Potential impacts on
surface water from other project activities and
components would remain the same as for the
proposed action.
Additional Backfill of the Carlota/Cactus Pit.
Under this alternative, the Carlota/Cactus pit would be
backfilled up to the approximate premining elevation
of Pinto Creek (3,520 ft-amsi). The surface of the
partially backfilled pit would be above the premining
elevation of the water table. As a result, no pit lake
would develop. Since there would be no pit lake, pit
lake water quality, or evaporative losses from the pit
lake surface would not be a concern. Based on the
geochemistry of the proposed backfill material and
the ambient ground water quality, interaction between
the backfill and the ground water is not anticipated to
degrade ground water quality. Potential impacts to
water resources associated with this alternative as
compared to the proposed action are summarized in
Table 3-48.
Additional backfill of the Carlota/Cactus pit would
potentially have similar types of impacts on surface
water quantities and erosion and sedimentation
considerations as the proposed action. However,
the additional backfill would restore the contributing
watershed area to near its premining state.
Reducing the size of the Main mine rock disposal
area would create beneficial effects by reducing
the erosion potential on that component. This
evaluation is based on the assumption that the
Pinto Creek diversion would remain in place in an
adequate postmining configuration. Restoration of
the Pinto Creek channel through the additional
backfill would not be a reasonable reclamation
alternative because of the additional disturbance
related to diversion removal and losses of Pinto
Creek surface flows into the porous backfill for an
unknown length of time.
Additional Backfill of the Eder South Pit. Additional
backfill of the Eder South pit would not create further
potential impacts beyond those previously described
under the proposed action. The removal of rock from
the Eder mine rock disposal area would reduce lateral
earth loading and would increase the sideslope
stability and reduce the risk of mine rock migrating or
sliding downslope and potentially affecting the
Powers Gulch diversion integrity regarding water
conveyance and sediment transport. This would be a
potential benefit of this alternative.
Leach Pad Alternative
Eder Side-Hill Leach Pad Alternative. The
alternative of constructing the heap-leach facility on
the side slopes of the Powers Gulch watershed while
leaving the channel in the valley floor would have less
potential for impacts from an erosion and channel
stability perspective. In the description of this
alternative (Knight Piesold 1993a), it is assumed that
the toes of the heap-leach pad and embankment
could be placed high enough to be out of the
floodplain for some given magnitude of event. With
the channel left as it is, its sediment transport
characteristics and sediment regime passed
downstream would remain as they are now. However,
some erosion protection would be required if the base
of the embankment were to be inundated during large
flow events in Powers Gulch. Although the need for
the Powers Gulch diversion would be eliminated with
this alternative, approximately 1 ,000 feet of Powers
Gulch could require realignment through the pad area
so that flows would not impinge on the embankments.
The possible need for an energy dissipation structure
downstream on Powers Gulch would be eliminated.
This alternative would temporarily remove
approximately 458 acres (0.7 square mile) from the
contributing Powers Gulch watershed (approximately
5.5 square miles). Based on mean annual watershed
runoff of 2.62 inches above the Pinto Valley weir,
removing this contributing watershed area would
reduce surface water runoff by approximately 98
acre-feet per year. This volume represents
approximately 13 percent of the runoff from the
Powers Gulch watershed and approximately 2
Carlota Copper Project Final EIS
3-127
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-48. Comparison of Potential Postmining Water Resource Impacts Associated with the Proposed
Carlota/Cactus Pit and the Additional Backfill of the Carlota/Cactus Pit Alternative
Proposed
Addftfotiai Backfin
Pit Lake Development
An approximately 500-foot deep lake
would eventually develop postclosure.
No lake will develop.
Ground Water Flow
Ground water in the vicinity of the pit
would flow towards and discharge into
the pit.
Ground water gradient should be
re-established to near premining
conditions.
Potential Water Quality
Concerns
The pit lake would become more saline
with time due to concentration by
evaporation and lack of outflow.
Interaction of ground water with
backfill is not anticipated to
degrade ground water.
Estimated Water Loss from
Evaporation Once Pit Water
Level Reaches Steady State
Approximately 480 acre-feet per year
(300 gpm) would be lost once the lake
level reaches equilibrium.
No loss of water from pit lake
evaporation.
Pinto Creek Diversion
Diversion channel would be maintained
postclosure.
Diversion channel would be
maintained postclosure.
Area Withdrawn from
Contributing Watershed Area
Approximately 0.5 square mile of
contributing watershed area would be
withdrawn.
No loss of contributing watershed
area.
percent of the runoff at the PC-7 gage site
downstream of the confluence of Haunted Canyon
and Pinto Creek. This impact would occur primarily
during storm events.
In addition, this alternative would involve substantially
less disturbance to the Powers Gulch stream channel
during operations than the proposed action. As with
the valley fill option (proposed action), the side-hill
alternative would incorporate solution storage within
the pad itself. However, this alternative would require
six different PLS ponds behind three embankments
as compared to two PLS ponds behind two
embankments for the proposed action. The solution
retention embankment length would be approximately
14,640 feet, almost 1 1 times the total embankment
length in the proposed action. As a result of the
increased embankment length, the required base pool
solution storage capacity would be 214 million gallons
as compared to 104 million gallons for the proposed
action. Therefore, the potential for the accidental
release of process solutions is significantly greater
with this alternative than with the proposed action.
Additionally, slope stability in this alternative would
require relatively large toe berms (in excess of 50 feet
in height) to generate marginally acceptable factors of
safety and accommodate internal solution storage.
The minimum factors of safety for this scenario were
1.3 and 1.0 for static and pseudostatic, respectively,
which are less than the minimum factors of safety
generally acceptable for dam design. The lower
factors of safety are largely a result of the lack of
buttressing at the toe of the pad. Therefore, the steep
side-slope configuration could increase the potential
for heap slope failure into Powers Gulch, and for a
heap-leach solution release.
Under this alternative, the reclaimed leach pad would
occupy more acreage, with longer slopes and less flat
surfaces, than under the proposed action. Erosion
and sediment yield would be expected to increase
from this alternative, creating more adverse impacts
than the proposed action.
Seasonally high ground water conditions would not be
a potential problem for this alternative. Potential
impacts to surface water and ground water quality
would be similar to those for the proposed action
because the low pH and toxicity of the heap-leach
solution would be identical.
Water Supply Alternatives
Low-Quality Water, Water Supply Wells, and
Dewatering Wells. This alternative consists of using
low-quality water that may have been degraded by
previous mining activities in the region to supply a
large portion of the water requirements of the project.
The low-quality water would be piped from one or
more of the following sources: Pinal Creek, BHP's
Cottonwood Storage Pond, BHP’s Copper Cities Pit
Water, and Cyprus’ Oxhide Pit. These potential water
3-128
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
sources range from 1 to 14 miles from the Carlota
Copper Project site as shown in Figure 2-18. Carlota
estimates that these low-quality sources could
provide up to 59 percent of the project’s water
requirements. The remaining water requirement
would be supplied by pit dewatering wells and water
supply wells in the well field. This alternative would
substantially reduce the amount of water withdrawn
from the well field. For example, this alternative would
reduce the maximum ground water withdrawal from
850 gpm (proposed action) to approximately 350 gpm
(this alternative). Reducing ground water pumping
from the well field area should substantially reduce,
but not eliminate, anticipated impacts to surface flow
and water levels in the alluvium in Haunted Canyon
and Pinto Creek.
Pinal Creek Water. One potential supplemental
source of water would be the low-quality, shallow
ground water from Miami Wash, a tributary of Pinal
Creek. The Pinal Creek Remediation Group (BHP
Copper Company, Cyprus Miami Mining Company,
and Inspiration Consolidated Copper Company) have
developed and implemented a remedial program
along Pinal Creek that involves pumping and
reclaiming or using the acidic alluvial water degraded
from past mining operations. The locations of the
Miami Wash, Diamond H Pit, existing BHP Copper
pipeline, and proposed pipeline route are shown in
Figure 2-18. The proposed pipeline would transport
untreated water from a pump station or storage
reservoir to the project site. Untreated or partially
treated water from this same source is reportedly
being piped to several other mining projects, including
BHP Copper’s Pinto Valley Mine and the Cyprus
Miami Mining Company. It is proposed that Pinal
Creek water would be used as process makeup
water; therefore, the proposed alternative does not
include treatment for use by the Carlota Copper
Company.
In this region of Pinal Creek, the surface flows are
ephemeral. The contaminated aquifer consists of
unconsolidated to consolidated alluvial sediments
composed of interbedded fine sand, coarse gravel,
and cobbles with occasional boulders up to several
feet in diameter. Clay interbeds of up to 40 feet thick
occur in the alluvium and may or may not be cal-
careous in nature. The Pinal Creek and tributary
channels are incised into the Gila Conglomerate,
which crops out along much of the Miami Wash area.
The Gila Conglomerate is composed of clay- to
boulder-sized material cemented primarily by calcite.
Water quality data compiled from the Miami Wash
alluvium {Table C5-4 in Appendix C, Water
Resources Data) indicate wide ranges of elemental
concentrations, possibly caused by variations in the
local geology and past mining practices. The overall
water quality of the Miami Wash, however, would
violate water quality criteria for most domestic or
industrial uses. Elevated concentrations of TDS
(average concentration = 4,640 mg/L) and sulfate
(average concentration = 3,400 mg/L) are reported.
The average pH was 4.8 standard units. Fluoride
concentrations averaged 12.7 mg/L. Elements with
concentrations below laboratory detection limits or
with sporadic trace concentrations included arsenic,
boron, barium, bromine, chromium, mercury,
molybdenum, selenium, and silver. Dissolved metals
concentrations with clearly elevated average
concentrations included aluminum, beryllium,
cadmium, cobalt, copper, iron, manganese, nickel,
strontium, vanadium, and zinc. The Miami Wash
alluvial water exceeds Pinto Creek stream water
quality standards for beryllium, cadmium, copper,
manganese, nickel, and zinc, and is below the
minimum allowable pH value of 6.5 standard units.
Federal primary and secondary MCLs for drinking
water and Arizona Aquifer Water Quality Standards
are exceeded by concentrations of TDS, sulfate,
fluoride, cadmium, copper, iron, manganese, and
zinc.
BHP Copper's Cottonwood Storage Pond. The water
that would be supplied from the Cottonwood storage
facility is a calcium-sulfate water with moderately high
TDS and a neutral pH; sulfate and TDS concen-
trations are greater than their respective federal
secondary MCLs. The Cottonwood tailings water
generally has lower dissolved metal concentrations
than those found in Pinal Creek, the BHP Copper
Cities Pit, and Cyprus' Oxhide Pit water sources
because some of the water is low-quality water that
has been treated. Because of the neutral pH and
lower metals concentrations, water from the
Cottonwood storage facility would be considered a
higher-quality water source than the other low-quality
alternative sources described in this section.
BHP Copper's Copper Cities Pit and Cyprus’ Oxhide
Pit Water. Low-quality water may be available from
Carlota Copper Project Final EIS
3-129
3.0 Affected Environment and Environmental Consequences - Water Resources
either BHP Copper's Copper Cities Pit or Cyprus’
Oxhide Pit (see Figure 2-18). Water quality analyses
for these pit waters are not available. For the purpose
of this EIS, these waters are anticipated to be similar
to the Pinal Creek water with low pH and high metals
concentrations.
Potential Impacts. The pipeline to any of these
sources, except for the Cottonwood Storage Pond,
would traverse several miles of mountainous terrain
and would cross the Cottonwood tailings facility and
roadways. Information on the existing soil and
geologic conditions along the route are not available.
However, considering the length of the route and the
terrain, it appears that there would be a low to
moderate risk that the pipeline could be damaged
during the life of the project. Potential threats could
likely include rock falls, landslides, flooding,
settlement (tailings impoundment), fire, and
vandalism. Water released from a failure of a pipeline
would be a potential pollutant to ground and surface
waters.
Potential localized impacts to springs and stream
channels could occur as a result of construction
activities and operation related to the alternative
pipelines. Excavation and increased traffic would
contribute to erosion and sedimentation. If released,
seepage of low-quality water could affect the quality
of flow at springs, such as Vigor of Life Spring,
Webster Spring, and Prince Charming Spring. These
potential surface water impacts would be of a
localized nature since existing open pits downgradient
of the rights-of-way would inhibit potential impacts
from migrating very far along the surface drainages.
The potential degree of seepage and migration of
spills in the ground water system is unknown. If use
were restricted to the heap-leach operation,
monitoring and mitigation measures for the water
alternative would be covered by the monitoring and
mitigation program established for the heap-leach
facility.
Alternative Water Supply Well Field Access
Roads
Potential surface water impacts related to these
alternatives would be increased erosion and
sedimentation of the Pinto Creek drainage as a result
of construction and operation of the access roads.
The actual impacts from these activities would be
minimized by Carlota’s commitment to employ BMPs
to control erosion and sedimentation under the
proposed action. It is assumed that such a
commitment would extend to either of the access
road alternatives, since the need for a well field
access road is an integral part of the project water
supply.
Without such drainage and erosion controls, either
road alternative would create substantial sediment
yield from disturbance in the immediate vicinity of
stream channels, which would be an adverse impact.
However, the potential for impacts from such
considerations would be minimized by Carlota’s
commitment to implement an approved Stormwater
Pollution Prevention Plan and appropriate erosion
and sedimentation controls, including BMPs.
Alternative A would require that Pinto Creek be forded
three times, with much of the road located within the
Pinto Creek floodplain. These conditions would
restrict access to the well field via this road during
periods of higher flow in Pinto Creek. These
conditions would not apply to Alternative B. Further
discussion of these alternatives is presented in
Section 3.2, Geology and Minerals, and Section 3.4,
Soils and Reclamation.
No Action Alternative
Ground water pumping would not change from
current conditions. No pumping and resultant
drawdown and reduction in surface flows would occur
in association with the Carlota Copper Project.
This alternative would result in no adverse water
quality impacts on ground water or surface water
resources other than those already associated with
current mining operations and abandoned mine
operations in the Pinto Creek (and its tributaries)
basin. Past releases of tailings and process solutions
to surface waters have been documented by ADEQ
and the EPA.
3.3.3 Cumulative Impacts
For water resources, the cumulative effects area
consists of the Pinto Creek watershed and adjoining
areas included in the Top-of-the-World community.
The Pinto Valley Mine is the only large-scale mining
project currently operating in this area. The Gibson
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
Mine and historic placer mining activities also occur in
the Pinto Creek \A/atershed. Pinto Valley Mine
operations cover large portions of the eastern flank of
the Pinto Creek watershed, extending from near the
project site north to Layton Ranch. The general
location of these mines is presented in Chapter 1 .0,
Figure 1-2.
Past, present, and future activities at Pinto Valley
Mine have the potential to impact ground water and
surface water quantity and quality. The location of the
primary mine facilities and water supply wells
associated with these operations are illustrated in
Figure 3-21. The overall consumptive use of ground
water and surface water at BMP Copper’s Pinto
Valley operations is approximately 1 0,200 acre-feet
per year (Arizona Department of Water Resources
1992). A portion of BMP Copper’s production water is
pumped from the alluvial system in Pinal Creek and
stored in the Cottonwood Reservoir. Additional water
is supplied from 10 production wells located in the
Pinto Creek watershed (Hargis and Associated, Inc.
1995). Pumpage from the wells varies according to
demand and recovery of water levels between
pumpings. Based on data supplied by Magma (now
BHP Copper) for the years 1 980 through 1 991 , the
average annual pumpage rate for the well field is
approximately 1,630 gpm (Hargis & Associates, Inc.
1995). Ground water is used to supplement available
surface water so that ground water pumpage is
generally reduced during wet years.
The ground water production wells are located in
Eastwater Canyon and Ripper Spring Canyon {Figure
3-21). Well construction information, along with static
depths to ground water, and pumpage drawdown
rates for BHP Copper’s production wells are
presented in Table 3-49. Recorded water level
drawdowns range from 5 feet at well Peak 48 to 355
feet at well Peak 51 {Table 3-49) (Hargis &
Associates, Inc. 1995). The cumulative change in
water levels throughout the area resulting from
ground water pumpage is not known.
The open pit at the Pinto Valley Mine, which is
located in the southeastern portion of the Gold Gulch
drainage basin {Figure 3-21), does not appear to
influence ground water elevations in the area. Hargis
& Associations (1995) state that only minimal and
sporadic seeps are present along the perimeter of the
walls of the pit. In addition, wells located near the pit
have significant differences in depths to water and
water level elevations.
Mining and ore processing facilities at BHP Copper’s
Pinto Valley Mine include low-grade ore leaching
facilities, the open pit, mine rock disposal area, the
concentrator and SX-EW plants, and No. 1 , No. 2,
No. 3, No. 4, and the Cottonwood Canyon tailings
impoundments {Figure 3-21). Seepage from some of
the tailings facilities has the potential to degrade
ground water in the area.
Ground and surface water studies conducted by
Hargis & Associates, Inc. (1995) indicate that
seepage from the No. 1 , No. 3, No. 4, and the
Cottonwood Canyon tailings impoundments is
affecting the ground water quality. Downgradient of
the No. 1 tailings facility, water quality data from
monitoring wells indicates that migration of seepage
containing elevated concentrations of sulfate, TDS,
iron, and manganese has occurred (Hargis &
Associates, Inc. 1995). Studies also indicate that
ground water quality downgradient of the Cottonwood
tailings facility may also be affected. Elevated
concentrations of sulfate and TDS in the ground
water adjacent to the southeastern margin of the
tailings impoundment area has been detected. The
studies also indicate that seepage from the No. 3 and
No. 4 tailings impoundments has locally effected
ground water quality beneath and, for some distance,
downgradient of these facilities. Several monitoring
wells located downgradient from the facility indicate
that the concentrations of calcium, sulfate, and TDS
have increased over time. However, because of the
dilution processes, Hargis & Associates, Inc. (1995)
concluded that the eventual migration of seepage
from these tailings impoundments should have
minimal impact on the alluvium system in Pinto
Creek.
The proposed action could potentially increase
cumulative impacts to the quantity of ground water
available and to local surface water discharge.
However, the proposed action is anticipated to have
minimal impacts on the quantity of ground water
available to the Top-of-the-World community or
surface flows below the Pinto Valley weir.
Although little is known about the premining water
quality of the watershed, it appears that existing
mining-induced impacts include increased TDS and
Carlota Copper Project Final EIS
3-131
3-132
3.0 Affected Environment and Environmental Consequences - Water Resources
Table 3-49. BHP Copper’s Pinto Valley Mine Production Wells
Weil ■
Num^r
Borehole
Depth
(feet)
* Open
interval
(feet^
static Depth
toWater^
fe- (feet^
Pumpage
^ Drawdown
(feet) i
Peak 46
760
215-515, 595-695
NA
NA
Peak 48
1200
840-1200
580
5
Peak 4
512
80-512
130
60-110
Peak 7
656
166-655
NA
160-460
Peak 50
620
90-590
17
10-20
Peak 23
765
open hole
145.5
NA
Peak 51
820
170-765
133
225-355
Peak 52
740
360-700
213.5
NA
Peak 53
840
300-800
253
NA
Peak 26
550
465-505
37
NA
See Figure 3-22 for well locations.
Source: Hargis & Associates, Inc. (1995).
Well Peak 26 has been observed by the Forest Service as an active pumping well. Peak 26 was not listed as a
production well by Hargis & Associates (1995).
sulfate and copper concentrations in surface water
and shallow ground water along stream reaches
downstream from some active and historic mining
properties. Periods of higher than average runoff and
flooding have caused breaching of tailings
impoundment facilities in the watershed. The released
materials subsequently flowed into Pinto Creek near
the proposed project area. Some of the tailings
material was deposited along the floodplain in Pinto
Creek. The tailings deposits, and possible seepage
from the existing tailings facility, could potentially
degrade the water quality in Pinto Creek. The existing
placer mining that occurs in the Pinto Creek drainage
is limited to small-scale operations, and the relatively
small size of these activities would suggest minor
additional effects on water quality in the drainage.
After reclamation and closure, approximately 310
acres (0.5 square mile) would remain withdrawn from
the watershed area contributing to runoff volume. This
would be approximately 0.5 percent of the contributing
watershed above the Pinto Valley weir and 0.3 percent
of the contributing watershed above Roosevelt Lake.
Approximately 2.8 percent of the contributing
watershed area above the Pinto Valley weir has
already been withdrawn in the locale by operations at
the Pinto Valley Mine. By implementing monitoring and
mitigation measures, negligible adverse impacts to
surface runoff and flood flows are anticipated from the
Carlota Copper Project.
With mitigation measures implemented, the long-term
sediment transport conditions and related stream
channel stability of the overall Pinto Creek watershed
would not be adversely affected to a significant degree
by the Carlota Copper Project. Although the potential
for increased erosion rates may affect on-site surface
stability, most eroded fine-grained materials would be
flushed through the channel system by high sediment
transport capacities. This has been demonstrated
previously by the distribution of tailings spilled by the
existing adjacent mine operation. Coarser eroded
materials may be initially deposited in channels near
the project area, but would eventually be dispersed
downstream. Implementation of the identified
monitoring and mitigation measures and the
commitment by Carlota to stabilize and reclaim the site
according to BMPs and to implement postclosure
diversion designs would mitigate the potential for
additional cumulative water resources impacts from
erosion and sedimentation beyond what has already
occurred in the Pinto Creek watershed and nearby
areas from existing exploration, mining, and grazing
operations.
Carlota Copper Project Final EIS
3-133
3.0 Affected Environment and Environmental Consequences - Water Resources
3.3.4 Monitoring and Mitigation Measures
3.3.4.1 Monitoring and Mitigation for the Proposed
Action
The proposed project could potentially impact wells
and surface water resources in the vicinity of the
proposed project. The recommended monitoring and
mitigation measures for the proposed action are
summarized below. Monitoring of the riparian aquatic
communities is addressed in Section 3.5, Biological
Resources.
Monitoring and reporting would enable impacts on
water resources directly attributed to the Carlota
mining operation to be anticipated so that mitigation
measures could be implemented to reduce the
potential impacts. The monitoring data would also
provide valuable information to help determine if
individual water resources, such as private water
supply wells, had been impacted whenever complaints
were registered.
Monitoring and maintenance to control erosion
and sedimentation would occur throughout the
operations phase and would extend into the
postmining phase. As proposed by Carlota, BMPs
would be employed to control erosion and
sedimentation on the project area. These practices
would be inspected periodically during operations
and for a selected period of time after reclamation.
The frequency of inspection and the duration of
the monitoring program would be determined by
the Forest Service and Carlota personnel during
project permitting and construction, with annual
reviews to assess the needs and success of the
program.
Monitoring would include the locations of erosion
and sedimentation controls, as well as overall project
area inspections, to identify any evolving critical
areas that may need attention. This would include
areas and practices such as unimproved road
crossings of stream channels, the leach pad
revegetation, and the drainage control effort. Heap-
leach pad embankments would be monitored for
stability in the recontoured, reclaimed configuration.
The Pinto Creek and Powers Gulch diversions would
be monitored for stability and postclosure functioning.
The methods, frequency of inspection, and duration of
these monitoring programs would be determined by
the Forest Service.
Monitoring Program
The Groundwater and Surface Water Monitoring Plan,
Carlota Copper Project, Gila and Pinal Counties,
Arizona (GWRC 1996a), a comprehensive ground
water and surface water monitoring plan, has been
prepared for the project. The monitoring plan (GWRC
1996a) is intended to satisfy ADEQ's requirements for
an Aquifer Protection Permit, Section 401 certification
by ADEQ for the EPA NPDES permit compliance, and
the COE for CWA 404 permit compliance. The
monitoring plan also includes the monitoring and
reporting requirements of the Forest Service. The
purpose of the monitoring plan is to monitor potential
effects of project development, operation, and closure
activities on water resources in the Pinto Creek,
Haunted Canyon, and Powers Gulch basins. The
monitoring plan includes the following activities; (1)
tracking the rates, volumes, and quality of ground
water extracted during pit dewatering and well field
operation; (2) monitoring ground water hydraulic
heads and ground water quality in both the alluvial and
bedrock ground water systems; (3) monitoring surface
flows and water quality in streams and springs; (4)
monitoring water quality from ephemeral water
courses and runoff detention basins located
downgradient from the mine rock disposal areas; (5)
monitoring sediment transport along the Powers Gulch
diversion channel; (6) and monitoring meteorological
conditions. The locations of proposed monitoring wells
and surface water monitoring stations are presented in
Figure 3-22. Details regarding all the monitoring
stations, monitoring frequency, parameters for field
and laboratory analysis, and quality assurance and
quality control are provided in the ground water and
surface water monitoring plan (GWRC 1996a).
The water monitoring program (GWRC, 1996a)
includes the following principal components:
• Several wells or piezometers located between the
Carlota/Cactus pit and Top-of-the-World and the
Eder South pit and Top-of-the-World to monitor
possible drawdown between the open pits and the
Top-of-the-World water supply wells
3-134
Carlota Copper Project Final EIS
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Proposed Pit
Mine Rock Area
Leach Pad
Diversion Channel
Proposed Pipeline Route
Proposed Power Line Route
County Line
Top-of-the-World Boundary
- — ~ Stream
Alluvial Monitoring Wells
Bedrock Monitoring Wells
Piezometers
Well Field Production Well
Continuous Surface Water Flow Monitoring Stations
Other Surface Water Monitoring Stations
Note: Stormwater runoff and sediment
sample sites are not shown.
AMW-124-
BMW-4-^
PZ-2-f-
TW-2 •
PC-7 A
SW-1 ▲
BMW-1
M18 N
BMW-28
I, \
AMW-12
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.AMW-15
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iPC-1
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Source: GWRC 1996a
I
Seal* In F«et
0 1000 2000
Riverside Technoiogy, inc.
CARLOTA COPPER
PROJECT
Figure 3-22
Proposed Ground Water and
Surface Water Monitoring
3-135
3.0 Affected Environment and Environmental Consequences - Water Resources
• Wells or piezometers located both upstream and
downstream of the Carlota/Cactus pit in the
alluvium in Pinto Creek to detect drawdown
• A piezometer located in the bedrock near Mule
Spring to monitor possible drawdown in the vicinity
of the spring
• Wells or piezometers located at selected sites in
Haunted Canyon and Pinto Creek to monitor
drawdown of water levels in the alluvium that
could result from well field development
• Flow rate monitoring from well field production
wells and pit dewatering wells for the
Carlota/Cactus pit and Eder pits
• Continuous streamflow monitoring in Haunted
Canyon and Pinto Creek in the vicinity of the well
field and at the inlet and outlet of the Pinto Creek
diversion channel
• Collection of water quality data on a quarterly
frequency from a network of alluvial and bedrock
monitoring wells, including wells located
downgradient of the PLS impoundments, leach
pad, SX/EW plant, raffinate and plant PLS/SX
ponds, shop and warehouse, Carlota/Cactus pit,
Eder North and South pits, Eder rock dump, and
portions of the Main and Cactus southwest mine
rock disposal areas
• Collection and analyses of water quality on a
quarterly frequency at selected continuous and
instantaneous streamflow monitoring stations in
Pinto Creek, Powers Gulch (when flowing), and
Haunted Canyon at sites located both upstream
and downstream from project components
• Monitoring of spring discharge on a monthly basis
(eight springs) and water quality (three springs) on
a quarterly basis at selected springs located near
the mine and well field areas
• Weekly collection and analysis of water quality
data (pH, TDS, sulfate, and copper) from the
underdrain collection pond associated with the
main pad embankment
• Collection and analysis of water quality from
sediment detention basins located below the Main,
Cactus southwest, and Eder mine rock disposal
areas during runoff events
• Collection of sediment samples during and after
runoff events at stations located above, within,
and below the Powers Gulch diversion to verify
the assumptions and modify, if necessary, the
post-closure design of the Powers Gulch diversion
For additional details regarding the monitoring
program, please refer to Appendix C, Water
Resources Data, Table C6-1,
Postclosure Monitoring. The water monitoring
program would continue at selected sites following
closure of the mining operation. Postclosure
monitoring would include periodically measuring water
levels in selected bedrock and alluvial wells and flow
in springs within the drawdown cones affected by the
pit dewatering and well field activities.
Facilities from the proposed action could potentially
impact ground water and surface water resources in
the vicinity of the project after mining operations
cease. Postmining monitoring of specific areas or
facilities would persist during reclamation efforts and
would continue after reclamation until it could be
reasonably demonstrated that the potential no longer
exists for these areas to degrade the waters of the
state.
The Forest Service, ADEQ, and Carlota would work
together to determine when and for which areas
or facilities this goal is accomplished. Some areas
and facilities could require only an additional year
of postmining monitoring to demonstrate that potential
risk to waters of the state no longer exist. However,
specific areas and facilities, including the heap-
leach pad and the Carlota/Cactus pit, would
require continued monitoring for a much longer
time to demonstrate that potential risk has been
minimized.
Mitigation
The following proposed monitoring and mitigation
measures would lessen or eliminate potential impacts
to water resources from the proposed action.
WR-1 : The ground water and surface water
monitoring plan (GWRC 1996a) would be revised to
3-136
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
include the following specifications and would be
submitted to and approved by the Forest Service prior
to initiation of project construction:
• Provide the Forest Service with the location, well
completion information, lithologic log, initial static
water level, pumping rates, and cumulative
volumes pumped for each dewatering well
• Monitor flow and water quality for the underdrain
collection pond below the north embankment
• Locate PC-1 on Pinto Creek upstream of 005
Gulch as shown in Figure 3 of the existing
monitoring plan (GWRC 1996a)
• Conduct surface water quality sampling at the
identified stations in Powers Gulch quarterly (if
there is sufficient flow) and during runoff events
• Add a sediment sampling station on the East
diversion channel
• Add continuous recording gages at PC-6 and Mule
Spring
• Add continuous water-level recording to BMW-31
• Add a monitoring well at the base of the raffinate
pond to monitor the bedrock surface
• Within the well field area, add sets of alluvial
monitoring wells near existing monitoring station
HC-3 in Haunted Canyon and PC-7 in Pinto Creek
or other appropriate locations approved by the
Forest Service
• Add an alluvial piezometer near AMW-21
The purpose of the additional alluvial monitoring well
sets would be to monitor the variations in ground water
levels across the alluvium perpendicular to the stream
channel. Each set would consist of a minimum of two
shallow alluvial wells installed along a line perpen-
dicular to the stream channel: one well located near
the stream channel and one located a reasonable
distance away from the channel (but still within the
alluvium). Based on the results of the monitoring,
Carlota, in conjunction with the Forest Service, ADEQ,
and other appropriate state and federal agencies,
would periodically evaluate the adequacy of the
monitoring plan and mitigation measures and revise
the plan and measures as deemed necessary by the
regulatory agencies.
WR-2: Additional aquifer and well field testing would
be performed during the mine construction phase
but prior to well field production for operating the mine.
This testing would not be performed until the
necessary access roads, power lines, pipelines for
water management, additional production and
bedrock and alluvial monitoring wells, continuous
streamflow stations, and water-level monitoring
instruments are in place. The full-scale testing would
be designed to simulate both average and peak
ground water withdrawal rates expected during the
life of the project, and would involve pumping the
water supply wells concurrently and monitoring the
effects on surface and ground water resources.
The purposes of the testing are to (1) confirm the
long-term sustainable yield from the well field, (2)
further quantify potential effects to the alluvial water
levels and streamflow in Haunted Canyon and Pinto
Creek, (3) evaluate the most appropriate locations
and methods (surface discharge, alluvial infiltration,
and/or alluvial injection) for discharging mitigation
flows (see WR-3), and (4) further evaluate the water
quality of the well field for use in mitigating
streamflows (see WR-3). A work plan for any
additional well field testing would be submitted to the
Forest Service and other appropriate agencies and
approved prior to initiating testing.
During the life of the project, it may be necessary to
conduct other aquifer or aquifer/stream interaction
tests. The purpose of additional aquifer tests would be
to refine the understanding of ground water/surface
water interactions and adjust the mitigation program, if
necessary, to protect water-dependent resources. The
need for and scope of additional aquifer testing would
be evaluated on a continual basis by the Forest
Service in conjunction with Carlota and other
appropriate agencies.
WR-3: A detailed plan to* mitigate potential flow
reductions in Haunted Canyon and Pinto Creek
(Appendix E) has been agreed to by the Forest
Service, ADEQ, ADWR, Salt River Project, COE, and
Carlota. The wellfield mitigation program is designed
to maintain aquatic and riparian resources at pre-
project levels and specifies a mechanism to augment
streamflows. In summary, the well field mitigation plan
Carlota Copper Project Final EIS
3-137
3.0 Affected Environment and Environmental Consequences - Water Resources
for Haunted Canyon and Pinto Creek includes (1)
continuous flow measurements at stream gaging
stations and at any required flow augmentation
discharge point(s), (2) trigger flow rates that identify
when flow augmentation should begin, (3) specific flow
rates that would be maintained in the stream to sustain
water-dependent resources at premining levels, and
(4) specific discharge rates from the mitigation flow
pipeline that would be required to maintain flow rates
in the streams. Ground water pumped from the well
field or water from other suitable source(s) approved
by the Forest Service and other appropriate agencies
would be discharged to the stream to maintain
streamflows.
Continuous surface water flow data and ground water
elevation data in bedrock and alluvial monitoring wells
would be provided to the Forest Service in accordance
with the ground water and surface water monitoring
plan (GWRC 1996a). If the streamflows fall below the
trigger flows identified in the Forest Service Wellfield
Mitigation Program (Appendix E), then the Forest
Service would be provided with weekly reports of well
field extraction rates and volumes for each production
well; water level elevations in each alluvial and
bedrock monitoring well within the well field area; and
streamflow measurements, including daily
instantaneous minimum and maximum flows and daily
mean and median flows (based on hourly
measurements) and rates and volumes of water
discharged to the stream systems at each discharge
point. Details regarding the specific data, summaries
and summary tables and graphs to be included in the
weekly reports, and report format would be described
in a revised ground water and surface water
monitoring plan submitted to and approved by the
Forest Service prior to project construction.
It is likely that over time the Wellfield Mitigation
Program and the ground water and surface water
monitoring plan would need to be modified, refined, or
expanded as necessary. Additional testing may be
required to improve individual components of the
mitigation program. The components of this mitigation
program that may require additional testing during the
project life or closure period include the putback point
locations, putback quantities, and putback methods to
ensure that water discharged to the stream meets
appropriate water quality standards. The Forest
Service would be responsible for evaluating the
adequacy of the monitoring program and mitigation
plan and defining the need and scope of any additional
testing that may be necessary on a continual basis
throughout the life of the project and for some period
after closure. The Forest Service would work closely
with Carlota and other agencies to update the
monitoring and mitigation plans as necessary.
Reductions in streamflow could occur both during the
project operation and for some period following the
cessation of all mine dewatering and well field
pumping activities. If reductions in flow attributable to
the project are recorded in Haunted Canyon and
reaches of Pinto Creek, flows would be supplemented
as specified in the Wellfield Mitigation Program until
adequate natural stream conditions are restored.
WR-4: Any water discharged to the stream through the
mitigation flow program (WR-3) would be required to
meet the Arizona surface water quality standards
established for the appropriate beneficial uses. If the
well water does not meet water quality standards, then
the water would need to be treated prior to discharge,
or a variance would need to be granted by the EPA or
ADEQ to allow discharge. Alternatively, Carlota would
need to provide another source of supplemental water
that met discharge permit requirements for flow
augmentation.
Existing water quality data for potentially affected
stream reaches and the well field alluvium, in addition
to possible sources of supplemental water (well field
bedrock ground water) are presented in Table C5-5 in
Appendix C, Water Resources Data. Analyses of
samples collected from the three bedrock test
production wells and Haunted Canyon {Table C5-5)
are the best estimates of the water quality for the
proposed supplemental water source and the
anticipated receiving waters. It should be noted that a
single maximum value for zinc (out of a total of six
reported values) exceeded Arizona surface water
quality standards for aquatic and wildlife uses.
Information is not available to evaluate whether
discharge of well field bedrock water would exceed
the maximum allowable increase in the ambient water
temperature of 3°C. Reported detection levels were
too high to evaluate water quality standard
exceedances or levels elevated above receiving
waters for the following constituents; cyanide, total
phosphorus, antimony, beryllium, cadmium, copper,
mercury, selenium, and thallium. Blending different
well field bedrock ground waters and selecting one
3-138
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
well field bedrock well over another are two methods
available to maintain constituent levels in the
supplemental water below Arizona water quality
standards. If the temperature of the water in the
bedrock varies from the surface water quality
standards for the stream, adjustments will be made
prior to discharge.
WR-5: Significant impacts to Pinto Creek from pit
dewatering activities are not anticipated. However, the
proposed alluvial and surface water monitoring
program would be used to help evaluate whether pit
dewatering is partially lowering water levels in the
Pinto Creek alluvium located upstream or downstream
from the pit, and depleting Pinto Creek flows. If
necessary, the monitoring plan would be expanded to
track potential impacts. Mitigation for these impacts
would depend on the ecological value of the affected
stream corridor. The Forest Service would be
responsible for evaluating impacts and determining the
appropriate mitigation. Mitigation for impacts to Pinto
Creek from pit dewatering activities could potentially
include a cutoff wall on the downstream end of the
Pinto Creek diversion and/or improvements to other
nearby stream reaches, wetlands, or riparian
corridors.
WR-6: A spring monitoring program is included within
the ground water and surface water monitoring plan
and consists of monitoring selected natural springs
and wells near springs. Various mitigation measures
would be used to effectively renovate or replace an
affected spring or seep. The appropriate mitigation
measure to be implemented on any affected spring
would be based, in part, on the ecological value of the
resource. Potential mitigation measures for affected
springs include the following:
• Supplementing or replacing the flow from springs
that support important wetland or wildlife habitat
by discharging ground water from wells. The well
water could either be piped from existing wells in
the area or from a new well drilled into an
underlying aquifer near the spring. Ground water
discharge could either be from natural artesian
flow or could be pumped using electric, solar, or
wind power.
• Improving existing spring sites to enhance
collection or water yield by (1) constructing
catchment basins or ponds to capture runoff, (2)
constructing tanks or troughs for storing the
collected surface water, and (3) installing devices
designed to provide water to wildlife or to
discharge to the surface at a relatively constant
rate.
• Developing or improving other nearby springs to
offset the impact to springs or seeps that are
difficult to repair or enhance.
• Replacing lost water from another water source
(pipeline, trucking) if other mitigation measures are
not practical.
WR-7: A comprehensive ground water monitoring
program has been established (GWRC 1996a) to
measure the extent and rate of expansion of the
cone(s) of depression from drawdown due to mine
dewatering activities. This monitoring plan is designed
to make information about changes in environmental
conditions available to the Forest Service, COE,
ADEQ, and ADWR. Carlota has indicated its intent to
assist affected parties by deepening existing wells,
drilling new wells, or providing a replacement water
supply of equivalent yield and general quality during
any period of effect. However, the Forest Service does
not have the authority to require mitigation of impacts
occurring off National Forest System lands.
WR-8: Water conservation measures would be
implemented to minimize the need for ground water
pumping. These measures could include solution
emitters (drip lines) to apply raffinate to the leach pad,
dust palliatives for dust control on unpaved mine
roads, and other measures for reducing evaporative
losses. To prevent water quality impacts, the types of
dust palliatives proposed must be approved by the
Forest Service before being applied to roads. Carlota
would prepare a water conservation plan that includes
these measures for approval by the Forest Service.
WR-9: Failure to contain the leachate within the heap-
leach pad could result in degradation of ground water
and surface water resources. Because a release of
solution with low pH and high metals concentrations
from the heap-leach pad to surface waters could
potentially be transported by streamflow to Powers
Gulch, Haunted Canyon, Pinto Creek, and eventually
Roosevelt Lake within a short time (less than a day),
an alarm system (including electric dialing and
personnel notification) would be installed in Powers
Carlota Copper Project Final EIS
3-139
3.0 Affected Environment and Environmental Consequences - Water Resources
Gulch downstream of the heap-leach pad to provide
real-time detection of a low pH release (e.g., less than
a pH of 4.0).
The potential for leakage from the facility would be
significantly reduced by installing the LCRS described
in the proposed action. Carlota's construction quality
assurance/quality control plan must be approved by
the Forest Service before construction on the leach
pad begins with regard to testing and placing
subgrade materials. Prior to final construction of the
heap-leach pad, Carlota would submit a report to the
Forest Service evaluating competent borrow sources
and estimating volumes of sources by material types.
Source material with the capability of achieving a
loaded permeability potential of 1 x 10"* cm/sec would
be targeted for preparing the subgrade in the most
critical areas (double-lined areas of the main and north
pads). Loaded permeability equates to demonstrating
that on lower gradient slopes of the critical areas, a
loaded permeability potential of 1 x lO"* cm/sec
can be achieved with the lowest ore lift heights.
Corresponding ore lift heights would be determined
from the laboratory analysis/modeling of competent
borrow sources and displayed in the report. The most
competent borrow sources would be used in the
critical areas that would create the lowest possible ore
lift heights prior to solution application.
Other portions of the leach pad would be
consecutively targeted to receive subgrade material
that would have a loaded permeability objective of 1 x
10"® cm/sec, which equates to demonstrating that on
lower gradient slopes of other portions of the leach
pad, a loaded permeability objective of 1 x 10"® cm/sec
can be achieved with the lowest ore lift heights.
Corresponding ore lift heights would be determined
from the laboratory analysis/modeling of remaining
borrow sources and displayed in the report.
In situations where a loaded permeability of 1 x 10"®
cm/sec for the critical areas cannot be achieved
through conventional methods used to place
subgrades, Carlota would submit a listing of BADCT
alternative procedures to the Forest Service. The list
would outline procedures that would be implemented
to meliorate the less than ideal source material to
achieve the targeted permeability potential. If all the
BADCT alternative procedures fail to achieve the
target permeability of 1 x 10® cm/sec, then source
material with the higher permeability potential would
be allowed depending on concurrence by the Forest
Service. Other state and federal agencies, where
applicable, would be advised if higher targeted
permeabilities would be allowed and at which locations
the higher permeabilities would be allowed.
As part of this mitigation, the spine drains beneath the
main and north portions of the leach pad would be
included as an integral part of the leak detection and
removal system.
Both the LCRS and the spine drains would be
monitored weekly for evidence of leakage, and results
of the monitoring would be furnished to the Forest
Service and ADEQ. Any leachate collected by the
system would be pumped back onto the heap. In
addition, process flow shutoffs and secondary
containment for piping between components would be
provided. The leach collection system and
downgradient aquifers for the heap-leach pad would
be regulated by an ADEQ aquifer protection permit.
Alert levels for the underdrain system would be
established after 12 months of ambient water quality
have been collected. Mitigation of adversely affected
surface or ground water quality or potential
degradation from uncontained leachate would include
identifying the potential contaminant source, correcting
the source of release where possible, and remediating
contamination, if necessary. The exact type of cleanup
and remediation procedures would be approved by the
ADEQ in coordination with the Forest Service, ERA
and other state and federal agencies.
In addition to the above requirements, the main heap-
leach reservoir must be equipped with pump systems
with the capacity to remove the volume of solution
generated by the 100-year, 24-hour storm event out of
the reservoir and into a suitable location available for
emergency containment within a 10-day or less period.
WR-10: The existing preliminary characterization data
indicate that the waste rock material would be non-
acid generating. However, considering that some
sulfide-bearing material would be mined, there is some
potential for acid-generating waste rock material to be
produced. The waste rock from mining activities would
be sampled and analyzed at a frequency of 1 sample
for every 1 million tons of waste rock using the EPA's
Method 1312, Synthetic Precipitation Leaching
Procedure. As part of the ADEQ's Aquifer Protection
Permit, Carlota has committed to continual
3-140
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
characterization during active mining as specified by
ADEQ (Carlota 1995a). In addition, as part of the
Aquifer Protection Permit, if geochemical testing
indicates that some of the material has the potential to
generate acid or leach metals, Carlota would develop
a materials handling plan to prevent impacts to surface
or ground water and submit it to ADEQ for approval.
WR-11: To control erosion, sedimentation, runoff, and
surface drainage, the proposed erosion and sediment
controls would be developed and implemented subject
to Forest Service, EPA, and ADEQ approval. A
Stormwater Pollution Prevention Plan would be
developed and implemented subject to approval by the
EPA. For the long term, a stable, free-draining
postmining topography would be restored on the
project area in the reclamation and closure phase.
Effects of erosion and sedimentation from access
roads and haul roads during and following reclamation
activities (as currently proposed) would have the
potential to degrade surface water quality: therefore, a
mitigation measure has been added in Section 3.4. 4.2,
Soils and Reclamation - Reclamation.
WR-12: Although failure of a properly designed
diversion is unlikely, the possibility of failure would
remain if flows exceeded the design flow or if there
were inadequate inspection and maintenance
activities. The final design of the heap-leach
embankments, inlet control structure, raffinate and
plant PLS/SX ponds, and associated diversions must
comply with the conditions specified in the Arizona
Department of Water Resources Dam Safety permit.
At a minimum, however, these facilities must comply
with the Forest Service requirement that, operating in
conjunction with one another, they must accommodate
(at a minimum) the peak flows and volumes resulting
from the 1/2 PMF in addition to the corresponding one-
time maximum monthly operating volume of process
solutions without any discharge of these solutions. The
following measures must be met:
• The main PLS embankment crest must be
maintained at a minimum height of 3,830 ft-amsi.
The maximum elevation permissible for storing
operational process solutions is 3,810 ft-amsI.
• The maximum elevation permissible for storing
process solutions in the North heap leach pad
embankment/PLS pond is 3,845 ft-amsI.
• The maximum elevation permissible for storing
process solutions in the raffinate pond is 3,891 ft-
amsl.
• The maximum elevation permissible for storing
process solutions in the plant PLS/SX pond is
3,919 ft-amsI.
• The Powers Gulch diversion, operating in
conjunction with the inlet control structure, the
heap and the east diversion channel, must be able
to safely convey the 6-hour 1/2 PMF peak flow
and volume (at a minimum) as defined by Knight
Piesold (1996f). The toe of the main ore heap
behind the main heap-leach embankment where it
parallels the Powers Gulch diversion must be
armored with large rock riprap or other suitable
material to prevent erosion of the heap in the
unlikely event that the diversion is overtopped.
• The East diversion channel must be designed to
safely accommodate the 6-hour 1/2 PMF peak
flow and volume (at a minimum).
WR-13: The Pinto Creek, Powers Gulch, and East
diversions are designed to safely convey the 500-year
thunderstorm event (Pinto Creek) and 1/2 PMF storm
event (Powers Gulch and east diversions) during the
operational phase of the project. These diversions
would be redesigned at closure to convey the full PMF
storm event. The designs would incorporate detailed
assessments of the range of hydraulic conditions and
sediment transport characteristics likely within the
channel systems. The need for energy dissipation
structures for the reach immediately downstream of
the proposed Powers Gulch diversion outlet would be
analyzed for both the operational and postclosure
phases.
Periodic inspections of the diversions are required for
a number of years after closure and would include
inspection of energy dissipation structures
downstream of the proposed Powers Gulch diversion
outlet, if such structures are necessary. The frequency
of inspections and the duration of the monitoring
program after closure would be set by the Forest
Service and other appropriate agencies. Monitoring
during the operational phase is described in the
monitoring program (GWRC 1996a). Monitoring and
review of the performance of the diversion channels
Carlota Copper Project Final EIS
3-141
3.0 Affected Environment and Environmental Consequences - Water Resources
and of the monitoring program would be conducted
during the operational phase of the project. A con-
sultant would be hired to evaluate the performance of
the channels, particularly their sediment transport
characteristics, to aid in developing a maintenance-
free design for the postclosure period. Maintenance
during the operational phase could include sediment
removal and repairs to channel structures. Providing
for long-term stability after closure could require
altering the channel geometries such that the need for
periodic maintenance and repair over a lengthy time
could be avoided.
WR-14; The design of the central spine drain to be
constructed beneath the main portion of the heap-
leach pad would be modified to include an upstream
access port. The purpose of the access port would be
to provide an upstream opening that could be used for
clean out, flushing, or inspection, if necessary. The
access port would be located in the vicinity of Powers
Gulch immediately upstream of the leach pad, and
would be designed such that it would not penetrate the
liner or compromise the integrity of the fluid contain-
ment system. The access port would include a locking
cap at the surface.
WR-15: For closure of the heap-leach pad, Carlota
has committed to investigating closure technology to
improve upon closure options already identified.
Carlota has also committed to experimenting with any
identified techniques on the North portion of the leach
pad since that portion would be closed before the main
portion of the pad. To provide oversight for this
research program, Carlota would prepare annual
reports of its investigations and findings for submittal
to the Forest Service. Submission of reports would
begin 1 year after commencement of the operational
phase of the project. Annual meetings would be
conducted to discuss the annual report and work
anticipated for the following year. One year prior to
actual closure of the full facility, Carlota would submit
a final proposal for closure of the heap leach pad to
the Forest Service and other regulating agencies for
approval. If a preferred closure technology, such as
neutralizing the heap, is identified during the life of the
operation the reclamation bond would be adjusted
accordingly.
WR-16: The main and north embankments would
have a seal zone keyed into bedrock. The need for
alluvial monitoring wells upgradient of the
embankments would be evaluated on the basis of site
conditions and depth of alluvium below the spine
drains.
Additional Mitigation Measure
The Forest Service would be responsible for
determining that adequate monitoring and mitigation
measures are implemented to protect water depen-
dent resources. Carlota would contribute funding to
the Forest Service, through a collection agreement, to
monitor project construction activities. The funding
would be used to finance a portion of the Forest
Service specialist's salary, a portion of a specialist’s
salary from another agency, or a third-party contractor
(under the guidance of the Forest Service) to monitor
project construction and facilitate the implementation
of operational monitoring programs.
3.3A.2 Additional Monitoring and Mitigation for
the Alternatives
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. Additional
monitoring of ground water and surface water quality
would be performed in the vicinity of the Cactus South
mine rock disposal area. The monitoring would include
upgradient and downgradient monitoring wells and
surface sampling points. Surface water monitoring
associated with this alternative would entail periodic
sampling and analyses of any ponding or drainage
outflow from the mine rock disposal areas.
Additional Backfill of the Carlota/Cactus Pit. Water
quality monitoring of the pit lake quality for some
unspecified period of time would not be required under
this alternative. Periodic inspections of the diversion
would be required for several years to ensure proper
function. Additional mitigation measures would be the
same as previously described for the proposed action.
Additional Backfill of the Eder South Pit. No
monitoring or mitigation measures beyond those
identified for the proposed action would be required for
this alternative.
Leach Pad Alternative
Eder Side-Hill Leach Pad Alternative. Although
monitoring points would change, no mitigation
3-142
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Water Resources
measures beyond those identified for the proposed
action would be required for this alternative.
Water Supply Alternatives
Low-Quality Water, Water Supply Wells, and
Dewatering Wells. A detailed plan would be
developed to define appropriate measures to (1)
reduce the potential for leaks or ruptures in the
pipelines, (2) conduct periodic monitoring of the
pipeline for integrity, and (3) implement remediation
measures to reduce the potential for degradation of
surface or ground water resources in the event of a
release. This plan would be approved by the ADEQ.
Pipeline integrity would need to be monitored
throughout the operational life of the low-quality water
supply alternative. This would occur as part of normal
project operations since system reliability would be a
major operational consideration. Monitoring would
include an automated leak detection system. Auto-
mated control valves would be placed along the
pipelines at locations or intervals as specified by
appropriate agencies. The pipeline would be con-
structed before leaching operations on the main pad
would begin. During construction, BMPs would be
implemented as erosion and sedimentation controls.
At the end of operations, the pipelines and appur-
tenances would be cleaned, drained, and removed.
The rights-of-way would be revegetated, and erosion
and sedimentation controls, such as water bars and
riprap, would be installed as needed. Carlota would
report the volume of water pumped through the low-
quality water pipeline to the Forest Service quarterly.
Alternative Water Supply Well Field Access Roads
Monitoring would consist of periodic inspection of
site conditions and erosion controls to ensure site
stabilization along the access roads. Mitigation would
consist of concurrent revegetation of roadside cuts
and fills and stabilization of all stream channel
crossings. Stabilization would consist of durable
riprap in the stream channel and along road
approaches.
Carlota Copper Project Final EIS
3-143
3.0 Affected Environment and Environmental Consequences - Water Resources
3-144
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
3.4 Soils and Reclamation
3.4.1 Affected Environment
3.4.1. 1 Soil Occurrence and Characteristics
A wide range of soil characteristics occurs in the
proposed Carlota Copper Project area because of the
complexity of geologic materials, slope and aspect,
and climatic factors. Within the project locale, the soil
features consist of shallow, very gravelly materials
with thin, loamy topsoil and subsoil layers. Typically
the soils are less than 20 inches deep over bedrock.
Some areas, particularly toeslopes and north- and
east-facing aspects, are overlain by deeper, more
strongly developed soils. Rock outcrops and rubble
are widespread in the project area. The occurrence of
these features varies over the project area, but
generally 15 to 40 percent of the land surface is
occupied by such materials.
Cedar Creek Associates, Inc. has conducted soil
mapping and has described the proposed project
area; the results of this work are presented in the
Soils Technical Memorandum for the project (Cedar
Creek Associates, Inc. 1994d). Twenty-four mapping
units were described and mapped; the major
characteristics of these units are summarized in
Table 3-50. Figure 3-23 shows the occurrence of the
soils within the project area.
For the purpose of general soil description, the
project area may be divided into four major sections
based on dominant soil units: north, central,
southwest, and southeast. These sections were
identified as the northern part occurring generally
north of the Kelly fault zone from Manitou Hill toward
Grizzly Mountain, the central part lying generally
south of the Kelly fault and west-southwest of Manitou
Hill, the southwestern part generally west of Powers
Gulch, and the southeastern part as the remaining
portion of the project area.
The northern section occurs north of the Kelly fault
zone from the Manitou Hill area west toward Grizzly
Mountain. Soils in this section of the project area
have developed in colluvium and residuum from
mixed sources, including dacite, breccia, conglom-
erates, and limestones. Gravelly and very gravelly
loamy and sandy textures predominate.
In this northern section, dominant soil mapping units
are A, C, D, L, and N (Cedar Creek Associates, Inc.
1994a). Much of the area consists of rubbleland and
rock outcrop (Unit A) where soils are very thin or
nonexistent. Where soils do occur, the surface layers
typically consist of very gravelly loams or sandy
loams, and underlying layers range in texture from
very gravelly sandy loams to gravelly clay loams
(Units C and D). Typically, bedrock occurs at depths
shallower than 20 inches. Dark, organically-enriched
surface layers occur on some north- and east-facing
slopes as a result of climatic and vegetative influ-
ences. Mapping unit L consists of deep soils formed
in residuum from conglomerate. Typically, the surface
layer is gravelly loam. The subsoil is gravelly clay
loam to a depth of approximately 8 inches. Underlying
materials are extremely gravelly sandy loams
weathered from conglomerate. Mapping unit N
consists of very shallow and shallow soils weathered
from igneous rocks. Textures range from very
gravelly sandy loams in the surface layer to extremely
gravelly sandy clay loams in the subsoil. Depth
ranges from 4 to 20 inches over hard bedrock.
Soils in the central section of the project area have
developed in colluvium, slope wash, and residuum
dominantly from basaltic diabase and Pinal Schist.
This section lies west and southwest of Manitou Hill
and is generally separated from the northern section
by the Kelly fault zone. Dominant soil mapping units
include G, H, R, and S (Cedar Creek Associates, Inc.
1994a). Units G and H are deep and moderately deep
soils that commonly contain gravelly loam surface
layers and silt loam to gravelly sandy clay subsoils.
Bedrock occurs at depths ranging from 22 to 55
inches or more. Mapping units R and S are typified by
very gravelly to extremely gravelly sandy loam
materials underlain by bedrock at depths less than 20
inches.
Soils in the southwestern section of the project area
formed in colluvium and slope wash primarily from
diabase and smaller occurrences of Pinal Schist. This
section generally occurs west of Powers Gulch.
Dominant soil mapping units include A, C, and V
(Cedar Creek Associates, Inc. 1994a). Unit A consists
of rubbly slopes and rock outcrops. Mapping unit C
consists primarily of shallow, very gravelly sandy
loams occurring under juniper on north and east
aspects. Dark-colored, organically-enriched surface
Carlota Copper Project Final EIS
3-145
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
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brush/
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dry-slope
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brush
chaparral
dry-slope
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brush
dry-slope
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brush
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stoniness,
rock outcrop,
slope
stoniness,
depth to
rock, slope
stoniness,
rock outcrop,
slope
stoniness,
rock outcrop,
slope, depth
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35% rock
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very shallow
soils
40% rock
outcrop and
very shallow
soils
40% rock
outcrop and
very shallow
soils
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very gravelly to
extremely gravelly
sandy loam, sandy
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igneous bedrock
very gravelly sandy
loam or loam
igneous bedrock
very gravelly loam
or clay loam
fractured limestone
very gravelly loamy
sand
very gravelly to
extremely gravelly
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igneous bedrock
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(inches)
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cobble,
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gravel,
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gravel,
cobble,
stones,
and
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40-50%
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3-146
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
Carlota Copper Project Final EIS
3-147
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
3-148
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
Carlota Copper Project Final EIS
3-149
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
layers are typical in this unit. Mapping unit V typically
consists of shallow, coarse-textured gravelly soils
less than 20 inches deep over schist bedrock.
Soils in the southeastern section of the project area
have developed in materials weathered from granites.
Mapping units H and W dominate this section; unit W
is by far the most extensive (Cedar Creek Associates,
Inc. 1994a). Mapping unit H primarily consists of
moderately-deep and deep, well-developed soils with
dark surface layers and clayey subsoils. Unit W
consists of rock outcrops of granite. Small inclusions
of shallow “grus” weathered from granites are
interspersed with rock outcrops.
Within each of these major sections of the project
area, other geologic materials and soils developing
from them occur to a lesser extent. For example, the
soils in major drainages, such as Powers Gulch and
Pinto Creek, are deep and coarse-textured with a
substantial content of rock fragments (mapping unit I).
The parent materials are narrow deposits of alluvium.
Textures are primarily extremely gravelly loamy
sands and sands with significant volumes of cobbles,
stones, and boulders in most locations. Coarse
colluvial deposits also occur, particularly along upper
drainages.
Climate and vegetation vary over the project area and
result in soil variations. The climate is semi-arid, with
summer thunderstorms (monsoons) and more gentle
winter rains and occasional snow. Two soil tempera-
ture regimes (thermic and mesic) and one dominant
soil moisture regime (ustic) occur in the project area.
The thermic soil temperature regime exists at lower
elevations and on warmer south- and west-facing
aspects. Generally in this regime, the mean annual
soil temperature is 15°C or higher, but less than 22°
C. In contrast, the mesic soil temperature regime
generally consists of mean annual soil temperatures
of 8°C or higher, but less than 15°C (Soil Conserva-
tion Service 1975). Within the project area, mesic soil
temperatures generally occur at higher elevations and
on north- and east-facing aspects or sheltered sites.
The ustic soil moisture regime is dominant within the
project area. This regime is generally characterized
by limited moisture, but moisture is usually available
at times when conditions are suitable for plant growth
(Soil Conservation Service 1975). Within the project
area, the ustic moisture regime transitions toward
both drier and wetter regimes, depending primarily on
elevation and aspect.
3.4.1. 2 Estimates of Existing Erosion Losses
Estimates of existing erosion, as calculated by the
Revised Universal Soil Loss Equation (RUSLE),
indicate that where soils occur, moderate to high
amounts of soil are lost on the project site in the un-
disturbed condition primarily because of steep slopes
and high-energy rainfall. Soil amounts up to approxi-
mately 12 tons/acre/year could be lost on the undis-
turbed Cactus Southwest mine rock disposal site,
with losses of approximately 3 to 7 tons/acre/year for
other mine rock disposal sites and the proposed
leach pad in their existing undisturbed condition.
3.4.1. 3 Existing Disturbance
Existing mineral-related disturbance in the project
area consists primarily of roads, shafts, drifts, mine
rock areas, and drill holes and drill pads from past
exploration and mining. The most prominent features
date back 50 years or more. The total acreage of
disturbance from pre-project mining features is small,
and most of the disturbed areas would be excavated
or buried during the construction of the proposed
project.
Surface exploration disturbance by Carlota has
primarily involved approximately 3.5 miles of road
construction or maintenance to allow drilling access
and well construction. Drilling sites are located within
the roadbed or at the road terminus. Water bars
would be constructed on all roads as necessary to
minimize erosion. All drill holes would be abandoned
in accordance with Arizona Department of Water
Resources specifications, or they would be mined
out. Test pits would be mined out or recontoured and
reseeded.
The Forest Service EIS objectives for reclamation
activities are given below:
• Conduct concurrent reclamation of project areas
where reasonable and practical.
• Provide for short-term and long-term protection of
surface and ground water quality.
• Remove facilities and appurtenances.
3-150
Carlota Copper Project Final EIS
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CARLOTA COPPER PROJECT
Figure 3-23
Soil Map Units
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
• Control short-term and long-term erosion and
runoff.
• Control and remove hazardous materials.
• Reshape and revegetate disturbed areas where
reasonable and practical.
• Restore productive postmining land uses,
including aquatic and wildlife habitat, livestock
forage production, and dispersed recreation.
• Mitigate potential public safety hazards.
3.4.2 Environmental Consequences
Issues related to soils and reclamation for the
proposed Carlota Copper Project include the potential
loss of soil resources or reduction of soil productivity
from project operations, and potential damage to
surface resources of the National Forest system
lands. Evaluation criteria used to describe project
impacts on soils and reclamation include the
following:
• Area (in acres) requiring restoration of topsoil
• Volume (in cubic yards) of salvageable topsoil
materials
• Projected postdisturbance soil erosion (in
tons/acre/year) for project component sites based
on the RUSLE
• Area (in acres) for which postreclamation
objectives cannot be met because of design or
placement of project components
• Anticipated annual postreclamation inspection
and maintenance costs
3.4.2. 1 Proposed Action
Reclamation Planning
Carlota Copper Company has provided a
Reclamation and Closure Plan as part of the Plan of
Operations. The removal of facilities, site
recontouring and drainage restoration, erosion and
sedimentation controls, stabilization of process
solutions, and topsoil replacement and revegetation
efforts are the basic components of the proposed
reclamation program. Carlota’s proposed plan
describes the reclamation and closure efforts for the
proposed action; Carlota’s proposed reclamation and
closure would also apply to the project alternatives.
The overall commitment by Carlota is to recreate
productive land uses; control erosion and sedimen-
tation; and restore stable, safe, and productive
postmining conditions to the project area to the
degree practical and achievable under available
technology and BMPs. Given that project designs are
in a detailed yet preliminary condition at the time of
this EIS, Carlota recognizes the need for continued
analysis, planning, and implementation of reclamation
practices as the project progresses. Such activities
would be an ongoing part of project activities and
would involve input from appropriate agency
personnel in developing and carrying out a coordi-
nated reclamation program.
General Reclamation Approach
Reclamation of the proposed project is planned and
designed to reasonably ensure public safety and to
return the land to productive postmining land uses
compatible with and supportive of its premining uses.
The proposed Reclamation and Closure Plan (Carlota
1994a) consists of the following key measures:
• At the time of closure, the project site will be
surveyed for potential public safety hazards. No
chemical or electrical hazards will remain after
closure. Physical hazards will be minimized using
measures such as berming, fencing, or filling,
depending on the specific perceived hazard.
• The Carlota/Cactus pit will be partially backfilled
to further stabilize the Pinto Creek diversion and
to enhance the postmining site configuration.
• The Eder pits will be recontoured so that excess
precipitation will exit as stormwater discharge.
• The leach pad slopes will be recontoured to a
continuous approximate 2.5:1 (H:V) slope.
• The leach pad surfaces will be reworked to
prevent deep surface water percolation into the
pad, thereby eliminating the potential for
discharge from the pad. This activity will consist
Carlota Copper Project Final EIS
3-153
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
of a combination of compacting, applying suitable
rock material and topsoil, and promoting the
establishment of adapted plant species. All
salvaged topsoil will be placed on the reworked
leach pad.
• The top surface of the mine rock disposal areas
will be revegetated on a growth medium
developed from the waste rock, amended as
necessary, and directly reseeded. Sideslopes of
the mine rock disposal areas will remain at the
angle of repose, except for the North Eder mine
rock disposal area. This component will be
partially recontoured so that sideslopes approach
2.5:1.
• Facilities will be dismantled and removed from
the site or buried.
• Erosion control measures other than re-
establishing vegetation will be implemented as
needed to prevent sedimentation of surface
drainages.
• Diversion channels will be prepared for
postclosure functioning.
• Ripping, grading, and seedbed preparation
will be performed on surfaces planned for
reclamation. A surface material survey will be
conducted before reseeding to determine the
need for seedbed amendments. Mulching may be
used in conjunction with revegetation practices.
• Grasses will be emphasized in reseeding mixes
to ensure short-term site stabilization, but shrubs
and forbs will also be seeded. To the extent
practical, native and adapted seed will be
purchased from a southwestern seed source.
• Methods of seeding and establishing vegetation
will be reviewed before planting. Where
topography and site conditions allow, drill seeding
is preferred. Hydroseeding and broadcast
seeding may also be employed as site-specific
conditions dictate.
• Test plots to further define reclamation practices
will be developed in close cooperation with Forest
Service specialists.
• Opportunities for innovative reclamation practices
may emerge during the life of the project. Areas
where special reclamation practices may be
warranted include wetland and riparian area
replacement, cactus habitat replacement, stock
pond construction, and riparian expansion. New
approaches to mine reclamation, such as
livestock and holistic management, which are
currently showing promise in the Globe-Miami
area, may have potential. A riparian/wetland
mitigation plan has been developed by the
Carlota Copper Company and reviewed by the
COE and the Forest Service (Aquatic and
Wetland Consultants, Inc. 1996a). A wetland and
waters of the U.S. Compensatory Mitigation Plan
for the Carlota Copper Project has been prepared
and approved by the COE. A plan to mitigate
potential impacts to the Arizona hedgehog cactus
{Echinocereus triglochidiatus arizonicus) has
been developed and approved by the U.S. Fish
and Wildlife Service (Cedar Creek Associates,
Inc. 1996a, 1996b).
On lands administered by the Forest Service, interim,
concurrent, and final reclamation of the proposed
project would be the responsibility of the project
proponent and would become a point of compliance
in the final approved Plan of Operations. The
responsibility to conduct reclamation is further
reinforced by requiring the operator to post a
reclamation bond that provides financial assurance
that the reclamation, as specified in the final approved
Plan of Operations, would be completed.
Additional details about proposed project reclamation
activities and goals are presented in the reclamation
portion of the Plan of Operations developed for the
project. This document served as the basis for the
following analysis of potential impacts.
A final Plan of Operations, which would include
specifics on reclamation and closure, would be
submitted and approved prior to project
implementation. The final Plan of Operations would
reflect the additions or changes to reclamation
generated by the analysis. In addition, preparation of
the final Plan of Operations would provide a
mechanism through which Carlota and the Forest
Service could ensure that postmining land uses are
compatible and supportive of premining uses.
3-154
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
The following sections address specific con-
siderations related to soils and reclamation that
would have a bearing on potential project operations
and ongoing reclamation efforts. Where necessary,
additional mitigation measures beyond those
described in the proposed action have been
recommended.
Potential Impacts to Soil Resources
Potential impacts to soils from the proposed action
include the physical loss of soil materials and
decreases in soil productivity. Physical losses would
occur as a result of accelerated erosion and removal
by excavation, construction uses, or burial. Soil
productivity would be affected by removal,
compaction, and fertility losses.
Affected Acreage. The proposed Carlota Copper
Project would disturb approximately 1,428 acres (in
plan view), of which approximately 1,207 would be
directly affected by excavation or other earthwork.
Approximately 221 acres of buffer strips and
construction traffic/staging areas would be disturbed
to a lesser extent. The acreages directly affected by
excavation or other earthwork within the proposed
component footprints are listed by component in
Table 2-2.
As proposed by Carlota in its Reclamation and
Closure Plan, all salvaged soil materials would be
respread on the top and sideslopes of the recon-
toured heap-leach pad (Carlota 1994a). This
represents an area of approximately 270 acres.
Reclamation of excavated areas that do not receive
topsoil would consist of ripping the seedbed on flatter
areas, testing and amending seedbed materials with
fertilizers and mulch as necessary, and seeding.
These activities would occur on approximately 447
acres of excavated areas on the top surfaces of the
mine rock disposal areas, the Carlota/Cactus backfill,
roads, the SX/EW plant, and small miscellaneous
areas. In total, 717 acres affected by earthwork would
be revegetated, 270 of which would be topsoiled.
Soils on the remaining project areas disturbed by
earthwork (approximately 500 acres) would be
removed from postmining land uses. These areas
consist mostly of angle-of-repose slopes, pit walls, or
other steep areas. In addition, soils on approximately
221 acres of buffer strips and staging areas would be
disturbed by grubbing and compaction. The buffer
strips and staging areas would be revegetated at the
end of operations.
Topsoil Used in Construction. Soil would be used
as both a construction material and a plant-growth
medium. Near-surface soil materials of suitable
quality for salvage and use as plant-growth medium
are referred to as topsoil in the subsequent text. A
certain amount of topsoil would be used as construc-
tion material to build roads, embankments, and pads.
The largest amount of topsoil likely to be used in
construction would occur at the proposed leach pad
area. Compacted soil bedding overlain by a synthetic
liner would be installed at this location to prevent
discharges of process solutions to ground water and
surface water. Although the topsoil used as a bedding
for the leach pad would be unavailable for postmining
revegetation and land use restoration efforts, it would
perform an important role in long-term environmental
protection.
The volume of material needed to provide a 1-foot
thick constructed earth bedding under the proposed
leach pad and PLS ponds (approximately 270 acres)
is on the order of 435,000 cubic yards. The bedding
would be primarily developed from the scarification
and compaction of in situ materials, including
potential topsoil sources. The construction volume
includes salvageable topsoil otherwise available for
reclamation in the proposed leach pad area. (The
actual volumes required and available would vary
from these preliminary estimates according to final
design and construction).
Other potential borrow sources have been identified
during project development. While preparing the EIS,
examination of the proposed leach pad design and
geotechnical appendix (Knight Piesold and Company
1993b) indicated that 100,000 to 300,000 cubic yards
of potential construction materials may occur in the
vicinity of the proposed leach pad. The actual volume
present may vary, depending on a more detailed
investigation during construction. The further delinea-
tion and use of borrow sources for construction
purposes would improve the availability of topsoil for
reclamation. As a result, mitigation measures are
recommended in Section 3.4.4, Soils and
Reclamation - Monitoring and Mitigation Measures.
Carlota Copper Project Final EIS
3-155
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
Topsoil Salvaged for Reclamation. To initiate a
proposed topsoil salvage plan, Cedar Creek
Associates, Inc. made salvage depth recommen-
dations for each mapped soil unit (Cedar Creek
Associates, Inc. 1994a). These recommendations are
shown in Table 3-51 and Figure 3-24. To subse-
quently estimate soil salvage volumes, Carlota used
these depth recommendations and incorporated
operational considerations. Because of heavy
equipment safety considerations, Carlota proposes to
limit topsoil salvage to suitable topsoil materials
present on disturbed areas with less than a 30
percent slope. The salvage volumes were estimated
by examining the proposed disturbance footprint,
buffer and traffic areas, and a slope map. Losses
equaling 15 percent of the potential salvageable
volume were also used to account for the size of rock
fragments, outcrops, inaccessibility, and losses in
Table 3-51. Soil Salvage Depth Summary
transport. The proposed total salvage volume is
estimated at approximately 460,000 cubic yards.
For the leach pad and other proposed components,
Carlota has estimated the volume of topsoil that could
be salvaged and stockpiled for reclamation. This is
shown by component in Table 2-11. The estimated
topsoil volume for reclamation from the leach pad
area (approximately 192,000 cubic yards) takes into
account the use of topsoil during construction.
The total volume estimate developed by Carlota
includes topsoil salvaged from the entire area of
disturbance exhibiting less than 30 percent slopes.
This includes areas for traffic and staging that may
not be affected by excavation and other earthwork
that would remove soils. If soils were left in place on
Map
Unit
Percent of
Sal^geabie
—
PrlmaiV^tvageymftatlons ’
A
0
0
Surface rubble, rock outcrops, slope
B
10
80
Depth to bedrock, slope
C
15
0
Slope, rock outcrop, surficial bedrock and rock cover
D
10
0
Slope, surficial bedrock, rock outcrops
E
6
0
Slope, surficial bedrock, coarse fragment content
F
0
0
Slopes, coarse fragment content
G
26
40
Slope, surficial bedrock, depth to weathered bedrock
H
22
25
Slope, surficial bedrock
1
12
35
Alluvial gravel/cobble/rock/boulder accumulations
J
34
50
Slope, existing disturbance, depth to bedrock
K
52
30
Slope, surficial bedrock
L
8
90
Coarse fragment content, depth to weathered bedrock, slope
M
12
35
Surficial bedrock, slope, coarse fragment content
N
0
0
Slope, coarse fragments, bedrock, existing disturbance
0
20
50
Basalt cap, slope
P
34
90
Surficial bedrock, depth to bedrock
Q
18
80
Slope, soil depth
R
12
40
Slope, surficial bedrock outcrops, depth to bedrock
S
6
10
Slope
T
70
100
None
U
10
40
Slope, surficial bedrock
V
18
80
Depth to bedrock, talus, surficial bedrock outcrops
w
0
0
Rock outcrops, surficial bedrock, lack of soil
X
16
90
Coarse fragment content, slope
Source: Cedar Creek Associates (1994a)
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
these areas (approximately 221 acres), the actual
volume of topsoil salvaged for the project under
Carlota's salvage approach could be less than the
estimated 460,000 cubic yards, perhaps by as much
as 20 percent. In order to ensure the appropriate
recovery of suitable topsoil resources, mitigation is
recommended in Section 3.4.4, Soils and
Reclamation - Monitoring and Mitigation Measures.
Topsoil Storage and Replacement. The proposed
locations of topsoil stockpiles are shown in the
Reclamation and Closure Plan. Locations occur
adjacent to the proposed Powers Gulch diversion
along the southwest side of the leach pad and to the
northwest of the Carlota/Cactus pit, between the pit
and the proposed Main mine rock disposal area.
Salvaged soil materials are proposed to be stockpiled
for the life of the leach pad (i.e., approximately 20
years).
During reclamation, the proposed placement of the
salvaged topsoil (roughly 460,000 cubic yards over
the entire disturbed area) on the top and sideslopes
of the leach pad (approximately 270 acres) would
result in an average topsoil replacement depth of
approximately 13 inches. The actual depth would vary
somewhat because of the amount of topsoil actually
salvaged and the equipment handling capabilities on
the areas to be topsoiled. The relatively flat top sur-
faces of the leach pad would occupy approximately
54 acres, and the sloping areas would occupy
approximately 216 acres having continuous slopes of
approximately 2.5:1 (H:V), or 40 percent.
Approximately 447 acres of relatively flat surfaces
would remain after operations at the mine rock
disposal areas, SX/EW plant, and pit backfills.
Sideslopes on the mine rock areas would be left at
the angle of repose. Under the proposed action,
topsoil would not be replaced on these areas. Plant-
growth media at these locations would be developed
from in situ mine rock materials and amended as
prescribed after a testing program.
A review of soils data for the project area (Cedar
Creek Associates, Inc. 1994a) indicates that
additional topsoil resources may be accessible, and
that the placement of topsoil on additional flatter
component surfaces would enhance the potential for
achieving reclamation goals. For this reason.
mitigation measures are recommended in Section
3.4.4.
Potential Excavation Losses. Approximately 1,207
acres would be directly affected by excavation or
other earthwork, and native soil materials would be
removed or buried over this area. Subsequently,
topsoil would be restored to approximately 270 acres
during reclamation. Ultimately, there would be a net
loss of soil resources over approximately 937 acres
because of earthwork. Although native soils are
poorly developed on the site, some soil profiles show
differentiation with depth as a result of biological
activity and geologic and climatic factors. During the
course of salvage and replacement, such profiles
would be disrupted, with effects on infiltration, soil
aeration and water-holding capacity, and fertility
relationships in the respread materials. These factors
would create an adverse impact on soil resources,
which would be offset by reclamation practices.
Potential Erosion Losses. The estimated erosion
losses on selected mine components during various
phases of development are shown in Table 3-52.
Components were selected by the extent of disturb-
ance and the location with regard to natural drain-
ages. These calculations were made using the
RUSLE manual and computer program and additional
inputs from other sources (Agricultural Research
Service 1990, Clyde et al. 1978, Soil Conservation
Service 1975, and Soil Conservation Service 1983).
Calculations were performed for the following
conditions: native undisturbed, during operations,
immediately after proposed reclamation efforts, and
several years after proposed reclamation. Typical soil
characteristics, slopes, vegetative cover, and erosion
control practices were selected for these various
cases from on-site resource information (Cedar Creek
Associates Inc. 1994a), project maps, and the
Reclamation and Closure Plan (Carlota 1994a).
Results of RUSLE calculations {Table 3-52) indicate
that a substantial amount of sheet and rill erosion
occurs naturally on the existing soil surfaces,
primarily because of steep slopes and high energy
rainfall. However, for the overall watershed, total
erosion rates are limited by large areas of rock out-
crops and other non-erodible surfaces. The predicted
amount of sheet and rill erosion would generally
change as a result of mining operations and recla-
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Table 3-52. Estimated Erosion Losses by RUSLE for Representative Erodible Slopes on
Selected Project Components' (in tons/acre/year)
Project Comoonent
,M(l>nditjor^
s 1 . Approximately
During After Proposed Proposed
OderMldns'' 1 R^ia'riieifti^^^lleciamation
Leach Pad
Sideslopes"
7.2
0.3
20 to 30
20 to 30
Proposed Top Surface
n/a
0.03
0.3
0.8
Main Rock Dump
Sideslopes"
2.6
4.9
4.9
4.9
Proposed Top Surface
n/a
0.03
<0.03
<0.03
Topsoiled Top Surface
n/a
n/a
0.3
0.8
Cactus SW Rock Dump
Sideslopes*
11.6
4.9
4.9
4.9
Proposed Top Surface
n/a
0.03
<0.03
<0.03
Topsoiled Top Surface
n/a
n/a
0.3
0.8
Eder Dump
Sideslopes'
5.5
4.9
4.9
4.9
Proposed Top Surface
n/a
0.03
<0.03
<0.03
Topsoiled Top Surface
n/a
n/a
0.3
0.8
’See text for constraints on these calculations: values are intended for comparative purposes only.
^Approximately 28 percent of the slopes in this area are non-erodible in the undisturbed condition.
^Approximately 58 percent of the slopes in this area are non-erodible in the undisturbed condition.
‘Approximately 48 percent of the slopes in this area are non-erodible in the undisturbed condition.
'Approximately 38 percent of the slopes in this area are non-erodible in the undisturbed condition.
mation primarily because of changes in topography
and the nature of exposed earth materials.
During operations, mining would result in coarser and
less erodible materials being exposed at the surface
compared to the undisturbed condition. However, it
should be noted that the predicted loss rate after
reclamation activities is high for replaced topsoil
(approximately 20 to 30 tons/acre/year). After
proposed recontouring, the leach pad would have
sideslopes of approximately 2.5H:1 V, with slope
lengths generally between 400 and 800 feet. If
unprotected, replaced topsoil may become unstable
on this configuration. Such surface instability would
inhibit the successful re-establishment of vegetation.
Eroded topsoil could move into the stream channel.
This would result in an adverse impact to surface
water quality. For this reason, additional mitigation
measures are recommended in Section 3.4.4.
As proposed in the Reclamation and Closure Plan,
topsoil stockpiles would be located northwest of the
Carlota/Cactus pit and adjacent to the Powers Gulch
diversion. Although these are preliminary locations,
stockpiles near the diversion would be subject to
erosion hazard from flooding and maintenance traffic.
The loss of topsoil resources from stockpiles would
be an adverse impact to both surface water and soil
resources. For this reason, additional mitigation
measures are recommended in Section 3.4.4.
There are specific features of the RUSLE that are
relevant to its application for this project. First, it can
be used as a predictive tool to compare the relative
effects of certain land management practices on soil
losses from sheet and rill erosion. The numerical
results do not predict actual erosion losses in a
quantitative sense, unless an extensive site-specific
calibration and testing effort has been undertaken.
The program has not been implemented in this way
for the project area. Second, the results indicate the
amount of soil removed from a slope rather than the
amount of sediment delivered to a stream, because of
the effects of downslope topography, vegetation, and
sediment controls. The RUSLE is site-oriented; it was
developed to examine erosion problems and controls
at the site of origin, rather than the movement of
sediment through the drainage system. Third, gully
erosion and the effects of concentrated runoff are not
accounted for in the RUSLE. These are often
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
significant problems along roads and drainages and
on steep or extensively disturbed sites.
Considering these features of the RUSLE, the
predicted erosion losses shown in Table 3-52 are
useful in a comparative sense rather than an absolute
sense. Sheet and rill erosion would decrease as a
result of mining on the mine rock disposal areas but
would substantially increase on the leach pad. Under
the severe rainfall conditions common to the project
area, topsoil placed on the leach pad sideslopes
would be difficult to revegetate under the proposed
reclamation program. The sideslopes would continue
to erode at near the unvegetated rates, creating an
adverse impact. For this reason, mitigation measures
are recommended in Section 3.4.4. In addition, gully
erosion and critical area conditions (i.e., erosion and
sedimentation along roads, drainages, and at the toes
of cuts and fills) may further accelerate soil losses. As
stated in the Reclamation and Closure Plan, Carlota
has committed to employing BMPs in controlling
sediment and implementing erosion control measures
other than revegetation, as needed. If appropriately
implemented and maintained, these activities would
mitigate most potential erosion impacts.
Potential Soil Productivity Losses. Long-term soil
productivity would be decreased by soil excavation,
erosion, compaction from traffic or construction in
buffer strips and staging areas, and by losses of
microbial populations during a lengthy period of stock-
piling. Approximately 221 acres would be affected by
traffic and/or light-duty construction activities that
would not involve significant removal of soil
resources. Compacted and denuded soils remaining
in these areas would be subject to accelerated
erosion, decreased infiltration and percolation, poorer
aeration, and decreased root penetration. The
ultimate effect of these factors would be to reduce soil
productivity in these areas, with detrimental effects on
postmining land uses.
Topsoil would be stockpiled for approximately 20
years. A number of studies have indicated that long-
term stockpiling creates conditions detrimental to soil
microbial populations (Reeves et al. 1979, Rives et al.
1980). In addition, plant growth media developed from
disturbed wastes typically have reduced populations
of soil biota needed for the successful establishment
of desirable vegetation (Miller 1979, Reeves et al.
1979, and Fresquez and Aldon 1984).
There is a potential for soil productivity impacts
associated with these conditions to occur at the
project site. For example, the beneficial effects of
nitrogen-fixing microorganisms on plant production
have been documented (Buckman and Brady 1969).
These organisms can be sensitive to acidity and low
macronutrient availability, conditions that may occur
on the disturbed site. In addition, an association with
fungi is necessary for optimum growth and possibly
even survival for the majority of plant species, especi-
ally in arid and semi-arid areas (Miller 1979). The lack
of appropriate fungal populations appears to favor in-
vasion by undesirable plants. If left unaddressed,
microbial conditions and the potential presence of
highly competitive undesirable species would inhibit
the re-establishment of desirable, successional plant
communities for a number of years following revege-
tation efforts (Reeves et al. 1979), which would result
in an adverse impact.
On areas to be reseeded, soil productivity impacts
could be successfully mitigated by Carlota's
commitment to test and amend plant growth
media (including replaced topsoil) as prescribed
in the Reclamation and Closure Plan. If necessary,
the addition of organic matter, fertilizer, and microbial
inoculants would largely mitigate the effects of
long-term topsoil stockpiling. Soil productivity
would be largely restored on approximately 54
acres of the flatter top surface of the leach pad,
where topsoil replacement would occur, and on
221 acres of buffer zones. However, if not protected,
predicted erosion losses on approximately 216
acres on sideslopes at the leach pad would severely
limit soil productivity at that location. Successful
reseeding and appropriate seedbed amendment
efforts on approximately 447 acres of the mine
rock disposal areas, roads, and pit backfill would
mitigate productivity losses on those areas. On
other areas, soil productivity would be adversely
affected where seedbed amendment and reseeding
are not undertaken, such as on the sideslopes
of mine rock disposal areas and pits. These areas
would comprise approximately 490 acres. However,
portions of this area may be suitable habitat for
relocating the endangered Arizona hedgehog cactus.
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Potential Impacts from Acid Mist. Based on
project-specific air quality modeling and other
analyses described in Section 3.1, Air Resources, no
adverse impacts to soil resources are anticipated
from acid mist or deposition.
Potential Reclamation Impacts
Erosion and Sedimentation. Sheet and rill erosion
on roads and gully erosion alongside roads can be
significant features of mining projects during opera-
tions. This erosion is primarily caused by the erodi-
bility of road surfaces built from compacted native
materials and the concentration of runoff from the
road and contributing watershed into roadside
ditches and culverts. Off-site impacts potentially
resulting from such conditions are related to the
erosion and sedimentation of watercourses from
concentrated flows and the deposition of eroded
material. On-site impacts could occur at areas such
as unprotected culvert outfalls, where concentrated
flows scour material from around the outfall.
Locations especially prone to such impacts include
areas where culvert pipes are suspended above
channels.
Without Carlota’s commitment to control drainage,
erosion, and sedimentation, these impacts could
occur during operations on the project area,
particularly along the proposed well field access road,
the main haul roads near the Eder pits and mine rock
disposal area, and along the mine shop and the
southeastern side of the Main mine rock disposal
area. All of these configurations drain to a major
channel: the Eder road system drains to the proposed
Powers Gulch diversion, and the others drain to Pinto
Creek.
Drainage and sediment controls for such road sys-
tems are addressed in the proposed action. Adverse
impacts to surface drainages would therefore be
minimized. Additional erosion and sedimentation
considerations are discussed in Section 3.3, Water
Resources.
The postclosure inspection and maintenance
of the Pinto Creek and Powers Gulch diversions
and the sediment control structures around the
proposed Main mine rock disposal area should
be addressed in the proposed action. Postclosure
inspection and maintenance activities would
be necessary for a period of time until
reclamation has been deemed successful. These
activities could prevent the long-term failure
of the diversions, which otherwise could create
extensive erosion and sedimentation impacts
downstream and could affect on-site reclamation
efforts, resulting in adverse impacts. Therefore,
monitoring and mitigation measures are
recommended in Section 3.4.4.
A review of the Main mine rock disposal area design
(Call and Nicholas 1992) did not indicate that seismic
considerations were factored into the proposed
design. Mass stability analyses were based on
unsaturated, free-draining conditions within the mine
rock disposal area. Reasonable construction,
drainage, and monitoring recommendations were
provided to encourage these drainage conditions
(Call and Nicholas 1992).
Since mine rock materials are likely to be coarse, the
amount of sediment yielded to a stream from a failed
mine rock face is not expected to be large, although
some fine sediments would be transported down-
stream. The stability of the mine rock disposal area
surface would be compromised to a limited degree. If
failure was extensive, rejuvenation of erosional condi-
tions on the surface could affect long-term stabiliza-
tion and revegetation until equilibrium is reached.
However, even if such a slope failure occurred, it
would probably affect only a limited area. Assuming
that streams or diversion channels were not blocked
by a mass failure, potential impacts from slope failure
of a mine rock area would be considered minor from
a reclamation standpoint. Further discussions of mine
rock disposal area considerations are presented in
Sections 3.2, Geology and Minerals, and 3.3, Water
Resources.
Restoration of Productive Postmining Land Uses.
Potential impacts to the restoration of productive land
uses may result from certain activities and conditions
associated with the proposed action. These impacts
would mainly result from the proposed postmining
topography. The proposed methods, materials, and
locations of revegetation efforts would also influence
the success of reclamation.
Extent. A large amount of the postmining configura-
tion would consist of steep slopes and pits. These
areas would comprise approximately 490 acres. This
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
acreage is characterized primarily by steep backfill
slopes and pit walls at the Eder and Cactus/Carlota
pits and angle-of-repose slopes at the mine rock
disposal areas. This acreage would not likely support
adequate vegetation or present adequate topography
for the land use goals identified in Chapter 2 unless
revegetation efforts and stable, suitable plant growth
media could be employed.
The Reclamation and Closure Plan does not describe
any revegetation efforts on the areas mentioned
above because the steep, rocky slopes would prevent
equipment access if common revegetation practices
were attempted. In general, low water-holding capa-
city, low fertility, and rapid drainage would be typical
of the materials on the mine rock disposal areas and
pit backfills. Given the high-energy rainfall common to
the region, microsites where plant-growth media does
occur would be exposed to considerable splash
erosion. These conditions would severely limit the
potential for successful re-invasion by desirable
vegetation on these sites.
The Carlota/Cactus pit would be partially backfilled,
which would recreate approximately 21 acres of
relatively flat surface on top of the backfill that could
be revegetated. Generally, the remaining part of the
backfill would be at angle-of-repose. An additional 27
acres of the pit area would be composed of access-
ible benches near the diversion that could be
reclaimed. Approximately 33 acres of the Eder pits
would consist of backfills that could be reclaimed.
Approximately 286 acres remaining within pit foot-
prints would not be reclaimable in the proposed
postmining configuration. This area (which is included
in the 490 acres of steep slopes and pits) would be
too steep for revegetation efforts. It may be suitable
for Arizona hedgehog cactus relocation or other
specialized postmining uses, but the capability for
typical productive uses would be highly restricted.
In addition, patented lands currently exist within the
project area, and the possibility exists for additional
lands to be patented over the life of the project. The
commitment to reclaim all patented lands to the same
level as public lands within the project area is not
specifically defined in Carlota's Plan of Operations
documents since the Plan of Operations is only
applicable to the surface use of National Forest
System lands. Project components proposed on
existing patented lands include the administration
building and parking lot; the Pinto Creek diversion
channel; the eastern half of the Carlota/Cactus pit;
parts of the mine shop area. Main mine rock disposal
area, and associated sediment controls; haul road;
and main access road. Reclamation activities are
proposed for these components; however,
reclamation on patented lands falls under the
jurisdiction of the State of Arizona Mine Inspector's
Office, rather than the Forest Service. Carlota has
submitted a reclamation plan to the State of Arizona
Mine Inspector's Office and will be bonded for this
reclamation.
Reveaetation Materials and Practices. A major goal of
the reclamation program is to revegetate suitable
disturbed areas and restore forage production and
wildlife habitat land uses. The types of premining
vegetation communities include interior chaparral,
rubbleland chaparral, dry-slope desert brush,
juniper/grassland, and riparian (Cedar Creek
Associates, Inc. 1994a). Shrubs and low-growing
trees, such as scrub live oak, pointleaf manzanita,
and junipers, dominate the project site.
The proposed revegetation composition on the
disturbed areas would involve three mixes of plant
species. These would consist of Seed Mixes L (for
the leach pad), R (for mine rock disposal areas and
other areas), and S (for topsoil stockpiles), as
presented in Section 2.1.9, Alternatives Including the
Proposed Action - Carlota’s Proposed Reclamation
and Closure. The mixes would be subject to modifi-
cation as the project and its associated reclamation
needs evolve. The proposed mixes consist primarily
of native and introduced grasses, accompanied by
lesser amounts of shrub and forb species.
In general, the highest proposed seeding rates are for
weeping lovegrass and yellow sweetclover, two
commonly used species for revegetation and erosion
control. An annual grass, red brome, is also included
in the proposed seed mix for the leach pad. The love-
grasses, yellow sweetclover, and red brome are
particularly competitive, aggressive species that tend
to dominate sites where they are seeded and are not
especially compatible with native species in seed
mixtures (Wasser 1982, Reichenbacher 1994). High
seeding rates for these species relative to more
desirable species in the mixes would inhibit the
redevelopment of successional plant communities on
the site. In addition, galleta, a species proposed for
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the leach pad, is widely acknowledged to have very
low seeding success (Moore 1994). Because these
approaches could adversely affect restoration of
productive postmining land uses, mitigation is
recommended in Section 3.4.4.
It should be noted that Executive Order 11987 (on
exotic organisms) limits the use of non-native
revegetation species; therefore, native species are
recommended. Introduced plant species should be
used only for specific purposes and if suitable native
species are unavailable.
The use of weeping lovegrass in Seed Mix S may
be suitable for providing short-term stability of soil
stockpiles, but it is not recommended for long-term
rehabilitation uses unless no other species is
suitable because it inhibits the re-establishment of
native species. Annual oats can spread to adjacent
areas and become a weed problem. Similarly,
Lehmann's lovegrass and red brome spread
aggressively and compete with more desirable
species.
Although seeding methods and seasons are not
specified in the Reclamation and Closure Plan for the
proposed action, Carlota has made a commitment in
the Reclamation and Closure Plan to discuss these
considerations with the Forest Service and additional
agencies. It is assumed that these discussions would
result in appropriate seeding methods and planting
seasons, and therefore no impacts would result from
these factors. However, further specifications of seed-
ing methods and seasons are needed to improve the
potential for successful revegetation, to schedule
revegetation activities, and to calculate the reclama-
tion bond.
Mulching is suggested as a conceivable application in
the Reclamation and Closure Plan. In areas to be
reseeded without topsoil replacement, several studies
have indicated that incorporating a usable source of
organic carbon into the seedbed may significantly
improve the establishment of desirable plants
(Fresquez and Lindemann 1982, Lindemann et al.
1984, Lindsey et al. 1977). Given the length of time
for topsoil stockpiling, organic amendments also
would probably be beneficial in restoring microbial
populations in topsoil.
Such organic sources would include hay or straw
mulches or manure. In addition to erosion control and
moisture-related benefits, these materials can provide
an energy source for microbial activity and, in turn,
improve nutrient uptake by desirable plants. The
application of supplemental nitrogen and phosphorus
fertilizers are typically beneficial in mulched condi-
tions. Carlota has committed to applying seedbed
amendments after they are prescribed from test
program results. Details of the test program, and
names of participants in its implementation and the
interpretation of results, would be defined later with
the Forest Service during the project.
Suitable implementation of the testing program, and
subsequent application of its results, is a significant
part of the project. It is likely that without mulches and
tackifiers or erosion control netting or matting on
topsoiled slopes, soil erosion impacts would result
from intense storm events. In addition, without
mulching and other amendments, major adverse
postmining land use impacts could occur if
revegetation efforts fail on approximately 663 acres
where topsoiling is not proposed or may not remain
stable. This area includes approximately 447 acres of
flatter surfaces on components other than the leach
pad and approximately 216 acres of steeper slopes
on the leach pad where replaced topsoil would be
more likely to erode.
Public Safety and Demolition/Removal of Facil-
ities and Infrastructure. According to the proposed
action, Carlota would minimize physical hazards
using measures such as berming, fencing, or filling,
depending on the specific perceived hazard. Public
access to the pits would be blocked by a substantial
rock berm. A barbed-wire or chain-link fence would
be erected to provide additional protection against
entry, if directed by the Forest Service. Weather-proof
“dangerous condition” signs, as required by state
statute, would be posted at intervals along the rock
berm to provide notice to the public. Postclosure
maintenance of fences and signs is not addressed in
the proposed action.
Currently, the primary safety hazard that would exist
as a postmining feature is the proposed Carlota/
Cactus pit. The remaining open pit would present
some degree of hazard to wildlife and the public. Pit
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
walls are located approximately 0.5 mile west of a
well-traveled Forest Service road. Control of access
to the pit and the lower reaches of Pinto Creek via the
remaining diversion should be specifically addressed
in the Reclamation and Closure Plan. Irr addition,
mass stability considerations and a postclosure
period of pit wall monitoring should also be addressed
because pit access and stability would influence the
location of protective berms and safety benches. The
nature of pit wall stability considerations is further
discussed in Section 3.2, Geology and Minerals.
Failure to address these factors would create wildlife
and public safety impacts. As a result, additional
mitigation is recommended in Section 3.4.4, Soils and
Reclamation - Monitoring and Mitigation Measures,
and in Section 3.2, Geology and Minerals.
The Reclamation and Closure Plan states that
building and infrastructure components would be
dismantled and disposed of off the site in accordance
with all applicable federal, state, and local laws,
regulations, rules, and ordinances (Carlota 1994a).
After closure, no chemical or electrical hazards would
remain. Foundations would be buried in place.
Building sites would be ripped to reduce compaction
and then seeded with an approved seed mix (Carlota
1994a).
Forest Service policy stipulates that foundations will
be removed. Burial of foundations in place could
create adverse impacts from long-term releases of
process-related substances remaining in foundation
materials or to public safety should the buried
materials become exposed over time. Because of
this, additional mitigation is recommended in Section
3.4.4, Soils and Reclamation - Monitoring and
Mitigation Measures.
Approximately 160 acres of roads would exist under
the proposed action. Portions of roads that are pro-
posed to remain for permanent access after opera-
tions are shown on the postmining topography map
{Figure 2-13). These road portions involve the main
access road, the road to the leach pad and the
SX/EW plant, and road sections in the Eder area.
These areas, comprising approximately 19 acres,
would remain to allow postclosure inspection and
monitoring.
The proposed reclamation of other roads would entail
ripping and seeding the road surfaces. In addition.
downhill fill or slopecast materials would be
broadcast-seeded. Natural drainage patterns would
be reestablished as much as possible, and water bars
or other sediment controls would be constructed as
needed. If roads that are planned for postclosure
access are wider than necessary, a portion of the
road width would be reclaimed in the manner
described above. Tonto National Forest policy, as
established in the Resource Access and Travel
Management Plan (USDA Forest Service 1990),
provides options for closure that are based on
resource management objectives and needs. The
options include passive closure, barrier construction,
or obliteration. Based on the potential for postclosure
soil and erosion impacts, public safety concerns, and
the presence of actual or potential habitat for an
endangered plant species, obliteration best meets
management needs. Therefore, additional mitigation
is recommended in Section 3.4.4, Soils and
Reclamation - Monitoring and Mitigation Measures. It
is anticipated that after all roads are successfully
reclaimed, potential soil and erosion impacts would
be minimal. The proposed reclamation and closure of
access roads and haul roads, as defined in Section
2. 1.9. 2, Roads, Conveyor Routes, and Yards, could
lead to potential soil and erosional impacts and
subsequent long-term erosion and sediment transport
if inspection and maintenance activities are
inadequate. Because of the potential need for
postclosure maintenance, additional mitigation is
recommended. Additional information regarding
Forest Service approval of final road configurations is
presented in Section 3.13, Transportation.
Control and Removal of Hazardous Materials.
According to the Reclamation and Closure Plan, no
chemical or electrical hazards would remain on the
site after closure, including chemicals in process
tanks, piping, or other containers. No impacts would
occur from these sources after successful closure
and reclamation efforts.
An additional consideration involves closing and
reclaiming the leach pad. This component presents
a potential long-term toxic materials hazard. In order
to limit infiltration and subsequent seepage outflows,
the Reclamation and Closure Plan calls for a
restrictive layer to be constructed on the leach pad
surface. Subsequent reclamation and closure
practices on the closed leach pad would involve
placing mine rock on top, applying topsoil, and
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
revegetating. Potential damage to the integrity of the
restrictive layer may occur during earthmoving
operations.
From a reclamation standpoint, the long-term
geomorphic and structural stability of the leach pad is
an important consideration. An erosion hazard exists
from the potential for rills and gullies to form on the
sideslopes. Erosional effects on the proposed pad
configuration after reclamation could compromise its
long-term integrity, creating adverse impacts to
downstream resources. Because of this potential,
additional monitoring and mitigation measures are
recommended in Section 3.4.4.
Postmining Site Stability. Physical site stability
considerations include pit wall stability, slope stability
at the mine rock disposal areas and leach pad, and
accelerated erosion on slopes and at drainage
structures. The stability of these facilities would affect
the ultimate success of proposed reclamation
practices. A reasonable duration of periodic inspec-
tion and maintenance would be necessary to ensure
the postmining integrity of the site configuration.
Adverse impacts would result from failure of diver-
sions, pit wall and pad embankment mass failures,
and accelerated surface erosion. While some of these
occurrences would be minor, others would create
major adverse impacts, depending on their location
and magnitude.
Additional discussions of postmining site stability,
particularly erosion and sedimentation considerations,
are presented in Section 3.3, Water Resources.
Mass movement of a pit wall could remove a
section of the protective berm and create a public
safety hazard. Additional disturbed area would be
added by such an occurrence. Depending on the
location, these would probably be minor impacts.
However, if the movement occurred along the
north or west sides of the Carlota/ Cactus pit, the
stability of the Pinto Creek diversion or the leach
pad could be compromised, respectively. Failure
of either of these components would create an
adverse impact. Further discussion of this consider-
ation is presented in Section 3.2, Geology and
Minerals, particularly under the topic of slope stability.
At critical areas, accelerated sheet and rill erosion,
gullying, and downstream sedimentation may occur
after operations without monitoring and maintenance
activities. Examples include water bar washouts and
erosion along ditches, steep slopes, and at culverts.
At locations such as the leach pad and along the
main haul roads, adverse impacts would result.
Because of this potential, mitigation measures are
recommended in Section 3.4.4.
Reveaetation Success. Erosion, sedimentation, and
land use productivity impacts would continue to occur
if revegetation efforts are not successful. The
potential for ongoing revegetation costs to both
Carlota and the public exist unless reasonable
agreed-upon revegetation success standards are in
place.
Potentially Hazardous Materials. The operational
design and inspection of the leach pad would
reasonably ensure its stability. However, the post-
mining stability of the leach pad would potentially be
affected by slumping and accelerated surface
erosion. Potential impacts from slope failures and
accelerated erosion would include the spread of
potentially toxic materials downslope and into
watercourses and the exposure of revegetation
seedings to adverse chemical conditions. Carlota has
proposed a postclosure monitoring program for water
resources (see Section 3.3, Water Resources). An
additional discussion of potential hazardous materials
considerations is presented in Section 3.14,
Hazardous Materials.
Reclamation and Closure Bonding. In accordance
with 36 CFR, the Forest Service has the authority to
require a reclamation bond for stabilizing,
rehabilitating, and reclaiming the area of operations
prior to approval of the Plan of Operations. This
authority extends only to lands administered by the
Forest Service; therefore, elements of the bond
required by the Forest Service would only reflect
those activities proposed on National Forest System
lands. Activities proposed on private lands within the
state are subject to bonding requirements under the
Arizona Mined Land Reclamation Statutes and
Aquifer Protection Program.
Bonding estimates proposed by Carlota and
presented in the Reclamation and Closure Plan
(Carlota 1 994a) reflect general reclamation
considerations in response to Forest Service
regulations (36 CFR 228.13). Estimates were based
Carlota Copper Project Final EIS
3-165
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
on costs that Carlota has calculated for both internal
work and subcontracting. They do not cover all the
activities detailed in the Plan of Operations that are
necessary to adequately close and reclaim the site in
accordance with state and federal regulations. In
particular, road obliteration and demolition and
removal of project facilities, process materials, and
equipment are not included in the bond estimates, nor
are long-term monitoring and maintenance costs.
Closing the leach pad would require expenditures for
drain-down and disposal of solutions, recontouring,
and placement of a low-permeability zone covered by
mine rock. Drain-down of the heap would be
necessary as a part of closure activities, and costs for
this should be included in bond estimates. Costs for
constructing and maintaining protective berms,
barricades, and fencing are apparently not included.
Furthermore, these estimates do not reflect unit costs
as they would be incurred by the Forest Service in the
event that the agency had to conduct reclamation
activities instead of Carlota. For these reasons,
mitigation has been proposed to ensure that the
amount of the reclamation bond is adequate (Section
3.4.4, Soils and Reclamation - Monitoring and
Mitigation Measures).
3A.2.2 Alternatives
It has been assumed in the following analysis and
discussion that soil salvage, erosion control, and
reclamation practices similar to those developed by
Carlota in the Reclamation and Closure Plan for the
proposed action would be applied to the alternatives.
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. The use of
mine rock disposal sites at the Cactus Central and
Cactus South locations would result in additional
disturbance to approximately 44 acres of native soils.
Soil removal and reduction in productivity would be
potential adverse impacts over this additional
acreage.
It is assumed that soil salvage operations would be
carried out on the additional mine rock disposal
areas. This would create additional resources for
reclaiming the leach pad. In the Cactus Central area,
which would be on private land, the affected soils
would consist of mapping units I, K, L, and O. In the
Cactus South area, disturbed soils would consist of
mapping units A, H, M, and N. Approximately 29,000
cubic yards of potentially salvageable topsoil exist on
these areas, taking into account salvage limitations
and transport losses.
Rather than devoting these topsoil resources to
reclaiming the leach pad, this volume would be
sufficient to replace a depth of approximately 8 inches
of topsoil on the flatter top surfaces of these mine
rock disposal alternatives. This practice would
improve the chances of successful restoration of soil
productivity and postmining land uses on these flatter
surfaces, which would comprise approximately 27
acres.
Additional Backfill of the Carlota/Cactus Pit. This
alternative would create an additional 110 acres of
reclaimable area within the proposed pit, representing
approximately 56 percent of the entire pit footprint
when combined with the 48 acres under the proposed
action. Approximately 36 acres of buffer zone would
be revegetated as with the proposed action. Addi-
tional flat acreage (approximately 43 acres more)
would be created on the Main mine rock disposal
area as its surface is lowered. These would be
beneficial impacts since such surfaces would be more
suitable to successful reclamation activities. The
erosion potential would also be reduced. Additional pit
backfilling would further mitigate potential public
safety hazards associated with the pit. The timing of
backfill operations would contribute to concurrent
reclamation. The potential impacts to soil resources,
beyond those of the proposed action, would be
negligible. Implementing this alternative would cost
approximately $50 to $52 million and would require
approximately 190 people for 3 to 4 years.
Additional Backfill of the Eder South Pit. This
alternative would create negligible impacts to soil
resources beyond those discussed previously under
the proposed action. Beneficial effects would result
from this alternative in that approximately 42 acres of
pit area would be reclaimed (16 acres more than
under the proposed action), and the resulting
elimination of the Eder mine rock disposal area would
increase the available reclaimed area by approxi-
mately 33 acres. Thus, an additional 49 acres of land
surface would be made more suitable for reclamation
activities than would occur under the proposed action.
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
The estimated cost for this alternative (approximately
$2.6 million, requiring 190 personnel for 2.3 months)
would be a substantial addition to reclamation costs.
However, the commitment of funds, labor, and
equipment to this alternative may be achievable.
Eder Side-Hill Leach Pad Alternative
This alternative would disturb approximately 458
acres of soils within the footprints of the pads
compared to 270 acres within the pad footprint for the
proposed action. However, this alternative would
create lesser disturbance associated with the
relocated Eder mine rock disposal area. Overall,
approximately 134 additional acres of soils would be
disturbed by earthwork for this alternative than would
be disturbed by earthwork on the proposed pad and
Eder mine rock disposal area. This additional
disturbance would consist of soil removal and the
associated loss of productivity, which would be
adverse impacts. Further acreage would be disturbed
to a lesser degree in the associated buffer zones
around the pads and mine rock disposal area.
Approximately 12 fewer acres of alluvial soils,
occupied in part by riparian habitat, would be
disturbed under this alternative than in the proposed
action.
The affected soils would consist of mapping units C,
E, U, and V. Additional topsoil resources consisting of
approximately 33,600 cubic yards could be salvaged
from these units under the pad footprints. In addition,
approximately 43,400 cubic yards would be available
from the relocated Eder mine rock disposal area.
Soils that would be disturbed to a lesser degree than
in the proposed action consist of mapping units A, H,
I, P, Q, R, and S. A decrease of approximately 56,500
cubic yards of potentially salvageable topsoil would
be available from these units under this alternative as
opposed to the proposed action. Overall, approxi-
mately 20,500 cubic yards of additional topsoil would
be salvageable under this alternative as opposed to
the proposed leach pad configuration. This would be
adequate to restore 5 to 6 inches of topsoil on the
additional disturbed area.
The alternative leach pad configuration would modify
the postmining topography from that of the proposed
action. Approximately 54 acres of flatter area on top
of the proposed pad would be lost under this
alternative, but approximately 20 acres of flatter
surfaces would be created on the relocated Eder
mine rock disposal area. Thus, a net 34 acres of
flatter surface area would be lost under this
alternative. The reclamation configuration would
consist of steep slopes throughout the leach pad
area. The erosional instability of these slopes, and the
questionable long-term geotechnical stability of
associated embankments, would inhibit reclamation
success. Major adverse impacts could result. Monitor-
ing and mitigation measures would be the same as
those recommended for the proposed action.
Water Supply Alternative
Minimal impacts to soils would result from these
alternatives, which would be similar to the water
supply component of the proposed action. This
conclusion assumes that the similar reclamation and
erosion control practices outlined for roads in the
Reclamation and Closure Plan would be implemented
for pipeline and access road disturbances associated
with these alternatives.
Alternative Water Supply Well Field Access
Roads
Two alternative routes are being considered to
access the water supply well field. Alternative A would
involve upgrading the existing access road located
within the Pinto Creek channel for approximately 1 .9
miles. Alternative B would involve constructing 1 .2
miles of new road and using 2.6 miles of existing
roads. Minimal impacts to soils would result from
these alternatives. This conclusion assumes that the
reclamation and erosion control practices outlined for
roads in the Reclamation and Closure Plan would be
implemented. However, any unprotected low-water
crossing would create a channel and bank stability
impact for which additional mitigation is
recommended.
Erosion and sedimentation considerations for the well
field access road alternatives are discussed further in
Section 3.2, Geology and Minerals.
No Action Alternative
No impacts to soils would result from the no action
alternative.
Carlota Copper Project Final EIS
3-167
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
3.4.3 Cumulative Impacts
The proposed Carlota Copper Project would affect
approximately 1,428 acres of watershed area within
the Pinto Creek watershed (approximately 2.2 square
miles). The overall watershed is approximately 178
square miles, and approximately 5 square miles of
the watershed have already been affected by existing
mining operations. These areas include open pits;
several tailings ponds; and associated roads, power
lines, and wells. Assuming that successful reclama-
tion and closure activities are carried out as described
in the Reclamation and Closure Plan and mitigation
sections of the EIS, cumulative impacts to soils from
the project would not be significant (Carlota 1994a).
3.4.4 Monitoring and Mitigation Measures
In addition to measures identified in the Reclamation
and Closure Plan (Carlota 1994a), and in the Plans of
Operations (Carlota 1992, 1993a), the following
measures are recommended to reduce the potential
for impacts to soil resources and to comply with
Forest Service regulations.
3.4.4. 1 Soils
SR-1: Carlota proposes to salvage approximately
460,000 cubic yards of material from slopes with
grades up to 30 percent. By salvaging suitable soils
and extending equipment operations onto slopes up
to 40 percent, a total of approximately 602,000 cubic
yards of topsoil could be replaced. (These figures
include 15 percent transport losses and the use of
salvageable materials in leach pad construction.)
Site-specific criteria for soil salvage are shown in
Table 3-53, and potentially additional salvage
volumes based on these criteria are presented in
Table 3-54.
Safety and operational constraints would be
recognized when salvaging suitable soils on slopes
approaching 40 percent. In the sequence of salvaging
suitable soils on the footprint of the leach pad and
pond areas, preference would be given to achieving
the volumes of fine-grained material necessary to
reach the design criteria for the liner subgrade.
During construction and operation, efforts would be
made to maximize soil salvage and minimize
excavation and transport losses of soil materials.
Materials collected from sediment control structures
over the life of the project and salvageable soils from
buffer areas subject to disturbance from excavation or
fill would be added to the salvage program in order to
maximize volumes. Alternative means of increasing
topsoil salvage, such as identifying new sources of
borrow materials (sources not currently known or
available), for leach pad construction would be
evaluated as part of the Topsoil Management Plan
(see SR-2).
SR-2: Topsoil stockpiles would be located in
protected sites approved by the Forest Service.
Carlota would include in the final Plan of Operations a
Topsoil Management Plan that would detail the
stockpile locations, stockpile volumes, footprint acres
of the stockpiles, and planned locations and volumes
for re-application. The plan would be revised annually
to show the subsequent increase or decrease of the
volumes in the stockpiles. The plan would include a
seed mix used for protecting soil materials. The seed
mix would be approved by the Forest Service. The
Topsoil Management Plan would also outline the
BMPs to minimize salvaged topsoil loss and to
maintain soil fertility. These BMPs may include, but
are not limited to, a variety of traditional mechanical
and non-mechanical methods, including silt fences;
crimped mulch; soil amendments, including
bacterial/fungal inoculates; hydroseeding;
hydromulching with tackifiers; and surface
scarification to retain moisture. Testing and
application of non-traditional BMPs would also be
considered but would be subject to approval by the
Forest Service. BMPs that evolve with future
technology would also be considered and would be
subject to testing and approval. The Topsoil
Management Plan would also outline periodic
inspections, reporting requirements, and practices to
ascertain the stability and success of
reseeding/revegetation to stockpiles.
SR-3: Carlota proposes to replace topsoil only on the
leach pad. At .closure (and for concurrent reclamation
during mine operation), the Forest Service, in
consultation with Carlota, would review and evaluate
reclamation priorities for topsoil placement and the
potential for placement of excess topsoil on other
areas proposed for revegetation in order to improve
the probability of success. Such replacement could
be achieved by implementing Mitigation Measures
SR-1 and SR-2 and distributing topsoil appropriately
between proposed project components. This measure
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
Table 3-53. Project-Specific Soil Salvage Criteria'
Topsoil Suitability Rating
sii|» : % ^ '“f*'
Cliaracteristic
Fair
Poor »
; lJlmitatfe>n {
Slope %
<10
10-40
>40
Slope
Rock Outcrop %
<10
10-20
>20
Rock Outcrop
Depth to Bedrock,
inches
>20
10-20
<10
Depth to Rock
Coarse Fragment
Content, % by Volume
<25
25-50
>50
Stoniness
Soil Texture
Those not rated
fair or poor
Loamy Sand, Clay
Loam, Silt Loam,
Silty Clay Loam
Sand, Sandy
Clay, Clay, Silty
Clay, Silt
Texture
' Based on dozer/truck/shovel equipment availability as indicated in the Plan of Operations (Carlota 1992)
would contribute to increasing the revegetated land
use base. Microbial conditions would be improved in
the restored topsoil using bacterial and fungal
inoculants or other seedbed amendments as
available.
SR-4: Prior to initiating construction or reclamation of
project components, Carlota would conduct an
analysis of BMPs for surface erosion. Subject to
Forest Service approval, appropriate BMPs would be
selected to prevent excessive erosion. Erosion
control practices would be designed to be consistent
with existing or postmining topography, to facilitate
and improve revegetation efforts, to minimize surface
and ground water impacts, to control surface
drainage, and to provide overall stability of the site(s).
Erosion practices for this mitigation measure are
described below:
• During final reclamation of the leach pad, graded
slopes would be evaluated for placement of slope
breaks and mulches to reduce accelerated
erosion to within soil tolerance limits (Soil
Conservation Service 1983) or other levels
approved by the Forest Service. Slope breaks
could consist of permanent features that would
minimize downslope runoff energy as a means of
controlling erosion. In addition, the slope breaks
would be designed on a gentle gradient across
the leach pad slopes to maintain free drainage of
surface flow and to minimize infiltration into the
pad. Flow paths would be stabilized by riprap or
vegetation. Leach pad and pond materials would
not be moved off of the liner system as a result of
recontouring until these materials have been
treated and determined to be neutralized.
Depending on the soil water-balance
relationships and the make-up of the seed-
bed/rootzone material of the topsoil to be placed
on the leach pad at final configuration, other
techniques to achieve erosion control and/or
water harvesting would also be evaluated. These
techniques may include contour furrowing,
moonscaping, gouging, land imprinting, basin
blading, terracing, or cat tracks along contours.
Because of intense rainfall in the area, mulches
would be evaluated for use on all disturbed areas
to be revegetated. Mulches may consist of
hydromulches with tackifiers on slopes, straw
mulch embedded into the soil mantle with
crimping disks, or other techniques approved by
the Forest Service.
• Implementation of BMPs for surface drainage
control on roads and associated disturbances
would be conducted in coordination with the
Forest Service and would be subject to Forest
Service approval. These BMPs would include (but
would not be limited to) such techniques as
interim revegetation, construction of
waterbars/rolling dips on non-engineered roads,
road sloping/crowning, inboard ditching, crown
ditching, berm breaks with energy dissipaters,
culvert installation with energy dissipaters, straw
bale sediment barriers, sediment traps/catch
basins, vegetated buffer strips, silt fence/filter
Carlota Copper Project Final EIS
3-169
Table 3-54. Recommended Salvageable Topsoil Volumes'
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
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3-170
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
fence, brush sediment barriers, soil stabilization
filter strips, and other BMPs that evolve with
future technology.
Additional erosion and sedimentation measures are
presented in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures.
3A.4.2 Reclamation
SR-5: Areas receiving final reclamation would be
evaluated after the third growing season to determine
if the reclamation practices achieve the reclamation
performance standards. Should success criteria
continue to meet with failure following two additional
good faith attempts, including the best reclamation
technology available, then alternative measures for
determining revegetation success would be
evaluated. Such alternative procedures would require
the approval of both Carlota and the Forest Service.
SR-6: As much concurrent reclamation would be
incorporated into proposed project operations as
possible. Related activities would include mulching
and reseeding unused traffic and buffer areas and
cuts and fills along roads; rip-rapping and maintaining
culvert inlets and outfalls; and appropriately using and
maintaining water bars, silt fences, check dams, and
straw bales throughout the life of the proposed
project. Additional concurrent reclamation would be
implemented once mining activities are completed for
a certain area.
SR-7: All building and facility foundations would be
removed and disposed of in accordance with
appropriate regulations.
SR-8: In order to estimate the amount of the
reclamation bond necessary to comply with all
reclamation measures on National Forest System
lands, specific measures need to be defined and
associated costs determined in detail. The existing
bond estimate would be revised by the Forest Service
accordingly. Annual reclamation meetings would be
held between Carlota and the Forest Service to
discuss any changes in reclamation scheduling or
methods and to review the bond for adequacy. The
bond would be adjusted to conform to the operations
as necessary throughout the life of the project. Similar
bonding and review would be implemented in
accordance with applicable state regulations for
project disturbances located outside National Forest
System lands.
Proposed bond estimates would include, but not be
limited to, removing and disposing of buildings and
appurtenances, reclaiming roads as specified in SR-
15, leach pad draindown, leach pad contouring and
covering, specific seedbed amendments, specific
seeding and planting methods, and administrative
costs for monitoring and maintenance.
SR-9: A defined closure and reclamation timetable
would be prepared by Carlota and implemented by
activity in order to organize and encourage a
successful sequence of erosion control, recontouring,
topsoiling, seeding, and maintenance. The schedule
should reflect the approximate progress of
reclamation activities, both concurrent and
postmining, in relation to project operation and
closure activities. In accordance with 36 CFR
228.8(g), all reclamation activities would commence
within 1 year of conclusion of operations.
SR-10: The schedule and location of the revegetation
testing program proposed by Carlota would be
defined during the construction and initial operation
phases to keep from delaying reclamation efforts. A
detailed plan has been developed and is presented
in the Biological Monitoring & Mitigation Plan (Cedar
Creek Associates, Inc. 1996a). As indicated in
this plan, testing would involve the dominant
seedbed/rootzone materials, particularly with regard
to pH and texture, that are anticipated on the final
project configuration. Testing would be conducted in
order to refine performance standards that would be
used as monitoring tools and measures of success
after revegetation efforts. Reclamation performance
standards have been developed as success criteria in
the Biological Monitoring & Mitigation Plan (pages 41-
48). The release of the reclamation bond would
depend on meeting these performance standards.
Annual reports of testing efforts would be provided to
regulatory agencies.
SR-11: The types and application rates for seedbed
amendments (including microbial inoculants) would
be incorporated into the revegetation testing program,
and their effectiveness would be identified to the
extent possible before they would be used. Regional
experts specializing in revegetation of disturbed lands
should be used as available from the ADOT, nearby
Carlota Copper Project Final EIS
3-171
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
mining projects, the Natural Resources Conservation
Service, the Agricultural Research Service, and
research studies (Brooks 1993). For example, agency
personnel in the region indicate that hydromulches
and tackifiers, straw mulches, and adapted native
seed species (including shrubs) are common
reclamation practices in the area (Taylor 1994).
These sources of information should be used early in
the reclamation planning and permitting process to
define revegetation approaches before they are
needed, to develop bond estimates, and to eventually
arrange for materials and services. Subsequent field
tests and sampling during the project can be used to
refine the seedbed amendment program and bond
estimates, if necessary.
SR-12: Drilling, broadcasting, and hydroseeding are
mentioned as potential methods in the Reclamation
and Closure Plan; however, the actual methods of
reseeding the various project components would be
further defined prior to implementation to include the
planned extent and location of these candidate
methods. These factors would affect bond estimates
and the likelihood of successful revegetation efforts.
Seed drilling would be undertaken on all relatively flat
surfaces to be revegetated and along suitable roads
and drainageways.
SR-13: The proposed seed mixes are subject to
substitutions and modifications, as appropriate to
evolving project needs, new technology, and
materials availability over the life of the project. As
described in the Reclamation and Closure Plan, all
substitutions would be comprised of locally native
plants where feasible. In order to accomplish land use
goals, revegetation testing and applications would
concentrate on the replacement of native grasses,
forbs, shrubs, and trees. For shrubs and trees (e.g.,
juniper), both seeding and planting containerized
nursery stock would be considered in the testing
program and for application. Seeding and planting
taller species in clumps or pods would improve cover
diversity for wildlife. Red brome, weeping lovegrass
and Lehmann lovegrass, oats, and galleta may be
removed from proposed species lists and substituted
with desirable species with reasonable chances of
establishment. The use of yellow sweetclover may be
necessary; however, its use should be minimized in
favor of adapted native species that are com.patible in
mixtures. Additional forb species will be investigated.
and all leguminous species should be inoculated with
appropriate bacteria.
SR-14: Additional monitoring and maintenance would
be required for the reclamation program, portions of
which would be determined during the testing pro-
gram. Such efforts would involve a team of Carlota
and agency personnel over a period of several years
until reclamation is deemed successful. Another key
consideration would be the success of revegetation
and erosion control efforts and the repair or
replacement of related reclamation features as
necessary. Protection of seeded areas from wildlife
and livestock may be necessary until vegetation is
established and erosion control is accomplished. This
would be critical for the heap-leach pad. Adminis-
trative costs for overview of reclamation monitoring
and maintenance would be included in bonding
estimates. Public safety issues would be addressed
and resolved throughout the life of the project.
Specific postclosure issues, such as safety around
open pits and highwalls, would be addressed at the
time of closure. Protective perimeter berms and
fences would be moved or maintained as necessary
to preclude public access, to the extent practicable. In
accordance with 36 CFR 228.1 1 , Carlota would
maintain fire prevention programs, firefighting
capabilities, and fire notification protocols until
reclamation and closure were deemed successful by
the agencies.
Additional monitoring and maintenance measures
related to erosion and sedimentation are recom-
mended in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures.
SR-15: With the exceptions of the roads in the pits,
roads designated for future used by the Forest
Service, and roads identified for specific reclamation
prescriptions, all roads (located on lands adminis-
tered by the Forest Service) constructed or impacted
by this project for the purpose of exploration activities
(existing and proposed), mining activities, and access
in support of general mine activities (including access
to the well field or alternative water sources) would be
closed to normal vehicular traffic. Culverts would be
removed; cross drains, dips, or water bars would be
constructed; the road surface would be shaped to as
near a natural contour as possible (full recontouring);
and the road would be stabilized. To facilitate the goal
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
of long-term, maintenance-free reclamation practices,
the end product of final reclamation and closure for all
roads no longer needed for operations (as defined
above) is to shape to as near natural contour as
possible, revegetate to meet Reclamation
Performance Standards, and be stabilized to
minimize erosion and sediment transport. Roads to
be left open for future use or existing roads that were
impacted by this project (those that would exist after
operations) would be stabilized to minimize erosion
and sediment transport.
SR-16: The impoundment area created by an
embankment on Powers Gulch upstream of the leach
pad would be backfilled with suitable waste rock, and
a drainageway would be recreated for surface flows
to ensure they would not impinge on the pad. The
area between the leach pad and the embankment
would also be lined and backfilled to improve the
postmining stability of the components. Backfilled
material would be revegetated. This mitigation mea-
sure would enhance the postmining stability of the
leach pad and diversion inlet area beyond what is
provided by the proposed action.
3.4A.3 Additional Mitigation for the Alternatives
Mitigation measures for all of the alternatives would
reflect the same content and objectives as those
described for the Proposed Action. Reclamation bond
estimates would be revised in accordance with SR-8
for any selected alternatives.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Soils and Reclamation
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
3.5 Biological Resources
3.5.1 Affected Environment
3.5.1. 1 Terrestrial Resources
Terrestrial resources discussed in this section of the
EIS include the existing vegetation and wildlife in the
Carlota Copper Project area. The discussion of
special status species includes species that have
been recognized by the U.S. Fish and Wildlife
Service, the Tonto National Forest, and the Arizona
Game and Fish Department as meriting special
management consideration because of their rareness
or vulnerability to threats. Field survey procedures
and the delineation of the vegetation in the project
area are discussed in the Vegetation and Wildlife
Technical Memoranda prepared for the Carlota
Copper Company to provide additional data on
project area resources (Cedar Creek Associates,
Inc. 1994b, 1994c).
Eight terrestrial species listed or proposed for listing
as federally endangered or threatened by the U.S.
Fish and Wildlife Service are addressed in this
document: 30 other terrestrial species of concern are
also discussed {Table 3-55). These species are listed
as (1) federal “Candidate” species for listing as
threatened or endangered by the U.S. Fish and
Wildlife Service, (2) Forest Service “Sensitive”
species, (3) state listed or candidate threatened
native wildlife, or (4) former C2 candidates listed by
the U.S. Fish and Wildlife Service. A summary of
each species' known or potential occurrence in the
project area is provided in the following sections.
Further discussion of species of concern is provided
in the Final Biological Assessment and Evaluation
(Cedar Creek Associates, Inc. 1994d).
On April 26, 1996, the U.S. Fish and Wildlife Service
issued its Biological Opinion (included in Appendix F)
regarding the effects of the Carlota Copper Project on
listed taxa. The Biological Opinion stated that “...the
Carlota Copper Project, as proposed, is not likely to
jeopardize the continued existence of the lesser long-
nosed bat or Arizona hedgehog cactus. No critical
habitat has been designated for these species,
therefore, none will be affected” (USDI Fish and
Wildlife Service 1996).
Vegetation Communities
Habitat Types. Five separate vegetation associations
were identified in the project area:
(1) interior chaparral, (2) rubbleland chaparral,
(3) dry-slope desert brush, (4) juniper/grassland,
and (5) riparian. Outside of the riparian corridors,
all habitat types are collectively referred to as
upland habitats. Upland and riparian habitats are
briefly described in the following subsections.
Further discussion of these habitat types is pro-
vided in the Vegetation Technical Memorandum
(Cedar Creek Associates, Inc. 1994b). The acreage
and percentage of the project area associated with
each vegetation type are indicated in Table 3-56.
The locations of individual vegetation types are
shown in Figure 3-25.
Interior Chaparral. Interior chaparral in the project
area is typical of that described in Brown (1982).
The vegetation is composed of relatively dense
stands of closed-canopied evergreen shrubs of
uniform height. It is the most extensive vegetation
type in the project area (1 ,532 acres, or 49.5 percent
of the project area. Figure 3-25 and Table 3-56). This
vegetation type is located along all slopes, aspects,
and topographic positions, except some of the drier
south-facing slopes. Dominant species of this
community include one-seed juniper {Juniperus
monosperma), pointleaf manzanita {Arctostaphylos
pungens), and shrub live oak {Quercus turbinella).
Birchleaf mountain mahogany (Cercocarpus
betuloides) and sugar sumac {Rhus ovata) are also
present but in lesser numbers. Herbaceous ground
cover is sparse. Ground cover for all types of plants
in chaparral averages 75 percent but reaches
values as high as 100 percent in the densest
stands (Cedar Creek Associates, Inc. 1994b). At
higher elevation sites, some elements of Madrean
evergreen woodland are present on mesic, north-
facing slopes in the southern portion of the project
area. The most common Madrean species are
Arizona pihon {Pinus fallax), Arizona white oak
{Quercus arizonica), and Emory oak {Quercus
emoryi).
Rubbleland Chaparral. Rubbleland chaparral is a
variant of interior chaparral resulting from local soil
types. This biotic community comprises 494 acres, or
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3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-55. Special Status Plant and Wildlife Species Potentially Occurring in the
Carlota Project Area
NaiDG
PLANTS:
Arizona agave
Agave arizonica
LE, S
Hohokam agave
Agave murpheyi
C2, S
Tonto basin agave
Agave delamateri
C2, S
Arizona hedgehog cactus
Echinocereus trichlochidiatus var. arizonicus
LE, SE, S
Mogollon fleabane
Erigeron anchana
C2
Apache wild buckwheat
Eriogonum apachense
C2
San Carlos wild buckwheat
Eriogonum capillare
C2, S
Fish Creek rock daisy
Perityle saxicola
C2, S
INSECTS:
Maricopa tiger beetle
Cicendela oregona maricopa
C2
AMPHIBIANS AND REPTILES:
Arizona toad
Bufo microscaphus microscaphus
C2
Chiricahua leopard frog
Rana chiricahuensis
C, SC, S
lowland leopard frog
Rana yavapaiensis
C2, SC, S
common chuckwalla
Sauromalus obesus
C2
desert tortoise
Gopherus agassizii
C2, SC, S
northern leopard frog
Rana pipiens
SC
Mexican garter snake
Thamnophis egues
C2, SC, S
narrow-headed garter snake
Thamnophis rufipunctatus
C2, SC, S
BIRDS:
southwestern willow flycatcher
Empidonax traillii extimus
LE, SE
buff-breasted flycatcher
Empidonax fulvifrons
C2, SE, S
loggerhead shrike
Lanius ludovicianus
C2
yellow-billed cuckoo
Coccyzus americanus
ST
northern goshawk
Accipiter gentilis
C2, SC, S
common black-hawk
Buteogallus anthracinus
SC, S
American peregrine falcon
Falco peregrinus anatum
LE, SC, S
ferruginous pygmy owl
Glaucidium brasilianum cactorum
PT, SE, S
bald eagle
Haliaeetus leucocephalus
LE, SE, S
Mexican spotted owl
Strix occidentalis lucida
LT, ST, S
MAMMALS:
California leaf-nosed bat
Macrotus californicus
C2, SC, S
Mexican long-tongued bat
Choeronycteris mexicana
C2, ST, S
Lesser long-nosed bat
Leptonycteris curasoae yerbabuenae
LE, SE, S
southwestern cave myotis
Myotis velifer brevis
C2, S
occult little brown bat
Myotis occultus
C2, S
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-55. Special Status Plant and Wildlife Species Potentially Occurring in the
Carlota Project Area (continued)
Common Name
Scientific Name
k.. . Vl
Statue
MAMMALS CONTINUED;
red bat
Lasiurus borealis
SC, s
southern yellow bat
Lasiurus eqa
sc, s
spotted bat
Euderma macu latum
C2, SC, S
greater western mastiff bat
Eumops perotis
C2, S
Yavapai Arizona pocket mouse
Peroqnathus amplus amplus
C2
Chiricahua western harvest mouse
Reithrodontomys meqalotis arizonensis
C2
Status:
Federal (U.S. Department of the Interior 1992, 1993)
LE = Taxa listed by the U.S. Fish and Wildlife Service as Endangered under the Endangered
Species Act (ESA).
LT = Taxa listed by the U.S. Fish and Wildlife Service as Threatened under the ESA.
PE = Taxa proposed for listing as Endangered under the ESA.
PT = Taxa proposed for listing as Threatened under the ESA.
C = Taxa for which the U.S. Fish and Wildlife Sen/ice has on file sufficient information on biological
vulnerability and threat(s) to support proposals to list them as endangered or threatened species.
C2 = Category 2 Candidate. Taxa with the C2 designation were listed as such at the initiation of the
Carlota EIS analysis. Since that time, the U.S. Fish and Wildlife Service has issued a more recent
listing of candidate species (Federal Register 61: 7596-7613, February 28, 1996). As a result of this
update, none of the plant and wildlife species addressed by the EIS are listed as candidate (C2)
species. Chiricahua leopard frog is the only species in Table 3-48 that still has a candidate (C)
designation (see above). Species that were listed as C2 candidates but are not listed as sensitive
(Mogollon fleabane, Arizona toad, common chuckwalla, loggerhead shrike, and Yavapai Arizona
pocket mouse) no longer have any special federal designation.
State (Arizona Game and Fish Department 1988)
SE = State Endangered as listed on the Arizona Game and Fish Department's list of Threatened
Native Wildlife (TNW) in Arizona. Species in imminent danger of extinction within Arizona.
ST = State Threatened as listed on the TNW list. Species with identified, serious threats and populations
lower than they were historically and/or extremely local and small.
SC = State Candidate as listed on the TNW list. Species with known or suspected threats, but for
which substantial population declines from historical levels have not been documented.
Forest Service (USDA Forest Service 1988)
S = Classified as “sensitive” by the Regional Forester when the species occurs on lands managed
by the Forest Service.
Carlota Copper Project Final EIS
3-177
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-56. Estimated Coverage by Major Vegetation Community Types in
the Carlota Project Area
Community Type
Peioent
Interior Chaparral
1,532
49.5
Rubbleland Chaparral
494
15.9
Dry-Slope Desert Brush
886
28.6
Juniper/Grassland
131
4.2
Riparian
57
1.8
TOTAL
3,100
100.0
15.9 percent, of the project area {Figure 3-25 and
Table 3-56). It is best represented along the south
side of the project area in the Shultze Granite
formation within 1 mile of U.S. Highway 60, and it is
bordered by interior chaparral. Species composition is
similar to interior chaparral, except it includes the
significant presence of rock outcrops and boulder
fields and an increased level of understory exposure.
Most areas of rubbleland chaparral include scattered
clumps of shrubs rather than a continuous impene-
trable shrub layer, as in the interior chaparral.
Dry-slope Desert Brush. The dry-slope desert brush
vegetation type is transitional between semidesert
grassland, Sonoran desertscrub (Arizona upland
subdivision), and interior chaparral, since it includes
components of all three of these biotic communities
(Brown 1982). Dry-slope desert brush covers approxi-
mately 886 acres, or 28.6 percent of the project area
{Figure 3-25 and Table 3-56). This type usually over-
lies poor soils on dry, south-facing slopes, and tends
to exhibit more of the characteristics of Sonoran
desertscrub than the other two types. Common
species in this biotic community include Wright's
buckwheat {Eriogonum wrightii), broom snakeweed
{Gutierrezia sarothrae), gray horse brush {Tetradymia
canescens), red brome {Bromus rubens), and shrub-
live oak (Cedar Creek Associates, Inc. 1994b). Dry-
slope desert brush is best represented along the
northern portion of the project area, but examples are
also found on drier slopes in the extreme western end
of the project area {Figure 3-25).
Juniper/Grassland. Juniper/grassland is a type of
semidesert grassland biotic community. It occupies
approximately 131 acres, or 4.2 percent of the project
area {Figure 3-25 and Table 3-56). A total of 59
species was observed in this vegetation type,
including hairy grama {Bouteloua hirsute), broom
snakeweed, one-seed juniper, and red brome (Cedar
Creek Associates, Inc. 1994b). The sparse cover
of perennial grasses and junipers may indicate
past overgrazing and fire suppression. Juniper
grassland vegetation is found only on three south-
facing hillsides in the central portion of the project
area.
Interior Riparian Deciduous Woodland. Riparian
vegetation in the Carlota project area is principally
composed of a low density, sparse canopy, mixed-
broadleaf community of interior riparian deciduous
woodland similar to that described by Brown (1982). It
is the least extensive vegetation type, occupying only
57 acres, or 1 .8 percent of the project area (Figure
3-25 and Table 3-56), but it supports greater species
diversity than the other biotic communities of the area
(approximately 6 percent more species than the next
most diverse community). The riparian community is
generally found where ground water or seasonal
storage of surface flow is sufficiently close to the
surface to allow moisture-dependent species to
become established and persist. These conditions
generally occur along the alluvial bottoms of Pinto
Creek, lower Powers Gulch below the confluence with
West Powers Gulch, and in lower Haunted Canyon.
Above the confluence of the main stem and western
tributaries of Powers Gulch, as well as in other
transitional areas, streamside vegetation is dominated
by interior chaparral species with an occasional
overstory of taxa more commonly associated with
Madrean evergreen woodland (these areas were
termed mesic chaparral to suggest their transitional
nature).
Within the principal riparian zone of Pinto Creek and
Powers Gulch, dominant overstory species include
Arizona sycamore {Platanus wrightii), Fremont
cottonwood {Populus fremontii), velvet ash {Fraxinus
pennsylvanica ssp velutina), tamarisk {Tamarix
chinensis), and Goodding’s willow {Salix gooddingii).
3-178
Carlota Copper Project Final EIS
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Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-25
Locations of Major
Vegetation Communities
3.0 Affected Environment and Environmental Consequences - Biological Resources
Emory oak {Quercus emoryi), an occasional Arizona
white oak {Quercus arizonica), and one-seed juniper
{Juniperus monosperma ) from the adjacent uplands
also contribute to the riparian canopy cover. In the
area of lower Haunted Canyon, the principal
overstory species are Arizona alder {Alnus
oblongifolia), velvet ash, Arizona sycamore, Arizona
black walnut {Juglans major), one-seed juniper, and
Arizona cypress {Cupressus arizonica). Common
scrub understory species include young overstory
plants, burrobush {Hymenoclea monogyra), desert
broom {Baccharis sarothroides), seepwillow
{Baccharis glutinosa), and from the adjacent uplands,
shrub live oak, broom snakeweed, and wait-a-minute
bush {Mimosa biuncifera).
Riparian vegetation within and downstream of the
project area is characterized by uneven and
irregularly distributed patches and belts of riparian
species of differing composition, densities, and ages.
This is typical of riparian systems in the arid and
semiarid Southwest. These differing riparian subtypes
were mapped and measured by Cedar Creek
Associates, Inc. (1994b) for over 45,000 lineal feet
from above the project area on Pinto Creek to the
Iron Bridge downstream of the project area. This
mapping included the entirety of Powers Gulch and
lower Haunted Canyon and resulted in the delineation
of seven subtypes.
Of these seven riparian subtypes, the Fremont
cottonwood/Goodding’s willow association did not
occur within the project area and did not occupy
sufficient acreage (1 .63 acres in the survey area) to
permit use of the Tonto Riparian Inventory and
Monitoring Methods (TRIMM). The Arizona alder
subtype occupied 1 1 .07 acres and only occurred in
lower Haunted Canyon and along a small segment of
lower Pinto Creek below the project area. Tree
density averaged 145 stems/acre, and canopy cover
was estimated at 95 percent. The velvet ash subtype
occupied only 2.06 acres (all within the project area
and principally within Powers Gulch) and was also too
small to allow measurement with TRIMM. The
Arizona sycamore/Emory oak subtype occupied
1 1 .39 acres in the survey area (5.29 in the project
area) and was principally located in Powers Gulch
and upper Pinto Creek. Tree density averaged only
90 stems/acre, and canopy cover was estimated at
less than 22 percent. The Arizona sycamore/Fremont
cottonwood subtype occupied 48.44 acres in the
survey area (1.42 in the project area) and was
located intermittently throughout the survey area, but
primarily below the project site. Tree density
averaged only 38 stems/acre, and canopy cover was
estimated at less than 16 percent. The Arizona
sycamore subtype occupied 51.54 acres in the
survey area (13.09 in the project area) and was
located intermittently throughout the survey area.
Tree density averaged 114 stems/acre, and canopy
cover was estimated at less than 29 percent. Finally,
the Arizona sycamore/tamarisk subtype occupied
35.34 acres in the survey area (34.88 acres in the
project area), and (as indicated by these acreages)
was the dominant subtype in the project area along
Pinto Creek. Tree density averaged 34 stems/acre
(discounting tamarisk, which is a non-native weedy
species), and canopy cover was estimated at a little
over 5 percent discounting tamarisk, or 12 percent
with tamarisk. In addition to these seven subtypes,
two non-riparian types (scoured channel and mesic
chaparral) were recorded during the TRIMM surveys.
These two types account for any differences in
acreage values.
Cedar Creek Associates, Inc. collected additional
data from the portion of Pinto Creek’s riparian
zone in the area of the proposed Carlota/Cactus
pit in 1996. These data were designed to be used
for the COE Section 404 mitigation plan, but also
provide additional characterization of the riparian
resources subject to potential impacts. It was
found that vegetation ground cover along the
COE-defined wetland in this area averaged only
5.77 percent, of which nearly half consisted of
two introduced weedy species, Bermuda grass
and tamarisk. Riparian species woody plant density
for stems greater than 2 inches diameter breast
height (dbh) was determined to be 46.6/acre, while
density for riparian stems less than 2 inches dbh was
determined to be 702.5/acre. Of these values,
tamarisk accounted for 7.3 and 262.0 stems/acre,
respectively.
As indicated by these data, Pinto Creek and Powers
Gulch, especially in the potential impact zones,
support relatively low quality stands of Arizona
sycamore and tamarisk. Total cover and density of
native riparian trees is low. These conditions are most
likely a result of two water-related factors and one
biological factor: (1) intermittent water flow that leads
to extended drought conditions, (2) occasional
Carlota Copper Project Final EIS
3-181
3.0 Affected Environment and Environmental Consequences - Biological Resources
destructive flood flows, and (3) competition from
introduced weedy species, such as tamarisk. Human
factors include livestock grazing and mining activities.
Haunted Canyon, a major tributary that enters Pinto
Creek below (north of) the project area, supports
approximately 16.1 acres of the highest quality
riparian habitat in the immediate Carlota project area
(Cedar Creek Associates, Inc. 1994b). This riparian
ecosystem, for approximately 0.7 mile, is supplied
with perennial water flows generated from ground
water discharged locally. Arizona alder dominates
much of this reach in association with Arizona
sycamore and Arizona cypress. The stream supports
large pools that are not found in other stream reaches
within the project area. As indicated previously,
canopy cover in this area approaches 95 percent.
Special Status Plant Species. This section
summarizes the known locations of special status
plant species, including the likelihood of occurrence of
these species within the Carlota project area. A
detailed discussion of each species is included in the
Vegetation Technical Memorandum and the Final
Biological Assessment and Evaluation prepared for
this project (Cedar Creek Associates, Inc. 1994b,
1994d).
Cedar Creek Associates, Inc., conducted surveys for
special status plant species in 1992 and 1993. The
surveys focused on areas of potential impact by the
Carlota Copper Project. The field survey methodology
is described in the Final Biological Assessment and
Evaluation (Cedar Creek Associates, Inc. 1994d).
Arizona Hedgehog Cactus (Federal Endangered.
Forest Service Sensitive). The Arizona hedgehog
cactus occurs in the interior chaparral community of
Pinal and Gila Counties, Arizona, at elevations
between 3,300 and 5,700 feet. According to
Crosswhite (1992), the vast majority of plants are
found on relatively open, rocky slopes and steep
fissured cliffs, although some isolated individuals
have been found in the moderately dense climax
stands of interior chaparral. Crosswhite’s definition of
Arizona hedgehog habitat has been significantly
expanded based upon habitat data collected from
1,150 specimens and is more completely presented
in the Final Biological Assessment and Evaluation
(Cedar Creek Associates, Inc. 1994d). Crosswhite
(1992) also suggested that, in areas where collection
is not a problem, the species is extending its range.
The Arizona representatives of the genus
Echinocereus are currently under revision by Dr.
Bruce Parfitt of the Missouri Botanical Garden. In
a draft copy of his report, E. triglochidiatus var.
arizonicus is elevated to E. arizonicus, although it
is not yet clear whether this revision will include
other populations of the genus Echinocereus in
the species arizonicus. Estimates based on
incomplete data in 1984 indicated that approximately
18,000 Arizona hedgehog cactus individuals
comprise the species. Since then, the Forest Service
has conducted several reconnaissance surveys for
Arizona hedgehog cactus and has documented
extensions of the population north and west from the
type locality near the project area. Estimates of
density in most of these areas were not taken (USDA
Forest Service 1991). Based on the detailed definition
of habitat developed during extensive project
investigations. Cedar Creek Associates, Inc.
reinvestigated several Forest Service sightings,
evaluated habitat conditions regionally and between
sightings, collected density data from 21 transects,
and extrapolated density information from eight
additional sources of information. As a result of these
efforts, an estimate of the Arizona hedgehog
population was refined to provide a realistic
population projection of 257,500 individuals (Cedar
Creek Associates, Inc. 1994d). The most
conservative population projection obtained from the
same information resulted in a population estimate of
at least 187,600 individuals (Cedar Creek Associates,
Inc. 1994d).
Of over 2,000 Arizona hedgehog cactus observed by
Cedar Creek Associates, Inc. during surveys for the
taxon in 1992 and 1993, 1,150 specimens were
located within the 100 percent survey areas which
were defined by the overlap of the project footprint
(including a 200 foot buffer) and areas of cactus
habitat (including a 500 foot buffer). The remaining
900+ cacti were observed outside of this area,
primarily during reconnaissance and density
determination surveys across the entire distributional
limits of the taxon. In addition to cactus location
efforts, suitable habitat for the Arizona hedgehog
cactus was defined and mapped. Further discussion
of this species is provided in the Final Biological
Assessment and Evaluation (Cedar Creek
Associates, Inc. 1994d).
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3.0 Affected Environment and Environmental Consequences - Biological Resources
Arizona Agave (Federal Endangered. Forest Service
Sensitive). Arizona agave {Agave arizonica) is
believed to be a sterile hybrid of golden-flowered
agave {Agave chrysantha) and Tourney agave {A.
toumeyana var. bella) (Cedar Creek Associates, Inc.
1994b, 1994d). The species (taxon) is known only
from extremely isolated clusters of one to several
rosettes that are all derived from the same seed and
are connected by underground rhizomes. Preferred
habitat is chaparral and juniper-grassland vegetation
on volcanic soils between 3,000 and 6,000 feet
elevation. Threats to the species include low
numbers, patchy distribution, poor reproduction, and
plant collecting (Arizona Game and Fish Department
1990).
The project area may contain appropriate habitat for
Arizona agave, but no plants were found. The only
parent species in the area is golden-flowered agave;
Tourney agave was not observed on the site. The
U.S. Fish and Wildlife Service concurs that this
species is not likely to occur in the project area, as
stated in the Vegetation Technical Memorandum
(Cedar Creek Associates, Inc. 1994b) and the Final
Biological Assessment and Evaluation (Cedar Creek
Associates, Inc. 1994d).
Other Plant Species of Concern. The distribution
and habitat requirements of the following plant
species of concern were reviewed in relation to the
Carlota project area.
• Tonto Basin agave
• Hohokam agave
• Mogollon fleabane
• Apache wild buckwheat
• San Carlos wild buckwheat
• Fish Creek rock daisy
Refer to Table 3-55 for a listing of their status.
It was determined that these species are not located
in the vicinity of the Carlota project area and/or
habitat is not present. Descriptions of distribution and
habitat for these species are discussed in the Final
Biological Assessment and Evaluation (Cedar Creek
Associates, Inc. 1994d).
Wildlife
This section discusses terrestrial wildlife species,
including insects, amphibians, reptiles, birds, and
mammals, that were observed or are known to exist
in the vicinity of the Carlota Copper Project. A
discussion of important game species and threat-
ened, endangered, and sensitive species is included.
Fish, aquatic insects, and other aquatic arthropods
are discussed in Section 3. 5.1. 2, Biological
Resources - Aquatic Resources. Further discussion
of wildlife is provided in the Wildlife Technical
Memorandum and the Final Biological Assessment
and Evaluation (Cedar Creek Associates, Inc. 1994c,
1994b). Scientific names of wildlife species discussed
in this section are provided in Appendix A of the
Wildlife Technical Memorandum (Cedar Creek
Associates, Inc. 1994c).
Amphibian and reptile species identified in the project
area include tiger salamander, Woodhouse toad,
canyon treefrog, bullfrog, Sonoran mud turtle, greater
earless lizard, eastern fence lizard, short-horned
lizard, plateau striped whiptail, Sonoran whipsnake,
gopher snake, black-necked garter snake, black-
tailed rattlesnake, and others.
General bird surveys and nesting raptor surveys were
conducted in the project area in 1992 and 1993.
Common birds in the upland habitats were primarily
dry shrubland-adapted species, such as scrub jay,
bushtit, canyon wren, crissal thrasher, rufous-sided
towhee, canyon towhee, rufous-crowned sparrow,
black-chinned sparrow, and others. Common avian
species identified in the riparian habitat along Pinto
Creek included mourning dove, ash-throated
flycatcher, Bewick’s wren, yellow-warbler, yellow-
rumped warbler, black-headed grosbeak, hooded
oriole, and others. Cedar Creek Associates, Inc.
(1994c) describes in detail the avian species
identified in each habitat type in the project area.
Six diurnal and four nocturnal raptor species were
documented on or near the project study area: turkey
vulture, sharp-shinned hawk. Cooper's hawk,
common black-hawk, red-tailed hawk, American
kestrel, barn owl, western screech-owl, great-horned
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3.0 Affected Environment and Environmental Consequences - Biological Resources
owl, and elf owl. Red-tailed hawk and Cooper's hawk
were found to be nesting in the project area.
Several species of mammals were directly or
indirectly identified in the project area during 1992
and 1993 field surveys, including cottontail, cliff
chipmunk, rock squirrel, brush mouse, woodrat, and
others. No special status small mammal species are
likely to inhabit the project area. Mist-netting was
used to survey for special status bat species in 1992
and 1993. Bat species captured in mist nets included
Yuma myotis, western pipistrelle, big brown bat,
hoary bat, pallid bat, Brazilian free-tailed bat, big free-
tailed bat, and others.
The project area is in Arizona Game and Fish
Department Management Unit 24B. Big game
animals potentially occurring in the area include mule
deer, white-tailed deer, collared peccary (javelina),
black bear, and mountain lion. According to the
Arizona Game and Fish Department, there have been
recent sightings of mountain (desert) bighorn in the
area, but they are probably not resident (Haughey
1993). Field surveys documented the presence of
mule deer, black bear, and collared peccary.
Black bears are widely distributed throughout
woodland and coniferous forests in the mountainous
portions of Arizona (Hoffmeister 1986). Black bears
are omnivorous and are known to eat a large variety
of foods, including grasses, berries, honey, fruits,
nuts, and carrion. Habitats in the project area that are
most likely to be used by black bear are riparian,
chaparral, and rubbleland chaparral. Because of their
generally sparse numbers, secretive nature, and
often inaccessible habitat, black bears are difficult to
count. The density of black bears in the region is
unknown. The Arizona Game and Fish Department
indicates that low to moderate bear numbers occur in
the Pinto Creek area (Haughey 1992). Sizes of home
ranges of black bear vary greatly from as small as 0.5
square mile to more than 60 square miles (Pelton
1987).
Mountain lions occur throughout the rugged,
mountainous portions of Arizona and are known to
occur on or near the project area (Haughey 1992).
The range of this species is closely associated with
deer, the primary prey species (Hoffmeister 1986).
Mountain lions follow the seasonal movement of deer,
and as a result of their wide ranging habits.
population densities are usually low. They are
typically shy and avoid areas with human activity.
Documented home ranges for mountain lions in the
western United States range from 12.5 to 185 square
miles (Anderson 1983). Although the presence of
mountain lions was not documented, it is likely that
portions of the project area occur within a territory
occupied by mountain lions.
The collared peccary occurs in Arizona primarily in
desert mountain ranges south of the Mogollon
Plateau (Hoffmeister 1986). The peccary is found
most often in desert scrub habitats, especially in
thickets along creeks and old streambeds. Preferred
foods include prickly pear and other cacti, agave,
forbs, grass, seeds, and nuts. Suitable habitat for the
collared peccary exists within the project area,
although the population density of the collared
peccary in the project area is unknown. The Arizona
Game and Fish Department indicates that collared
peccary densities are low to medium (one to three
animals per square mile) in the Pinto Creek area.
Peccary densities vary considerably depending on
habitat and food availability (Bissonette 1982).
Mule deer and white-tailed deer are known to occur
within the project area (Cedar Creek Associates, Inc.
1994c). The ranges of these two species overlap
throughout much of the southeastern portion of
Arizona (Hoffmeister 1986). The project area is within
year-round range for both species. Where these
species occur close together, white-tails usually exist
at somewhat higher elevations in oak-pine
woodlands, while mule deer are more common in
chaparral (Hoffmeister 1986).
Chaparral habitat provides important browse for deer
during the summer and winter, but in dense stands of
chaparral much of the palatable new shrub shoots are
beyond the reach of deer. Dense stands of chaparral
vegetation are used by deer as fawning habitat and
for cover from predators and the elements.
The Arizona Game and Fish Department has
conducted game surveys in Unit 24B since the 1940s
(Shroufe 1995). The surveys have indicated that the
white-tailed deer densities are high (7 to 15 animals
per square mile) west of the project area at
Government Hill; mule deer densities are low to
medium (1 to 7 animals per square mile) in the Pinto
Creek area. Population estimates for 1992 indicated
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3.0 Affected Environment and Environmental Consequences - Biological Resources
1,896 white-tailed deer, 3,351 mule deer, and 1,300
collared peccary in Unit 24B. All three populations
have increased over the past 3 years. Hunter demand -
in this section of Unit 24B for 1993 and the average
for 1 991 -1 993 is over one applicant per permit.
Approximately 10 percent of hunters with permits do
not hunt.
The mule deer is the only deer species recorded by
the April 1992 field surveys and by Carlota personnel
(Whitman 1992). White-tailed deer are more shy and
secretive than mule deer and are less likely to be
recorded by incidental observations.
Other important species that potentially occur in or
near the project area include predators and
furbearers, such as coyote, gray fox, raccoon, ringtail,
white-nosed coati, striped skunk, western spotted
skunk, hooded skunk, hog-nosed skunk, and bobcat.
Field surveys documented the presence of coyote,
raccoon, striped skunk, and spotted skunk. Given the
secretive nature and nocturnal habits of many of
these species, little information is available on their
distribution and population densities within the project
area.
Coyotes are expected in all habitats within the project
area wherever suitable small mammal or rabbit prey
exist. Coyote scat was encountered occasionally
along transects in all habitats within the project area.
This species is expected to be the most common
predator within the project area. Gray fox occur in
Arizona in desert shrub, chaparral, and oak and
pihon-juniper woodlands (Hoffmeister 1986). Their
preferred foods are small mammals, reptiles, insects,
and the fruits of a variety of plants. Like the coyote,
the gray fox is expected to occur throughout the
project area.
In drier habitats within the project area, raccoons are
seldom found far from water (Kaufmann 1982).
Raccoon tracks were noted in two areas along
portions of Powers Gulch with flowing water during
the April flood. One raccoon and raccoon tracks were
noted along Pinto Creek during the July bat surveys.
The ranges of white-nosed coati and ringtail overlap
the project area. Like the raccoon, white-nosed coati
and ringtail are omnivorous and are usually found
near water. In Arizona, white-nosed coati prefer
woodlands consisting of oaks, sycamores, and
walnuts (Hoffmeister 1986). Riparian areas along
Pinto Creek, West Powers Gulch, and lower Powers
Gulch represent the only suitable habitat for this
species within the project area. Ringtails prefer rocky
canyons near water, but typically avoid heavily
wooded areas (Hoffmeister 1986). Areas of rocky,
dry-slope desert brush near permanent water in Pinto
Creek and lower Powers Gulch provide the most
suitable habitat for ringtail within the project area.
All four skunk species (western spotted, striped, hog-
nosed, and hooded) are potential inhabitants of the
project area. Hooded skunks are more common in the
lower elevation desert habitats, but have been found
as high as pine-oak woodland habitat (Howard and
Marsh 1982). Striped skunk was the most commonly
observed species near the project area. It was
encountered on several occasions along Pinto Creek
below the project area.
Bobcats, like coyotes, occur in a wide variety of
habitats throughout Arizona. Rugged areas
supporting caves, rock outcrops, and ledges are often
preferred by bobcats (Hoffmeister 1986). Preferred
prey includes large rodents, rabbits, and hares.
Bobcats are expected to occur wherever prey and
habitat are present, especially in the rimrock areas
along the western and northern boundaries of the
project area.
Haunted Canyon below the Powers Gulch confluence
supports a well-developed riparian habitat. A wide
floodplain is provided with perennial water flow,
deep pools, and riffles. Cedar Creek Associates,
Inc. (1994b) mapped an Arizona Alder Riparian
Subtype in addition to smaller areas of Sycamore
Riparian Subtype. The Alder Subtype included
areas of 95 percent canopy cover of deciduous
trees. Riparian vegetation and the proximity of
perennial water in Haunted Canyon attract a wide
variety of wildlife species, especially songbirds.
Trees and snags in riparian vegetation provide
important foraging and nesting habitat for accipiters,
buteos, owls, songbirds, and woodpeckers. Cedar
Creek Associates, Inc. (1994b) found the highest
relative abundance and diversity of bird species in
riparian habitat. Several songbirds, including acorn
woodpecker, brown-crested flycatcher, verdin,
ruby-crowned kinglet, solitary vireo, yellow warbler,
MacGillivray’s warbler, summer tanager, northern
cardinal, and black-headed grosbeak, were only
found in riparian habitats along Pinto Creek and in
Haunted Canyon.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Biological Resources
Mammals, such as the mule deer, raccoon, striped
skunk, white-nosed coati, coyote, black bear, and
collared peccary, use the Haunted Canyon riparian
area for obtaining food and water. In addition, riparian
corridors along stream courses are used as travel
routes by many of these species. Because riparian
habitat supports a diversity of flying insects, many
bat species are likely to be present as nocturnal
foragers. Haunted Canyon also would be expected to
support populations of characteristic riparian
amphibians, such as canyon treefrog and red-
spotted toad. Canyon treefrog was the only
amphibian observed during vegetation, fisheries, and
general wildlife surveys in Haunted Canyon.
Special Status Wildlife Species. This section
summarizes the habitat preferences and distribution
of special status wildlife species, including the
likelihood of these species occurring within the
Carlota Copper Project area. A detailed discussion of
each species and the survey methodology are
included in the Wildlife Technical Memorandum and
the Final Biological Assessment and Evaluation
prepared for this project (Cedar Creek Associates,
Inc. 1994c, 1994d).
American Peregrine Falcon. The American peregrine
falcon is a bird-eating raptor that nests on cliffs
(Palmer 1988). Peregrine falcon populations have
been identified in Arizona on the Colorado Plateau
and in the sub-Mogollon mountain ranges of the
southeastern portion of the state (Ellis and Glinski
1988, Skaggs et al. 1989). Peregrine falcon
populations appear to have increased in Arizona
since 1980, and many subpopulations within the state
are either recovered or well on their way to recovery
from the precipitous declines observed prior to the
mid-1970s (Arizona Game and Fish Department
1988, Ellis and Glinski 1988).
No nesting, foraging, transient, or migrating peregrine
falcons have been observed in the project area
(Arizona Game and Fish Department 1989-1993).
Cliffs and pinnacles along the western edge of the
project area may be marginally suitable for nesting
peregrines and could be appropriate for foraging
purposes. The Arizona Game and Fish Department
Heritage Data Management System (Cedar Creek
Associates, Inc. 1994c) indicates that the two closest
known peregrine nest sites are located in the Sierra
Ancha Wilderness and in the Salt River Canyon. The
nearest suitable cliff nesting habitat occurs along
Pinto Creek, approximately 12 miles north of the
project area between the confluences of Bell Gulch
and Blevens Wash.
Bald Eagle. The bald eagle is a very large diurnal
raptor that primarily occurs near water and feeds
predominately on fish (Palmer 1988). Arizona is
home to a resident population of 25 to 30 pairs of
bald eagles that breed along major rivers and
reservoirs in central Arizona (Hunt et al. 1992a).
Bald eagles nest on cliff ledges and live trees or
snags overlooking bodies of open water. Arizona
is also on the southern edge of the wintering range
of bald eagles that migrate from frozen northern
nesting grounds each year (Millsap 1986). An
estimated 150 to 200 transitory bald eagles winter
in north-central Arizona each year (Grubb et al. 1989,
Beatty 1992).
No bald eagles have been obsen/ed along Pinto
Creek in or near the project area (Hunt et al. 1992b,
Cedar Creek Associates, Inc. 1994b). Suitable habitat
for bald eagles does not exist in or near the project
area. A bald eagle nesting territory is located
approximately 15 miles north of the project area at
Roosevelt Lake (Hunt et al. 1992b).
Mexican Spotted Owl. This medium-sized owl is
widely but patchily distributed in forested mountain
and canyon habitats in the southwestern United
States to central Mexico (McDonald et al. 1991). In
the sub-Mogollon region of Arizona, the species has
been found from 3,750 feet to near 9,000 feet
elevation (Duncan et al. 1993).
No spotted owls have been identified in the project
area, and no suitable spotted owl habitat exists in or
immediately adjacent to the project area. The nearest
suitable spotted owl habitat is located approximately 7
miles southeast of the project area in the higher
elevations of the Pinal Mountains and approximately
7 miles northwest of the project area in the
Superstition Mountains (Arizona Game and Fish
Department 1992, Duncan et al. 1993).
Southwestern Willow Flycatcher. Southwestern willow
flycatcher is a member of the genus Emp/donax that
breeds locally in dense willow and salt cedar
associations in Arizona (Phillips et al. 1964).
Populations of this subspecies have declined in
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3.0 Affected Environment and Environmental Consequences - Biological Resources
recent decades as a result of loss and fragmentation
of riparian habitat, brood parasitism by brown-headed
cowbirds, and predation (Unitt 1987). The species
was reported on the decline as early as the mid-
1960s in Arizona (Phillips et al. 1964, Pollock 1994).
The willow flycatcher has been found primarily along
the Colorado, Verde, and San Pedro Rivers, although
scattered populations are known to exist in other
riparian areas. The highest breeding densities of
willow flycatcher in 1994 in Arizona were on Tonto
Creek and the Salt River in the Tonto Basin (Pollock
1994).
No southwestern willow flycatchers were found in the
project area during a survey in June 1993. Habitat for
this species is not well developed along Pinto Creek.
The dense willow understory required by this species
is absent from most of the stream. A few willows
downed by recent flooding are resprouting along the
formerly vertical trunks. Such willows may eventually
form dense thickets in the absence of other
catastrophic flood events.
Lesser Long-Nosed Bat. The lesser long-nosed bat is
a migratory, nectar-feeding bat that occurs as a
summer resident in southern Arizona (Hoffmeister
1986, Cockrum 1992). In Arizona, it is known to
forage mainly on saguaro cacti (Carnegiea gigantea)
and agave {Agave spp.) nectar and pollen and roosts
primarily in caves and mine tunnels (Howell 1972,
Cockrum 1992). Currently, there is some question as
to the present status of this bat species and whether
or not the species did, in fact, experience a decline in
numbers during the last 25 years (Cockrum and
Petryszyn 1991).
No individuals of this species were captured during
1992 and 1993 mist net surveys, and none were
found in searches of inactive mine shafts in the area.
Potentially suitable summer foraging habitat for the
lesser long-nosed bat is present in and near the
project area, but there is no evidence that this
species occurs in the general area. The Carlota
Copper Project area lies well to the east of the
known range of the lesser long-nosed bat
(Hoffmeister 1986, Cockrum 1992). Howell (Cedar
Creek Associates, Inc. 1994b) considers the
accuracy of this range delineation questionable
and believes the project area contains sufficient
quantities of agave to support foraging nectar-feeding
bats. The closest documented occurrences of
this bat in relation to the project area include
Picacho Peak, southeast of Casa Grande, and
Phoenix (Hoffmeister 1986, Cockrum 1992). Both
sites are located over 50 miles from the project area.
Maricopa Tiger Beetle. The Maricopa tiger beetle is
known from a wide variety of habitats in California,
Arizona, Nevada, and New Mexico (Cazier 1993). It
occurs in habitats associated with sandy or gravelly
streambeds or river banks, springs, reservoirs, lakes,
swamps, livestock watering tanks, leaky campground
faucets, irrigated fields, canals, and irrigation ditches
(Cazier 1993). Sandy or silty substrates near these
water sources provide suitable habitat for the
burrowing larvae of this species The presence of
some form of water appears to be the main habitat
consideration. Water quality does not appear to be an
important factor since this beetle has been collected
in areas with fresh, slightly brackish, or saline water
and in small streams red with mine waste beside both
the Bisbee and Douglas, Arizona, slag and mine
dumps (Cazier 1993). As a result, favorable habitat in
the occupied four state area is extensive, and much
of it is occupied by viable populations of Maricopa
tiger beetle, either permanently or by transient groups
(Cazier 1993). Populations of the tiger beetle genus
{Cicindela ) are able to maintain themselves with low
numbers and are well adapted for survival and
adjusting to environmental changes. Local
populations may disappear, but chances of overall
extinction of the Maricopa tiger beetle are remote
(Cazier 1993).
Banks of deposited sand and silt along the Pinto
Creek drainage represent suitable habitat for
Maricopa tiger beetle larvae, and one adult beetle
was collected in Pinto Creek below the project area in
1993.
Arizona Toad. This true toad is found in drainages
supporting free-flowing water along the Mogollon Rim
in central Arizona and western New Mexico and in
scattered locations in southern Utah, Nevada, and
California (Stebbins 1985). Threats to the species
probably include habitat destruction, pollution, and
introduction of waterdogs (tiger salamander larvae),
bullfrogs, and crayfish (Lowe 1985, Fernandez 1993).
Arizona toads were identified at several locations
along the Pinto Creek drainage downstream of the
project area between the Iron Bridge and Henderson
Carlota Copper Project Final EIS
3-187
3.0 Affected Environment and Environmental Consequences - Biological Resources
Ranch (Cedar Creek Associates, Inc. 1994b). In the
project area, portions of Pinto Creek, Powers Gulch,
West Powers Gulch, and Haunted Canyon that flow
during the spring and summer represent potential
breeding habitat for this species.
Lowland Leopard Frog. The lowland leopard frog is a
true frog species that is an obligate riparian species
at elevations from approximately 1 ,900 to near 6,000
feet (Lowe 1985, Stebbins 1985, SredI and Howland
1992). The Arizona range of this species includes the
central part of the state below the Mogollon Rim,
where it overlaps with the range of the Chiricahua
leopard frog. Threats to the species are similar to
those described for the Arizona toad.
Within the Carlota project area, lowland leopard frogs
were located at Yo Tambien Spring in 1992 and in
lower Powers Gulch and an isolated pool in Pinto
Creek in 1993. Numerous leopard frog observations
have been recorded at downstream portions of Pinto
Creek, including sites near Henderson Ranch and the
weir site (Cedar Creek Associates, Inc. 1994d).
Common Black-hawk. This medium-sized hawk is
found in riparian and riverine habitat in central and
southern Arizona (Palmer 1988). The rapid loss of
riparian habitat is suspected to be the most significant
threat to this species (Arizona Game and Fish
Department 1988).
Two common black-hawk observations were made
along Pinto Creek in the project area during July
1992. In 1993, two additional observations were
made downstream from the project area along Pinto
Creek. The 1992 and 1993 observations indicate that
the common black-hawk probably forages in and near
the project area along Pinto Creek. Potential nesting
habitat occurs along Pinto Creek; however, no nests
or evidence of nesting activity were observed.
Yellow-billed Cuckoo. In Arizona, this member of the
genus Coccyzus is known to breed in riparian
woodlands and mesquite bosques (Phillips et al.
1964, Monson and Phillips 1981). Threats to this
species include loss and destruction of riparian
habitat.
The yellow-billed cuckoo was not found in the project
area in 1992; however, three observations on three
consecutive days were recorded in June of 1993
along Pinto Creek downstream from the project area.
The closest site to the study area was 3 miles
downstream near the Iron Bridge. Riparian areas
along Pinto Creek downstream to near Roosevelt
Lake represent potential habitat for this species.
Loggerhead Shrike. This songbird prefers open, thinly
wooded, or scrubby land characterized by frequent
clearings and prominent perch sites (Terres 1980).
Phillips et al. (1964) report the loggerhead shrike to
be a common summer resident in Arizona in open
habitats below the Transition Zone. Dry-slope desert
shrub and juniper/grassland represent suitable habitat
for the loggerhead shrike in the project area.
No loggerhead shrike were noted during the 1992
surveys, but this species was seen in April and May
of 1993. Two observations were recorded in open
chaparral west of upper Powers Gulch, and several
were observed in the dry-slope desert brush south of
Grizzly Mountain near the proposed mine rock
disposal site.
Southwestern Cave Mvotis. This bat is a migratory,
insectivorous species ranging from Honduras to
southern Nevada (Hoffmeister 1986). It generally
inhabits mine shafts, tunnels, caves, and bridges in
desert areas of Arizona (Hoffmeister 1986). Currently,
there is some question as to the taxonomic validity of
this subspecies. Most professional mammalogists
familiar with the species agree with Hayward (1970)
that Arizona individuals belong to the subspecies M.
V. ve//fer(Sidner 1990). Threats to this species have
not been identified, but as with many bats, habitat
destruction and roost disturbance may locally affect
small colonies or subpopulations.
Two individuals of this species, one in 1992 and one
in 1993, were captured during mist net surveys in the
project area.
Occult Little Brown Bat. In Arizona, the insectivorous
occult little brown bat is found along the Mogollon Rim
and in other central Arizona mountain ranges
(Hoffmeister 1986). Habitats of ponderosa pine and
oak woodland near water are preferred by this
species, but it has also been found in lower desert
areas along permanent watercourses supporting
riparian habitat (Hoffmeister 1986). Natural roost sites
are not mentioned in the literature, but recent
unpublished work by Morrel (1993) demonstrates the
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
importance of snags and other crevices as roost sites
for this species.
No individuals of this species were captured during
1992 and 1993 mist net surveys, although riparian
habitat along Pinto Creek, West Powers Gulch, lower
Powers Gulch, and Haunted Canyon with water could
be used by this species. The occult little brown bat is
not expected to be common in the project area
because of a lack of pine and oak woodland habitats,
and the closest confirmed sightings of occult little
brown bat to the project area are in the nearby Pinal
Mountains at 7,520 feet elevation (Hoffmeister 1986).
Greater Western Mastiff-Bat. This bat species is a
year-round resident and is primarily associated with
desert scrub habitat near cliffs and rocky canyons
with abundant crevices. It inhabits these suitable
habitats below the Mogollon Rim from northwestern
Arizona to southeastern Arizona (Hoffmeister 1986).
They forage for flying insects at considerable
distances from roost sites.
Rock outcrops along the western and northern
portions of the project area may provide suitable roost
sites for this species, but no individuals of this
species were captured during 1992 and 1993 mist net
surveys. The closest confirmed sighting of a greater
western mastiff bat to the project area is Tonto
National Monument (Hoffmeister 1986).
Chiricahua Western Harvest Mouse. Harvest mice
inhabit a wide variety of habitats and elevations within
Arizona. Grassy habitats usually associated with
streams, fences, irrigated areas, and bottomlands are
preferred (Hoffmeister 1986). Harvest mice feed on
the seeds of grasses and other species. Hoffmeister
(1986) does not recognize R. m. arizonensis as a true
subspecies.
Throughout most of the project area, grass cover is
minimal, and the Chiricahua western harvest mouse
is not expected to be present. Marginal habitat for this
species exists along the lower portions of Pinto Creek
north of the project area, where some grassy areas
were observed.
Other Wildlife Species of Concern. The distribution
and habitat requirements of the following wildlife
species of concern were also reviewed in relation to
the Carlota project area:
• Chiricahua leopard frog
• Desert tortoise
• Common chuckwalla
• Mexican garter snake
• Narrow-headed garter snake
• Northern goshawk
• Cactus ferruginous pygmy-owl
• Buff-breasted flycatcher
• California leaf-nosed bat
• Mexican long-tongued bat
• Red bat
• Southern yellow bat
• Spotted bat
• Yavapai Arizona pocket mouse
Refer to Table 3-55 for a listing of their status. It was
determined that these species are not located in the
vicinity of the Carlota project area and/or suitable
habitat is not present. The Final Biological
Assessment and Evaluation (Cedar Creek
Associates, Inc. 1994b) provides descriptions of their
distribution and habitat.
3.5. 1.2 Aquatic Resources
The aquatic resources potentially affected by the
implementation of the proposed Carlota Copper
Project or the alternatives occur in Pinto Creek,
Haunted Canyon, and Powers Gulch. Pinto Creek
has both intermittent and perennial reaches. Based
on observations during the baseline period (1992-
1996), the segments upstream and through the main
portion of the project area are intermittent.
Downstream of the confluence of Haunted Canyon,
at the lower end of the well field area (Site 3,
Figure 3-26), Pinto Creek exhibited a short reach of
perennial flow during baseline monitoring. The creek
then appears to have intermittent flows downstream
to below the confluences of the West Fork of Pinto
Creek and Horrell Creek. From that point, near the
Pinto Valley weir, it has perennial flows for the next 8
to 9 miles (Lewis 1977). Below that segment, it again
is intermittent for the last 3 to 4 miles before it
reaches Roosevelt Lake (Lewis 1977). Haunted
Canyon exhibits perennial flows from just above the
confluence of Powers Gulch to just above its
confluence with Pinto Creek. Haunted Canyon above
Powers Gulch is intermittent. Powers Gulch is an
intermittent stream until just above its confluence with
Haunted Canyon, where it becomes perennial.
Aquatic resources are limited within the intermittent
Carlota Copper Project Final EIS
3-189
D\A210\CDR\FIG3-26.CDR REVISION: 3/17/97
Henderson Ranch
I
N
Pinto Valley Weir
4
Pinto Creek
^^Flow
Iron Bridge
HC
Haunted Canyon
Legend
Proposed Diversion
Study Site I
Note; Figure not to scale
Riverside Technology, inc
CARLOTA COPPER PROJECT
Figure 3-26
Study Site Locations for
Aquatic Biology Sampling
3-190
3.0 Affected Environment and Environmental Consequences - Biological Resources
reaches of these streams. Dry stretches occur
during summer and fall, resulting in higher water
temperatures in available standing water, stagnation,
and organic deposition. In addition, there have
been impacts to Pinto Creek from past and current
mining activity in the drainage. The aquatic biota
in Pinto Creek were recently influenced by unusually
high rainfall in late 1992 and early 1993, which
flooded local streams and carried PLS and tailings
material from the Pinto Valley Mine into Pinto
Creek. Heavy metals were primarily associated with
the PLS.
Few studies have described the existing aquatic
resources in Pinto Creek. Lewis (1977) evaluated the
effects of the Pinto Valley Mine on the aquatic
ecology in Pinto Creek using biotic surveys (fish and
macroinvertebrates), laboratory bioassays, water
chemistry, and bioaccumulation in sediments and
biota. Several macroinvertebrate inventories have
been conducted by the Tonto National Forest in Pinto
Creek (USDA Forest Service 1992a). The Arizona
Game and Fish Department and the Tonto National
Forest sampled the fish population in Pinto Creek in
July and September 1992 and March 1993 upstream
and downstream of the Pinto Valley weir (T2N, R13E,
Sec 25) (Miller 1993). Miller & Associates (1995)
conducted aquatic sampling at the beginning of low
flow season in May and in September 1993 in
locations on Pinto Creek and Powers Gulch
immediately in or downstream of the proposed
Carlota project area. Haunted Canyon was sampled
in April 1994 by Miller & Associates. The following
data were collected during the aquatic inventory: fish
population data, macroinvertebrate data, habitat
quantification, and water chemistry characteristics
(Miller & Associates 1995). Additional data collected
for other disciplines, such as hydrology, water quality,
sediment, and riparian conditions, were used to
augment existing aquatic resource data.
The most recent description of fish habitat in Pinto
Creek and Powers Gulch was conducted by Miller &
Associates (1995). Intensive habitat mapping was
conducted in Pinto Creek upstream of the planned
diversion (Site 1), Pinto Creek within the diversion
area (Site 2), Pinto Creek downstream of the diver-
sion (Sites 3, 4, and 5), and Powers Gulch in the
diversion area (Site 6) (see Figure 3-26). Mapping
was conducted using a Forest Service basin-wide
protocol. Results of the habitat mapping indicated that
riffles were the dominant habitat type in Pinto Creek
at reaches above, within, and downstream of the
project area {Table 3-57). Within the area of the
proposed diversion in Pinto Creek, pools, riffles, and
glides represented approximately 2, 64, and 34 per-
cent, respectively, of the total area. Riffles were also
dominant in Powers Gulch, representing 86 percent
of the total area. The most abundant substrates in the
reaches where fish were sampled were mainly
boulders and rubble.
Unlike Pinto Creek and Powers Gulch, which are
dominated by riffle habitat. Haunted Canyon has
almost equal areas of pools and riffles (approximately
37 percent and 39 percent, respectively). The
percentage of pool habitat area in Haunted Canyon
is over four times higher than any section of Pinto
Creek or Powers Gulch. These pools provide
important refuge habitats for fish during periods
of low flow. Pinto Creek supports a warmwater
fishery (ADEQ 1992c) dependent on surface flow
or temporary pools for survival during dry periods.
Seven species of fish have been identified in Pinto
Creek in previous surveys by Lewis (1977) and
Miller (1993) {Table 3-58). Lewis (1977) found six
species of fish in the middle and lower portions of
Pinto Creek in 1975 and 1976. Three fish species,
desert sucker, longfin dace, and green sunfish,
were found in areas adjacent to the old Carlota
Mine by Miller (1993). Desert sucker and longfin
dace are native to Arizona and are on the Forest
Service sensitive list (Miller 1993). The mosquitofish
is a non-native species. Species diversity has
apparently declined since 1976; however, the species
lost were not native to the drainage. The Tonto
National Forest collected only three species, longfin
dace, desert sucker, and green sunfish, in 1992 near
the Pinto Valley weir on Pinto Creek (Miller 1993).
Longfin dace was the most abundant species. The
green sunfish is an introduced species. Special status
fish species are listed in Table 3-59 and discussed in
the Special Status Fish Species section.
Recent surveys conducted by Miller & Associates
(1995) in Pinto Creek identified four species: longfin
dace {Figure 3-27), desert sucker {Figure 3-28),
mosquitofish, and green sunfish. The most abundant
species was the longfin dace. Collections in May 1993
were dominated by juvenile and young-of-the-year of
all species. Few adult specimens were collected at any
site. Adult numbers were higher in the September
Carlota Copper Project Final EIS
3-191
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-57. Summary of Habitat Characteristics at Study Sites in Pinto Creek and Powers Gulch
May 1993 and Haunted Canyon April 1994
Site
Total
Length
m
Percent of Total Areli
I Average Dept
th(ft)
Average Width (ft)
Average
Pool
Residual
Depth (ft)
Pool
Riffle
Glide
: Pool
Riffle
Glide
Pool
jRiffie
Glide
1
8,263
8.45
67.34
24.21
1.09
0.51
0.72
14.2
9.29
15.73
2.14
2
9,269
2.02
64.13
33.85
1.40
0.49
0.66
11.6
10.08
13.29
2.28
3
1,945
8.42
40.25
51.34
1.10
0.54
0.98
14.0
11.38
17.67
2.17
4
1,818
8.31
42.81
48.88
2.30
0.69
0.96
26.5
19.88
21.20
4.75
5
4,878
0.70
84.19
15.10
1.60
0.94
0.88
18.0
18.27
19.17
2.50
6
4,922
8.60
86.19
5.21
1.68
0.46
0.83
10.8
4.89
8.00
3.32
HC
3,547
36.69
39.58
23.73
1.75
0.49
.94
16.15
9.29
13.86
2.52
HC = Haunted Canyon
Table 3-58. Summary of Fish Species Identified in Pinto Creek and Haunted Canyon
1 ^ Species
CtWimon Name
i Scientific Name
1 Lewis
1(1977)
Miller
(1993)
study :
Miller & Associates
(1995)
Fathead minnow
Pimephales promeias
X
Golden shiner
Notemigonus chrysoleucas
X
Longfin dace
Agosia chrysogaster
X
X
X
Mosquitofish
Gambusia affinis
X
X
Desert sucker
Catostomus clarki
X
X
X
Green sunfish
Lepomis cyanellus
X
X
sampling, but were relatively uncommon {Table 3-60
and Figures 3-27 and 3-28). The presence of desert
sucker juveniles at Site 3 may indicate that colonizatiorj
of Pinto Creek is occurring from fish populations in
Haunted Canyon. The 1992 and 1993 flood and spill
may have influenced fish densities, particularly adult
longfin dace and desert sucker, during the May 1993
sampling. Adult desert sucker and longfin dace were
relatively common in Haunted Canyon collections
taken in April of 1994 (Miller & Associates 1995).
Haunted Canyon may serve as the source of fish that
recolonize Pinto Creek after extreme flood events or
spills. Miller & Associates (1995) reported that no fish
were collected or observed in Powers Gulch in May or
September 1993. The Arizona Game and Fish Depart-
ment reported an occurrence of longfin dace in Powers
Gulch, downstream of Mule Spring, in November 1992.
Total fish densities and catch-per-unit effort in Pinto
Creek are shown in Figures 3-29 and 3-30. In
general, total fish densities were relatively low in May,
when fish/meter (m)^ was less than 0.2 at all sites.
Total fish densities in September were considerably
higher at sites 2, 3, and 4, with numbers ranging from
approximately 2 to 5 fish/m^. Sites 1 and 5 exhibited
densities of 0 and 0.14 fish/m^, respectively, in
September. Catch-per-unit efforts ranged from
approximately 0.1 to 10.3 fish/minute in May and 0 to
64.7 fish/minute in September. Haunted Canyon
sampling in April 1994 resulted in 1 .82 fish/m^ and a
catch rate of 27.9 fish/minute.
Based on surveys conducted by Miller & Associates
(1995) in May and September of 1993, macroin-
vertebrate communities in Pinto Creek and Powers
Gulch exhibited low to high densities, depending upon
the sampling site and sample date. In Pinto Creek,
mean densities ranged from approximately 2,083 to
23,218 individuals/m2 in May and 1,454 to 10,437
individuals/m2 in September {Figure 3-31). The mean
density in Powers Gulch was 3,153 individuals/m^ in
May. Samples were not collected in this stream in
3-192
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-59. Special Status Fish Species Potentially Occurring or Historically Occurring in
the Carlota Project Area
Common Name
Scientific Name
Status
Gila topminnow
Poeciliopsis occidentalis
LE, S
Longfin dace
Aqosia chrysoqaster
C2, S
Desert sucker
Catostomus clarki
C2, S
Gila chub
Gila intermedia
C
Status:
Federal (USDI Fish and Wildlife Service 1992, 1993)
LE = Taxa listed by the U.S. Fish and Wildlife Service as Endangered under the ESA.
Forest Service (USDA Forest Service 1988)
S = Classified as “sensitive” by the Regional Forester when occurring on lands managed
by the U.S. Forest Service.
C2 = Category 2 Candidate. Taxa with the C2 designation were listed as such at the initiation of the
Carlota EIS analysis. Since that time, the U.S. Fish and Wildlife Service has issued a more recent
listing of candidate species (Federal Register 61: 7596-7613, February 28, 1996). As a result of
this update, none of the fish species addressed by the EIS are listed as candidate (C2) species.
C = Candidate species by the U.S. Fish and Wildlife Service. Three preserved specimens of Gila chub
recently were found at the University of Michigan, Museum of Zoology. The Gila chub specimens
were collected from Haunted Canyon on July 2, 1959 by C.R. Gilbert (Collection No. Z176179).
No Gila chub were found during the multiple aquatic surveys conducted in 1977, 1993, and 1994.
September because water was not flowing. The
highest macroinvertebrate densities occurred at Sites
3 and 4 in Pinto Creek. Macroinvertebrate biomass
varied at the sampling sites during both sampling
periods. Mean biomass in Pinto Creek ranged from
0.43 to 3.34 grams (g)/m2 in May and 1 .1 8 to 3.48
g/m2 in September.
The most abundant macroinvertebrate taxa were
generally similar in Pinto Creek and Powers Gulch. In
May, mayflies {Baetis sp.), chironomid midges
(Orthocladiinae and Tanytarsini), and blackflies
{Simulium) dominated the macroinvertebrate
numbers. Blackflies accounted for the relatively high
macroinvertebrate densities at Sites 3 and 4 in May.
In September, mayflies continued to dominate the
macroinvertebrate numbers. Caddisflies and
chironomid midges were the other abundant
macroinvertebrate groups in September. Mayflies
caddisflies, and blackflies are indicators of generally
good water quality conditions. However, many of the
species present in the samples are early colonizers,
which suggests that good water quality and/or
sufficient flow may have only existed for a few
months. Macroinvertebrate community structure in
Pinto Creek and Powers Gulch during the May 1993
sampling period appears to have been primarily
influenced by the flooding or spills that occurred 6
months prior to the sampling. Acute levels of copper
exceeded ADWR standards (Hargis & Associates
1993). Species diversity and Diversity and Taxa
(DAT) indices were relatively low in both streams
in May. The DAT indices resulting from the survey
by Miller & Associates (1995) were similar to
values that were reported by the Forest Service
(USDA Forest Service 1992a). The majority of
invertebrates collected in large numbers {Baetis,
Simulium, and Orthocladiinae) from each station
were typically those insects associated with rapid
colonization. It is likely that the low diversity values
listed in Table 3-61 are the result of community
assemblages that had not attained a balanced state
since the flooding. Thus, rapidly colonizing
invertebrates were dominant, and they represented
an atypically large proportion of the
macroinvertebrate community.
Macroinvertebrate species diversities in September
were higher at Sites 3, 4, and 5 in Pinto Creek when
compared to the May survey. Mean diversities
ranged from approximately 2.7 (Sites 2 and 5) to
3.1 (Sites 3 and 4). The DAT indices increased at
all four Pinto Creek sites that were sampled in
September, with values ranging from approximately
10.4 (Site 3) to 17.6 (Site 5). Since DAT indices
at Sites 2, 4, and 5 ranged from 11 to 17,
macroinvertebrate communities were indicators
of good water quality conditions. A DAT of 10.4 at
Carlota Copper Project Final EIS
3-193
3.0 Affected Environment and Environmental Consequences - Biological Resources
Number
Figure 3-27. Number of Longfin Dace Collected at Pinto Creek Sites in 1993 by Age Class
Figure 3-28. Number of Desert Sucker Collected at Pinto Creek Sites in 1993 by Age Class
3-194
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-60. Species and Age Class of Fish Collected In Pinto Creek in May and September
of 1993 and in Haunted Canyon in April of 1994
’ Size range for all fish captured.
YOY- young of the year
Juv- juvenile
Carlota Copper Project Final EIS
3-195
3.0 Affected Environment and Environmental Consequences - Biological Resources
Fish Density
Figure 3-29. Fish Densities in Pinto Creek, May and September, 1993
Bectrofishing Catch-Per-Effort
Figure 3-30. Catch-Per-Effort from Electrofishing Surveys Conducted in
Pinto Creek, May and September, 1993
3-196
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Macroinvertebrate Densities
* No samples collected because flowing water was lacking.
Figure 3-31. Macroinvertebrate Densities in Pinto Creek (Sites 1-5) and Powers Gulch (Site
6), May and September, 1993
Carlota Copper Project Final EIS
3-197
3.0 Affected Environment and Environmental Consequences - Biological Resources
Table 3-61. Summary of Shannon-Weaver Diversity, Evenness, DAT Index, and Number of
Taxa in Pinto Creek and Powers Gulch
versity
li Evenneas
DAT
Mean
No. of Taxa
site*
May
September
1 May
September
' ' May 1
September
September
1
1.865
3
0.466
---
6.29(0.37)
—
12.3
...
2
2.886
2.730
0.679
0.436
9.48(1.26)
14.41(2.44)
14.7
20.7
3
1.854
3.110
0.517
0.837
5.28(0.66)
10.43(2.28)
9.7
14.3
4
1.473
3.140
0.347
0.486
6.43(1.20)
17.17(1.51)
16.0
24.7
5
1.649
2.725
0.370
0.360
6.34(0.11)
17.59(1.24)
13.3
25.0
6
2.453
3
0.600
—
8.34(1.21)
...
12.3
—
' Sites 1-5 (Pinto Creek), Site 6 (Powers Gulch).
^ Scale for DAT: 18-26=excellent, 11-17=good, 6-10=fair, and 0-5=poor.
(Number in parentheses is the standard deviation.)
^ Since flowing water was not present, no macroinvertebrate samples were collected at these sites.
Site 2 indicated fair water quality. The relatively
higher species diversity and DAT indices in
September indicated recovery from the flood and spill,
as well as seasonal changes in the macroinvertebrate
community. Studies by the Forest Service (USDA
Forest Service 1992a) also reported seasonal
increases in DAT indices from spring to fall sampling
periods. Lewis (1977) identified 53 species of
macroinvertebrates from Pinto Creek, whereas Miller
& Associates (1995) accounted for 60 taxa. A
macroinvertebrate list for Pinto Creek at Henderson
Ranch reported by the Forest Service (USDA Forest
Service 1992a) on May 5, 1991, accounted for 13
taxa, which was very similar to the mean number of
taxa (13.3) collected by Miller & Associates at this
site. However, the Forest Service collected three
insect taxa at this site (Leuctridae, Capniidae, and
Carabidae) that Miller & Associates (1995) did not
detect at any station on Pinto Creek or Powers Gulch.
The most logical explanation for this apparent shift of
taxa in the community assemblage is that some
species may still be in the process of recovering from
the flood event and spills.
Fish and macroinvertebrate tissues collected from
Pinto Creek were analyzed for bioaccumulation of
heavy metals by Lewis (1977) and Miller & Asso-
ciates (1995) {Table 3-62). Sufficient fish biomass for
tissue analyses was obtained only from Sites 3, 4,
and 5 in Pinto Creek by Miller & Associates (1995).
Sufficient macroinvertebrate tissue was collected at
all sites. It is important to point out that the majority of
the macroinvertebrate biomass was composed of
dobson flies (Megaloptera). Dobson flies are relatively
long-lived invertebrates in their aquatic stage of
development (1 to 3 years), which would allow
extended exposure to water quality conditions. Low
levels of copper, manganese, and zinc were
detected in fish and macroinvertebrate tissues
at all sites. Cadmium was detected in macro-
invertebrates at Sites 3, 4, and 5 in Pinto Creek
and in Powers Gulch (Site 6). Cadmium was found
in fish tissues at Sites 4 and 5. Lewis (1977) reported
noticeably higher levels of heavy metals in macro-
invertebrates compared to the May 1 993 samples
and generally higher levels in fish viscera samples.
Copper values were similar between Lewis’ (1977)
eviscerated body and Miller & Associates’ (1995)
whole body samples.
Special Status Fish Species. Three fish species,
Gila topminnow (Poeciliopsis occidentalis), desert
sucker (Catostomus clarki), and longfin dace {Agosia
chrysogastei), were evaluated for the proposed
Carlota Copper Project based on their historic and
current distribution in the general region. The Gila
topminnow is a Federal Endangered species and
Forest Service Sensitive species; the desert sucker
and longfin dace are Forest Service Sensitive
Species.
Gila Topminnow. This species is native to the Salt
River basin in Arizona. Pinto Creek is within the
historic range, although no fish surveys conducted on
Pinto Creek reported Gila topminnow in the collec-
tions. The Gila topminnow was formerly abundant in
streams below 1,500 meters elevation in the Gila
River basin. It is now restricted in occurrence and
classified as Federal Endangered (listed March 11,
1967). The Gila topminnow habitats include vegetated
3-198
Carlota Copper Project Final EIS
Table 3-62. Results of Aquatic Biota Tissue Analyses for Pinto Creek and Powers Gulch
3.0 Affected Environment and Environmental Consequences - Biological Resources
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Carlota Copper Project Final EIS
3-199
3.0 Affected Environment and Environmental Consequences • Biological Resources
springs, brooks, and the margins and backwaters of
larger water bodies.
Surveys were conducted at six locations in Pinto
Creek and Powers Gulch in May and September of
1993. Haunted Canyon was surveyed in April 1994.
No individuals of Gila topminnow were found at any of
the sites during the collection periods. The absence
of the Gila topminnow in the Pinto Creek drainage
may be caused by competition with the mosquitofish
and habitat modifications. Mosquito fish are known to
exclude populations of Gila topminnow when they
come in contact through direct predation and
competition.
Desert Sucker. This sucker species is native to Pinto
Creek and the Gila River basin. The desert sucker
was reported in historic fish surveys of Pinto Creek in
the 1970s, 1980s, and 1990s. The desert sucker is
characteristic of small to moderate size streams with
pool and riffle habitats. Young desert sucker inhabit
riffles. Larger adult desert sucker inhabit pools during
the day and move to riffles at night to feed. The
desert sucker was generally common but is now
becoming rare in some locations. The species is
usually sedentary with little seasonal movement or
displacement even during normal high flows. Larval
sucker can drift downstream with flow. Juveniles feed
mainly on chironomid larvae and adults are primarily
herbivorous, feeding on algae scraped from stones as
well as plant detritus.
Spawning occurs in riffles in late winter through spring
(January through May) in Arizona. Larvae are mature
at the end of the second year of life at a length of 85-
120 millimeters (mm). The desert sucker showed
evidence of reproducing in the Pinto Creek drainage
in 1993. Juvenile desert sucker were collected in a
perennial reach of Pinto Creek in the downstream
project area by Miller & Associates (1995).
Six locations in Pinto Creek and Powers Gulch were
surveyed in May and September 1993 for the desert
sucker and other fish species. The desert sucker was
collected from Site 3 on Pinto Creek approximately
0.25 mile upstream of the Iron Bridge. At this site one
adult desert sucker was collected in May 1993 and
several juvenile desert suckers were collected in
September. Additional sampling in Haunted Canyon
in April 1994 resulted in the collection of all age
classes of desert sucker. Spawning was observed at
one location. Previous surveys in 1992 by the Forest
Service and the Arizona Game and Fish Department
report collecting desert sucker at locations
downstream of the project area near the Henderson
Ranch (approximately 10 miles downstream of the
proposed project). The Forest Service and Arizona
Game and Fish Department did not conduct any
sampling in the project area in 1992.
Longfin Dace. The longfin dace is native to Pinto
Creek and the Gila River basin according to the
historic collections in the 1970s, 1980s and 1990s,
and is the most abundant species found in Pinto
Creek. The longfin dace is found in small to moderate
streams. Young longfin dace are found in slow
velocity habitats near stream margins. Adults are
found in deep shaded pools as well as in larger
substrate, faster velocity habitats.
Longfin dace spawning occurs from December
through May over sand. Larvae become mature
within the first year of life. Longfin dace exhibit a
high tolerance for elevated water temperatures
and reduced oxygen, and it is commonly the only
native species present at the terminus of desert
streams where flows disappear. Adults feed on
detritus, zooplankton, aquatic insects, and fila-
mentous algae.
Surveys were conducted in Pinto Creek and Powers
Gulch in May and September of 1993 and in Haunted
Canyon in April of 1994. Longfin dace were collected
or observed at all Pinto Creek sites upstream, within,
and downstream from the project area. It was the
most abundant species collected in the drainage.
Most of the specimens collected in 1993 were young-
of-the-year or juveniles. The only adult specimens
collected in May of 1993 were at the Iron Bridge
location. Several adults were observed at other
locations but were not captured. The abundance of
juveniles in the September survey also indicates that
adults were present in the drainage. The April 1994
survey had an almost even distribution between adult
and juvenile longfin dace.
Waters of the U.S. COE regulates the discharge of
dredged and/or fill material into waters of the U.S.,
including adjacent wetlands, under Section 404 of the
Clean Water Act (33 U.S.C. 1344). Waters of the U.S.
are defined as “all waters which are currently used,
were used in the past, or may be susceptible to use in
3-200
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
interstate or foreign commerce including all waters
which are subject to the ebb and flow of the tide; all
interstate waters including interstate wetlands; all
other waters such as intrastate lakes, rivers, streams
(including intermittent streams), mudflats, sandflats,
wetlands, sloughs, prairie potholes, wet meadows,
playa lakes, or natural ponds, the use, degradation or
destruction of which could affect interstate or foreign
commerce: all impoundments of waters otherwise
defined as waters of the U.S.; tributaries of
waters identified above; territorial seas; and
wetlands adjacent to waters identified above"
(33 CFR 328.3).
Waters of the U.S. are determined by the presence
of an ordinary high water mark. Of the 157 evaluated
stream reaches in the project area, 55 were
determined to be waters of the U.S. for a total area
of 34.1 acres {Figure 3-32). Of the 34.1 acres of
jurisdictional waters identified, 3.81 acres were
delineated as wetlands using the 1987 COE
Wetlands Delineation Manual {Figure 3-32).
Wetlands are defined as areas that are inundated
or saturated by surface or ground water at a
frequency and duration to support, and that under
normal circumstances do support, a prevalence of
vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps,
marshes, bogs, and similar areas [(33 CFR 328.3(b)].
A wetland delineation in the well field area has not
been conducted.
Small intermittent springs occur at scattered locations
throughout the project area. Three perennial springs
were identified in the project area: (1) Yo Tambien,
(2) Mule, and (3) Grizzly Bear. The Forest Service
maintains water rights on these three springs. The
COE has delineated Yo Tambien and Mule springs as
jurisdictional wetlands.
Yo Tambien Spring is located in the southeastern
portion of the project area, where seepage from an
old collapsed mining adit (Yo Tambien Mine) flows
across the old facilities pad and down into Pinto
Creek {Figure 3-32). At the point where seepage
crosses the old pad, a very small wetland (less than
0.05 acre in total area) has formed. This spring is
dominated by cattail {Typha sp.). Mule Spring is an
undeveloped perennial spring near the head of West
Powers Gulch drainage {Figure 3-32). This spring
appears to be perennial and one of the long-term
contributors of moisture to lower Powers Gulch. Flow
from this spring has contributed to the development of
a small wetland area. This wetland is approximately
0.33 acre in area. Grizzly Spring is an undeveloped
spring that remains moist year-round, though there is
often no surface water.
3.5.2 Environmental Consequences
This section describes the direct and indirect
effects of the proposed action and alternatives
on biological resources. The biological issues
identified during the scoping process are listed
below.
• Loss or degradation of on-site and off-site aquatic
and terrestrial habitat
• Impacts to wildlife habitat caused by reduction
in streamflow, habitat fragmentation, movement
restriction, or decreased access to water
• Direct, indirect, and cumulative impacts to special
status plant, wildlife, and fish species
• Direct, indirect, and cumulative impacts to other
plant and wildlife species
• Chemical contamination of flora and fauna
3.5.2.1 Proposed Action
Terrestrial Resources
Criteria that were used to evaluate potential impacts
of the proposed project and the alternatives on
vegetation and wildlife resources are listed below.
• Vegetation
Acres of habitat loss or degradation by
general type (e.g., upland, wetland or
riparian, waters of the U.S.) and specific
type (e.g., cottonwood-willow, chaparral)
Relative value of habitat types
Number of threatened or endangered plant
species affected by the project and number
of individuals affected relative to species
status elsewhere
Carlota Copper Project Final EIS
3-201
3.0 Affected Environment and Environmental Consequences - Biological Resources
Acres of potential and occupied habitat for
threatened or endangered species affected,
rated according to habitat quality
Sensitive species whose viable populations
may be affected
Air quality impacts to native vegetation from
chemicals or particulates
. Wildlife
Habitat fragmentation or corridor disruption
impacts
Number of threatened or endangered wildlife
species affected by the project and number of
individuals affected
Acres of potential and occupied habitat for
threatened or endangered species
Sensitive species whose viable populations
may be affected
Impact to other wildlife species and estimated
populations displaced
Potential exposure of wildlife to contaminated
water sources
Impacts to wildlife species from accidental
release of chemicals
Vegetation.
Interior Chaparral. Interior chaparral is a very
common habitat on the northern slopes of the nearby
Pinal and Superstition mountains. It is used by a
variety of wildlife species including deer, collared
peccary, black bear, and white-nosed coati, for
foraging and cover. Of the 1 ,532 acres (49.5 percent
of the project area) of interior chaparral that occur
within the project area, approximately 798.14 acres
(including 7.14 acres of mesic chaparral) would be
directly affected by the proposed action. A few
additional acres of this habitat type adjacent to the
immediate impact area may be indirectly affected by
erosion. Relative to the amount of this habitat
available in the Pinal Mountains, the number of acres
directly and indirectly affected by the proposed action
would be relatively inconsequential.
Rubbleland Chaparral. Rubbleland chaparral is used
to a somewhat lesser degree by the same species as
discussed for interior chaparral. Although approxi-
mately 494 acres of rubbleland chaparral occur
within the project area, this vegetation type would not
be directly or indirectly affected by the proposed
action.
Drv-Slope Desert Brush. A total of 886 acres
(28.6 percent of the project area) of dry-slope desert
brush occurs within the project area. Of this area,
approximately 488 acres would be directly affected by
the project. An additional 2 acres of rock outcrop
(associated with the Dry-slope Desert Shrub type)
would be directly affected by the project. A small
number of additional acres of this habitat type
adjacent to the immediate impact area may be
indirectly affected by erosion. Relative to the
amount of this habitat available in the Pinal and
Superstition mountains, the loss of dry-slope desert
brush habitat by the proposed action would be very
small.
Juniper/Grassland. A total of 131 acres (4.2 percent
of the project area) of juniper/grassland habitat
occurs within the project area. Of this area, 118
acres would be directly affected by the project.
A few additional acres of this habitat type adjacent
to the immediate impact area may be indirectly
affected by erosion. Since this habitat type also is
found at scattered locations throughout the Pinal and
Superstition mountains, the loss of a small amount of
juniper/grassland would be inconsequential.
Riparian Habitat. A total of 57 acres (1 .8 percent
of the project area) of interior riparian deciduous
woodland, including spring-related habitats, occurs
within the project area (see Section 3.5. 1.1, Biological
Resources - Terrestrial Resources, for a description
of these areas). The riparian community is mapped in
Figure 3-25. Of this area, 21 .86 acres would be
directly affected by the proposed action. A large
portion of this riparian habitat occurs along the two
stream reaches that would be cut off from stream-
flows because of the Pinto Creek and Powers Gulch
diversions. In total, the 12.40 acres of directly
affected riparian zone habitats is composed of the
3-202
Carlota Copper Project Final EIS
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CARLOTA COPPER PROJECT
Figure 3-32
Location of Jurisdictional
Waters of the U.S
3.0 Affected Environment and Environmental Consequences - Biological Resources
following: 3.40 acres of riparian public land in Pinto
Creek, 8.10 acres of riparian private land in Pinto
Creek, and 0.90 acre of riparian public land in Powers
Gulch. Within the riparian zone, additional acreage of
wetlands and Waters of the U.S. would be directly
affected (see Waters of the U.S. discussion in the
Aquatic Resources section). In addition, approxi-
mately 16.1 acres of riparian vegetation occur in
lower Haunted Canyon in the vicinity of the well field.
An additional 15.9 acres of riparian vegetation are
located in Pinto Creek across from the well field.
These latter two areas are beyond the area of direct
impact of the pit and other project features
immediately adjacent to the pit but could be indirectly
affected by well field operations.
The potential exists for additional impacts to riparian
vegetation from spills or short-term changes in water
quality during construction or as a result of changes
in hydrology associated with excavation and the
ground water drawdown associated with pumping the
water supply wells. Other potential indirect impacts to
this vegetation type include siltation in the immediate
vicinity of the diversion intake control structure and
downstream of the proposed Pinto Creek diversion,
and changes in air and water quality. The loss of
riparian habitat would be considered important
because of its value to wildlife and its limited
existence in the project area.
The anticipated levels of surface and ground water
drawdowns from stream diversion, pit dewatering,
and well field development are discussed in Section
3.3.2, Water Resources - Environmental
Consequences. The actual effects of such activities
on riparian ecosystems would mainly result from an
incremental increase in the aridity of the riparian
habitat. Pools would be smaller and more infrequent,
and intermittent stretches would become more
predominant. This increasing aridity would place an
increased stress on the deciduous trees that
dominate the floodplain environment and could cause
increased mortality, especially during the normal
May-June drought period. More importantly,
increasing aridity could limit successful recruitment of
young trees.
Special Status Plant Species. Based on information
presented in the Final Biological Assessment and
Evaluation (Cedar Creek Associates, Inc. 1994d), the
Arizona hedgehog cactus is the only federally listed
threatened, endangered, or proposed plant species
that could be affected by development of the Carlota
Copper Project.
Arizona Hedgehog Cactus. Approximately 23.94
acres of occupied Arizona hedgehog cactus habitat
would be directly affected by the proposed action. In
terms of acres disturbed and numbers of individual
plants affected, the majority of the impacts would be
associated with the mine pits and a few project area
roads. The Powers Gulch stream diversion channel
and the leach pad would result in relatively few
conflicts with the cactus. The mine rock disposal
areas, access roads, conveyors, warehouse facility,
and mine pits could affect potential, but unoccupied,
Arizona hedgehog cactus habitat. Of these latter
project components, most of the impacts to
unoccupied habitat would be associated with the mine
rock disposal areas. The number of individual cacti
and acreages for both occupied and potential habitat
are quantified for the various project components in
the Final Biological Assessment and Evaluation
prepared for the project (Cedar Creek Associates,
Inc. 1994d). Of the 1,150 cacti within the 100 percent
survey area, only 207 were found to be in direct
conflict with planned project facilities. An additional 12
cacti were located close enough to mine pits and/or
roads and rooted upon unstable material such that
vibration from blasting activities could place them at
risk.
A few additional cactus plants may be subject to
additional direct effects by the proposed action
because of their proximity to the proposed pits or their
location immediately adjacent to the Powers Gulch
diversion outfall. These individuals could be affected
by a potential spill of contaminated water from the
leach pad or erosion as a result of waterflow as it
exits the diversion. These potential impacts are
discussed further in Section 3.3, Water Resources.
Mitigation measure WR-12 addresses outfall erosion.
The U.S. Fish and Wildlife Service accounted for
such possible additional effects in its Biological
Opinion (see Appendix F).
Despite the loss of 23.94 acres of occupied habitat,
217 individual plants, and 237.6 acres of potential
habitat as direct effects of project implementation,
mitigation measures discussed under Section 3.5.4
are expected to compensate for these losses. The
U.S. Fish and Wildlife Service (1996) has concurred
Carlota Copper Project Final EIS
3-205
3.0 Affected Environment and Environmental Consequences - Biological Resources
with this conclusion with its issuance of a “non-
jeopardy” opinion in its Biological Opinion on the
effects of the Carlota Copper Project. Even without
mitigation, there would be a natural recovery of
losses over time since additional habitat would be
created (similar to cactus colonization sites observed
along Highway 60) and since a positive recruitment
ratio of 1 .65 new recruits to each mortality was
documented for the cactus in the field by Cedar
Creek Associates, Inc. (1994d).
Wildlife. Numerous species of wildlife, including
insects and other arthropods, amphibians, reptiles,
birds, and mammals, would be directly affected.
Both upland and riparian vegetation types, which
provide foraging and breeding habitat for wildlife
species, would be affected by the proposed action.
Acreages of vegetation types lost are discussed in
the previous vegetation section. The loss of habitat
would result in indirect effects to wildlife that use the
project area for foraging or breeding but are
sufficiently mobile to escape direct impact. This would
include many species of birds, bats, and other small
animals that would be driven out of the area by
construction and operation activities.
Big game species that may be indirectly affected by
implementation of the proposed action would include
mule deer, white-tailed deer, collared peccary, black
bear, and mountain lion. Reliable population
estimates are not available for the vast majority of
wildlife species inhabiting the project area, but
Arizona Game and Fish Department big game
surveys conducted in Unit 24B (which includes the
project area) provide information on the potential
impacts of the project on populations of the most
common large mammals. These data indicate mini-
mum and maximum density estimates of 7 to 15
white-tail deer per square mile, 1 to 7 mule deer per
square mile, and 1 to 3 collared peccary per square
mile. The total loss of 1 ,428 acres of habitat for all of
these species could result in the loss of
approximately 17 to 37 white-tail deer, 2 to 17 mule
deer, and 2 to 7 collared peccary. It is important to
note that there would be a loss of future generations
of these animals, as well as nongame wildlife, through
time until the habitat value of the site is restored.
Habitat fragmentation is a concern where loss of
habitat continuity could result in populations of a
species becoming isolated from others of the same
species, thereby preventing genetic interchange and
resulting in the potential loss of viability as large-scale
habitats are converted from being suitable to hostile. :
For the Carlota Copper Project, fragmentation would I
not be an issue for any species since habitat
conversion would not be on a large enough scale to
be a threat to any given species (see following
discussions on threatened, endangered, and other
wildlife species of concern). :
Project development would result in a short-term
disruption of the Pinto Creek stream channel until
development of the Pinto Creek diversion channel
has been completed. For birds and mammals, this
would not disrupt any movement linkages between
populations or important habitat areas. Wildlife
species that use the Pinto Creek stream channel as a
movement corridor have already adapted to a number
of naturally occurring areas along the creek bottom
where riparian vegetation is lacking and/or vegetation
cover is nearly absent.
The disruption of the Pinto Creek channel could
isolate upstream populations of amphibians from
downstream populations over the short-term until the
diversion channel is completed. However, this
situation would not result in any loss of species
viability because local populations have already
adapted to periods of isolation and habitat loss since
Pinto Creek seldom carries continuous surface flow
between its upstream and downstream segments.
Once the diversion channel has been completed,
potential interchange between local amphibian
populations in the drainage would be maintained
during periods when the creek carries continuous
flow.
The potential for wildlife exposure to contaminated
water sources would be very low with the Carlota
Copper Project. There would be only three possible
sites during the life of the operation where wildlife
could be exposed to potentially toxic process
solutions. These sites would be the plant PLS
pond and the raffinate pond within the plant
operations area and the top of the heap-leach pad
if surface pooling of the leachate solution (raffinate)
occurs as it is distributed on the heap-leach pad.
All other aspects of ore processing would take place
within enclosed structures with no risk of wildlife
exposure.
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Raffinate consists primarily of a sulfuric acid solution
(approximate pH of 1 to 2), which could be harmful to
wildlife if exposure pathways are provided. The PLS
would contain metals and other potentially toxic
constituents in solution, in addition to being acidic
(see Appendix C, Table C5-3).
Copper ore in the leach pad would be leached by
raffinate distributed over the leach pad by solution
emitters (drip lines), impulse sprinklers, and/or
wobbler sprinklers. Under most conditions, solution
emitters would be the preferred distribution
mechanism (see Section 2. 1.4.2). This distribution
method would be the least likely to cause pooling on
the heap-leach surface. Operationally, it is not
efficient or cost-effective to allow raffinate to pool on
the top of the heap-leach facility. As a result, the
distribution of raffinate on the heap-leach surface
would be constantly monitored by Carlota personnel
to ensure its proper distribution and that surface
pooling does not occur (see Section 3.5.4).
Therefore, the risk of wildlife being attracted to
potentially toxic water sources on top of the heap-
leach facility would be very low.
Once metal bearing leachate passes through the
heap-leach facility, it would be collected within two
PLS ponds. The two PLS ponds would be
constructed as internal structures within the heap-
leach facility; therefore, there would be no surface
exposure of PLS at the ponds. However, reclaimed
PLS could be recirculated for distribution back on the
heap-leach surface to enhance PLS grade or solution
management. The risk for wildlife exposure to PLS on
the heap-leach surface would be low for the same
reasons that exposure risk to the raffinate would be
low.
Most of the PLS would be pumped via pipelines from
the heap-leach PLS ponds to the plant PLS pond in
the operations area (see Figure 2-5) and be held
there until it is pumped to the SX plant for mineral
extraction. Once the metal extraction processes are
completed, barren raffinate would be returned and
stored in the raffinate pond in the operations area
(see Figure 2-5) prior to redistribution on the heap-
leach surface. The plant PLS and raffinate ponds
would be approximately 1 acre in size and would be
constructed with a double liner and leak detection
system. The pond and pond embankments would be
of sufficient size to contain a 72-hour (1/2 - PMF)
storm event (see Section 2. 1.3.2). Carlota has not
proposed any fencing for these ponds and both would
have open surface water that could attract wildlife.
However, the ponds would be surrounded by mine
facilities and operational activities (see Figure 2-5)
and would not be an attractive water source for
wildlife. In addition, the high acidity of the solutions in
both ponds would give off an acrid odor and a bitter
taste that would repel wildlife before a potential lethal
or debilitating dose would be ingested. The chemical
makeup of process solutions in Carlota’s ponds would
be similar to other copper mine operations in Arizona.
In contrast to the wildlife mortalities documented for
cyanide solution process ponds used by the gold
mining industry, wildlife agency personnel in Arizona
have not documented similar problems related to
wildlife consumption of water from copper mine
process solution ponds (Haughey 1997, King 1997).
The raffinate and plant PLS ponds would be
monitored on a regular basis by Carlota personnel to
determine if there are any wildlife mortalities at the
ponds (see Section 3.5.4).
Another potential surface water quality concern for
wildlife is the lake that would form in the
Carlota/Cactus pit after mine closure. It is projected
that a pit lake would form as a result of ground water
inflow, collection of surface runoff from the
contributing watershed area, and direct precipitation
(see Section 3.3.2.1). The pit lake would be available
for use by water birds as well as by other more
mobile terrestrial species, such as deer, coyote, and
songbirds. Modeled projections of water quality in the
pit lake (see Section 3.3.2. 1 and Appendix Table C5-
1) at equilibrium (125 years after closure) indicate
that although the pit lake is not subject to Arizona
surface water quality standards (Arizona
Administrative Code R1 8-1 1-102), the only violations
of potentially applicable water quality standards would
be the predicted value of 4.36 mg/L of fluoride
(exceeds the Arizona Aquifer Protection Program
standard of 4.0 mg/L) and the predicted value of 275
mg/L of sulfate (exceeds federal secondary MCL for
drinking water). There are no agricultural livestock
water quality standards or aquatic life criteria for
fluoride or sulfate as these constituents are
considered to be relatively non-toxic. Projected levels
of fluoride and sulfate at the time of pit lake
equilibrium would not be expected to have any
deleterious effects on water birds or other terrestrial
Carlota Copper Project Final EIS
3-207
3.0 Affected Environment and Environmental Consequences - Biological Resources
wildlife that may occasionally use the lake for drinking
water. Even though the concentrations of some major
ions (sodium, chloride, sulfate) and TDS in the pit
lake water are likely to increase over time after
equilibrium is reached (see Section 3.3.2. 1), an
increase in these constituents would be unlikely to
produce potentially toxic water conditions for wildlife.
If levels of sodium, chloride, and sulfate become too
high, an unpleasant taste would likely repel wildlife
before a debilitating quantity of water could be
ingested.
Special Status Wildlife Species. Based on
information presented in the Final Biological
Assessment and Evaluation (Cedar Creek
Associates, Inc. 1994d), the bald eagle is the only
federally listed threatened, endangered, or proposed
wildlife species that could be affected by development
of the Carlota Copper Project.
The Final Biological Assessment and Evaluation
prepared for the Carlota Copper Project (Cedar Creek
Associates, Inc. 1994d) also evaluated the potential
for project-related impacts on a number of other
species of concern (see Table 3-55). Maricopa tiger
beetle, Arizona toad, lowland leopard frog, common
black-hawk, yellow-billed cuckoo, and loggerhead
shrike were determined to be the only species that
could be subject to adverse effects. A summary of
conclusions from the Final Biological Assessment and
Evaluation is provided for each species in this
section.
Bald Eagle. No bald eagles were observed in the
project area. This species would not be directly
affected by the proposed action.
A bald eagle nesting territory is located approximately
15 miles north of the Carlota Copper Project area at
Roosevelt Lake (Hunt et al. 1992b). Indirect effects
could potentially include the reduction of prey in
perennial waters downstream from the project site by
accidental releases of contaminated surface waters
from leach ponds or seepage into the Pinto Creek
drainage, or the build-up of toxic substances in adult
or juvenile eagles as a result of ingestion of
contaminated prey.
Although a release from the heap-leach facility is not
expected during operation or after closure, any major
release could have the potential to degrade the
quality of Pinto Creek water entering Roosevelt Lake
and have an adverse effect on local nesting pairs of
bald eagles or on winter transient eagles feeding in
the lake.
As indicated in Sections 3.3.4 and 3.5.4, numerous
monitoring and mitigation measures are proposed to I
avoid potential impacts and to reduce or alleviate '
adverse effects associated with potential changes in
surface water quality and quantity. Reductions in I
surface and near surface flow in Pinto Creek and j
Haunted Canyon would be mitigated by augmenting j
flow from the well field or other sources (Cedar Creek j
Associates, Inc. 1996a). Water quality degradation
would be mitigated by promptly identifying the
contaminant source, correcting the release source,
and implementing remedial measures as necessary.
As long as recommended monitoring and mitigation
measures are implemented, indirect impacts on
eagles feeding in Roosevelt Lake would not occur.
The U.S. Fish and Wildlife Service has concurred with
this conclusion with its issuance of a non-jeopardy
opinion in its Biological Opinion (Appendix F) on the
effects of the Carlota Copper Project.
Maricopa Tiger Beetle. The direct loss of stream
channel along Pinto Creek and Powers Gulch in the
project area would reduce potential foraging habitat
for adult Maricopa tiger beetles. This loss of foraging
habitat would be mitigated, to a large extent, by the
creation of new diversion channels that would carry
water during flow periods. The larval stages of this
species use undisturbed silty or sand substrate. The
predominant substrate along the portions of Pinto
Creek and Powers Gulch proposed for direct removal
is composed primarily of cobble, gravels, and/or
bedrock and would not provide suitable habitat for the
burrowing Maricopa tiger beetle larvae. Potential
reductions in surface flow along the intermittent Pinto
Creek stream channel 2,000 feet above and below
the Carlota/Cactus pit would result in minor
reductions in the extent of suitable foraging habitat for
Maricopa tiger beetle within the Pinto Creek drainage.
As indicated in Section 3. 5. 1.1, populations of
Maricopa tiger beetle are widespread and highly
mobile. Further, populations are able to maintain
themselves with low numbers and are well adapted
for survival and adjusting to environmental changes.
Local populations may disappear, but chances of
overall extinction of Maricopa tiger beetle are remote.
3-208
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
The Final Biological Assessment and Evaluation
(Cedar Creek Associates, Inc. 1994d) concluded that
project development may adversely affect a few adult
Maricopa tiger beetles and reduce the total extent of
foraging habitat, but would not likely adversely affect
populations of Maricopa tiger beetle within the Pinto
Creek drainage.
Arizona Toad and Lowland Leopard Frog. These
species were identified at several locations in and
near the project area along Pinto Creek (Cedar Creek
Associates, Inc. 1994b). In the project area, as well
as downstream, flowing portions of Pinto Creek,
Powers Gulch, West Powers Gulch, and Haunted
Canyon represent potential breeding habitat for these
species. Direct effects would result from siltation of
aquatic habitat located upstream and downstream of
the proposed diversions, and the loss of breeding
habitat as a result of pit and diversion construction.
Populations of Arizona toad downstream from the
project site may be indirectly affected by changes
in surface water quality, as a result of releases or
seepage from leach ponds or by changes in hydro-
logy in the drainage system from excavation activities
and drawdown from pumping the water supply wells.
Reductions in water quality in Pinto Creek have been
attributed to past mining activity in the drainage (see
Section 3.3.1 .2). Recent flooding and associated
leach solution and tailings releases into Pinto Creek
from the Pinto Valley Mine provide an example of a
large-scale release into the drainage. Although
mining-related water quality impacts have occurred in
the Pinto Creek drainage, the effects of these impacts
on the Pinto Creek populations of Arizona toad and
lowland leopard frog are unknown. The documented
presence of young and breeding adult Arizona toads
and lowland leopard frogs in downstream portions of
Pinto Creek in 1993 indicates that these species have
been able to survive and persist in the drainage in
spite of past flood flows and mine-related
perturbations.
As indicated in Section 3.3.4 and 3.5.4, numerous
monitoring and mitigation measures are proposed to
avoid potential impacts and to reduce or alleviate
adverse effects associated with potential changes in
surface water quality and quantity. Reductions in
surface and near surface flow in Pinto Creek and
Haunted Canyon would be mitigated by augmenting
flow from the well field or other sources (Cedar Creek
Associates, Inc. 1996a). Water quality degradation
would be mitigated by promptly identifying the
contaminant source, correcting the release source,
and implementing remedial measures as necessary.
Therefore, the Final Biological Assessment and
Evaluation prepared for this project (Cedar Creek
Associates, Inc. 1994d) concluded that, as long as
recommended monitoring and mitigation measures
are implemented, water quality and quantity impacts
in Pinto Creek and Haunted Canyon should be
minimized. Impacts to Arizona toad and lowland
leopard frog would result primarily from minor
reductions of suitable breeding habitat along Pinto
Creek within the project area, but project
development is not likely to adversely affect
populations of these species in Haunted Canyon or in
the downstream portions of Pinto Creek.
Common Black-hawk. Observations of the common
black-hawk in 1992 and 1993 indicated that this
species probably forages along Pinto Creek. Potential
nesting habitat occurs along Pinto Creek; however,
no nests or nesting activity were observed. This
species would not be directly affected by the pro-
posed activity.
The elimination of the riparian type by the proposed
action may indirectly affect the common black-
hawk by reducing the foraging area for individuals
and reducing prey. Indirect effects could also
occur from a reduction of baseflows in Haunted
Canyon or Pinto Creek, or from any increase in
the presence of toxic substances in the common
black-hawk’s prey base (aquatic and semi-aquatic
species).
As indicated for Arizona toad and lowland leopard
frog, numerous monitoring and mitigation measures
are proposed to avoid potential impacts and to reduce
or alleviate adverse effects associated with potential
changes in surface water quality and quantity. These
same measures would also limit the risk of adverse
effects to potential common black-hawk nesting and
foraging habitat. Impacts to common black-hawk
would result primarily from minor reductions of
suitable foraging habitat within the project area.
Therefore, the Final Biological Assessment and
Evaluation (Cedar Creek Associates, Inc. 1994d)
Carlota Copper Project Final EIS
3-209
3.0 Affected Environment and Environmental Consequences - Biological Resources
concluded that the Carlota Copper Project may
impact individuals or habitat of common black-hawk,
but would not likely contribute to a trend toward
federal listing or cause a loss of viability to the
population or species.
Yellow-billed Cuckoo. The yellow-billed cuckoo was
not found in the project area. This species would not
be directly affected by any proposed activities.
Observations of yellow-billed cuckoo were recorded
in riparian habitat along Pinto Creek downstream from
the project area. Yellow-billed cuckoo prefer riparian
habitats with dense shrub understory. Riparian
habitat in downstream portions of Pinto Creek and in
Haunted Canyon between Powers Gulch and Pinto
Creek could be indirectly affected
by water withdrawals associated with well field
development and pumping. A reduction in surface
and near surface flows would increase the aridity
of the existing stream channels and riparian habitat.
Reductions in water flow could increase mortality
and decrease successful germination and establish-
ment of woody riparian species. However, as long
as historic flow regimes are maintained in lower
Pinto Creek and Haunted Canyon, project develop-
ment would not have any direct, indirect, or cumu-
lative effect on suitable riparian habitat or populations
of yellow-billed cuckoo in Haunted Canyon or
downstream portions of Pinto Creek (Cedar Creek
Associates, Inc. 1994d).
Loggerhead Shrike. Concerns for declining numbers
of this species are associated primarily with
populations in the midwestern and northeastern
United States. The loggerhead shrike is fairly
common throughout western portions of its range,
including Arizona. Dry-slope desert brush and
juniper/grassland communities represent suitable
habitat for this species within the project area.
Several observations of loggerhead shrike were
recorded in dry-slope desert brush habitat south of
Grizzly Mountain near the proposed Main mine rock
disposal area.
Approximately 488 and 118 acres of dry-slope desert
brush and juniper/grassland, respectively, would be
lost or disturbed by project implementation. Within the
Pinto Creek drainage basin, this would result in a
relatively minor reduction of suitable habitat. Suitable
habitat is not limited in this region; therefore, minor
reductions in habitat may affect a few individual birds,
but would not adversely affect regional populations
(Cedar Creek Associates, Inc. 1994d).
Acid Deposition and Ozone Analysis for Terrestrial
Biota. An evaluation was conducted to estimate
the potential for the Carlota Copper Project's air
emissions to affect terrestrial resources within
the Superstition and Sierra Ancha Wilderness areas,
the Tonto National Monument, and the Carlota
Copper Project area, including impacts to the Arizona
hedgehog cactus. This evaluation is presented in
Appendix D, Acid Deposition and Ozone Analysis,
of this EIS. One of the main conclusions of this
analysis was that no adverse effects to populations
of the Arizona hedgehog cactus would be associated
with air emissions from the Carlota Copper Project.
Aquatic Resources
The evaluation criteria for assessing impacts of the
proposed action or the alternatives on aquatic
resources are listed below.
• Acres of aquatic habitat loss or degradation
• Effects of changes in water quality parameters on
aquatic species (bioaccumulation)
• Impacts to aquatic habitat during critical months
of use caused by temporarily increased
sedimentation
• Number of threatened, endangered, and sensitive
aquatic species potentially affected by the project
• Amount of habitat suitable for the recovery of
extirpated species that may be affected by project
activities
• Indirect air quality impacts to aquatic biota from
chemicals or particulates
• Risk of impacts to aquatic species from
accidental releases of chemicals
The primary potential impacts to aquatic resources
would include habitat loss from two open-channel
diversions, potential flow alterations in the Pinto
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Biological Resources
Creek drainage from pit dewatering, potential flow
reductions in Haunted Canyon and Pinto Creek from
water supply well pumping, temporarily increased
sedimentation from construction activities, and
accidental releases of chemicals to the Pinto Creek
watershed.
Construction of two diversion channels, one in Pinto
Creek and one in Powers Gulch, would result in the
loss of existing stream habitat. In Pinto Creek, the
length of the diversion channel would be approx-
imately 5,250 feet, which would result in the loss of
approximately 5,400 feet of existing Pinto Creek
stream channel. Site 2 of the habitat mapping in
Pinto Creek and Site 6 in Powers Gulch were
located within the reaches that would be affected.
The average width of Pinto Creek is 10 feet within
the affected reach, the total habitat lost would be
approximately 1.24 acres. The diversion channel in
Powers Gulch would be approximately 7,900 feet
long, resulting in a loss of existing stream channel of
approximately 7,300 feet. The average width in
Powers Gulch was approximately 5 feet. This equates
to an area of approximately 0.84 acre. Based on
habitat characteristics summarized in Table 3-57, the
habitat loss at Site 2 in Pinto Creek is composed of
approximately 2 percent pool, 64 percent riffle, and 34
percent glide habitat types. The average pool residual
depth is 2.28 feet. Dominant substrate at the fish
sample reach in Site 2 is composed of 50 percent
boulder and 50 percent sand in the pools and 60
percent rubble and 20 percent gravel in the riffles. In
Powers Gulch, habitat loss is composed of 9 percent
pool, 86 percent riffle, and 5 percent glide. The
average pool residual depth is 3.32 feet in Powers
Gulch.
Fish sampling at Site 2 in Pinto Creek and Site 6 in
Powers Gulch (Miller & Associates 1995) identified
fish species that would be affected by the removal of
natural stream habitat. Fish species collected at Site
2 included the green sunfish, longfin dace, and
mosquito fish. The longfin dace is the only special
status fish species (Forest Service sensitive) in the
project area. Dewatering, habitat modification, and
habitat loss would cause a loss of populations for
these species. It is not possible to quantify the
number of fish that would be affected by project
actions. Although fish were not observed in 1993,
Powers Gulch is used occasionally as fish ranges
fluctuate. This may have been the case in November
1992 when longfin dace were reported in Powers
Gulch. Dewatering of the Carlota/Cactus pit could
potentially affect the intermittent stream upstream and
downstream of the pit (see Section 3.2.3. 1 for
discussion). If this occurs, a reduction in fish and
aquatic habitat would likely occur.
Effects on downstream areas include potential
changes in water quality and quantity, both of
which could impact the longfin dace and desert
sucker. Reproducing populations of the desert
sucker are found in Haunted Canyon and Pinto
Creek downstream of the main portion of the project
area, but within the well field area. Decreases in
surface water quality and quantity in this area
could cause reductions in the desert sucker and
longfin dace populations in Haunted Canyon and
Pinto Creek (see Section 3.3.2, Water Resources -
Environmental Consequences, for a discussion of the
anticipated impacts to the quality and quantity of
these streams).
Potential water quality changes also could occur in
adjacent receiving streams because of surface water
and ground water runoff from the disposal sites. The
types of water quality changes include possible
increases in metal concentrations and reduced pH.
However, the duration of these water quality changes
would be limited to the periods of high runoff.
Although elevated levels of metals and low pH can
cause potential reductions in biotic diversity and
density through direct toxicity and bioaccumulation of
metals in tissues, the expected short duration of
runoff events would likely minimize these types of
changes.
The pit lake that would form after mine closure could
potentially impact aquatic resources. The lake would
be accessible to aquatic macroinvertebrates and
would have suitable water quality for survival. The
lake likely would not be managed for fish species
because of access and safety concerns; however, it
is possible that unauthorized stocking of non-native
species could occur. Since the final pit water surface
elevation would be approximately 135 feet below the
Pinto Creek stream elevation and the stream and pit
lake would not be interconnected, downstream
escapement of non-native species would not be
expected to occur.
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Sedimentation impacts resulting from construction
activities would affect the aquatic resources in
localized sections of Pinto Creek, Powers Gulch, and
Haunted Canyon on a temporary basis. Sedimen-
tation would occur as a result of surface disturbance
to soil in the mine areas and along the road corridors.
One intermittent stream section in Pinto Creek would
be crossed by the main access road, while the Eder
access road would cross one intermittent section in
Powers Gulch. There would be impacts to aquatic
resources associated with increased sedimentation
during construction and operation of the well field
access road along the west side of Pinto Creek. The
well field access road would cross Haunted Canyon
near the TW-1 well site with an unimproved crossing.
Small ephemeral stream sections also would be
crossed by the main access road and the haul roads.
Sedimentation increases would be minimized by
implementation of BMPs by Carlota.
The effects of suspended solids and sedimentation
on aquatic biota are well documented. Silted
substrates reduce areas of attachment and support
less diverse biotic communities than clean gravel and
rubble substrates (Tarzwell 1973; Westlake 1975).
Sedimentation of pools and riffles can result in
destruction of permanent and refuge habitats
important in maintaining biota during drought
conditions (Lewis 1977). Increased suspended solids
can also reduce survival either through reduction in
spawning success (Peters 1965) or by increasing
susceptibility to disease (Herbert and Richards 1963).
Lewis (1977) found that high suspended solids had
two effects on the heavy metal content in Pinto
Creek. First, the suspended solids adsorbed heavy
metals in the water column, thereby reducing soluble
metals. Second, a buildup of complexed insoluble
metallic compounds in the sediments resulted from
the settling of the metal-enriched suspended solids.
The effects of these sedimentation changes were to
bind potentially toxic heavy metals and to serve as
the major source of metals for the food chain.
Although heavy metals are known to adsorb to
sediments, there are several processes that release
contaminants bound in sediments (Reynoldson
1987), increasing the bioavailability of these toxicants.
Some aquatic organisms could eventually be re-
established in affected areas after sediments were
removed by a high flow event that would scour the
stream channel. As discussed in Section 3.3.2 (Water
Resources - Environmental Consequences), long-
term sedimentation effects on the watersheds within
the project area would be considered minor with the
implementation of BMPs by Carlota.
Pinto Creek and Powers Gulch are intermittent
streams in the area proposed for diversion channels.
The very nature of intermittent streams makes them
an unstable environment for fish and invertebrates.
Most specimens of fish and invertebrates collected in
the area proposed for the diversions are
representative of species that directly reflect the
unstable nature of these streams. These species are
often referred to by biologists as “r-selected” species.
They are defined by several qualities, among which is
the ability to quickly colonize and establish
populations in unstable environments. The longfin
dace is a good example of an “r-selected” species
that occurs in Pinto Creek. Longfin dace can be
sexually mature within 1 year after hatching and are
fractional spawners, which have an extended
breeding season that can begin in January and run
through November (Lewis 1978a). Grimm (1988)
determined that the longfin dace is a common and
abundant opportunistic omnivore that can change its
diet depending on food availability. Historical data
provided from studies on Pinto Creek (Lewis 1977;
USDA Forest Service 1992a; Miller & Associates
1 994) suggest that the macroinvertebrate
communities vary considerably and are influenced by
heavy metal toxicity, low dissolved oxygen levels, and
the compounding effects of seasonal and annual
events (e.g., flooding, droughts, etc.). Because the
existing conditions in Powers Gulch and Pinto Creek
support aquatic communities that are moderately
resilient, it is likely that short-term sedimentation
impacts from the Carlota Copper Project would have
minimal effects on aquatic biota. Additionally,
Fairchild et al. (1987) determined that short-term
exposure to sediment had no significant effect on
benthic invertebrate community dynamics.
The potential exists for impacts on aquatic biota from
accidental discharges of heavy metals into Powers
Gulch and Pinto Creek. The level of impact would
depend on the magnitude, duration, and timing of the
spill. The discharge could be continuous and in
relatively low volumes, or it could produce a large spill
of polluted water, which vyould travel downstream
from a leach pad or from high runoff following heavy
rainfall (Lewis 1977). The recent flooding and
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3.0 Affected Environment and Environmental Consequences - Biological Resources
associated leach solution and tailings spills into
Pinto Creek from the Pinto Valley Mine in the spring
of 1 993 are an example of the latter scenario (see
Section 3.5.1. 2). Resulting impacts from a toxic
discharge of heavy metals into Pinto Creek or
Powers Gulch would include altered chemical and
physical quality of the stream and an associated
reduction in biotic diversity and density. The adverse
effects of heavy metals in the aquatic environment
have received considerable attention pertaining to
fish (Roch et al. 1982, Dallingerand Kautzky 1985,
Giles 1988) and macroinvertebrates (Smock 1983,
Clements 1994, Rees 1994). Lewis (1978b) provides
information on the toxicity of various heavy metals
to the longfin dace. The extent to which heavy
metals are affecting an aquatic system can be
ascertained through biomonitoring (Winner et al.
1980).
Waters of the U.S. The Pinto Creek diversion
around the Carlota/Cactus pit would result in the
loss of 7.28 acres of waters of the U.S., which
includes 0.34 acre of jurisdictional wetlands. The
Powers Gulch diversion around the heap-leach
pad would result in the loss of 2.18 acres of waters
of the U.S. and no losses of jurisdictional wetlands.
A total of 9.46 acres of waters of the U.S., which
includes 0.34 acre of wetlands, would be lost due
to the proposed action; these areas are mapped
on Figure 3-32.
The COE will require full mitigation for these wetland
and waters of the U.S. losses as one aspect of the
Section 404 permitting process. As a result, the
Carlota Copper Company, in cooperation with the
COE and the Forest Service, has developed the
Wetland and Waters of the U.S. Compensatory
Mitigation Plan for the Carlota Copper Project
(Aquatic and Wetland Consultants, Inc. 1996a). The
plan must be approved by the COE before any
impacts to these resources can occur (see Section
3.5.4.2).
Special Status Aquatic Species. The Gila
topminnow was not identified within the overall Pinto
Creek drainage; therefore, there would be no impacts
to this species.
The potential impacts to the longfin dace and desert
sucker are discussed in the preceding section.
Acid Deposition and Ozone Analysis for Aquatic
Biota. An evaluation was conducted to estimate the
potential for the proposed project's air emissions to
affect aquatic resources within the Superstition and
Sierra Ancha Wilderness areas, the Tonto National
Monument, and the project area. This evaluation is
presented in Appendix D, Acid Deposition and Ozone
Analysis, of this EIS. Based on this analysis, no
impact to aquatic resources is expected from acid
deposition.
3.S.2.2 Alternatives
Terrestrial Resources
The following sections describe the terrestrial biology
impacts of the project alternatives. Impacts not
specifically discussed would be similar to those
discussed for the proposed action.
Mine Rock Disposal Alternatives.
Alternative Mine Rock Disposal Sites. Impacts on
vegetation and wildlife species associated with the
alternative mine rock disposal sites would be greater
than the proposed action. An additional 18 acres and
26 acres would be affected for chaparral and dry-
slope desert brush habitats, respectively. This could
result in the loss of 44 acres of upland habitat for a
variety of wildlife species, including deer and collared
peccary.
Additional sedimentation would result from hauling
the mine rock along roads near the streams. Initial
construction of the disposal sites would also con-
tribute sediment to the downstream drainageways.
Depending on the time of year and the level of
instream flow, sedimentation would either be localized
or carried farther downstream. Potential water quality
changes would probably be similar to those expected
in the proposed action.
Additional Backfill of the Carlota/Cactus Pit. The
additional backfill of the Carlota/Cactus pit would
provide for the reduction of long-term impacts to
vegetation by increasing the reclaimed area of the pit
and the Main mine rock area. Under this alternative,
approximately 153 additional acres associated with
these project components would be reclaimed and
revegetated.
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3.0 Affected Environment and Environmental Consequences - Biological Resources
During mining operations, potential sedimentation
impacts to sensitive amphibian species (Arizona toad
and lowland leopard frog) would be similar to the
impacts expected as a result of the proposed action.
During postclosure, however, sedimentation impacts
from this alternative would be less than for the
proposed action. Sedimentation would be reduced
because the additional backfill would decrease the
elevation of the Main mine rock area by 300 feet.
Such a reduction in elevation would reduce potential
erosion and subsequent input of fine sediments into
downstream drainageways.
Backfilling of the Carlota/Cactus pit and the reduction
of the Main mine rock area would provide an oppor-
tunity for revegetation to offset the loss of upland
habitat important to the loggerhead shrike.
Additional Backfill of the Eder South Pit. Excavation of
the Eder South pit and Eder mine rock area would
impact approximately 140 acres of upland habitat.
The additional backfill of the Eder South pit and the
reclamation and revegetation of the Eder mine rock
area would partially offset impacts to vegetation types
through the reclamation of approximately 49 addi-
tional acres. Reclamation of the areas where the mine
rock is removed would reduce the overall permanent
loss of upland habitat.
During mining operations, potential sedimentation
impacts to sensitive amphibian species (lowland
leopard frog and Arizona toad) would be similar to
impacts expected as a result of the proposed action.
During postclosure, however, sedimentation impacts
from this alternative would be less than for the
proposed action. Sedimentation would be reduced
because the Eder mine rock area would be removed
and reclaimed, thereby nearly eliminating the
accelerated erosion potential from that area.
Arizona Hedgehog Cactus. Most of the Arizona
hedgehog cactus that would be impacted by the
project are currently located in the proposed Eder
complex. Excavation of the Eder South pit could
potentially result in the loss of 6.9 acres of habitat that
supports approximately 177 individuals. The backfill
alternative for the Eder South pit could partially offset
these impacts. In addition, this alternative could
provide an opportunity to offset long-term losses in
suitable unoccupied habitat through remediation and
enhancement.
Loggerhead Shrike. Backfilling the Eder South pit and
reclamation of the Eder mine rock area would provide
an opportunity for revegetation to offset the loss of
upland habitat important to this species.
Eder Side-Hill Leach Pad Alternative. Direct
impacts of this alternative would be the disturbance of
approximately 495 acres of upland habitat and
associated wildlife species associated with the leach
pad and Eder mine rock area. Of primary concern is
the potential for accidental releases of leach solution
related to the potential instability of this alternative.
Terrestrial biological resources potentially impacted
by this alternative are discussed below.
Riparian Habitat. The best example of this habitat on
the project area occurs at the confluence of Powers
Gulch and Haunted Canyon downstream from the
proposed embankment and retention pond.
Implementation of the side-hill leach pad alternative
would increase potential for accidental releases of
leach solution into Powers Gulch and downstream.
Arizona Hedgehog Cactus. Implementation of this
alternative would require relocating the Eder mine
rock area. As stated above, the exact location and
extent of this mine rock area is not specifically
described. It would be located immediately south of
the Eder South pit. A worst case estimation might be
the loss of approximately 120 individuals and 20
acres of occupied habitat. The heap-leach pads
would also impact a few satellite individuals and
additional acreage of occupied habitat.
Arizona Toad and Lowland Leopard Frog. These
amphibian species would be vulnerable to habitat
degradation from accidental releases of toxic
chemicals into the surface or subsurface water.
Implementation of the side-hill leach pad alternative
would increase potential for accidental releases of
leach solution into Powers Gulch and downstream.
This alternative could result in moderate adverse
indirect effects to these species.
Common Black-hawk. This alternative could
potentially affect amphibian food sources and riparian
habitat used by the common black-hawk, if there
were a failure of the side-hill leach pad facility. A
reduction in available foraging habitat and prey
species might impact individuals of common black-
hawk, but would not likely contribute to a trend toward
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3.0 Affected Environment and Environmental Consequences - Biological Resources
federal listing or cause a loss of viability to the
population or species.
Water Supply Alternative. Implementation of the
low-quality water pipeline alternative would result in
direct and indirect effects similar to those identified in
the proposed action. Additional vegetation may need
to be cleared for this alternative within the project
area, depending on the actual alignment of the
pipeline. Vegetation in much of the area would
include chaparral, dry slope desert brush, and juniper
grassland. No populations of special status species
are likely to occur in these areas, although specific
sun/eys have not been conducted. Potential water
quality effects from accidental spills or leaks of low-
quality water could have indirect effects on wildlife
and vegetation downstream. Lowland leopard frogs
and Arizona toads would be especially vulnerable to
changes in water quality. Other wildlife species
dependent on the streamflow for watering or breeding
sites also may be affected.
The advantage to the alternative water source is
that less water would need to be extracted from the
well field during baseflow conditions in Pinto Creek/
Haunted Canyon. Therefore, impacts to riparian
vegetation in this area may be reduced. Impacts
would not be eliminated, however, since water would
still be pumped from the well field, and the alluvial
water table is partially connected to the aquifer below.
Alternative Water Supply Well Field Access
Roads. Access to the well field below the confluence
of Powers Gulch and Haunted Canyon would be
provided by one of two alternative routes. Alternative
A would require improving 1.9 miles along an existing,
mostly reclaimed road in the bottom of Pinto Creek.
Alternative B would require clearing 1 .2 miles of
upland vegetation and would not enter the riparian
vegetation along the portion of Pinto Creek between
the Iron Bridge and Powers Gulch.
Improving the old road in the bottom of Pinto Creek
would involve clearing some vegetation that has
begun to recolonize the area. This road would require
frequent maintenance after flood events. Assuming a
20-foot corridor of disturbance, approximately 4 acres
of previously disturbed riparian vegetation would be
impacted by Alternative A.
Assuming a 20-foot corridor of disturbance, con-
struction of Alternative B would involve clearing
approximately 7 acres roughly equally divided be-
tween interior chaparral and dry-slope desert brush
vegetation. The eastern portion of this road would
travel along the existing road identified in the
proposed action, which is located on the bench above
the riparian area.
Alternative A would result in the improvement of an
existing road along the Pinto Creek riparian corridor.
Aside from the loss of 4 acres of previously disturbed
riparian vegetation, project-related use of this road
would result in a minor incremental increase in human
disturbance impacts to wildlife species along this
portion of the riparian corridor. The road/trail has
previously been used, and would continue to be
available, for recreational access to the area.
Alternative B would impact fewer acres of the more
abundant upland habitats.
Long-term effects of disturbance to vegetation from
either alternative would be minimized by revegetation
efforts to be undertaken by Carlota.
Impacts to special status species from the alternative
access roads are discussed below.
Arizona Hedgehog Cactus. Alternatives A and B were
not specifically surveyed for Arizona hedgehog.
Alternative A is within the floodplain of Pinto Creek,
which is not potential habitat for the species. The
effect of Alternative B is unknown, although the actual
alignment could likely be adjusted to avoid individual
cacti if they are present in the area.
Arizona Toad and Lowland Leopard Frog. Preferred
stream bank habitat for these species is character-
ized by small rocks and cobble, while lowland leopard
frogs prefer sandy to muddy banks with at least some
emergent vegetation. With Alternative A, the only
areas where the road could affect potential breeding
habitat for the lowland leopard frog and Arizona toad
would be at the three stream crossings. Habitat at the
crossings consists primarily of non-vegetated stream
channel with a substrate of small rocks and cobble.
These crossing sites represent marginal habitat for
lowland leopard frog but could provide suitable
breeding habitat for Arizona toad when surface water
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3.0 Affected Environment and Environmental Consequences - Biological Resources
is present. However, the stream crossings would be
located at points where crossings for the existing road
currently exist, and the potential for construction and
operation of the Alternative A road to result in adverse
impacts to Arizona toad breeding habitat would be
relatively minor. Maintenance and operation of the
well field would result in a slight increase in existing
vehicular traffic on the Alternative A road, which could
increase the risk of toad mortalities during their
season of peak activity (April through August).
However, the risk of toad road-kills would be
increased only slightly over the current potential for
road-kills associated with existing vehicle use of the
road.
Erosion from road construction and operation could
result in indirect impacts to amphibian breeding sites
through sedimentation of aquatic habitats in Pinto
Creek and Haunted Canyon, but this potential indirect
impact would be minimized by the implementation of
BMPs by Carlota.
The Alternative B road would be constructed
outside of the Pinto Creek and Haunted Canyon
riparian zones and would not result in any direct
impacts to potential lowland leopard frog or Arizona
toad breeding habitat. There would be a slight risk
of indirect impacts from sedimentation, but
Carlota would minimize this risk by implementing
BMPs.
Common Black-Hawk. No direct or indirect effects
would occur with Alternative B for the common
black-hawk. Alternative A would not result in a
direct effect to this species but could have relatively
minor indirect effects. As indicated previously.
Alternative A would impact 4 acres of riparian
habitat and could result in direct impacts to Arizona
toad through habitat loss (at stream crossings) and
road mortalities. Since common black-hawks use
riparian habitats for foraging, and amphibians
represent a principal prey item, these impacts
could reduce the extent of foraging habitat and the
available prey base for common black-hawk.
However, the overall adverse effect on common
black-hawk use of Haunted Canyon and Pinto Creek
riparian corridors would be negligible since potential
nesting habitat would not be affected, and projected
adverse effects on Arizona toad populations would be
relatively minor (see preceding Arizona toad
discussion).
No Action Alternative. Under the no action
alternative, the terrestrial biological conditions of the
project area would remain in their current condition,
allowing for natural ecological changes. The adverse
direct and indirect impacts to terrestrial biological
resources associated with the proposed action and
alternatives would not occur.
Aquatic Resources
The following sections describe the impacts of the
project alternatives on aquatic resources. Impacts not
specifically discussed would be similar to those
described for the proposed action.
Mine Rock Disposal Alternatives.
Alternative Mine Hock Disposal Sites. Impacts from
sedimentation on the longfin dace and desert sucker
would be greater for this alternative than for the
proposed action. Additional sedimentation would
result from hauling the mine rock along roads near
the streams. Initial construction of the disposal sites
would also contribute sediment to the downstream
drainages. The relative changes in sediment levels in
the adjacent streams would depend on the time of the
year. During periods of high runoff, sediment reaching
the streams would be carried farther downstream and
could be mixed with high background levels of
suspended solids. In contrast, increased sedimen-
tation would be more localized during the low runoff
periods, and background suspended solid
concentrations would be relatively low.
Water quality impacts could increase as a result of
the movement of existing poor quality water through
the Cactus South location, thereby increasing the
potential to affect aquatic biota.
Additional Backfill of the Carlota/Cactus Pit. During
mining operations, sedimentation impacts on the
longfin dace and desert sucker would be similar to
impacts expected as a result of the proposed action.
During postclosure, however, sedimentation impacts
from this alternative would be less than for the
proposed action; sedimentation would be reduced
because the additional backfill would decrease the
elevation of the Main mine rock area by 300 feet.
Such a reduction in elevation would reduce potential
erosion and subsequent input of fine sediments into
downstream drainages.
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Additional Backfill of the Eder South Pit. During
mining operations, sedimentation impacts on the
longfin dace and desert sucker would be similar to
impacts expected as a result of the proposed action.
During postclosure, however, sedimentation impacts
from this alternative would be less than for the
proposed action. Sedimentation would be reduced
because the Eder mine rock area would be removed
and reclaimed, thereby nearly eliminating the
accelerated erosion potential from that area.
Eder Side-Hill Leach Pad Alternative. This
alternative leach pad location would place the pads
outside the main channel of Powers Gulch, which
would not result in a loss of Powers Gulch aquatic
habitat. Of primary concern is the potential for
accidental releases of leach solution related to the
potential instability of this alternative. Measures would
be in place to reduce the potential for a spill of
material into Powers Gulch. During construction and
operation, sedimentation and erosion would be similar
to the proposed action. Sedimentation impacts would
occur in localized areas of Powers Gulch and Pinto
Creek on a temporary basis. Because of increased
acreage and slopes, erosion and sedimentation would
increase during postclosure.
As part of this alternative, the PLS ponds would be
located within the side-hill leach pads behind a water-
retention embankment. Leaks or spills would result in
degraded water quality. However, the probability of
containment failure for this alternative is greater than
for the proposed action. The magnitude and duration
of this containment failure would depend upon the
volume of material leaked or spilled, the time of year,
and the effectiveness of the containment and control
effort.
Water Supply Alternative. The impacts of using low-
quality water on water quality and biological
resources would depend upon the proper storage and
containment of the low-quality water within the
Carlota Copper Project area. If a spill or leak occurred
in the pond and the low-quality water reached adja-
cent streams, water quality would be degraded. The
magnitude and duration of the impact would depend
upon the volume spilled or leaked, location of the spill
or leak, time of year, and effectiveness of the
containment and control effort. A pipeline would be
constructed to deliver the water for these alternatives.
Temporary sediment increases would occur during
pipeline construction at stream crossings. Potential
leaks or spills also could occur during the transport of
water through the pipeline. Proper monitoring and
maintenance of the pipeline operation would minimize
the risk of a pipeline spill or leak. Using low-quality
water would reduce the requirement for pumping
ground water; therefore, the potential for reducing
surface water flow and associated impacts to aquatic
biota would be reduced.
Alternative Water Supply Well Field Access
Roads. Two alternative routes are being considered
to access the water supply well field from the north.
Alternative A would involve upgrading the existing
access road located within the Pinto Creek channel
for approximately 1 .9 miles. Alternative B would
involve constructing approximately 1 .2 miles of new
road and using 2.6 miles of existing roads, but would
not involve entering the riparian vegetation along
Pinto Creek.
Both alternatives would result in an initial increase in
sediment levels during the construction/upgrading of
the roads. However, because of future flood events,
the road in the Pinto Creek floodplain (Alternative A)
would require much more maintenance than would
the upland road in Alternative B. The required
maintenance actions under Alternative A would result
in higher, long-term sedimentation impacts to the
longfin dace and desert sucker than would the
maintenance of the upland road in Alternative B.
Improving the old road in the bottom of Pinto Creek
(Alternative A) would involve clearing some riparian
vegetation that has begun to recolonize the area. It
would also preclude future recolonization of the road
corridor by riparian vegetation during the life of the
project. This would contribute to reduced stream bank
stability, thereby reducing the quality of the habitat for
the longfin dace and desert sucker. In addition, the
stability of the stream banks would be reduced in the
vicinity of each road crossing. Alternative B would
result in no loss of riparian vegetation and no reduc-
tion of bank stability.
In summary. Alternative B would result in only minor,
indirect impacts to the longfin dace and desert
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3.0 Affected Environment and Environmental Consequences - Biological Resources
sucker, while Alternative A would result in moderate,
adverse direct and indirect impacts to these species.
No Action Alternative. Under the no action
alternative, the aquatic biological conditions of the
project area would remain in their current condition
allowing for natural ecological changes. The impacts
described for the proposed action and alternatives
would not occur.
3.5.3 Cumulative Impacts
This section describes the cumulative impacts of the
proposed action and interrelated projects on
terrestrial and aquatic resources. For most terrestrial
resources, except for bald eagle and Arizona
hedgehog cactus, the cumulative effects evaluation
area consisted of the entire Pinto Creek drainage
basin. For bald eagle, nesting and foraging use of
Roosevelt Lake was also a consideration. For Arizona
hedgehog cactus, the entire known population area
was evaluated for cumulative effects. The cumulative
effects area for aquatic resources consisted of Pinto
Creek within and downstream of the project area until
surface flow disappears near Roosevelt Lake, as well
as flowing portions of Haunted Canyon downstream
of the project area.
Nine categories of regional interrelated actions have
been identified and are considered in the cumulative
impact analysis. These regional interrelated actions
include mining projects, grazing, energy and
transmission systems, Pinto Creek Wild/Scenic River
designation, private land development, highway
development, land exchange, dam modifications, and
development of recreational facilities at Roosevelt
Lake.
Past and projected mining, grazing, power line
construction, and roadway construction in the region
have impacted vegetation communities and are
projected to continue. The amount of these vegetation
communities in the region to be impacted by these
interrelated activities is impossible to determine at this
time, but the rate of habitat loss is expected to be
comparable to what has occurred in the past.
Interrelated mining projects that are located in the
Pinto Creek drainage include the Old Carlota Mine,
Pinto Valley Mine, and placer mining. Although the
Old Carlota Mine has subsurface disturbance, there
are no extensive tailings ponds or other types of
disturbance that would contribute to degraded
water quality in the Pinto Creek drainage. However,
as ground water flows through the mined subsurface
areas, water quality may be affected. The Pinto
Valley Mine is an existing mining operation that
has surface and subsurface disturbance in the
Pinto Creek drainage. During periods of high
runoff, spills or leaks from the Pinto Valley Mine
could combine with effects from the proposed
Carlota Copper Project. While spills from the Pinto
Valley Mine are possible, they are less likely than
past spills because of recent redesign efforts by
BHP Copper. The existing placer mining that
occurs in the Pinto Creek drainage is limited to
small-scale operations. These operations could
contribute slight increases in sediment levels, but
the relatively small size of these activities would
suggest minor additional effects on water quality
in the drainage.
Past, present, and reasonably foreseeable future
actions have the potential to affect riparian and
aquatic habitat, depending on the location. The
impacts may be adverse, in the case of disturbance,
or beneficial when riparian and aquatic habitat
restoration occurs.
Riparian loss associated with the dam modifications
has been mitigated and has resulted in improvements
to riparian habitat. Recent Forest Service range
management plans are generally designed to improve
riparian and aquatic habitat; however, grazing may
continue to degrade the habitat, depending on the
habitat location within the allotments. Land
exchanges are often structured to ensure the
protection of biological resources, so land exchanges
likely to occur in the foreseeable future are unlikely to
adversely impact biological resources. The
Wild/Scenic River program has the potential to benefit
riparian and aquatic habitat in the Pinto Creek
drainage system. Any activities that would reduce the
quantity or affect the quality of water in the Pinto
Creek watershed could have deleterious effects on
the quality and extent of the natural riparian
vegetation and aquatic habitat. Similarly, the BOR
created the Tonto Creek Riparian Unit, which
converted existing year-long or seasonal grazing to
short duration, winter seasonal pastures. This activity
is being treated as an experimental mitigation, but the
scheme is an accepted management practice when
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the goal is to improve riparian and aquatic conditions
within grazing allotments.
Special status species that could be affected by
cumulative impacts from the proposed action and
interrelated actions include the Arizona hedgehog
cactus, Arizona toad, lowland leopard frog, common
black-hawk, yellow-billed cuckoo, loggerhead shrike,
longfin dace, and desert sucker. Where appropriate,
cumulative impacts for these species have been
addressed in the Final Biological Assessment and
Evaluation (Cedar Creek Associates, Inc. 1994d).
3.5.4 Monitoring and Mitigation Measures
As part of the proposed project, Carlota would
implement BADCT to minimize the potential for
seepage or spills from the heap-leach pad (Knight
Piesold 1995a). Carlota would also implement a Spill
Control and Hazardous Materials Management Plan
to detect, contain, and remediate leaks or spills from
project facilities (Carlota 1996a). Carlota would also
implement measures identified in the Biological
Monitoring & Mitigation Plan (Cedar Creek
Associates, 1996a). These mitigation and monitoring
measures are summarized in the remainder of this
section.
Measures to monitor and mitigate potential impacts to
ground water and surface water quantity and quality
are identified in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures. These water
resource measures are also designed to mitigate
potential adverse impacts to terrestrial and aquatic
resources.
Carlota’s proposed reclamation plan (see Section
2.1.9) is designed to restore vegetation and the
associated wildlife habitat on disturbed lands.
Supplemental mitigation for soils and reclamation is
identified in Section 3.4.4 of this EIS.
3.5.4.1 Terrestrial Resources
The monitoring and mitigation measures identified
below have been designed to reduce the overall
effects of the project on terrestrial biology resources.
Monitoring would be required to assess the severity
of impacts arising from project activities and to ensure
that mitigation efforts are meeting their objectives. In
those cases where impacts may extend beyond the
life of the project, postclosure mitigation measures
are designed to continue as appropriate. Specific
details of these mitigation measures are presented in
the Biological Monitoring & Mitigation Plan (Cedar
Creek Associates, Inc. 1996a). The Biological
Monitoring & Mitigation Plan details monitoring
measures to be implemented, threshold criteria (the
exceedance of which would trigger additional
mitigation), appropriate mitigation measures,
responsible parties, and success criteria. Establishing
success criteria ensures minimal or acceptable levels
of impact.
Monitoring
The following monitoring measures, as detailed
in the Biological Monitoring & Mitigation Plan, would
be necessary to determine the levels of effect
and results of mitigation to the Arizona hedgehog
cactus.
• Approximately 30 cacti would be identified that
would be expected to receive the greatest
sulfuric acid mist concentrations from the acid
tank house. Following initiation of the operation
of the tank house, these cacti, as well as a
control set of cacti, would be monitored on a
regular basis for injury to the plants. Should
injury be noted in comparison to the control set,
consultation with the Forest Service and/or
the U.S. Fish and Wildlife Service would be
reopened. The objective of this monitoring
would be to ensure that if the acid mist does
indeed prove to be detrimental, appropriate
actions can be undertaken to prevent further
loss.
• Those areas that are staked or fenced to protect
cacti from direct impact from mining activities
would be visually monitored on an annual basis to
ensure that the integrity of the protected area is
maintained. In addition, those individual plants
that are considered to be proximal enough to
planned activities to potentially be impacted by
blasting (200 feet from pits, 100 feet from roads)
would be monitored within 1 year of blasting to
determine if additional losses through indirect
impacts has occurred.
• In accordance with the reclamation test plan,
those Arizona hedgehog cacti in conflict with
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project facilities would be transplanted to test
plots and then monitored to determine the best
reproducible substrate that can be used in
reclamation.
Monitoring also would be necessary to detect residual
effects on riparian vegetation in the vicinity of and
immediately below the well field. Should adverse
changes occur, additional mitigation would need to
occur quickly to reverse the impacts. In order to
detect such changes, efforts intended to provide
information that would identify trends in riparian
habitat condition have been initiated prior to full-scale
operation of the wells. The following measures among
others, have been instituted and would be maintained
through the life of the project, as necessary;
• Changes in riparian vegetation and amphibian
populations would be monitored. Methods,
frequency, and data requirements have been
developed and are described in the Biological
Monitoring & Mitigation Plan. Monitoring of
amphibians would occur in conjunction with
aquatic species monitoring.
• Riparian vegetation sampling would be conducted
in accordance with the Biological Monitoring &
Mitigation Plan.
• Photographic documentation of the riparian
corridor would be collected from permanent
stations in the well field area.
Additional monitoring would be implemented to
ensure that no wildlife mortalities occur as a result of
exposure to contaminated water sources on the
heap-leach facility or in the plant PLS or raffinate
ponds. If any wildlife mortalities are detected on the
heap-leach facility or at the plant PLS and raffinate
ponds, the incidents would be promptly reported to
the Forest Service and the appropriate wildlife agency
(Arizona Game and Fish Department or U.S. Fish and
Wildlife Service). Mitigation or operational measures
would be developed in consultation with these
agencies to ensure that there would be no re-
occurrence of wildlife losses as a result of exposure
to contaminated water sources.
Mitigation
TB-1: Arizona Hedgehog Cactus Mitigation - Subject !
to the U.S. Fish and Wildlife Sen/ice Biological i
Opinion (included in Appendix F), the following !
measures have been identified to mitigate impacts to j
the Arizona hedgehog cactus and are fully described j
in the Biological Monitoring & Mitigation Plan.
• Facility sites and alignments (e.g., roads, build- j
ings, or power lines) have been reviewed for
relocation and have been redesigned, to the
extent possible, to avoid Arizona hedgehog
cactus plants.
• Clearing limits near occupied habitat would be
staked or fenced to protect plants from equipment
or project activities.
• In accordance with reclamation procedures
described in Section 3.4, Soils and Reclamation,
revegetation test plots would be established to
determine the best methodology for reestablish-
ing vegetative cover during reclamation of the
major features of the project. Where avoidance of
Arizona hedgehog cactus is not possible, cactus
plants would be transplanted into test plots
designed to determine optimum re-establishment
habitat for the species, the objective being to use
the plants and/or their progeny to reestablish the
species into the reclaimed mine area. A plan
covering the development and implementation of
these test sites has been developed prior to the
record of decision for the project and is presented
in the Biological Monitoring & Mitigation Plan. The
Forest Service would work with the U.S. Fish and
Wildlife Service to determine if there is a need by
researchers, botanical gardens, etc. for any
remaining Arizona hedgehog cacti that cannot be
avoided by the project and will not be needed for
' testing.
• Carlota has agreed to assist the Forest Service in
the permanent withdrawal from mineral entry of
selected parcels that support populations of
Arizona hedgehog cactus. One 186-acre parcel
would be within the project area. This process, in
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conjunction with the consen/ation plan (last
bulleted item below), would effectively protect
nearly 400 acres of occupied habitat, including
the taxon’s type locality.
• A grazing permit that includes Arizona hedgehog
cactus populations would be acquired, and non-
use would be initiated in the occupied habitat to
protect that particular parcel from one of the
minor threats to the species during operations
and reclamation.
• A conservation plan for the Arizona hedgehog
cactus has been developed in coordination with
the Tonto National Forest to identify several safe
areas for protecting the cactus over the long
term.
TB-2: In order to mitigate impacts associated with a
potential release from the heap-leach pad to
Roosevelt Lake on nesting pairs of bald eagles or
winter transient eagles feeding in Roosevelt Lake,
Carlota would implement the monitoring and
mitigation measures described in Section 3.3.4 to
reduce or alleviate adverse effects associated with
changes in surface water quality and quantity. The
contaminant source would be promptly identified, the
source of the release would be corrected, and
remedial measures would be implemented as
necessary.
TB-3: Riparian Mitigation - As identified in
Section 3.5.2, Environmental Consequences, 12.40
acres of riparian habitat would be directly impacted.
This equates to a net loss of 3.40 acres of riparian
public land in the Pinto Creek drainage under the
jurisdiction of the Tonto National Forest, 8.10 acres of
riparian private land in the Pinto Creek drainage for
which the COE has assumed jurisdiction, and 0.90
acre of riparian public land in the Powers Gulch
drainage under the jurisdiction of the Tonto National
Forest. Mitigation measures that would offset these
effects are summarized below and are fully described
in the Biological Monitoring & Mitigation Plan.
• A grazing permit would be acquired and grazing
non-use would be implemented during the project
life. Upon waiver back to the Forest Service at the
end of the project, continued protection of riparian
habitats would revert to the Forest Service and
would be accomplished through NEPA review.
Furthermore, the Powers Gulch pasture of the
Bellevue Allotment would be retired for the life of
the mine, at a minimum.
• An off-site riparian area (Arnett Creek) would be
protected from livestock grazing using protective
fencing.
• Subject to COE approval and in compliance
with the requirements of the CWA Section 404
permit, a mitigation plan has been developed
to improve/enhance riparian and aquatic habitats
in amounts and/or quality equal to or greater
than the area affected by the proposed project.
This mitigation would be implemented to establish
and enhance appropriate riparian and aquatic
habitats in the designed diversion structures
and is fully described in the CWA 404 permit (see
AB-3).
TB-4: Haunted Canyon Riparian Mitigation - A
complete baseline description and photo documen-
tation of the Haunted Canyon riparian area would be
developed prior to the initiation of well field pumping
as discussed in the Biological Monitoring & Mitigation
Plan. Monitoring and mitigation of alluvial water levels
in the vicinity of the well field are identified in Section
3.3.4, Water Resources - Monitoring and Mitigation
Measures. Although it is anticipated that streamflow
augmentation would also support the riparian
vegetation that exists in the well field area, there is
the potential that the relationship is more complex. In
this regard, additional monitoring specific to the
riparian vegetation would be initiated (see the
Biological Monitoring & Mitigation Plan). Should
monitoring indicate that riparian habitats in this area
are being negatively affected by the pumping,
measures, such as increased water augmentation
from the well field, as well as others proposed in the
Biological Mitigation & Monitoring Plan to alleviate
these impacts would be initiated. If established
measures are ineffective, additional mitigation would
be developed in consultation with the Forest Service.
TB-5: Bat Roost Mitigation - If bat roosts are identified
in disturbance areas during construction, Carlota
would work with the Forest Service to identify
abandoned mine adits or shafts on its property that
could be preserved as alternative roost sites for bat
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species. Grating devices or other means would be
used to allow bats to enter and exit the adits.
TB-6: Lesser long-nosed Bat Mitigation - Prior to
construction, native agaves would be transplanted
from areas of greatest density to similar densities in
appropriate habitat within the project area.
TB-7: In order to mitigate impacts to upland
vegetation and the associated wildlife habitat, Carlota
would implement a combination of (1) fencing of
mining areas and other key areas, (2) acquisition of
grazing permits and implementation of non-use during
the project life, (3) closure of certain project area
roads, and (4) maintenance of existing off-site water
developments.
3.5A.2 Aquatic Resources
Monitoring
Aquatic biology monitoring would be conducted to
detect possible impacts from water withdrawals and
upstream mining activity on aquatic resources,
particularly longfin dace and desert sucker
populations. Sampling would monitor possible
population changes, habitat changes, and the
effectiveness of mitigation measures. The specific
monitoring protocol and schedule should be
determined in consultation with the Forest Service,
the Arizona Game and Fish Department, and other
resource agency biologists.
Sites. According to the Biological Monitoring &
Mitigation Plan, fish and macroinvertebrate commu-
nities and aquatic habitat would be monitored at four
sites in Pinto Creek and two sites in Haunted Canyon.
The proposed Pinto Creek sites would be located
above the diversion (near water quality site PC-3),
within the proposed pit area (near water quality site
PC-4), immediately below the diversion and above
Miller Springs (PC-MS), and upstream of the Iron
Bridge (downstream of Haunted Canyon near water
quality site PC-7). After mining begins, a site would
be added to the new diversion channel at PC-4A to
replace the pit area station lost to mining. The
Haunted Canyon sites would be located near water
quality sites HC-4 and HC-2. An optional site would
be included near water quality site PC-10 only if it is
determined that an impact has occurred and data
from this site might be beneficial in assessing the
spatial extent of effects.
Fish Community and Macroinvertebrate
Monitoring. Quantitative sampling would be
conducted twice a year for macroinvertebrates and
once a year for fish prior to the onset of construction
and for 3 years after construction. Thereafter,
sampling frequency would be determined by pro-
fessional personnel implementing the monitoring
protocol (refer to page 66 in the Biological Monitoring
& Mitigation Plan for a description of the process to
be used in determining additional postconstruction
monitoring). This practice would effectively (1)
provide further baseline data regarding benthic
community structure and ecology before the onset of
construction, (2) monitor the effects of sedimentation
on the stream ecosystem during the construction
process, and (3) monitor impacts from mining,
including sedimentation and heavy metal toxicity
during the years that mining operations are
conducted. The detailed procedures for both fish and
macroinvertebrate sampling and the indices used to
describe aquatic conditions are described in the
Biological Monitoring & Mitigation Plan for the Carlota
Copper Project on the Tonto National Forest (Cedar
Creek 1996a). Fish sampling would consist of both
visual and active capture methods. Macroinvertebrate
sampling would be quantitative with replication at
each site.
The spring effort would focus on visual surveys to
document spawning activities. The fall sampling
would include electrofishing and seining to sample
fish communities and quantitative samples and
analysis of the macroinvertebrate community.
Sampling dates would coincide with major spawning
periods in spring and in the late fall after the summer
monsoon season.
Habitat Monitoring. Habitat at each site would be
measured and analyzed once during each fish and
macroinvertebrate survey in the fall.
Mitigation
The following mitigation measures have been
identified to reduce the effects on aquatic biology
resources in Powers Gulch, Haunted Canyon, and
Pinto Creek. The measures are designed to reduce
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the effects of the proposed Carlota Copper Project on
aquatic habitat, aquatic species, and wetlands and
waters of the U.S.
AB-1: Construction activities with the potential to
generate sediment in Pinto Creek or Powers Gulch
would be coordinated with the Forest Service to
ensure that measures designed to reduce
sedimentation are incorporated and promptly imple-
mented. Activities that could produce higher sediment
levels would be scheduled to avoid periods of fish
spawning.
AB-2: Wetlands Mitigation - Subject to Forest Service
and COE approval, a mitigation program to replace
wetlands impacted by the project is proposed to
comply with the conditions of Carlota's CWA Section
404 permit. The Forest Service and the COE are
reviewing potential mitigation projects to offset the
loss of 0.34 acre of designated wetlands within the
project area. The impacts would be mitigated by
constructing a new 1-acre wetland area along Pinto
Creek, extending upstream from the Pinto Creek
cutoff wall at a ratio of 3 to 1 (mitigation acres to
impact acres). Native wetland vegetation would be
planted, maintained, and monitored.
AB-3: Waters of the U.S. Mitigation - As stated in
Section 3.5.2, Environmental Consequences, 9.12
acres of designated waters of the U.S. are anticipated
to be lost because of the project. Subject to Forest
Service and COE approval, and in compliance with
the requirements of Carlota’s CWA Section 404
permit, mitigation for impacts to waters of the U.S.
would include creating a replacement channel in Pinto
Creek; the Pinto Creek diversion channel would have
biological habitat characteristics similar to the
impacted channel. The ratio of mitigation acreage
(11.40 acres) to impacted acreage (9.12 acres) would
be approximately 1 .25:1 . The mitigation for wetlands
and waters of the U.S. is fully described in Wetland
and Waters of the U.S. Compensatory Mitigation Plan
for the Carlota Copper Project (Aquatic and Wetland
Consultants, Inc. 1996a).
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3.6 Cultural Resources
3.6.1 Affected Environment
3.6. 1. 1 Description of Historic Context
Development Area
The Forest Service has identified a Carlota Historic
Context Development Area (HCDA) encompassing
the proposed Carlota Copper Project (SWCA 1993b,
1993c). The study area facilitates assembly of
regional cultural resource information and, ultimately,
permits development of specific historic contexts
within which individual prehistoric and historic sites
may be evaluated. The HCDA, with the proposed
project in the approximate center, encompasses 290
square miles and is bounded roughly on the north by
the Salt River and on the south by the Gila River. To
the east, it extends approximately to the community
of Globe, and to the west to the town of Superior. The
HCDA is within the Forest Service's Globe-
Superstition analysis area and encompasses parts of
three Forest Geographic Study Areas. These are the
Superstition Mountain, Pinal Mountain, and Pinal
Creek study areas. The HCDA is quite rugged and
lies physiographically within the Central Mountain
Transition zone. Vegetation of the interior chaparral
community is typical (SWCA 1993b, 1993c).
3.6.1. 2 Previous Archaeological Research in the
Area
The record of prior research within and near the
Carlota HCDA has been detailed in Wood et al.
(1989) and SWCA (1993b) and is summarized here.
For organizational purposes, these studies are split
into two broad groups: early investigations and recent
investigations.
The earliest significant archaeological study of record
is that of Harold S. Gladwin et al. working through the
Gila Pueblo Archaeological Foundation. Gladwin
conducted excavations at Gila Pueblo, located near
Globe (Gladwin and Gladwin 1934, 1935; Haury
1988). In the late 1920s, Erich Schmidt excavated the
pueblo of Togetzoge and Rogers Cliff Ruin, located in
the upper Pinto Creek drainage and Superstition
Mountains, respectively (Hohmann and Kelley 1988).
In 1932, Florence Hawley conducted partial
excavations at the Bead Mountain pueblos, a
complex of three pueblos with smaller sites nearby
(Hawley 1932). Irene Vickery, operating in the context
of 1930s Depression-era public works programs,
conducted a major excavation of the pueblo of Besh-
bagowa situated in Globe. In the following decade,
she also excavated the site of Inspiration I along
Miami Wash (Vickery 1939, 1945).
Recent work in the study area has occurred from the
early 1970s to the present, with an emphasis on the
context of cultural resource management (that is,
research prompted by proposed development and
mandated by historic preservation statutes). All of the
studies named below, except the last one (for the
Carlota Copper Project), were conducted by the
Arizona State Museum.
In the early 1970s, Ric Windmiller undertook surveys
and small-scale excavations in the Globe-Miami-Pinto
Creek vicinity (Windmiller 1972, 1974). During this
same time, a small pueblo called Central Heights was
excavated at a separate project site located near
Globe (McGuire 1975). Doyel's (1978) work along
State Highway 88, known as the Miami Wash Project,
was also undertaken in the early 1970s, and it
consisted of eight sites that were excavated a few
miles north of the proposed Carlota Copper Project
area. As a result of this work, the Miami phase —
temporally between Salado and Hohokam — was
defined.
The Orme Reservoir Project was undertaken in the
1970s in the vicinity of the confluence of the Salt and
Verde Rivers in the northwestern portion of the
Globe-Superstition Mountains area; it consisted of a
large-scale inventory (without excavation) along both
streams (Canouts 1975).
The Cholla Transmission Line Project, conducted
along an Arizona Public Service line through the
study area, occurred in the late 1970s. Sites were
found concentrated in the Devore Wash area, which
is located a few miles north of the Carlota Copper
Project area; again, no excavations were undertaken
(Reid 1982a, 1982b).
Finally, an intensive inventory of over 2,600 acres
was conducted for the Carlota Copper Project by
SWCA, Inc. in 1991 and 1992 (SWCA 1993a), and an
intensive ethnohistoric documentation program was
completed by SWCA, Inc. in 1997 (Newton et al.
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1997). As a result of this inventory, 89 cultural sites
are known to exist in the project area proper,
including 83 prehistoric and historic archaeological
sites and 6 locations identified by Tribes as traditional
cultural properties (TCPs) not specifically associated
with other prehistoric or historic sites (see following
discussion). The archaeological sites were test-
excavated in the fall and winter of 1993-1994
(Goodman et al. 1994; Mitchell et al. 1994). Data
recovery excavations were undertaken in 1996-97,
and data currently are being analyzed and reported.
3.6.1. 3 Cultural-Historical Overview
Four periods of prehistoric occupation have been
identified in the Carlota HCDA (SWCA 1993b, Wood
et al. 1989): Preceramic (Archaic) period. Ceramic
period/preclassic. Ceramic period/classic, and
Protohistoric/Historic period.
The Preceramic, or Archaic, period dates circa
7500/8000 B.C. to A.D. 500 and may be subdivided
into Early, Middle, and Late phases. No pre-existing
Paleo-Indian period has been firmly established in the
immediate study area. The Preceramic period is
characterized by a mobile to semisedentary hunter-
gatherer lifestyle.
The Ceramic period/preclassic dates circa A.D. 500
to 1200 and may be subdivided into successive Early
Preclassic, Santa Cruz, and Sacaton phases; the
Miami phase, at the end of the period, is transitional
with the subsequent Ceramic period/classic. The
Ceramic period/preclassic is synonymous with early
Hohokam occupation and is characterized by
agriculture-based sedentary villages and pottery-
making.
The Ceramic period/classic dates from A.D. 1200 to
1500, growing out of the transitional Miami phase into
subsequent Roosevelt and Gila phases. This period
may be correlated with the Salado culture, which
exhibits distinctive architectural, ceramic, economic,
and settlement traits. As in the previous period,
settlement in the Ceramic period/classic is essentially
sedentary and agriculture-based.
The final period, the Protohistoric/Historic, dates A.D.
1500 to the mid-1860s in the study area. It is
associated with Western Apache and Yavapai Indian
groups, which, although poorly understood, are
believed to have been semisedentary hunter-
gatherers and part-time horticulturists.
Prehistoric archaeological sites known to exist in the
immediate vicinity of the Carlota Copper Project area
include cobble masonry structures, pit houses,
ceramic and lithic scatters, rock art, and pueblos of
varying sizes (SWCA 1993a). Functionally, the known
aboriginal sites of the HCDA may be broken down as
follows: temporary encampments, residential sites,
resource procurement/processing sites, agricultural
sites, quarries/mines, and rock art (SWCA 1993b).
Two principal historic themes of the Carlota HCDA
are mining and agriculture/ranching. Initial prospect-
ing and mining, oriented strictly toward gold and silver
deposits, probably began in the 1850s, although
significant early discoveries were not made in this
region. Gold and silver (particularly silver) were mined
through the turn of the 20th century. Early Anglo-
American encroachment in the area resulted in
conflict with the Apache Indians, and by the 1870s,
the U.S. government had established a military
presence. The occurrence and importance of copper
deposits in the area became known in the 1870s, and
by the early part of the 20th century, copper had
eclipsed silver in importance. Although copper
production dipped substantially after World War I, it
has nevertheless continued to be an economic
mainstay of the region. Settlers with livestock entered
the region as early as the 1860s, and during the
following decade, numerous cattle ranches were
established. Ranching continues in the area to the
present day (SWCA 1 993c, Wood et al. 1 989, SWCA
1993a).
Historic sites in the HCDA tend to be associated
mainly with mining and agriculture, but numerous
other historic themes are also represented. Mining-
related sites consist of structural remains, structure
platforms, shafts and adits, camps, and exploration
sites. Sites relating to ranching and agriculture
consist of ranches, homesteads, stock-related
features, production areas, and trash dumps. Other
historic site types known to occur in the HCDA
include non-agricultural residential locations, graves
and cemeteries, transportation-related features (e.g.,
railroad sidings), rock art/graffiti, construction camps
(including camps associated with Depression-era
public works projects), and military posts and facilities
(SWCA 1993a, 1993c).
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3.6.1. 4 Consultation with Tribal Governments
Nine Tribal Governments have been consulted
concerning archaeology, TCP, and the disposition of
human remains. Tribes consulted include the White
Mountain Apache, San Carlos Apache, Fort McDowell
Yavapai, Salt River Pima-Maricopa, Tonto Apache,
Yavapai-Prescott, Yavapai-Apache, Hopi, and Zuni.
Field tours of the proposed project area have been
provided to representatives of the Tonto Apache,
White Mountain Apache, San Carlos Apache, and the
Salt River Pima-Maricopa Indian communities. In
addition, information on the project has been
presented to the Hopi and Zuni cultural preservation
groups. All tribes have been furnished with copies of
survey testing plans and reports, data recovery plans,
and ethnohistoric investigation reports for review and
comment.
Ethnohistoric investigations have been undertaken to
determine if there are any TCPs within the project
area. These investigations began with a literature
review, which was followed by informant interviews
and field visits with Tribal representatives. Traditional
Tribal interests in the archaeological sites were
documented and several additional areas were
identified by Tribes as TCPs to be considered under
the procedures of section 106 of the NHPA, as
amended. These additional sites included several
possible prehistoric shrines, a historic clan origin
place, and an area historically used for collecting
plants, camping, and ceremonial dancing.
These investigations are documented in Newton
et al. (1997). Because of the sensitive nature of
some of the information obtained from Tribal
informants, portions of this documentation are
considered confidential.
In evaluating the identified TCPs for their eligibility for
the National Register of Historic Places (NRHP), as
required by 36 CFR 800, not all of the sites were
determined eligible as recommended by the Tribes.
While recognizing that all of the identified TCPs have
cultural significance to those Tribes identifying them,
this determination reflects the fact that some of the
identified TCPs lack specific locations, boundaries, or
physical manifestations while others are represented
by physical features whose identity and association
could not be verified. For those TCPs that cannot be
avoided by project impacts, the Forest Service will
consult further with the concerned Tribes regarding
ways to alleviate their concerns prior to project
implementation.
3.6.1. 5 Information Sources
Information about the general prehistoric and historic
cultural setting of the Carlota Copper Project vicinity
was gleaned from several literature sources. Most
notable among these are the Tonto National Forest
Cultural Resources Assessment and Management
Plan (Wood et al. 1989) and two recent documents
produced for the Carlota Copper Company by SWCA,
Inc.: Historic Context Development and Testing Plan
for the Carlota Project (SWCA 1 993b) and Historic
Context Development and Testing Plan for Historic
Sites in the Carlota Project Area, Gila and Pinal
Counties, Arizona (SWCA 1993c). Site-specific
information from within the project boundaries was
drawn from the report of an intensive 2,626-acre
cultural resource inventory conducted on behalf of
Carlota Copper Company by SWCA (1993a) and
from respective reports of SWCA’s historic and
prehistoric site testing programs for Carlota Copper
Company (Goodman et al. 1994; Mitchell et al. 1994).
3.6. 1.6 Cultural Data Summary
Four hundred and twenty-seven cultural localities
were identified and reported in the Carlota Copper
Project survey by SWCA (1993a: Appendices A, B, C;
Newton et al. 1997). These properties consist of 87
prehistoric and historic sites, 120 prehistoric and
historic isolated occurrences (lOs), and 220
properties classified as “other historic-to-recent or
recent remains.” These figures include previously
recorded sites within the study area boundaries. The
total number of sites included in the EIS analysis has
subsequently been reduced to 83; 7 sites lie outside
of project boundaries as currently defined, and 3
additional sites have been recorded within the project
boundaries since SWCA’s major inventory (1993a).
Of the 83 sites, 45 are prehistoric, 32 are historic-to-
recent, and 6 are multicomponent prehistoric/historic.
Of the 120 lOs, 71 are prehistoric, 47 are historic-to-
recent, and 2 are multicomponent prehistoric/historic.
Fifty-five of the archaeological sites also are
considered to be TCPs by Tribal informants, either as
perceived manifestations of Tribal migration histories
and origin myths or by virtue of containing features
Carlota Copper Project Final EIS
3-227
3.0 Affected Environment and Environmental Consequences - Cultural Resources
interpreted by Tribal religious practitioners as
prehistoric shrines or other locations associated with
religious or ceremonial activities. Six TCPs were
identified by Tribes as separable locations from any
specific archaeological site. Several of these were
noted as isolated occurrences in the original
archaeological inventory, but others were not
recognized before the field visits and interviews with
Tribal informants. This was largely because three of
these six have no physical manifestations other than
a remembered setting in the landscape (Newton et al.
1997).
For purposes of project impact assessment, lOs
and “other” remains will not be considered since
they are categorically regarded as non-eligible
properties. The discussion from this point forward
is thus limited to the 83 archaeological sites and 6
additional locations identified as TCPs.
Of the prehistoric sites (including multicomponent
sites with a prehistoric component), 15 exhibit
architecture (compound pueblos, one- to two-room
structures, rock features), 42 exhibit artifact scatters
(ceramics, chipped stone, or ground stone), and 2
include rock art. Of the historic sites (including
multicomponent sites with a historic component), 14
exhibit architecture or structural remains, 14 have
mine shafts or adits, 5 have test pits (prospect holes),
at least 8 have other mining-related features, 9 have
refuse concentrations or scatters, and 1 has rock
art/graffiti (SWCA 1993a).
Of the six TCPs identified by Tribes that are not
associated with previously recorded archaeological
sites, three are identified as isolated prehistoric
shrines, one as a historic clan origin area, and two as
areas used historically for collecting plants, camping,
and ceremonial dancing (Newton et al. 1997).
3.6.2 Environmental Consequences
The evaluation criterion for cultural resources is the
number of prehistoric and historic sites and TCPs
directly or indirectly affected by the proposed Carlota
Copper Project. The NRHP, in its modern form, was
created by the NHPA of 1966 (as amended).
Eligibility criteria are enumerated in 36 CFR 60
(implementing federal regulations) and consist of the
following:
The quality of significance in American
history, architecture, archaeology, and
culture is present in districts, sites, buildings,
structures, and objects that possess integrity
of location, design, setting, materials, work-
manship, feeling, and association, and:
(a) That are associated with events that
have made a significant contribution to
the broad patterns of our history:
(b) that are associated with the lives of
persons significant in our past;
(c) that embody the distinctive character-
istics of a type, period, or method of
construction, or that represent the work
of a master, or that possess high artistic
values, or that represent a significant
and distinguishable entity whose
components may lack individual
distinction; or
(d) that have yielded, or may be likely to
yield, information important in prehistory
or history.
The NFIPA makes it clear that a site need not be of
national historic significance to be considered eligible;
sites of local, state, and regional importance may also
be listed and are thus significant in the legal sense.
The phrasing of the NHPA is critical with respect to
the actual management of cultural resources; a site
need not be included on the NRHP to be afforded
protection under the law, but simply must meet the
requirements of eligibility.
Significance, however, is not the only factor in
determining eligibility of historic properties. Integrity is
an equally important factor that reflects the fact that
properties to be listed on the NRHP must, first of all,
be tangible properties with recognizable physical
characteristics and finite geographic locations and
3-228
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Cultural Resources
boundaries. These considerations are especially
critical in regard to certain types of properties.
Contexts for prehistoric and historic sites known to
exist in the Carlota Copper Project area were
developed by SWCA, Inc. in consultation with the
Forest Service and the State Historic Preservation
Officer (SWCA 1993b, 1993c). A context of this type
is defined as “an organizational framework devised by
the federal government to assist in the evaluation and
treatment of historic properties” (SWCA 1993b).
Essentially, sites that meet one or more of the NRHP
criteria for eligibility and that specifically have the
potential to contribute information relevant to one or
more of the themes identified within the contexts will
be assessed as significant. Prehistoric themes
include (1) Preclassic sociopolitical-ideological
systems, (2) Classic period sociopolitical-ideological
systems, (3) Prehistoric subsistence, (4) Classic
period exchange-trade-commerce, and (5) Classic
period demography. Sites with the potential to
produce information about prehistoric chronology may
also be regarded as significant (SWCA 1993b).
Historic themes include (1) demography, (2)
technology and architecture, (3) exchange, trade, and
commerce, and (4) subsistence (SWCA 1993c). Of
the 89 cultural sites, 59 were determined eligible for
the NRHP under NRHP Criterion (d). This includes
the 55 archaeological sites identified by the Tribes to
be TCPs.
For purposes of analysis, two types of impacts are
identified: direct and indirect. A direct impact to
cultural resources is one that results from an
immediate consequence of project actions. It would
include impacts resulting from open-pit mining:
construction of roads, buildings, and parking areas;
construction of leach pads and rock dumps;
installation of water pipelines and power lines; and
other project activities. An indirect impact is one that
exists outside of specific project disturbance areas
and is frequently manifested as an impact resulting
from increased human access to an area or
accelerated erosion.
Either type of impact may result in irreversibly
compromising a site's integrity and losing its historic
or scientific values. Sites in the proposed Carlota
Copper Project area are regarded as threatened with
direct impact if they lie within the boundaries of
planned project facilities, such as mining pits, parking
lots, roads, etc. Sites threatened with indirect impact
are those lying outside of, but within 500 feet of,
project facilities.
Based upon the results of the information generated
during the preparation of the HCDA analysis, a review
of the results of the archaeological and ethnohistoric
surveys, and the geographic setting of the project
area, it became apparent that the Carlota Copper
Project area encompassed a distinct prehistoric and
historic settlement area centered around the Pinto
Creek/ Powers Gulch area. Further review of the
proposed alternatives revealed that all alternatives
(with the exception of the no action alternative) would
result in significant impacts to the sites that comprise
this settlement area. Therefore, while analysis of the
alternatives is framed in terms of direct and indirect
impacts to specific properties, mitigation options and
actions will focus on treatment of the impacts to the
overall settlement system.
3.6.2. 1 Proposed Action
Eighty-nine prehistoric and historic sites (including
several with both prehistoric and historic components)
and TCP sites have been recorded in the project
area. Of this total, 56 sites lie within direct impact
areas, and another 12 sites are in indirect impact
areas. The remaining 21 sites are not threatened by
any type of project-related activity. Many of the 56
sites in direct impact areas also lie within 500 feet of
other project facilities, and thus are threatened with
indirect as well as direct impacts. Impacts to specific
cultural resources relative to the proposed action are
detailed in Table 3-63. Of the 56 sites located within
direct impact areas, 35 are assessed as meeting
eligibility criteria of the NRHP; the remaining 21 sites
are not NRHP-eligible. Of the 12 sites within indirect
impact areas, 8 are NRHP-eligible, and 4 are not
eligible.
3. 6. 2.2 Alternatives
Mine Rock Disposal Alternatives
Of the 89 sites recorded in the project area, 6 would
be affected, either directly or indirectly, by various
mine rock disposal alternatives {Table 3-64). Potential
impacts to known sites are as follows:
Carlota Copper Project Final EIS
3-229
3.0 Affected Environment and Environmental Consequences - Cultural Resources
Table 3-63. Cultural Resource Impacts - Proposed Action
1
AR-03-12-
Apsite
No. AZ-
NRHP
Status'
Type of
impact^
FocIlIttosAo^'SM
02-425
V:9:244
E
D, 1
Haul Road (D)
Leach Pad (D)
Main Mine Rock Area (D)
Main Water Pipeline (D)
Power Line(D)
Service Road (D)
Stockpile/Secondary Crushing
Area (1)
02-432
V:9:236
E
D. 1
Eder North Pit (1)
Haul Road (1)
Leach Pad (1)
Powers Gulch Diversion (D)
02-433
V:9:237
E
D
Leach Pad
02-434
None
E
1
Leach Pad
PLS Ponds
Underdrain Collection Pond
02-436
V:9:233
E
D, 1
Access Road (1)
Leach Pad (D)
PLS Pipeline (1)
Power Line(l)
Stockpile/Secondary Crushing
Area (1)
02-437
U:12:66
E
None
N/A
02-438
V:9:222
E
D. 1
Leach Pad (D)
Access Road (1)
02-848
V:9:247
E
D. 1
Carlota/Cactus Pit (D)
Access Road (1)
02-1091
V:9:212
NE
None
N/A
02-1092
V:9:213
E
None
N/A
02-1093
V:9:214
E
None
N/A
02-1094
V:9:215
E
None
N/A
02-1096
V:9:217
E
None
N/A
02-1097
V:9:218
NE
None
N/A
02-1098
V:9:219
NE
None
N/A
02-1099
V:9:220
NE
None
N/A
02-1100
V;9:221
E
D
Leach Pad
02-1101
V;9:223
NE
D
Leach Pad
02-1102
V:9:224
E
D. 1
Access Road (1)
East Diversion Channel (1)
Inlet Control Structure (1)
Leach Pad (D)
Powers Gulch Diversion (1)
Spillway (1)
02-1103
V;9:225
E
D
Leach Pad
02-1104
V:9:226
NE
D, 1
Access Road (1)
Leach Pad (D)
02-1105
V;9:227
E
D. 1
Access Road (1)
Carlota/Cactus Pit (1)
Leach Pad (1)
North Diversion Channel (1)
Power Line (1)
SX-EW Plant Area (D)
Water Pipeline (1)
3-230
Carlota Copper Project Final EIS I
3.0 Affected Environment and Environmental Consequences - Cultural Resources
Table 3-63. Cultural Resource Impacts - Proposed Action (continued)
Forest No.
AR-03-12-
No. AZ»
NRHP
Status^
Typsof
impact
Facilities Association*
02-1106
V:9:228
NE
D, 1
Leach Pad (D)
Access Road (1)
Main Water Pipeline (1)
Power Line (1)
02-1107
V:9;229
E
D. 1
Carlota/Cactus Pit (D)
Pinto Creek Diversion (1)
02-1108
V:9:230
E
D, 1
Leach Pad (D)
PLS Ponds (1)
02-1109
V;9:231
NE
D. 1
Leach Pad (D)
PLS Ponds (1)
02-1110
V:9:232
E
D. 1
Leach Pad (D)
PLS Pipeline (1)
PLS Ponds (D)
02-1 1 1 1
V;9:245
NE
D, 1
Main Mine Rock Area (D)
Sediment Control Structure (1)
02-1112
V:9:234
E
D. 1
Leach Pad (1)
PLS Pipeline (1)
PLS Ponds (D)
Powers Gulch Diversion (1)
Underdrain Collection Pond (1)
02-1113
V:9:235
E
D. 1
Leach Pad (D)
Powers Gulch Diversion (1)
PLS Pipeline (1)
PLS Ponds (1)
02-1114
V:9;238
E
D
Leach Pad
02-1115
V:9:239
E
D. 1
Leach Pad (D)
Powers Gulch Diversion (1)
02-1116
V:9:240
E
D
Leach Pad
02-1117
V:9:241
E
D
Leach Pad
02-1118
V:9:242
NE
D, 1
Main Mine Rock Area (D)
Main Water Pipeline (1)
Power Line (1)
Service Road (1)
02-1119
V:9:243
NE
1
Main Mine Rock Area
Sediment Control Structure
02-1120
U:12:58
E
None
N/A
02-1121
V;9:246
NE
D, 1
Main Mine Rock Area (D)
Main Water Pipeline (1)
Power Line (1)
Sediment Control Structure (1)
02-1122
U;12:59
E
D, 1
Head Tank (D)
Main Water Pipeline (1)
Power Line (1)
Service Road (1)
02-1124
V:9:248
E
D. 1
Access Road (1)
Carlota/Cactus Pit (D)
Main Water Pipeline (1)
Power Line (1)
02-1125
V;9:249
E
D. 1
Access Road (1)
Carlota/Cactus Pit (D)
02-1126
V:9:250
E
D
Carlota/Cactus Pit
02-1127
V:9:251
E
D
Carlota/Cactus Pit
02-1128
V:9:252
E
D. 1
Carlota/Cactus Pit (D)
Pinto Creek Diversion (1)
Carlota Copper Project Final EIS
3-231
3.0 Affected Environment and Environmental Consequences - Cultural Resources
Table 3-63. Cultural Resource Impacts - Proposed Action (continued)
Forest No.
AR-03-12-
ASM Site
NO.AZ*
NRHP
Status'
Typo of
impact*
02-1129
V:9:253
E
D
Carlota/Cactus Pit |
02-1130
V:9;254
E
D. 1
Access Road (D)
Power Line (1)
02-1131
V:9:255
E
D
Carlota/Cactus Pit
02-1132
U:12;60
NE
None
N/A
02-1133
U;12;61
NE
None
N/A
02-1134
U;12:62
E
None
N/A
02-1135
V:9:256
E
D
Carlota/Cactus Pit
02-1136
V:9:257
E
D
Carlota/Cactus Pit
02-1137
V:9:258
E
None
N/A
02-1138
V:9:259
NE
D
Cactus SW Mine Rock Area
02-1139
V;9:260
E
D, 1
Access Road (1)
Leach Pad (D)
02-1140
U:12:63
E
None
N/A
02-1141
U:12:64
E
1
Powers Gulch Diversion
02-1142
U;12:65
E
None
N/A
02-1144
V:9:261
NE
1
Leach Pad
PLS Pipeline
02-1145
V:9:262
E
1
Leach Pad
PLS Pipeline
02-1146
U:12:67
E
1
Leach Pad
PLS Pipeline
PLS Ponds
02-1147
U:12:68
E
1
Main Mine Rock Area
Sediment Control Structure
02-1148
V:9:263
NE
D, 1
Haul Road (1)
Leach Pad (1)
Main Water Pipeline (1)
Power Line (1)
Service Road (1)
Stockpile/Secondary Crushing
Area (D)
02-1149
V:9:264
NE
D. 1
Access Road (1)
Carlota/Cactus Pit (1)
Haul Road (1)
Leach Pad (1)
Main Water Pipeline (1)
Power Line (1)
Stockpile/Secondary Crushing
Area (D)
02-1150
V:9:265
E
1
Access Road
Haul Road
Main Mine Rock Area
Overland Conveyor
Power Line
Water Pipeline Branch to Truck
Shop
02-1151
V:9:266
NE
D, 1
Haul Road (1)
Main Mine Rock Area (D)
Water Pipeline Branch to Truck
Shop (1)
3-232
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Cultural Resources
Table 3-63. Cultural Resource Impacts - Proposed Action (continued)
Forest No*
AR-03«12-
ASM Site
No. AZ-
NRHP
Status^
Type of ^
Impact*^''*
% Facilities Association^
02-1154
V:9:269
NE
D, 1
Access Road (1)
Power Line (D)
02-1155
V:9:270
NE
1
Administration building
Power Line
02-1156
V:9:271
E
D
Carlota/Cactus Pit
02-1157
V:9:272
E
D
Carlota/Cactus Pit
02-1158
V:9:273
E
D
Carlota/Cactus Pit
02-1159
V:9:274
E
1
Carlota/Cactus Pit
Pinto Creek Diversion
02-1160
V:9:275
E
None
N/A
02-1161
V:9:276
E
None
N/A
02-1162
V:9:277
E
1
Crusher
Eder South Pit
Haul Road
02-1163
V:9:278
E
D, 1
Haul Road (D)
Leach Pad (1)
Powers Gulch Diversion (1)
02-1164
U:12:69
E
None
N/A
02-1166
V:9:280
NE
D, 1
Leach Pad (D)
PLS Pipeline (1)
PLS Ponds (1)
02-1169
V:9:281
NE
D
Leach Pad
PLS Pipeline
02-1170
V:9:282
NE
D. 1
Access Road (1)
Leach Pad (D)
02-1194
None
E
1
Powers Gulch Diversion
02-1195
None
E
None
N/A
02-1196
None
E
None
N/A
02-1217
None
NE
D
Leach Pad
02-1218
None
NE
D
Leach Pad
02-1219
None
NE
D
Carlota/Cactus Pit
02-1220
None
NE
D
Leach Pad
Eder South Pit
Eder Mine Rock Area
Powers Gulch Diversion
PLS Pipeline
Eder Area Access Road
Stormwater Drainage Control Ditch
Eder North Pit
Eder Middle Pit
Sediment Control Structures
02-1221
None
NE
D
Carlota/Cactus Pit
Pinto Creek Diversion
Sediment Control Structures
Mine Access Road
Primary Crusher
Overland Conveyor
02-1222
None
NE
D
Main Mine Rock Area
'NRHP Status: E = Eligible for National Register of Historic Places
NE = Not eligible for National Register of Historic Places
^Impact Type: D = Direct
I = Indirect
Carlota Copper Project Final EIS
3-233
Table 3-64. Cultural Resource Impacts - Project Alternatives
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Cultural Resources
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Carlota Copper Project Final EIS
3-235
Table 3-64. Cultural Resource Impacts - Project Alternatives (continued)
3.0 Affected Environment and Environmental Consequences - Cultural Resources
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3-236
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Cultural Resources
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Carlota Copper Project Final EIS
3-237
3.0 Affected Environment and Environmental Consequences - Cultural Resources
• Alternative mine rock disposal sites (Cactus
Central, Cactus South): 4 sites (2 direct impact, 2
indirect impact), an increase of 4 sites when
compared to the proposed action
• Additional backfill of the Carlota/Cactus pit
(Carlota/Cactus pit. Main mine rock area); 0 sites,
which would be the same as the proposed action
• Additional backfill of the Eder South pit: 1 site
(indirect impact), which would be the same as the
proposed action
Eder Side-Hill Leach Pad Alternative
A total of 35 sites (19 direct impact, 16 indirect
impact) would be affected by this alternative {Table
3-64), which would be the same as the proposed
action.
Water Supply Alternative
No sites would be impacted by the water supply
alternative. This represents no change when
compared to the proposed action.
Alternative Water Supply Well Field Access
Roads
One site would be indirectly impacted by this
alternative. This would represent an increase of 1 site
compared to the proposed action.
No Action Alternative
No project-related impacts to known cultural
resources would occur under this alternative {Table
3-64). It is possible, however, that sites in the project
area could be affected in the future because existing
roads into the mine provide access to the general
public.
3.6.3 Cumulative Impacts
The cumulative impact analysis area for cultural
resources encompasses 290 square miles and is
bounded roughly on the north by the Salt River and
on the south by the Gila River. To the east, it extends
approximately to the community of Globe, and to the
west to the town of Superior. This corresponds to the
HCDA that was developed for the archaeological
contextual study. Within this area, 17 major
interrelated actions were identified that have, or have
had, the potential to affect cultural resources. These
actions include 10 mines, 2 reservoir projects, 2
highway projects, 1 power line project, and 2 areas of
continuing residential or commercial development.
Grazing also may affect sites; however, these effects
are of a much lower magnitude than those possible
from the 17 actions mentioned above. In addition, the
trend in the study area has been toward reduced
grazing intensity.
All of the identified interrelated projects entail ground
disturbance with the potential to impact cultural
resources. In addition, one of the dam modification
projects could impact sites through inundation since
that modification could result in raising reservoir
floodpool levels.
The impact to cultural resources from past mining
activities cannot be directly quantified. It is possible,
however, to produce some indirect estimates of these
impacts using the results of recent archaeological
surveys within the analysis area. The Carlota Copper
Project, the Cyprus-Miami project, and the BMP
Copper project surveys covered a combined 5,831
acres. These surveys identified 136 historic and
prehistoric sites for an average site density of
approximately 1 site for every 43 acres. While it is
recognized that there is a great deal of variation in
patterning of cultural resources within the analysis
area, this composite site density appears to be typical
of the overall density. Within the analysis area,
16,525 acres were estimated to have been disturbed
by past mining activities {Figure 1-3). Using the
composite site density as a guide, it is estimated that
approximately 384 sites may have been impacted by
past mining activity. This would be approximately 8.9
percent of the projected 4,316 sites in the analysis
area.
Within the analysis area, new mining (Carlota
Copper Project) and expansions of existing mining
facilities (Cyprus-Miami and BMP Copper) have the
potential to disturb as much as 4,633 acres. As
mentioned above, surveys of the project areas
identified 136 historic and prehistoric sites that
could be potentially affected. Of the 136 sites
identified, 110 are within the direct and indirect
impact areas of these projects. Effects to these
110 sites would add another 2.5 percent to the
3-238
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Cultural Resources
number of sites impacted by mining activity in the
analysis area.
Past, present, and reasonably foreseeable future
mining activities in the analysis area may affect, or
have already affected, 11 .4 percent of the estimated
4,316 cultural resource properties.
Other major actions with impacts to the cultural
resources of the analysis area are the reservoir
projects at Roosevelt and Coolidge dams. Upgrading
Coolidge Dam will result in minor disturbance to the
construction area.
At Roosevelt Dam, the original construction of the
dam inundated an unknown number of sites. The
recent actions at Roosevelt Dam have affected 73
historic and prehistoric sites in the dam modification
direct and indirect impact areas. The original reservoir
inundated approximately 3,900 acres that are
included in the analysis area. Using the estimated site
density calculated above, 87 sites might have been
impacted as a result of this action. Compounded,
reservoir projects contribute another 3.9 percent to
the number of sites impacted in the analysis area.
Highway improvement projects also will impact a
number of sites within the analysis area. Construction
activities along the Wheatfield section of State Route
88 will impact 16 sites. These 16 sites can be
included in the cumulative impact analysis. These
sites represent 0.4 percent of the estimated number
of sites in the analysis area. While other
improvements are planned for State Route 88, it is
not possible to calculate impacts to cultural resources
at this time. Along U.S. Highway 60-70, several
upgrades and alterations have been proposed. Plans
for these various activities are not at a sufficient stage
to estimate the impacts to cultural resource.
The archaeological survey for the reliability
maintenance improvements to the 1 15-kv
transmission line between Superior and Ray also
identified cultural resource sites within the project
area. Project design, however, was such that there
were no impacts to any of these properties.
Estimates of the impacts resulting from past and
continued growth of the Globe-Miami and Top-of-the-
World areas are, as with mining, only indirectly
quantifiable. The Globe-Miami area covers
approximately 25,600 acres and Top-of-the-World
approximately 960 acres. Using the site density
estimate calculated earlier, approximately 618 sites
have been or are potentially being impacted by
development in these communities. This would be
14.3 percent of the estimated sites in the analysis
area.
Overall, it is possible to roughly estimate that
cumulative impacts to cultural resources involve
approximately 1 ,288 sites, or 30 percent of the
properties in the analysis area. Over the last 25
years, these impacts have been lessened by the fact
that mitigation has been required for actions with
federal or state involvement. Data recovery
procedures, approved by federal agencies and the
State Historic Preservation Office, are intended to
recover the information potential of impacted sites
prior to project impacts. Over the years, these
procedures continue to improve so that better
information is recovered. As a result, while site loss to
actions continues, better mitigation procedures are
reducing the amount of information loss. This,
coupled with the federal and state goal of avoiding
impacts to sites where possible, has slowed the
impacts to the resource base.
These mitigation procedures are not required for
projects without federal or state involvement. In
instances that do not involve federal or state
involvement, unless the project proponent acts
responsibly, site and information loss will continue.
3.6.4 Monitoring and Mitigation Measures
3.6.4. 1 Mitigation Options
Mitigation is defined as any of several forms of
management action that has the effect of reducing or
eliminating adverse impacts to heritage resource
properties. The choice of management options for
mitigating impacts to properties is dictated by three
factors; assessment of the property’s significance, the
physical nature of the property, and the nature of the
proposed impact. As a general guideline, the best
mitigative options are those that ensure the continued
existence of a property (e.g., avoidance, protection).
Such options are desirable not only from a
conservation standpoint but, in most instances, from
a cost perspective as well. However, the effects of
unavoidable impacts must be handled through data
Carlota Copper Project Final EIS
3-239
3.0 Affected Environment and Environmental Consequences - Cultural Resources
retrieval. The data retrieval process must account for
the physical composition of the property and the
types of information used to characterize it, as well as
the nature and severity of the proposed impact.
The remaining options are designed to manage
significant properties that are threatened. These
options include avoidance/protection, recording/
documentation (including such actions as mapping
or archival research), collection, partial or complete
excavation, and treatment or maintenance. In
practice, impact mitigation often involves a combi-
nation of two or three of these actions, e.g., surface
collection in combination with partial excavation.
Avoidance and protection differ only in that the latter
requires some form of action, such as fencing.
3.6A.2 Recommended Mitigation Actions
CR-1: As the first stage in mitigating the impacts to
the remains of the prehistoric and historic settlement
areas, all 83 prehistoric and historic sites in the
Carlota Copper Project area were test excavated by
SWCA, Inc. during the fall and winter of 1993-1994
(Goodman et al. 1994; Mitchell et al. 1994).
The proposed action would result in direct impacts to
56 sites, of which 35 are NRHP-eligible, and indirect
impacts to 12 sites, of which 8 are NRHP-eligible.
Mitigation consisting of data retrieval was conducted
at the 35 directly impacted sites that are NRHP-
eligible. Mitigation was carried out in the context of
comprehensive prehistoric or historic research
designs. The locations of the 8 NRHP-eligible sites in
indirect impact areas would be monitored regularly by
an archaeologist, and the locations fenced if evidence
of encroachment is found. If continued monitoring
suggests that fencing is not adequately protecting the
sites, mitigative actions consisting of data retrieval
would be undertaken.
No mitigation would be conducted at the 15
non-eligible sites in direct impact areas or the 4
non-eligible sites in indirect impact areas.
Considerations for mitigating NRHP-eligible sites
associated with various project alternatives would be
identical to those employed for sites associated with
the proposed action.
The TCPs identified in the project area either were
found to be eligible for their information potential
or were found not to be eligible under the conditions
imposed by the NRHP. Mitigation measures designed
for the prehistoric archaeological sites are applicable
for retrieving any significant information from
these eligible sites said to have traditional cultural
significance. No mitigation would be required under
the NHPA for the six non-eligible TCPs. However,
consultation may continue with the concerned
Tribes to identify possible ways to alleviate their
concerns.
No management actions are necessary for other
cultural localities (lOs and “other” cultural properties)
that lie in or near the project area.
3-240
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
3.7 Socioeconomics
Section 3.7 complies with Forest Service Manual
(FSM) Section 1970 concerning economic and social
impact analyses. FSM Section 1 973 states that a
social impact analysis should be initiated if the
potential social effects of Forest Service policies or
actions affect the quality of peoples' lives and social
well-being.
3.7.1 Affected Environment
This section describes the existing population,
economy, housing conditions, financial resources,
and facilities and services in the project area in order
to determine whether employment and population
impacts from the proposed project or alternatives
would beneficially or adversely affect public or private
conditions in the area.
The study area for social resources focuses on
portions of Gila and Pinal Counties. The communities
most likely to be affected by the project include the
towns of Miami and Globe and the communities of
Claypool, Central Heights, and Midland City in Gila
County, and the town of Superior and community
known as Top-of-the-World in Pinal County. The
geographical area extends from the mine site east to
the San Carlos Indian Reservation, north to
Roosevelt Lake, west to Superior, and south to
Winkleman.
3.7.1. 1 Population and Demography
In 1993, the population of Gila County was estimated
at 42,075. Of this total, an estimated 6,399 people live
in Globe and 2,041 in Miami. An estimated 5,100
Table 3-65. Study Area Population - 1987 to 1993
people live in the unincorporated areas of Central
Heights, Claypool, and Midland City, assuming the
same percentage as in 1990 (Arizona Department of
Economic Security 1993a). Annual average increases
in population in Globe and Miami from 1987 to 1993
were 0.2 and minus 1.9 percent, respectively.
Population growth within the county has fluctuated
from 1987 to 1993 because of the instability of the
copper mining economic sector. Although population
in the Globe-Miami area declined from 1987 to 1993
{Table 3-65), signs of improvement in the mining
and mining-related manufacturing sectors should
boost the population figures somewhat in the
future (Arizona Department of Economic Security
1993a).
Population growth that has occurred in Gila County is
generally in the northern part of the county, where
increasing tourism has stimulated the trade and
service sectors of the economy. The San Carlos
Indian Reservation, situated east of the Globe-Miami
area, has also experienced some growth. The most
recent population estimate on the reservation was
between 7,000 and 10,000; the town of San Carlos
had a 1990 population estimate of 2,918 (Noline
1993).
Compared to Gila County, the population in Pinal
County has grown much more rapidly from 1987 to
1993. Most of the growth has occurred in the Apache
Junction area, adjacent to the Phoenix metropolitan
area. The 1993 population in Pinal County was
estimated at 124,700.
The population in Superior, the town in Pinal County
closest to the Carlota Copper Project, has declined
County/
Town
1
Year
'"9
Total
Percent
Change
^ Average 1%!^;
, Annual Percent
Change
1987
1988
Il989!
1991
Il998'’
Gila
39,600
39,900
40,100
40,300
41,050
41,700
42,075
6.3
1.1
Globe
6,315
6,260
6,149
6,071
6,215
6,255
6,399
1.3
0.2
Miami
2,289
2,219
2,159
2,018
2,025
2,030
2,041
(10-8)
119}
Pinal
107,600
110,300
112,600
116,800
119,650
122,600
124,700
15.9
2.5
Superior
3,812
3,779
3,586
3,470
3,470
3,480
3,501
(8.2)
(1.4)
Sources: Arizona Department of Economic Security (1993a)
U.S. Department of Commerce, Bureau of Census (1991)
Carlota Copper Project Final EIS
3-241
3.0 Affected Environment and Environmental Consequences - Socioeconomics
during the same period. The 1993 estimated
population in Superior was 3,501 , a decrease of 25
percent from 1980. This population decline was
caused by declining production from the Superior
Mine, which ceased operations in 1996.
The demographic makeup of the area is primarily
composed of Caucasians (68 percent), Hispanics (18
percent), and Native Americans (12 percent).
3.7. 1.2 Employment and Economy
The economy in Gila County has historically
depended largely on the copper mining industry. With
the decline in copper prices in the 1980s, the
County’s economy experienced a significant slow-
down in the Globe-Miami area. In 1993, the economy
was still dependent on mining; however, the trade and
services sectors and the government sector also play
important roles in Gila County's economy. Many of
the former mine workers have remained in the area
by taking jobs in different sectors.
The economy in Pinal County is more diverse than
that of Gila County. Pinal County is one of Arizona's
five major agricultural counties. Cotton, grain, and
alfalfa are the principal crops. State and local govern-
ment is the largest employer in Pinal County; major
government facilities include the maximum security
state prison. Central Arizona College, the county,
local school districts, and local community
governments.
Mining continues to be an important economic sector
in Pinal County, along with manufacturing, trades,
and services. Much of the growth in the economic
sectors is related to the rapid growth occurring in the
Phoenix metropolitan area (Maricopa County), which
is adjacent to Pinal County.
In September 1992, the civilian labor force in Gila
County was 14,141, while the number of employed
persons averaged 12,784 (Arizona Department of
Economic Security 1 992). The unemployment rate in ]
Gila County reached a high of 25.4 percent in 1983,
when the bottom fell out of the copper industry. After
1983, the unemployment rate steadily declined to an
annual average low of 8.8 percent in 1991, although
in 1992, the average unemployment rate increased to
9.6 percent. Unemployment has decreased partially
because of a decrease in the labor force resulting
from people slowly moving out of the area. Since
1 990, there has been an increase in the labor force in i
the county.
Table 3-66 shows labor force, employment,
unemployment, and percent unemployed in the
Globe-Miami area for 1992. In the Globe-Miami labor
market in 1992, the unemployment rate averaged 9.3
percent; this was slightly higher than for Gila County
as a whole. In 1993, the unemployment rate dropped,
along with the size of the labor force. Through June
1993, the average unemployment rate was 7.5
percent.
Generally, economic activity in the area has remained
relatively subdued; businesses are maintaining a
conservative attitude towards the state of the
economy and expansion activities. In 1991, there was
limited expansion in the retail trades and some
activity in the copper industry. The price of copper
has been volatile and has affected the overall ,
condition of the economy in the Globe-Miami area. In •'
1 992, the civilian labor force in Pinal County averaged \
39,781 , while the number of employed persons j.
averaged 36,347. The unemployment estimate in *
1992 was 3,434, with an average rate of 8.6 percent, i
The labor force and unemployment in Pinal County 1
have also fluctuated throughout the past decade. The
Table 3-66. Labor Force and Unemployment - 1992
CalMorv
Globe
Midland ;
City/Cenlral
Heights
Claypool
Subtotal
i!
Superior
Total
Labor Force
2,363
650
1,092
629
4,734
960
5,694
Employed
2,179
575
970
569
4,293
846
5,139
Unemployed
184
75
122
60
441
114
555
Percent
Unemployment
7.8
11.5
11.2
9.5
9.3
11.9
9.7
Source: Arizona Department of Economic Security (1992)
Carlota Copper Project Final EIS I
3-242
3.0 Affected Environment and Environmental Consequences - Socioeconomics
1992 labor force represents one of the highest labor
force figures in the recent past; however, the
unemployment in 1992 is also considered relatively
high compared to recent years.
The town of Superior had a 1 992 labor force of 960,
with 846 employed, 114 unemployed, and an
unemployment rate of 1 1 .9 percent {Table 3-66).
From January through June 1993, the labor force
increased to 983, the number of persons employed
increased to 888, and the number of persons
unemployed decreased to 95, with an unemployment
rate of 9.7 percent. When combining the Superior
labor market with Globe-Miami (1992), statistics
include a labor force of 5,694, a total of 555
unemployed, and an average unemployment rate of
9.7 percent.
In addition to the labor forces in the towns of Globe,
Miami, and Superior, the San Carlos Indian
Reservation, located just east of Globe, has a
significant labor pool. In 1992, the total labor force in
San Carlos was estimated at 799 (537 employed and
262 unemployed) with an average unemployment rate
of 32.8 percent (Arizona Department of Economic
Security 1992). According to the Tribal Employment
Rights Office (TERO), the actual unemployment on
the reservation is closer to 60 percent (Noline 1993).
The estimated number of unemployed on the
reservation is between 1 ,000 and 1 ,500 in the
summer and 2,500 and 3,000 in the winter. Many of
the Native Americans take seasonal jobs, such as
forest fire fighting. Other surrounding towns within
potential commuting distance of the proposed project
also have some labor availability. These include the
towns of Kearny, Hayden, and Winkelman.
The residents of Gila County, particularly those of the
Globe-Miami area, are heavily dependent upon a
limited number of activities for jobs. Table 3-67 shows
the types of employment in Gila and Pinal counties for
1 992 and 1 993. More than 90 percent of those
classified as manufacturing employees in Gila County
are actually employed in the copper smelting, refining,
and fabrication activities directly associated with the
county's copper mining industry. Because of the
relatively high wage levels in the copper industry of
Gila County compared to other industries, personal
income estimates better reflect the importance of
certain industries to the county's economy rather than
employment figures.
3.7. 1.3 Personal Income
Total personal income in Gila County has increased
significantly since the early 1980s. Most of the wages
and salaries result from a small number of sources,
one of the largest of which is the copper industry,
including copper fabrication, refining, and smelting, as
well as copper mining. The largest contributor is the
government sector, including federal, state, and local
government agencies {Table 3-68). Retirement,
welfare (net transfer payments), dividends, interest,
and rents form the largest source of basic personal
income: mining and mining-related manufacturing are
major sources of personal income, as well as federal
and state government jobs.
Personal income has been estimated from the 1990
census. For Globe, Miami, Claypool, Central Heights-
Midland, and surrounding areas, the following
incomes were estimated for 1989:
Average Household Income - $29,213
Median Household Income - $22,951
Average Family Income - $33,856
Median Family Income - $26,572
Per Capita Income - $11,108
3.7.1. 4 Housing
According to the 1990 census, 5,623 housing units
are located in the Globe-Miami area; 88 percent are
estimated to be occupied (4,968), and 12 percent are
vacant (655). Of the occupied units, 67 percent
(3,756) are owner-occupied, and 22 percent (1,212)
are rental units.
More recently, the Globe Area Economic Develop-
ment Corporation contracted a housing study to
assess the housing market and housing stock in
the Globe-Miami area. To evaluate the accuracy
of the high vacancy rate reported in the 1990
census, a housing market study was completed by
the Drachman Institute for Land and Regional
Development Studies (1992) for the Globe-Miami
area. The conclusions of the study determined that a
large percentage of the vacant housing is
substandard and marginally habitable. A more
realistic vacancy rate for habitable single-family and
multi-family housing was estimated at 2 percent,
which suggests a very limited housing market in the
area.
Carlota Copper Project Final EIS
3-243
3.0 Affected Environment and Environmental Consequences - Socioeconomics
1
Table 3-67. Total Non-Agricultural Employment
-
County
Industry
Employees
1992
Gila County
Mining
1,300
1,300
Manufacturing
1,375
1,300
Construction
725
750
Transportation,
Communication, and
Public Utilities
425
450
Trade
2,600
2,550
Finance, Insurance, and
Real Estate
300
300
Services
2,250
2,350
Government
2,875
2,900
TOTAL
1 1 ,850
11,875
Pinal County
Mining
3,850
3,800
Manufacturing
3,975
3,925
Construction
875
900
Transportation, Utilities,
and Communication
1,100
1,100
Trade
5,875
6,150
Fire
550
550
Services
5,125
5,300
Government
10,100
10,800
TOTAL
31 ,425
32,600
’By place of residence
^Annual average based on January through May 1993 data
Source: Arizona Department of Economic Security (1993b)
3-244
Carlota Copper Project Final EIS
Table 3-68. Earnings by Industry (in thousands of dollars)
3.0 Affected Environment and Environmental Consequences - Socioeconomics
€
II ll
^ iS
T“
V
II
o
CD
CVJ
Id
CD
4.7
12.8
CO
CD
C\J
T—
CM
o
o
T~
1.7
21.4
10.1
3.8
4.2
12.4
00
CD
CO
CD
CO
o
CD
o
1 . " ®
.-'i a
527
Q
63,281
Q
14,959
40,541
4,556
51,416
66,936
315,770
14,599
184,197
85,913
32,850
36,474
106,574
15,185
119,391
264,236
859,419
1
1990 1
450
Q
55,807
19,754
13,861
38,623
6,599
Q
61,211
299,526
14,335
151,482
104,669
30,418
41,405
100,302
20,739
CO
o
251,304
819,067
1
1989
o
50,477
52,299
CD
CD
13,968
35,144
6,324
43,380
59,190
276,008
13,422
130,639
108,715
33,140
36,496
99,622
1^
CD
CM
CD
100,454
o
00
o
co'
CO
CM
774,835
1988
502
Q
49,777
17,571
12,667
CO
6,294
Q
55,849
CM
1^
co‘
CM
13,267
166,840
CD
00
CM
co'
O
40,275
CJ)
CO
00
co'
CO
90,827
18,869
87,205
219,538
773,996
£o
o>
T-
o
in
44,545
42,805
17,864
12,765
32,672
6,105
35,324
50,292
CD
CD
cm'
CM
O)
CO
•r“
108,339
96,460
49,221
34,616
81,215
17,735
81,578
193,151
673,709
Agricultural Services,
Forestry, and Fisheries
Mining
Manufacturing
Construction
Transportation, Utilities,
and Communication
Trade
Fire
Services
Government
TViOl II
Agricultural Services,
Forestry, and Fisheries
Mining
Manufacturing
Construction
Transportation, Utilities,
and Communication
Trade
Fire
Services
Government
II TOTAL
|S::
s
* * \
Gila County
Pinal County
CO
CD
O)
W
c
g
00
0)
.
Z3
V)
O
O
CD
E
<D
W
>.
CO
c
g
ro
E
g
E
o
c
o
o
LU
15
c
g
'cn
o>
<0
Si «/)
o o>
CD o
O Q.
■9 CD
ra 00
>
cc c
o
CO
c
<
g
E
o
c
o
o
aj
■D O
o
C CD
O CO
•^3 XJ
CD .
E ■C3
E 0)
O 15
c e
II w
Q
3
CO
0)
3
CD
0)
o
3
o
(T>
Carlota Copper Project Final EIS
3-245
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Conversations with several local realtors verified
the information contained in the housing market
study. According to these realtors, the vacancy
rate is estimated at between 2 and 5 percent.
Housing for sale is typically either in the upper end
of the market or is older, less desirable property.
Many people are currently living in recreational
vehicles (RVs) because they are unable to find
suitable housing to rent or buy. At the time of this
interview (February 1993), approximately 90 homes
were listed for sale by four realty companies. These
homes ranged in price from $8,500 to $179,000;
only six of the homes were built after 1980. If
available, a standard two-bedroom apartment or
mobile home rents for $400, and a three-bedroom
single-family home rents for $600 to $1,000. Rental
rates at Top-of-the-World are comparable to the
Globe-Miami area.
Records at the Gila County Assessor's Office
indicated that over 94 percent of all housing in the
Globe-Miami area was built before 1980 (Horn 1993).
From 1987 through 1991, only 66 single-family and
50 multi-family unit building permits were issued.
More recently, the town of Globe has three sub-
division proposals, with a total of 103 lots. To date,
none of the plans have obtained final approval
(Moseley and Stanton 1993).
Table 3-69 shows an inventory of apartment and
mobile home rental units in the Globe-Miami area for
1991, which is considered to depict present condi-
tions. Land for housing development is scarce in the
Globe-Miami area, primarily because the topography
of the area does not lend itself to development. The
most developable land is located to the east and
south of Globe. There are fewer than 100 subdivided
lots with utilities available for development. Land
prices tend to be high; therefore, few developers
are interested in building in the area. The demand
for housing is greater than the availability of lots or
existing marketable housing units (Long 1993).
The town of Superior had a total of 1 ,730 housing
units counted in the 1990 census; 73 percent were
occupied (1,260) and 27 percent were vacant (470).
Of the occupied units, an estimated 914 were owner-
occupied and 346 were rentals. According to the
1990 census, the median rent was $156, while
the value of a single-family home averaged
approximately $33,109. These figures from the
census appear to be somewhat misleading.
According to a local real estate company in
Superior, there are virtually no rentals available in
Superior, except for smaller sized units. There were
10 housing units listed for sale; these ranged from
$10,000 to $39,000. The upper-end homes are
livable; however, no new homes have been
constructed for approximately 30 years (Cagalj 1993).
In addition, most of the private land in the area is
owned by BHP Copper Company and is unavailable
for development, although there are a few smaller
parcels that could be developed for single-family
units. There is one mobile home park in Superior,
which currently has 7 occupied permanent spaces
and 13 RV spaces. Trailer park and RV spaces are
also available at Top-of-the-World. The RV spaces
are available on a nightly, weekly, or monthly basis.
Currently, there are 7 temporary spaces available
(Ruiz 1993).
Table 3-69. Inventory of Apartment and Mobile Home Units in Globe-Miami Area
1 Market Rate Apart-
mint Complexes
M Government-Assisted |
Aparbneiit Compiexesi
Mobile HornemV
Parks
Complexes/Mobile Home Parks
7
2
11
Units/Spaces/RV
117
78
758/23
Vacant
1
0
42
Monthly Apartment Rental Rates: 1 bedroom $200 - $315
2 bedroom $245 - $350
3 bedroom n/a
Mobile Home Monthly Costs: Utilities $75 - $200
Water Only $50 -$125
RV Daily Space Rental: $13 per day
Source: Drachmae Institute for Land and Regional Development Studies (1992)
3-246
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
3. 7. 1.5 Public Facilities and Services
Within the study area, public facilities and services
are the responsibility of a number of public and
private entities. The types of services and facilities
include public safety, public utilities, health services,
recreation and cultural services, education, and
government and public finance. Table 3-70 summar-
izes services and facilities for public safety, public
utilities, and health and social services. Narrative
summaries are provided for education, recreation and
cultural services, and government and public finance.
Water and sewer service to the unincorporated areas,
including Top-of-the-World, are provided by individual
wells and septic systems. There are 99 known wells
at Top-of-the-World. The wells have relatively low
yields, ranging from less than 1 gpm to 40 gpm and
averaging 10 gpm. Wells in the area experience
seasonal fluctuations, and declining water levels and
decreased yields have occurred in recent years
(scoping letters). These wells are discussed in
Section 3.3, Water Resources.
Recreational and Cultural Services
Recreational facilities and programs are provided to
the Globe-Miami area primarily by the town of Globe
and private groups or businesses. The town of Globe
has 3 major ball fields, 6 T-ball fields, 12 parks, a
municipal pool, a senior citizens’ center, an
archaeological park and museum, and a library.
Magma Copper recently donated land, equipment,
and manpower to build a park, including a soccer
field, a football field, and two baseball fields, as well
as a picnic area, on the north side of Globe. This park
is currently under construction. A botanical garden is
being built near the Besh-ba-Gowah Archaeological
Park. There is no public golf course in the Globe-
Miami area, although there is a private course in
Miami.
Recreation programs are operated by the town of
Globe; however, Gila County participated in the
operation of the youth program in 1993 by providing
personnel. The town of Globe provides recreation
programs for most of southern Gila County. The
public works director feels that the recreation
programs and facilities are adequate for the existing
population and that they would be able to support
additional growth in the area.
The town of Superior has three parks, including one
with a children's playground. The Superior Recreation
Department operates during the summer months by
providing recreation programs, such as youth and
adult basketball, softball, and swimming (Serrano
1994).
Education
The Globe Unified School District has two elementary
schools, a junior high, and a senior high. The grades
that are provided in these four schools are shown in
Table 3-71. All schools have substantial excess
capacity {Table 3-71). The school enrollment has
been the same or has increased slightly during the
past several years.
The Globe Unified School District employs 116
teachers, administrators, and classified personnel.
There are currently no plans for expansion; additional
teachers would be required for growth increments of
25 students. The current staff should be adequate
into the future, assuming current growth remains
constant. The financial status of the Globe District is a
concern because of its limited bonding capacity
(Nutting 1993). The district is seeking legal action to
deal with this issue.
The Miami Unified School District has four elementary
schools, one junior high, and a senior high. School
enrollment has stabilized over the past few years. As
shown in Table 3-71 all of the schools have some
excess capacity. There are 1 97 certified teachers,
administrators, and classified employees. The Miami
District has a strong fiscal condition because it
maintained a budget override for long-range planning,
district reorganization, and facilities consolidation
(Blazevich 1993).
The Superior Public Schools have one elementary
school, one junior high school, and one senior
high school. Enrollment has been steady or
slightly declining for the past several years. As
shown in Table 3-71, all of the schools have
substantial excess capacity. The size of the
current staff is 48. The current fiscal condition is
considered poor because of the limited bonding
capacity of the district (Lennan 1993). Although the
high school needs to be replaced, there are no funds
or funding mechanisms available for construction.
The tax rate in Superior is one of the highest in the
Carlota Copper Project Final EIS
3-247
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-70. Summary of Public Facilities and Services for the Globe-Miami and
Superior Areas
Type of
Service/Jurisdiction
1 Adequate to Meet
Exieting
Description of Services I Population Needs?
PUBLIC SAFETY
Law Enforcement
Globe
• 18 officers, 5 dispatchers, 51 records clerks,
and 1 animal control officer
Yes
Miami
• 6 officers and 4 dispatchers
Yes
Gila County
• Short-term jail facility with 144 beds and
average occupancy of 100 to 1 10 persons per
day
Yes
Gila County Sheriff's
Department
• 115 employees including patrol officers,
detectives, dispatchers, and other support staff
No
Superior
• 8 officers and 1 animal control officer
Yes
Fire Protection
Globe
• 9 paid and 18 volunteer personnel
• Fire station with one 1 ,500-gpm pumper, one
1,500-gpm aerial ladder truck, one 750-gpm
pumper, and one 0.75-ton utility truck
Yes
Miami
• 1 5 volunteer personnel
Yes
Canyon Fire Department
• 1 6 volunteer personnel
• Equipment consisting of one 3,000-gpm tanker,
one 650-gpm pumper, one 450-gpm brush
truck, one 250-gpm pumper, one 1,250-gpm
pumper, and one 450-gpm pumper
Yes
Tri-City Fire Department
• 30 volunteer personnel
• Equipment consisting of one 1 ,500-gpm
pumper, two 750-gpm and one 1 ,500-gpm
tankers, and one rescue vehicle
Yes
Central Heights Fire
Department
• 44 volunteer personnel
• Equipment consisting of three pumping units,
one rescue truck, four 4-wheel drive vehicles,
and three ambulances
Yes
Canyon Ambulance
Service
• 14 personnel
Yes
Superior Fire Protection
District
• 19 volunteer personnel
• Equipment consisting of one 1 ,000-gpm
pumper, one 750-gpm pumper, and one 500-
gpm pumper
Yes
PUBLIC UTILITIES
Water and Sewer
Globe
• 5 active wells and 1 inactive well
• Pump 1 .7 to 2.5 million gallons/day (mgd) in
summer and 0.6 to 1 .0 mgd in winter
• No water treatment needed except for chlorine
• Sewage treatment capacity of 1 .2 mgd;
currently treat 0.6 mqd
Yes
Miami
• Water provided by Arizona Water Company
• Sewage treatment by Town of Miami
No
Superior
• Water provided by Arizona Water Company
• 4 wells and surface water from Queen Creek;
water pumped 23 miles
• Sewage treatment capacity of 0.75 mgd with
current use of 0.25 mgd
Yes
3-248
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-70. Sumnfiary of Public Facilities and Services for the Globe-Miami and
Superior Areas (continued)
Description of Services
rTpuBHCI
Solid Waste
Globe-Miami
• Russell Gulch landfill provides services
Yes
Superior
• Pinal County Landfill Department operates
transfer of solid waste to landfill in Florence
Yes
Electrical Power and Gas
Globe-Miami
• Power provided to residents and most
businesses by Arizona Public Service Company
of Phoenix
• Salt River Project and Electric Power
Cooperative provide power to the major mining
companies
• Southwest Gas Corporation of Las Vegas
supplies natural gas
Yes
Superior
• Southwest Gas Corporation of Las Vegas
supplies natural gas
• Arizona Public Service Company supplies
electrical power
Yes
Telephone
Globe-Miami
• U.S. West Communications of Denver,
Colorado, provides service
Yes
Superior
• U.S. West Communications of Denver,
Colorado, provides service
Yes
HEALTH AND SOCIAL SERVICES
Globe-Miami
• 16 private physicians, 5 chiropractors, and 1 1
dentists
• Hospital care provided by the Cobre Valley
Community Hospital (49 beds with 22 percent
occupancy)
• Hospital has 1 6 active medical staff, 1 2 rotating
emergency staff, and 23 visiting specialists
• Social services provided by Gila County
Yes
Superior
• 1 dentist and 1 physician
• Health care provided by Superior Medical
Center; Cobre Valley Community Hospital
provides hospital care
Yes
Sources: Barron and Corso (1993), Bribiescas (1994), Dalmolin (1993), Hoopes (
993), Luevano (1993),
Malcovich (1993), Serrano (1994), and Stratton (1993)
Carlota Copper Project Final EIS
3-249
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-71. Student Enrollment and School Capacities
city
School
Grade
1991
1992
III 1
' '' 1
s' ^
C '4
Globe
Copper Rim
K-4
744
757
800
950
150
East Globe
5-6
350
325
400
650
250
Globe Jr. High
7-8
325
350
400
630
230
Globe Sr. High
9-12
643
625
750
1200
450
Miami
Central Heights
K-4
...
264
300
36
Inspiration
K-4
...
...
264
275
11
Las Lomas
K-4
...
...
270
300
30
Bullion Plaza
5-6
...
...
276
300
24
Lee Kornegay
Jr. High
7-8
—
—
348
500
150
Miami High
7-12
...
...
521
700-1000
179-479
Superior
Kennedy
K-6
382
378
384
550
166
Roosevelt Jr.
High
7-8
110
105
115
200
85
Superior High
9-12
183
179
173
350
177
Source: Public School Superintendents, (Blazevich 1993, Lennan 1993, Nutting 1993)
state because of the low valuation on property in
Superior.
Government and Public Finance
The principal governing bodies in Gila County include
the county commissioners, the school district, the
town of Globe, and the town of Miami. The three
Gila County commissioners supervise county oper-
ations, which include administrative, landfill, law
enforcement, road maintenance, and social
services. The school district is governed by an
elected school board. Globe and Miami each have
a mayor/council/manager form of government.
The principal governing bodies in Pinal County
include the county commissioners, the school district,
and the town of Superior. Pinal County also has three
county commissioners, and the town of Superior has
a mayor/council/manager form of government.
The governmental revenue sources and
expenditures in Gila and Pinal Counties are
useful in helping to determine the financial impacts
of industrial development on the counties and i
local communities. The fiscal and economic health
of an area can often be evaluated based on the .
growth in assessed valuation. Table 3-72 shows j
assessed valuation and the most recent tax rate j
for the counties and communities within the study
area.
Both Gila and Pinal Counties receive their revenues
from property taxes, disbursements of severance,
sales, and other taxes from the State of Arizona
under a formula established by the legislature. The
revenues are based on local property taxes levied
and total collections of state sales and other taxes
within each county. In fiscal year 1991-1992, Gila
County received $3,210,870 from the state through
such disbursements, while Pinal County received
3-250
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-72. Assessed Valuation by Jurisdiction (in thousands of dollars)
l^unty/Ctty
1992-93 Tax Rate/
$100 /^sessed
1 Vait^ation
1990-91
1991-92
1992-93
Percent
Increase
Average
|t Annual
Increase
Gila County
3.40
248,421
253,726
275,958
11.0
5.4
Globe
1.53
17,027
17,135
17,078
0.3
0.2
Miami
3.98
3,535
3,489
3,395
(4.0)
(2.0)
Pinal County
4.32
546,869
552,282
559,031
2.2
1.1
Superior
None
3,387
3,989
3,507
3.5
1 .8
Source: Horn (1993) and Pinal County Assessor (1993)
$6,941 ,000. That same year, Gila County collected
$8,917,356 in county property taxes, while Pinal
County collected $24,394,000. The incorporated
municipalities of Globe, Miami, and Superior get their
revenues from local sales taxes, local property taxes,
and the disbursement of state sales, severance, and
other taxes based on population. Property taxes form
a relatively small part of municipal government
revenues.
School districts obtain their revenues from taxes
levied on the property within their jurisdictions and
through disbursements of state sales and other taxes,
including mining severance taxes, according to a
formula established by law and based on average
daily student enrollment. Tables 3-73 and 3-74 show
expenditures and revenues for Gila and Pinal
Counties from 1989 to the current budget year.
3.7. 1.6 Social Impact Assessment
The social setting of the area can typically be
described as composed of small communities,
historically dependent on mining and mining-related
manufacturing for growth and economic viability.
Mining continues to finance the local economies and
provide the major source of stability in the region,
although tourism is becoming an increasing economic
factor.
The area has undergone numerous boom and bust
periods with the copper mining industry; populations
and unemployment rates have fluctuated throughout
the history of the towns of Globe, Miami, and
Superior.
Cultural diversity exists in the study area, with three
prevalent cultures represented, including Caucasians,
Native Americans, and Hispanics. The population is
largely working class; however, there are a number of
retirees who are moving into the area, representing a
larger portion of the overall population. Lifestyles,
social organizations, beliefs, values, and attitudes are
representative of “small town America” with a strong
work ethic. Each of the cultures represented main-
tains the general lifestyle that is representative of that
particular culture living in a small urban/rural environ-
ment. There does not appear to be any major cultural
conflicts between the diverse groups.
The San Carlos Indian Reservation currently has a
very high unemployment rate; the Tribal government
and the Bureau of Indian Affairs are working to create
a more stable economic situation for the Apache
population on the Reservation.
3.7. 1.7 Environmental Justice
In February 1994, President Clinton issued Executive
Order 12898, “Federal Actions to Address
Environmental Justice in Minority Populations and
Low-Income Populations.” The Executive Order
promotes environmental justice by directing federal
agencies to coordinate and formulate agency
strategies that identify and address, as appropriate,
disproportionately high and adverse human health or
environmental effects on minority and low-income
populations.
The Forest Service has adopted USDA guidelines,
which are based on the draft guidance for the EPA
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-73. Gila County - Expenditures and Revenues 1989 to 1993 (in thousands of dollars)
19^93
to
1990
1990;-
to
1991^
1991
to
:1992ft
1992
to
1993
(percentag^!>;;
Exoenditures:
General Government
2,387
2,551
2,760
3,217
10.5
13.3
Public Safety
2,721
3,194
3,497
3,585
9.6
14.8
Courts
2,331
2,580
3,037
3,386
13.2
14.0
Community
Development
558
594
772
1,097
25.3
4.5
Education
640
719
705
720
4.0
3.0
Health and Welfare
4,124
4,308
2,094
2,108
(20.0)
8.7
Solid Waste
580
961
834
621
2.3
2.6
Contingency
395
446
273
93
n/a
<1
Special Revenue
6,439
7,132
7,571
9,277
12.9
38.2
Special District
156
23
13
13
n/a
<1
Enterprise/Other
6,734
5,526
1,417
149
n/a
<1
TOTAL
27,065
28,034
22,973
24,266
100.0
Revenues:
Property Taxes
7,757
8,834
8,917
10,071
9.1
40.0
General Fund
Revenues:
Other Taxes
3,075
4,393
3,211
3,555
5.0
14.1
Licenses/Permits
59
55
58
80
10.7
<1
Intergovernmental
1,836
2,753
2,160
2,491
10.7
9.9
Charges for Services
378
422
815
657
20.2
2.6
Lines/Tel/Misc
1,310
1,657
1,392
1,357
1.2
5.4
Special Revenue
Funds
5,573
6,666
6,248
6,939
7.6
27.6
Other Funds
6,303
4,424
760
20
n/a
<1
Expenditures over
(under) Revenues
774
(1.170)
(587)
(904)
n/a
TOTAL
27,065
28,034
22,974
24,266
100.0
Source: Gila County (1989-1993) and Pinal County (1989-1993)
NEPA compliance program. These guidelines (1)
ensure that the Forest Service has fully analyzed
environmental effects on minority and low-income
communities, including human health, social, and
economic effects; and (2) assist in achieving the
goals of NEPA by identifying project impacts, a
range of reasonable alternatives, and mitigation
measures that avoid or minimize adverse
environmental effects, including identifying and
addressing impacts to minority communities and low-
income communities.
In the case of the Carlota Copper Project, the
potentially affected minority communities include the
Hispanic and the Native American populations
that comprise approximately 18 percent and 12
percent, respectively, of the current study area
population. Both of these minority communities also
represent some of the low-income population in the
area.
The most comprehensive statistics available on
minority and low-income families come from the 1990
Census of Population and Housing, Summary Tape
File 3A. More recent data are not available. Census
Tract and Block Group population, income, and
occupation information was collected for areas
potentially affected by the proposed project. Miami,
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-74. Pinal County - Expenditures and Revenues 1989 to 1993 (in thousands of dollars)
•
.
Actual
1989 to
1990
Estiniate^^
Estimated
^1991 to^
y 1992"^
Budgeted
^ 1992 to
^993^^
Average
JfncW^ ^
(b^centagef
1992 to
^1993 #
.rJPercent of
Total
Exoenditures:
General Government
16,111
19,674
13,417
16,896
1.6
22.6
Public Safety
6,692
7499
12,552
13,231
25.5
17.1
Highway and Streets
10,930
11,839
11,195
9,061
(6.1)
12.1
Sanitation
1,039
796
713
1,048
0.3
1.4
Health
12,325
1 1 ,450
2,636
2,862
n/a
3.8
Welfare
2,408
1,464
5,462
4,994
27.5
6.7
Culture and Recreation
291
321
448
697
33.8
1.0
Education
312
337
341
346
3.5
0.5
Special Revenue
Funds'
6,766
6,997
8,316
1 1 ,890
20.7
16.0
Debt Service
0
447
778
1,338
n/a
1.8
Enterprise Fund
9,256
6,921
8,730
1 1 ,735
8.2
15.7
Special Districts
436
436
523
522
6.2
0.7
TOTAL
66,566
68,181
65,111
74,620
3.9
100.0
Revenues:
Property Taxes
23,869
23,331
24,394
25,836
2.7
34.6
Other Taxes
3,844
3,896
4,644
4,478
5.2
6.0
Intergovernmental
(including sales tax)
24,953
23,246
18,898
21,845
(43.6)
29.3
Licenses and Permits
492
522
513
543
3.3
0.7
Charges for Services
3,069
3,532
2,444
3,256
2.0
4.4
Lines/Tel/Misc
2,351
2,379
3,015
2,477
1.8
3.3
Other Funds
6,654
2,369
8,595
11,085
18.6
14.9
Expenditures Over
(under) Revenues
1,334
8,906
2,608
5,100
6.8
TOTAL
66,566
68,181
65,111
74,620
3.9
100.0
'Except “Highway and Streets” and “Culture and Recreation” (General Fund and Special Revenue Fund)
Source: Pinal County (1989-1993)
Globe, Claypool, Midland, and surrounding rural
areas were represented by five census tracts. The
Hispanic and Native American population represented
29.2 percent and 1 .5 percent respectively of the total
1990 census population of 18,106 within these five
census tracts. The San Carlos Indian Reservation is
also broken out as a census tract. Although the San
Carlos Indian Reservation is outside the
geographically defined study area, some Native
Americans living on the Reservation may become
employed either directly or indirectly because of mine
development. The Native American population
represents approximately 93 percent of the total 1990
population of 3,616 in this census tract. The Top-of-
the-World subdivision, which is located directly south
of the proposed project, is located in Pinal County,
Census Tract 2, Block Group 2.This Block Group
encompasses approximately 200 square miles; it
also includes areas not included in the study area.
However, this Block Group provides the best
available data on Top-of-the-World. The Hispanic
population represents only 4 percent and the Native
American population represents only 1 .2 percent of
the total 1990 population of 1,284 in this Block Group.
Poverty status by race and by census tract was also
evaluated for environmental justice. Of the 5,293
Hispanic individuals in the census tract representing
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
Globe/Miami and the surrounding area, an estimated
764 (14 percent) were below the poverty level. In the
same area, approximately 111 (40 percent) of the
279 Native Americans were below the poverty
level (Summary Tape File 3A, 1990 Census of
Population and Housing). On the San Carlos
Indian Reservation, 2,099 (62 percent) of the 3,382
Native Americans were below the poverty level. In
Census Block 2, Block Group 2, which includes the
Top-of-the-World subdivision, an estimated 235 (18
percent) of the 1 ,284 people were below the poverty
level.
Table 3-75 shows 1990 minority and low-income
populations that would potentially be affected by the
proposed project. It is assumed that a similar
percentage of the minority and low-income population
would be represented in the census tracts and blocks
described in Table 3-75.
3.7.2 Environmental Consequences
The primary socioeconomic issues addressed relative
to the Carlota Copper Project included the following:
(1) beneficial and adverse impacts of the project on
the local labor market; (2) beneficial and adverse
impacts to the local housing market and property
values at Top-of-the-World; and (3) beneficial and
adverse effects from the project to state, county, and
local community economies from tax revenue
generation and the demand for public services. This
section complies with the requirements of FSM
Section 1970 concerning economic and social impact
analyses.
Evaluation criteria that were used to analyze
socioeconomic impacts included the following:
• Change in short-term and long-term employment
associated with the project in a number of primary
and secondary jobs
• Change in demand for temporary and permanent
housing during construction and operations
based on estimated changes in population
• Change in property values in project vicinity
• Change in economic base from recreation and
ranching to mining
• Change in demand for public services based on
estimated changes in population
• Change in annual tax revenues directly related to
project expenditures
This section evaluates potential social and economic
impacts of the proposed Carlota Copper Project. The
existing social and economic environment of the local
area, including the economic slowdown evident
during the past decade, was considered as part of the
evaluation of the impacts associated with the
proposed project. The project-related impacts, both
temporary and permanent, were related to changes in
the overall economic conditions in the area, including
continued mining exploration, potential expansion,
development, lay-offs, and construction of other
proposed projects.
An economic base model was designed to evaluate
the socioeconomic impacts of mining in the west
(Kathol 1985). This model has been calibrated to
reflect the most current conditions and to make pro-
jections of future impacts based on local and regional
parameters. The model estimates the direct and
indirect employment effects of the proposed project,
population impacts, housing demand by type and
location, and the number of new school age children
in each affected school district.
Impact analyses were based on known character-
istics of the affected area, supported by professional
planning standards and empirical data from other
mining projects. In addition, employment and income
multipliers from recent mining economic impact
analyses were used to make the most reasonable
projections.
Continuous operation of the Carlota Copper
Project would depend on the future market price
of copper. In the past, mines have experienced
temporary and long-term shutdowns because
of declining markets and prices of the mineral
produced. If the price of copper declines below a
break-even operations cost, management could
shut down the Carlota operation. If this situation
occurred, both the beneficial and adverse impacts
discussed in the following sections would be
reversed until the price of copper increased and
operations resumed.
3-254
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Carlota Copper Project Final EIS
3-255
3.0 Affected Environment and Environmental Consequences - Socioeconomics
3. 7.2. 1 Proposed Action
Population and Demographics
The population in Gila and Pinal Counties is
primarily dependent on two industries: mining and
government. Non-basic sectors, such as services
and trade primarily related to the mining industry,
have also contributed to the population base.
Fluctuations in population are likely to occur because
of the uncertainty of the market for copper metals,
as evident in the slowdown in the industry since the
early 1980s. To date, exploration and mining activity
continue at a limited level. An additional impact on
population would occur primarily in the Gila County
area during the period of construction of the Carlota
Copper Project.
Construction. The effect of the project on the area
population will depend largely on the number of
in-migrating workers and the characteristics of their
families. Another factor affecting construction impacts
is the management style of the construction contrac-
tor. The construction company for the Carlota Copper
Project has not yet been selected. Most contractors
try to hire locally; however, depending upon the skill
level required, some contractors bring a portion of
their workforce with them. If the construction contrac-
tor is hired from the Phoenix or Tucson area, it is
more likely that the workers would commute daily
from their places of residence. If the contractor is
hired from outside the area, more of the construction
workforce is likely to come from outside the study
area.
A best estimate of in-migrating construction
workers has been incorporated into the analysis
based on recent employment statistics from the
local area Arizona Employment Security Division.
The peak construction workforce is estimated at 177
workers in the fifth month of construction. The
majority of the construction workforce (approximately
70 to 80 percent) would need to be skilled workers.
During the peak construction period, this computes
to an estimated 123 to 142 skilled workers. The
impact scenario would suggest that approximately
40 percent (71) of the workforce would come from
outside the area {Table 3-76), based on other
ongoing construction projects in the area and the
availability of a local skilled labor force.
Since there is limited housing available, it is
anticipated that only a small number of construction
workers would relocate or bring their families. The
resulting peak, non-local, construction-related
population, including families of construction workers
and indirect labor, would be an estimated 92 people.
This population level would continue for approxi-
mately 2 months and then decline.
The construction workforce would average 91 work-
ers over the 10-month construction period {Table
3-77). Because of the limited availability of housing
throughout the study area (i.e.. Globe, Miami,
Claypool, Midland, and Superior), indirect employ-
ment is estimated to be minor for the construction
phase. Non-local, indirect employees are estimated at
four during peak construction and two during the
overall construction period based on an employment
multiplier of 1 .2. This multiplier suggests that for every
new construction job, an additional 0.2 indirect jobs
would be created (Dobra 1993). The construction of
the mine would provide additional jobs to the local
employment base, which would be considered a
beneficial impact.
Operations. Employment during operation of the
project would average 282 workers during the first
8 years, with a maximum of approximately 301
workers. In the following 7 years of operations, the
employment level would decline to an average of 255.
Subsequent decreases in employment would occur
the last 7 years during recovery, closure, and
reclamation.
The operations labor force would consist of
more than 90 percent skilled labor and less than
10 percent unskilled labor. Because of the uncertainty
of the timing of operations start-up, low-impact
{Table 3-78) and high-impact {Table 3-79) scenarios
were made to reflect the uncertainty of the availability
of local labor. Conversations with local mining
representatives are mixed with respect to the
level of skilled workers in the Globe-Miami area.
Some say it is extremely difficult to find skilled labor
within the local labor pool (Benson 1993, Hetrick
1993, Burrell, 1994). Others suggest that most
trades are available locally, except for electricians
and operating engineers (Palmer 1993). The
Arizona Department of Economic Security concluded
that skilled labor for specific construction and
3-256
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-76. Projected Employment, Population, Housing, and School-Age Children
(Peak Construction Phase)
Employment:
!
Peak Annual ^
Employment'
Local
Direct*
N(mi» I
,, Local ^
1 Direct
,\lotaf:
i Direct
Local
Indirect
Local
Indirect
Indirect*
Total New
Empioynwnt
New
Employment
177
106
71
177
10
4
14
191
Housing:
Nort^Lodai Direct
Non-Lccat indirect
New Househoide
New Households"'
New Workers
71
4
Single^
64
2
33
Married (1 Worker)
7
1
8
Married (2 Workers)^
0
1
1
Total New Households
39
3
42
Population and School-Age Children:
^ -?«Slobe
Miami
^ Other;;- : .v:
TCtai
New Household Allocation
34
6
2
New PoDulation®
Single Household
53
10
3
93
Married Household
22
4
1
TOTAL
75
14
4
New School Children''
Secondary
2
0
0
6
Primary
3
1
0
TOTAL
5
1
0
Housina Preference’"
Single-Family
5
1
42
Multi-Family
2
0
Mobile Home
7
1
1
Other (RV or Motel)
20
4
1
TOTAL
34
6
2
'The average construction \workforce is 91 over the 10-month construction period. The peak workforce of 177 would commence in the fifth month.
n"he construction workforce is assumed to be 60 percent local and 40 percent non-local. Local workers would commute to and from their places of
residence to work on a daily basis.
’Indirect construction employment is calculated using a construction employment multiplier of 1.2 based on 1978 employment location quotients and
basic/non-basic employment. It is assumed that 70 percent of the members of the indirect labor force are second persons in the direct labor households
or current residents of the study area.
‘The construction workforce is composed of 90 percent single workers or married without family, and 10 percent married workers with family. For indirect
workers, it is assumed 50 percent are single or without family present and 50 percent are married with family present.
’It is assumed that single-worker households would average 1 .5 members because of the lack of rental housing in the project area.
‘Both husband and wife of 10 percent of the married workforce are assumed to work at the mine during construction; for indirect workers, 30 percent are
assumed to be two-worker households.
’"Other" represents areas in or around Superior.
'Population estimates are based on 1 .5 persons per household for single households with direct workers. 1 .5 persons per household for single households
with indirect workers, 3.1 persons per household tor married households in Globe, and 3.3 persons per household for married households in Miami or
Superior.
‘School-age children are estimated at 0.75 per married household. Fifty-five percent of school-age children are primary students, and 45 percent are
secondary students.
Globe (80%)
Miami (15%)
Other (5%)
Single-Family (SF)
15
15
15
Multi-Family (MF)
5
5
5
Mobile Home (MH)
20
20
20
Other (RV Site or Motel)
60
60
60
Note: All projections in this table are estimates and do not represent actual figures.
Carlota Copper Project Final EIS
3-257
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-77. Projected Employment, Population, Housing, and School-Age Children
(Average Construction Phase)
Employment:
Annual
Employment'
Local
Direct
Non-
Local
Direct
Total
Direct
Local
Indirect
Non-
tndir^t
Total
indirect^
Total New
Employment
New
Employment
91
55
36
91
5
2
7
98
Housing:
Non-Local Direct
Non-Local Indirect
New Households
New Households"
New Workers
36
2
Single'
33
1
17
Married (1 Worker)
4
1
4
Married (2 Workers)'
0
0
0
Total New Households
20
1
21
’opulation and School-Age Children:
-
: Qlobe : if*
Miami
Other'
Totai
New Household Allocation
17
3
1
New PoDulation“
Single Household
27
5
2
47
Married Household
11
2
0
TOTAL
38
7
2
New School Children^
Secondary
1
0
0
4
Primary
2
1
0
TOTAL
3
1
0
Housino Preference"
Single-Family
3
0
0
21
Multi-Family
1
0
0
Mobile Home
3
1
0
Other (RV or Motel)
10
2
1
TOTAL
17
3
1
'The average construction w/orkforce is 91 over the 10-month construction period. The peak workforce of 177 would commence in the
fifth month.
^The construction workforce is assumed to be 60 percent local and 40 percent non-local. Local workers would commute to and from
their places of residence to work on a daily basis.
'Indirect construction employment is calculated using a construction employment multiplier of 1.2 based on 1978 employment location
quotients and basic/non-basic employment. It is assumed that 70 percent of the members of the indirect labor force are second
persons in the direct labor households or current residents of the study area.
The construction workforce is composed of 90 percent single workers or married without family, and 1 0 percent married workers with
family. For indirect workers, it is assumed 50 percent are single or without family present and 50 percent are married with family
present.
'h is assumed that single-worker households would average 1 .5 members because of the lack of rental housing in the project area.
Both husband and wife of 10 percent of the married workforce are assumed to work at the mine during construction; for indirect
workers, 30 percent are assumed to be two-worker households.
'"Other” represents areas in or around Superior.
“Population estimates are based on 1 .5 persons per household for single households with direct workers, 1 .5 persons per household for
single households with indirect workers, 3.1 persons per household for married households in Globe, and 3.3 persons per household
for married households in Miami or Superior.
“School-age children are estimated at 0.75 per married household. Fifty-five percent of school-age children are primary students, and
45 percent are secondary students.
Globe (80%)
Miami (15%)
Other (5%)
Single-Family
15
15
15
Multi-Family
5
5
5
Mobile Home
20
20
20
Other (RV Site or Motel)
60
60
60
Note: All projections in this table are estimates and do not represent actual figures.
3-258
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-78. Projected Employment, Population, Housing, and School-Age Children
(Operations Phase/Low-Impact [Larger Local Workforce] Scenario)
Employment:
k
i Annual
1 Employment
Direct'
Non- ,
Ip'caL
^Direct f
Direct
. . .
Local
Indirect
Non- 3
^ Locals
tlndirect.
^ Total New
Employment
New
Employment
282
225
57
282
29
13
42
324
Housing:
Non-Local Direct
Non-Local Indirect
^ New HoUiiiirftibidtl
New Households
New Workers'’
57
13
Single
11
5
11
Married (1 Worker)
36
3
39
Married (2 Workers)'
5
2
7
Total New Households
48
9
57
Population and School-Age Children:
.
Globe---"
Miami
Otfier*
Total
New Household
Allocation'
46
8
3
New PoDulation'
Single Household
13
2
0
161
Married Household
115
23
8
TOTAL
128
25
8
New School Children®
Secondary
13
2
1
35
Primary
15
3
1
TOTAL
28
5
2
Housino Preference'
Single-Family
34
6
2
57
Multi-Family
5
1
1
Mobile Home
6
1
0
Other (RV or Motel)
1
0
0
TOTAL
46
8
3
'For the low-impact scenario, the operations workforce is assumed to be 80 percent local and 20 percent non-local.
'Indirect operations employment is calculated using an operations employment multiplier of 1.74 (Dobra 1993). It is assumed that 70
percent of the members of the indirect labor force are second persons in the direct labor households or current residents of the study
area.
The operations workforce is composed of 20 percent single workers and 80 percent married workers. The indirect workforce is
composed of 40 percent single workers and 60 percent married-with-family workers.
‘Both husband and wife of 10 percent of the married workforce are assumed to work at the mine.
^’Other” represents areas in or around the town of Superior.
'During operations, it is assumed that 80 percent of the new employees would live in the Globe area, 15 percent in the Miami area,
and 5 percent in Superior or areas around Superior.
'Population estimates are based on 1.5 persons per household for single households, 3.1 persons per household for married
households in Globe, and 3.3 persons per household in Miami and Superior.
‘School-age children are estimated at 0.75 per household. Fifty-five percent of school-age children are primary students, and 45
percent are secondary students.
‘Housing preferences shown are based on the following
jercentage distribution:
Globe (80%)
Miami (15%)
Other (5%)
Single-Family
75
75
75
Multi-Family
10
10
10
Mobile Home
13
13
13
Other (RV site or Motel)
2
2
2
Note: All projections in this table are estimates and do not represent actual figures.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
Table 3-79. Projected Employment, Population, Housing, and School-Age Children
(Operations Phase/High-Impact [Smaller Local Workforce] Scenario)
Employment:
Annual
Employment
Local
Direct’
Non-
Local
Direct
Total
Direct
Local
indirect
Non-
Looai
Indirect
Total
IndlrcKSt^
Total New
Employment
New
Employment
282
168
114
282
59
25
84
368
Housing:
Non-Locai Direct
Iton-Local indirect
New Houseltolda
New Households
New Workers^
114
25
Single
23
10
22
Married (1 Worker)
73
6
79
Married (2 Workers)"'
9
5
14
Total New Households
97
17
114
Population and School-Age C
hildren:
Globe W'
Miami ::
Other^
Total
New Household
Allocation'
91
17
6
New Population'
Single Household
26
5
2
323
Married Household
229
46
15
TOTAL
255
51
17
New School Children'
Secondary
25
4
1
68
Primary
30
6
2
TOTAL
55
10
3
Housino Preference'
Single-Family
68
13
4
114
Multi-Family
9
2
1
Mobile Home
12
2
1
Other (RV or Motel)
2
0
0
TOTAL
91
17
6
'The new operations workforce is assumed to be 60 percent local and 40 percent non-local for the high-impact scenario.
^Indirect operations employment is calculated using an operations employment multiplier of 1.74 (Dobra 1993). It is assumed that 70
percent of the members of the indirect labor force are second persons in the direct labor households or current residents of the
study area.
^he operations workforce is composed of 20 percent single workers and 80 percent married workers. The indirect workforce is
composed of 40 percent single workers and 60 percent married-with-family workers.
'Both husband and wife of 10 percent of the married workforce are assumed to work at the mine.
‘"Other” represents areas in or around the town of Superior.
‘During operations, it is assumed that 80 percent of the new employees would live in the Globe area, 1 5 percent in the Miami area,
and 5 percent in Superior or areas around Superior.
'Population estimates are based on 1.5 persons per household for single households, 3.1 persons per household for married
households in Globe, and 3.3 persons per household in Miami and Superior.
‘School-age children are estimated at 0.75 per household. Fifty-five percent of school-age children are primary students, and 45
percent are secondary students.
Housing preferences shown are based on the following
jercentage distribution:
Globe (80%)
Miami (15%)
Other (5%)
Single-Family
75
75
75
Multi-Family
10
10
10
Mobile Home
13
13
13
Other (RV site or Motel)
2
2
2
Note: All projections in this table are estimates and do not represent actual figures.
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
mining-related job categories was limited in the area
(Jenkins 1993).
Based on these findings, a low-impact scenario
{Table 3-78) would represent 80 percent (225)
of the operations labor force coming from the
local area. For the high-impact scenario {Table 3-79),
an estimated 60 percent (168) of the total labor
force would be from the area. The more training
programs provided by Carlota, the higher the
likelihood that jobs can be filled by local labor.
For example, the San Carlos Indian Reservation
provides a large, principally unemployed,
unskilled labor force that could be used if trained
appropriately.
From 1995 through approximately 2010, the
new population associated with this level of
operations employment is estimated at 161 for
the low-impact scenario and 323 for the high-impact
scenario. The projected population increase for
the high-impact scenario represents a less than
1 percent increase for Gila County, and
substantially below 1 percent for Pinal County.
The population increase related to operations is
expected to primarily affect the Globe-Miami areas,
including Claypool and Midland (306), with fewer
operations workers locating in Superior or rural
areas (17).
For the Globe-Miami area, the 3.6 percent
population increase would be considerably higher
than the growth rate for the past 6 years, where
population has either declined or grown at a very slow
rate of less than 1 percent. Superior would show
minor growth (0.5 percent), which is a change from
the average annual decline in population of 1.4
percent since 1987. This growth in population would
have a positive impact on the economic vitality of the
area.
Following the completion of mine production, there
would be a reduction in the workforce. The reclama-
tion workforce would be considerably smaller than the
operations workforce, and if no additional activities
were occurring in mining or related fields in Gila and
Pinal Counties, people directly and indirectly
employed by the project would probably leave the
area.
Employment and Economy
The principal economic effect of the proposed project
would be an increase in mining employment in Gila
and Pinal Counties, as well as some growth in the
retail and service sectors — potentially in Globe,
Miami, and Superior. There would be a relative
increase in the economic base due to the change
from recreation and ranching to mining.
Total income in the area would increase, since the
mining sector provides the highest wage rate of any
wage and salary employment sector in Arizona
(Arizona Department of Economic Security 1993).
Most of the economic impact would occur in Globe,
where the influx of new employment and population
would stimulate the local economy. Employment
impacts of the proposed project are listed in Tables
3-78 and 3-79.
There is a skilled labor force in the Globe-Miami area
that is currently underutilized. Some skilled mine
workers have stayed in the area and have taken other
types of jobs. When Carlota starts mining, there will
likely be a transfer of workers from other mining jobs
or lower paying jobs to positions offered by Carlota.
Despite the large unemployed labor force at the San
Carlos Indian Reservation, it is not anticipated that
there would be a large number of Native Americans
working at the new mine unless Carlota decides to
create an intensive recruitment and training program
for the Native American population. Traditionally,
there has been a very small percentage of Native
Americans employed in the mines (Noline 1993,
Hetrick 1993). If the Native American population is
strongly recruited and trained, there is potentially a
local labor force of 1 ,000 to 2,000 workers. However,
according to the TERO representative, long-term
employment for Native Americans usually is not
pursued. These employment issues have to do with
cultural differences and may require active
participation by the TERO office in proposed training
programs.
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
As shown in Tables 3-76 through 3-79, local indirect
employment would also be generated from the
development of the proposed project. Indirect
employment is typically generated in the services and
trade sectors. These jobs may attract some of the
Native American population on the San Carlos
Reservation, as well as the population that lives in the
surrounding area. The increase in secondary jobs
would be considered a positive impact to this minority
population.
Construction. As discussed in Section 3. 7.1.1,
Socioeconomics - Population and Demography, the
majority of the construction workforce would likely
come from the local labor market. Inmigrant labor
would primarily come from other areas around the
state and throughout the west (Hertzog 1992).
Secondary employment related to constructing the
project would average 14 based on a multiplier of 0.2
indirect local jobs per direct job (Dobra 1993). The
majority of these jobs are expected to be filled by
local residents or second persons in a direct worker
household. The increased level of employment during
the construction phase would be regarded as a
beneficial impact, given that the study area
unemployment rate is over 9 percent.
Operations. The permanent operations workforce is
expected to average 282 workers the first 8 years and
peak at 301 in Year 8. The new jobs would represent
a 22 percent increase in comparison to the 1993
estimated mining employment in Gila County. In the
following 7 years of operations, the employment level
would decline to an average of 255, a 19.6 percent
increase in employment as compared to the 1993
estimated mining employment level. Subsequent
decreases in employment would occur the last 7
years during recovery, closure, and reclamation. This
overall increase in employment would be considered
a positive impact. Indirect employment is estimated at
84 new workers. These jobs represent a 2 percent
increase in total services and trade sector employ-
ment in the Gila County area.
The indirect employment generated during operations
was estimated using an employment multiplier of 1 .74
(0.74 indirect local jobs per one permanent mining
position). The 1.74 multiplier was a variation on the
multipliers defined in studies by Dobra (1993), and
the U.S. Department of Commerce (1991). The
updated employment multiplier for the gold mining
sector is 19 jobs per million dollars of direct
expenditure, which represents an employment
multiplier of 3.0. This multiplier means that 2.0 indirect
and induced jobs are created statewide from one
permanent mining job. In the 1988 study, the
statewide multiplier was further disaggregated to the
local rural (60 percent) and statewide urban areas
(40 percent). Applying this split suggests a local
rural indirect job impact of 1 .2 and a statewide
urban indirect job impact of 0.8 for each permanent
mining position created. These are the employment
multipliers that were used in Tables 3-76 and
3-79 to estimate indirect impacts from the mine
development.
Despite the local and non-local employment
estimates shown in Tables 3-78 and 3-79, the
production status of other mining projects in the
near future would determine the availability of local
labor that could be hired by Carlota for the Carlota
Copper Project. If mineral exploration and production
has stabilized at the time of project development,
a higher percentage of local labor may be available.
If the reverse is true, the overall non-local impact of
the proposed project would be greater. Conversations
with area mines (Morano 1993, Brown 1993, James
1993) indicate that employment levels should remain
somewhat static since expansions have recently been
completed (Morano 1993). Some mines may increase
employment while others are uncertain about future
employment levels. Gains in area-wide permanent
employment for the duration of the project would be
considered a beneficial impact.
Higher direct cumulative employment figures may
increase the indirect employment multiplier. Losses in
direct and indirect employment would result upon
project completion in 2010.
Personal Income
The proposed project would generate an annual
payroll averaging $10,114,000 over the 15 years of
mining. This total personal income from the Carlota
Copper Project would represent 2.2 percent of all
personal income received by Gila County residents
(Carlota Copper Company 1993a). A large portion of
this total income would be spent in the area and
would result in increased sales tax receipts
throughout the area. Personal income effects would
be considered beneficial to the area.
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
Housing
As described in Section 3.7. 1.4, Socioeconomics -
Housing, the existing housing market throughout the
study area is very limited, especially for rental units
and single-family housing. Prospects for increased
numbers of rental units within the study area are low.
Development is difficult because of the topography of
the private land in the area and the large percentage
of publicly held property. The permanent housing
market is also very limited, with a strong, existing
demand for new housing. If there is a large influx of
people seeking permanent housing, demand will most
likely exceed the supply.
Construction. Assumptions used in the housing
impact assessment are listed in Tables 3-76 through
3-79.
The Carlota Copper Project would create an
estimated 42 new households from construction
during the peak period and 21 households for
the overall average construction period. These
estimates are based on an assumption of 1 .5
single construction workers per household because of
the lack of rental housing in the study area. If workers
prefer not to share housing, the estimated demand for
temporary housing would be greater.
If the temporary rental housing supply remains at the
current level, construction workers would have a
difficult time finding housing for rent throughout the
study area, including Globe, Miami, and Superior.
There are a few RV parks with spaces available;
however, these spaces fill up rapidly, especially
during the winter months. If rentals continue to remain
fully occupied, the primary source of housing in
Globe-Miami would be motels. Motels could
accommodate much of the workforce, provided that
blocks of rooms throughout the area are reserved in
advance. In Globe-Miami, there are eight motels that
would rent some rooms on a weekly basis. Over 296
rooms could potentially be available for construction
workers. If motels were to provide the majority of
construction workers' accommodations, the tourist
business could be adversely affected, particularly
during the winter months. A shortage of housing
creates several related problems if not resolved in a
timely manner. Overcrowding in units that are avail-
able may cause worker dissatisfaction and higher
employment turnover rates; both situations are
expensive and potentially socially disruptive.
Most construction workers prefer rental units that
provide some kitchen facilities, so motel rooms are
generally less desirable than RV parks or mobile
homes. Tables 3-76 through 3-73 show potential
housing demand during the peak and average
construction period.
Operations. The availability of housing for sale also
appears to be inadequate for the permanent opera-
tions workforce, according to local representatives
and realtors (Long 1993, Globe/Miami Chamber of
Commerce 1993, McGinley 1993, Cagalj 1993). The
housing market is very tight in Globe, Miami,
Claypool, Midland, and Superior. Five out of the
seven real estate offices in the Globe-Miami area
showed a total of 60 listings in November 1993. The
median price range of housing is $50,000 to $60,000,
with housing costs ranging from $10,000 to $180,000.
Lot availability is limited because of the scarcity of
private land that is developable. Tables 3-78 and 3-79
show potential housing demand and distribution dur-
ing operations. In order to meet the projected low (57)
and high (114) demand for housing units, there would
need to be a substantial increase in the current level
of building activity in the study area.
In regard to the effect the project would have on the
residential properties located in Top-of-the-World,
there are two possible changes: (1) property would
increase in value given its proximity to the project
(Long 1993), or (2) the increased noise, traffic, and
visual impacts would reduce the value of the property.
Based on professional opinion and current conditions
in the Globe-Miami area, it is difficult to predict
whether the property values would increase or
decrease substantially in this area because of the
Carlota Copper Project. The properties immediately
adjacent to the project area are considered small-
acreage ranchettes. These properties are located
close to a large transmission line, and there are no
covenants restricting animals, junk cars, or types of
housing, although zoning is limited. The properties
are moderately priced, but they are not currently in
demand. There would be no direct visual impact to
the properties, except for one current commercial
property, although views of the mine would dominate
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
over the ridge top. Noise impacts could affect the
properties; however, the associated economic impact
cannot be measured directly. If drawdown of water
levels occurs in residential water supply wells from pit
dewatering, decreases in property values may occur;
further residential development at Top-of-the-World
may also be limited if ground water availability
decreases.
Based on research related to other residential
properties and new development throughout the
Globe-Miami Mining District, proximity to mine
operations from both a visual and a noise standpoint
has not resulted in obvious impacts to property
values. The Chaparral development, in particular,
was recently built close to the Cyprus-Miami mine
tailings (approximately 1 mile from the tailings). The
price of these homes exceeds $100,000.
Public Facilities and Services
Public Safety. The following list summarizes
impacts of the Carlota Copper Project on public
safety. The Globe, Miami, and Superior municipal
law enforcement departments feel that they
have adequate facilities, personnel, and
equipment to provide services to additional
population.
• The Gila County Sheriffs Department feels that
the staff has a current shortage of three officers
in the Globe District given the size of the juris-
dictions. This shortage would be aggravated with
the addition of 93 new people during the peak
construction period and 161 to 323 new people
during the operations phase.
• The Pinal County Sheriffs Department would not
be adversely affected by the additional population
resulting from the project.
• Throughout the project area, there are seven
municipal or volunteer fire departments that
provide fire protection and mutual aid. Based on
conversations with these departments, it does not
appear that the influx of new people would have
an adverse impact on service delivery in their
service areas, except for the Miami Fire
Department.
Public Utilities. Growth-related impacts to utilities
and services depend on the capacities of the
systems affected, current demand, and projected
growth.
In Globe, there is adequate capacity to supply water
to the estimated population related to the proposed
project. The Globe public works director feels that the
area has adequate water for the next 50 years.
Currently the Globe wastewater treatment facility is
operating at 50 percent of total capacity; there is
adequate capacity to accommodate growth from the
proposed project.
Water is supplied to Miami by the Arizona Water
Company. The existing water supply is inadequate
for the existing population and additional growth
in the area. Information on the Miami sewer system
and sewer treatment facility is unavailable at this time.
The Superior water supply system operates at 82
percent of capacity; the wastewater treatment system
operates at 33 percent of capacity. Additional demand
from project-related growth could easily be
accommodated.
Rural areas within the two-county region have
individual wells and septic systems.
• The water supply at Top-of-the-World comes
solely from individual water supply wells. The
wells in the area have experienced declining
water levels and decreased yields. These
problems are described in Section 3. 3.2.1, Water
Resources - Proposed Action. Dewatering at the
Carlota/Cactus and Eder South pits could
potentially have an impact on the supply of water
available to existing and proposed housing in the
area. Pit dewatering and water supply well field
development used in project operations could
potentially draw down the well water levels below
acceptable levels. Comprehensive monitoring
and mitigation for potential impacts to water
supply wells are proposed in Section 3.3.4, Water
Resources - Monitoring and Mitigation Measures,
to attempt to mitigate water supply problems at
Top-of-the-World and other rural residences in
the vicinity of the project attributable to Carlota’s
operations.
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• Existing solid waste disposal capacity in Gila
County is adequate to serve the estimated
project-generated population. The remaining life
of the landfill is 8 to 10 years. However, the life of
the landfill may be shortened depending upon the
level of use.
• The solid waste transfer system in Superior has
adequate capacity to serve the project-related
population.
• All growth-related impacts from the proposed
project to the supply of natural gas, electricity,
and telephone service could be accommodated
by the existing systems in all affected areas.
• Additional supplies of propane are available from
local sources.
Health Care and Social Services. Health care
facilities and personnel are expected to be adequate
to accommodate population growth related to the
proposed project. Most major health care services for
area residents are provided by Cobre Valley
Community Hospital in Globe or major hospitals in the
Phoenix metropolitan area. Current occupancy at the
Cobre Valley Community Hospital averages 22
percent, which suggests sufficient excess capacity to
handle the population growth related to the project.
Other social services provided by Gila County are
adequate to serve the new population. No major
impacts on health care are anticipated in the Superior
area. Other social services provided by Pinal County
are adequate to serve the new population.
Recreational and Cultural Services. The following
impacts would occur for recreational and cultural
services:
• Recreational and cultural programs and facilities
provided by the town of Globe, with some
assistance from Gila County, are perceived to be
adequate to serve additional population. In the
past, the mines have contributed land or in-kind
services to the recreation department to build
parks and ball fields. These contributions have
provided facilities that the town would not other-
wise be able to construct and operate.
• Library services are not expected to be adversely
affected by the project-related population.
• The Superior Recreation Department operates
only in the summer. The town representative
feels that two parks and summer programming
would be adequate for the population growth
related to the Carlota Copper Project.
• Local community facilities, including parks and
libraries, are believed to be adequate to
accommodate project-related population growth.
Education. Impacts on education would include the
following:
• Based on construction and operations projections
listed in Tables 3-76 through 3-79, the estimated
number of school-age children for the proposed
project would not adversely affect the Globe
Unified or Miami Unified School Districts. As
shown in Table 3-71, all schools in the two
districts have adequate capacity for the projected
new school-age children.
• With the high-impact scenario {Table 3-79), two
new teachers would be required based on the
projected 55 new students in the Globe Unified
School District. The Globe Unified School District
superintendent suggested new staffing require-
ments for increments of 25 students.
• As shown in Tables 3-76 through 3-79, the
projected impacts to the Superior Unified School
District during construction and operations would
be minor. The school district has more than
adequate capacity for the estimated new school
children during both construction and operations.
Government and Public Finance. With the influx of
new population to an area, there would be certain
associated costs and revenues. Typically, new
population requires incremental increases in services
from municipal and county service providers.
However, in the case of the Globe-Miami and
Superior areas, much of the infrastructure is in place
to serve a larger population because of peak growth
in the 1960s through early 1980s. Although the basic
infrastructure exists to provide services to a larger
population, it has aged and deteriorated to some
extent. Funding is no longer available to hire
personnel to maintain and operate the systems.
Nevertheless, in many cases, upgrading the existing
facilities and adding staff would be adequate to
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3.0 Affected Environment and Environmental Consequences • Socioeconomics
provide services to the additional population related to
the Carlota Copper Project. The capital investment
would typically be much less because the towns have
supported larger populations in the past. Annual
operating costs would increase, given the necessary
additions of personnel and equipment to serve an
increased population.
The following information summarizes impacts of the
Carlota Copper Project on government and public
finances:
• Based on its expected rate of production,
expected 1 995 copper prices, and existing
Arizona tax rates, it is expected that the Carlota
Copper Project would pay an average of approxi-
mately $700,000 per year in severance taxes to
the State of Arizona. Part of this annual sever-
ance tax payment would be retained by the state,
but part would be distributed to county and
municipal governments, as well as school districts
throughout the state, including those in Gila and
Pinal Counties. These increased revenues would
be considered a beneficial impact.
• It is estimated that the Carlota Copper Project
would pay annual property taxes of approximately
$1,160,000 to Gila and Pinal Counties (as collec-
tors) for the State of Arizona, the counties them-
selves, the Miami Unified and Superior Unified
School Districts, the Gila Pueblo Campus of
Eastern Arizona College, the Central Arizona
College, and other local taxing jurisdictions.
Because of the location of the known ore
reserves, it is expected that 74 percent of the
assessed property valuation would be assigned
to the Miami Unified School District of Gila
County, with the other 26 percent assigned to the
Superior Unified School District of Pinal County.
In addition, Carlota would pay annual corporate
income taxes, sales taxes, unemployment
compensation and workers' compensation taxes,
and miscellaneous other taxes and fees, primarily
to the State of Arizona. These increased
revenues would be considered beneficial.
• Estimates of corporate income taxes payable to
the State of Arizona would average $584,000 per
year. Most of the taxes would be retained by the
state, but a portion would be distributed to
Arizona’s incorporated cities and towns under the
state's Urban Revenue Sharing Program. These
increased revenues would be considered a
positive impact.
• Many of the products and services purchased by
Carlota for the proposed project in Arizona would
be subject to the state sales tax. Based on the
expected quantity of products and supplies
purchased in Arizona ($15,876,000), it is
estimated that the Carlota Copper Project would
pay state sales taxes averaging $563,000. The
largest share ($7,081,000, 44.6 percent) of these
supplies and products would be purchased from
suppliers located in the Phoenix metropolitan
area. Other suppliers in the Tucson metropolitan
area ($4,573,000, 28.8 percent), the Globe-Miami
area ($3,380,000, 21.2 percent), and Pinal
County ($413,000, 2.6 percent) would also be
used. These increased purchases would be
considered positive.
• The municipal governments of Globe, Miami, and
Superior would receive minimal sales, severance,
and corporate tax distributions from the state. The
Globe Unified School District would not receive
any tax distribution from the project, since the
project is not located in this school district.
• With the increase in population and school-age
children, there would be increases in government
service and facility demands requiring town and
school district expenditures. The town of Globe
and the Globe Unified School District would
experience increased expenditures, with minor
increases in direct tax revenues from the mine.
These expenditure/revenue imbalances would
occur in both the construction and operation
phases of the project. There would likely be a
financial shortfall for these government entities
during the life of the project.
• Operation and maintenance costs for school
districts throughout Arizona are equalized by
the state on a per student basis. However,
capital costs have historically been funded
solely by the school district property tax.
Recently (July 1994), the Arizona Supreme
Court ruled that the capital fund inequities need
to be rectified to equalize bonding capacities
for capital projects throughout all state school
districts. The legislature will provide a more
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
equitable funding plan in due time (Supreme
Court of Arizona 1994).
Social Impact Assessment
It is not anticipated that there would be major
changes in lifestyles, social organizations, attitudes,
beliefs, or values associated with the proposed
project. There could be minor changes in population
characteristics caused by the number of in-migrating
construction and operations workers; however, these
changes would not affect the social characteristics of
the area. If adequate housing is not available, there
may be some worker dissatisfaction, and potential
conflicts could occur.
Environmental Justice
The potential impacts described in Sections 3.7.2. 1
through 3. 7.2.5 represent both positive and adverse
impacts that would affect the entire population, not
exclusively the minority or low-income populations
described in Section 3.7.1. 7, Environmental Justice. It
is evident from reviewing the minority and low-income
population statistics that these population bases do
not represent a large percentage of the overall
population affected by the proposed project. It
appears that all population segments in Globe/Miami
and surrounding areas would be affected equally. In
Pinal County, the Block Group that includes Top-of-
the-World has a minority population of only 5 percent
of the total population and a low-income population of
18 percent. This population would not be
disproportionately affected by the proposed project. In
particular, the potential site-specific impacts to the
population residing at Top-of-the-World are primarily
related to water resources and air quality: these
impacts would not affect one segment of the
population more than another.
3.7. 2.2 Alternatives
Most of the socioeconomic impacts discussed in this
section are common to all of the alternatives. These
impacts include the following:
• At least 60 percent of the workforce would
likely come from within the study area. There
would be some transfer to the Carlota Copper
Project of skilled workers currently working in
lower paying jobs. Those currently employed
at other mines at comparable wages would not
likely apply for jobs at the Carlota Copper
Project. Increased employment levels would
benefit the overall economic condition of the
area.
• Personal income in the area would increase,
which would beneficially affect the local and
regional economic climate.
• Temporary rental housing availability would be
limited for all surrounding towns (Globe, Miami,
Claypool, Midland, and Superior). There would be
some motel units and RV/mobile home spaces
available, but these would not be sufficient for the
in-migrating construction workforce. Permanent
housing may also be a problem. Carlota may
need to provide incentives to area builders to
ensure an adequate market for speculative
building.
• School capacity would be available throughout
the study area. The Globe Unified School District
has the greatest capacity, while the Miami Unified
School District has a lesser capacity.
• Public utility infrastructure appears to be ade-
quate for additional growth in Globe and Miami.
• Additional law enforcement personnel may be
required in Gila County.
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. The impacts
associated with the alternative mine rock disposal
sites would be similar to the impacts discussed for the
proposed action. However, the additional backfill of
the Carlota/Cactus pit and the additional backfill of the
Eder South pit would differ from the impacts
discussed for the proposed action because of the
additional personnel required for backfilling activities
and the extended project life.
Additional Backfill of the Carlota/Cactus Pit. This
alternative would require an estimated 190 workers
for 3 or 4 additional years of operation to fill the pit.
Mining costs would increase because of additional
work.
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3.0 Affected Environment and Environmental Consequences - Socioeconomics
Additional Backfill of the Eder South Pit. This
alternative would require a workforce of 190 for 2.3
months.
These alternatives would affect the population,
employment, housing, public facilities and services,
and fiscal conditions of the affected communities of
Globe, Miami, and Superior for the period required for
pit backfilling. Additional property tax revenues would
be generated for Pinal and Gila Counties and the
Miami Unified and Superior Unified School Districts
from these alternatives because of the additional
capital cost associated with these activities in each
respective county.
Eder Side-Hill Leach Pad Alternative
The impacts associated with the Eder side-hill leach
pad alternative would be similar to the impacts
discussed for the proposed action. However, this
alternative would have more visual and noise
impacts to the Top-of-the-World area, which may
adversely impact property values more than the
proposed action. In addition, project costs would
increase by constructing this alternative.
Water Supply Alternative
The impacts associated with the water supply
alternative would be similar to the impacts discussed
for the proposed action. The low-quality water
pipeline would increase the total project cost, which
would increase assessed valuation and total property
tax revenues in the region.
Alternative Water Supply Well Field Access
Roads
The impacts associated with the alternative water
supply well access roads would be similar to the
access road components of the proposed action.
No Action Alternative
The no action alternative would preclude the
development of the Carlota Copper Project. Thus,
both the beneficial and adverse socioeconomic
impacts associated with the proposed action and the
other development alternatives would not occur. The
estimated workforce of 282 operations workers would
not be employed within the study area, adding no new
employment, income, population, or revenues to the
region.
The adverse impacts associated with the in-migrant
population would not occur with the no action
alternative. The already limited rental and temporary
housing market would not experience the increased
project-related demand of 42 units during peak
construction, 21 units during the average construction
period, and between 57 and 114 units during
operations.
Potential project-related impacts to water supply wells
at Top-of-the-World would not occur.
Fiscal impacts to local governments from increased
demands on public sen/ices and facilities would be
avoided with the no action alternative.
The beneficial impacts of increased employment
during both the 8- to 10-month construction period
and the 23-year project operations period would not
occur. An estimated average of 91 jobs during the
construction period and 177 direct jobs during peak
construction would not be created. An estimated
average 282 direct jobs during operations would not
be created.
Increased incremental annual income from
operations employment payroll (an estimated $10
million during operations) would not be generated in
the local area. The associated induced economic
effects of local spending by construction and
operations workers would not occur.
Additional Carlota Copper Company expenditures in
the local area would also not occur, which would
preclude collection of additional sales and use taxes
for the state, counties, and communities. Estimated
annual property tax revenues of approximately $1.2
million to Gila and Pinal Counties and other taxing
jurisdictions would not occur.
3.7.3 Cumulative Impacts
Cumulative socioeconomic impacts would result
from the construction or operation of other projects
that contribute to changes in local population,
employment, housing, public services and facilities,
the economy, and the transportation network.
Most of the interrelated actions discussed in
3-268
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Section 1.6, Introduction and Purpose and Need -
Interrelated Actions, would affect the overall socio-
economic environment of the project area, primarily in
the areas of increased population and employment,
increased demand for scarce temporary and
permanent housing, increased income in the study
area, and increased revenues generated in Gila and
Pinal Counties and the town of Globe.
The specific projects that would affect the socio-
economic character of the study area include the
ongoing construction of the electrorefinery at the
Cyprus Miami Mining Company and the proposed
leach facility and supportive facilities expansion at the
Cyprus Miami Mine. No new permanent workforce is
projected for either of these projects. Other cumula-
tive projects that would affect socioeconomic
conditions include the following: the Magma Pinto
Valley Land Exchange; the Nugget Wash Land
Exchange: the Upper Queen Creek Limestone Mine,
which is projected to have a permanent workforce of
15 or more; the Magma Copper Florence Project,
which may have some impact on the Superior/Globe/
Miami area; the Coolidge Dam Safety Project on the
San Carlos Navajo Reservation; the Roosevelt Dam
improvements and the Roosevelt Dam Plan 6 recrea-
tion improvements: highway improvements to U.S.
Highway 60/70, Arizona State Highway 88, and
Arizona State Highway 188, which would improve
access to the area for tourists; commercial and
residential development activity in rural areas of Pinal
and Gila Counties and the town of Globe; and
changes in grazing management practices associated
with National Forest lands.
If each of the interrelated actions listed in Table 1-1
would occur during the construction and operation
phases of the Carlota Copper Project, the following
beneficial impacts would be expected:
• Demand for employment could reduce the
unemployment rate in the area.
• The sluggish economy would be stimulated.
• Personal income areawide would increase
because of increased employment.
• Direct expenditures from development activity
and indirect expenditures from the employment
workforce to the local area businesses would
occur.
• Revenues to local and state government budgets
would increase from increased property, income,
and sales taxes.
In addition to these positive impacts, the potential
influx of new population would put extra pressure
on an already limited housing market for both
short-term rentals and permanent housing in the
Globe-Miami area. Certain cumulative projects could
affect the provision of services by the local
governments.
Most of the interrelated actions mentioned herein
would have a greater direct impact during the
construction phase; however, it is difficult to identify
the secondary growth effects related to improved
transportation systems in the region, additional
recreational opportunities, expansion of operations on
mining projects, and increased growth in commercial
and residential activity.
The lack of more specific information regarding
projected construction and operations schedules,
workforce requirements, and fiscal data precludes a
quantitative assessment of cumulative impacts based
on existing and reasonably foreseeable projects in
the affected area.
3.7.4 Monitoring and Mitigation Measures
Two adverse socioeconomic impacts have been
identified for which mitigation is recommended:
(1) inmigration of workers, given the relatively high
level of unskilled, unemployed workers within the
local labor force; and (2) a housing shortfall for
both the construction and operations phases of the
Carlota Copper Project. The following measures have
been identified to provide a range of available options
that could be implemented to mitigate adverse
impacts.
SE-1: Carlota would provide recruitment and
training opportunities for the Native American
workforce of the San Carlos Indian Reservation
and for other local unskilled labor in order to
ensure the use of the largest possible percentage of
local labor during construction and operations.
Carlota Copper Project Final EIS
3-269
3.0 Affected Environment and Environmental Consequences - Socioeconomics
Cooperative training programs with the Arizona
Department of Economic Security and the San
Carlos Reservation (TERO) already exist.
SE-2: In order to mitigate potential housing impacts,
Carlota would work through local government
agencies to provide a schedule of project
development. Furthermore, Carlota should
encourage permanent housing construction in the
Globe-Miami area. Mitigation measures related
to the potential impacts to residential well water at
Top-of-the-World are discussed in Section 3.3.4,
Water Resources - Monitoring and Mitigation
Measures.
3-270
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Land Use
3.8 Land Use
3.8.1 Affected Environment
3.8. 1. 1 Land Status/Ownership
Gila County contains approximately 2,865,920 acres,
for a total area of 4,752 square miles. Land ownership
in Gila County is shown in Table 3-80.
Table 3-80. Summary of Land Ownership in
Gila County
Ownership
Square Miles
PerwrH
Forest Service
2,661
56
Indian
1,758
37
Private
143
3
BLM
95
2
State
48
1
Other Public
47
1
Source: Bigando (1993)
The land ownership pattern of Gila County is
generally consolidated. The majority of the land is
within the administrative boundary of the Tonto
National Forest with a lesser amount within a portion
of the San Carlos Indian Reservation. There are two
areas of the county not within these administrative
boundaries, the Globe-Miami area and the southern
tip in the Hayden-Winkelman area. These county
areas are interspersed private, state, and BLM lands.
Within the Tonto National Forest, concentrations of
private lands are found in the mining area north and
west of Globe, in the Wheatfields area along State
Route 88, in Tonto Basin near the community of
Young, and in the vicinity of the town of Payson.
Pinal County contains approximately 3,447,000
acres, for a total area of 5,386 square miles. Land
ownership in Pinal County is shown in Table 3-81.
Table 3-81. Summary of Land Ownership In
Pinal County
Ownership *
Square MiiesI
Percent
Forest Service
346
6.4
Indian
1,098
20.4
BLM
634
11.8
Other Public/Private
3,308
61.4
Source: Felix (1993)
The Carlota Copper Project is located within both Gila
and Pinal Counties. The heap-leach pad for the
project is located on the county line. The land in the
vicinity of the project area is within the administrative
boundary of the Tonto National Forest. Eighty-one
percent of the project area is Forest land and 1 9
percent, including the major portion of the Carlota/
Cactus pit and all of the Pinto Creek diversion, is
private land that was purchased by the Carlota
Copper Company from Magma Copper Company.
A 20-acre patented mining claim owned by another
party is located partially within the southwestern
portion of the project area. Private land owned by
BMP Copper is located adjacent to the Carlota land to
the northeast and is the site of the Pinto Valley Mine.
Eight hundred and fifteen acres of private land, known
as Top-of-the-World, are located southwest of the
project area. This land has multiple ownership, and
the eastern portion has been subdivided for
residential purposes. Another tract of patented
(private) mining claims is located south of U.S.
Highway 60 around Five Points Mountain. Figure 3-33
illustrates the project vicinity.
The Carlota Copper Project is located approximately
6 miles due west of the town of Miami, within the
western portion of the Globe-Miami Mining District.
Property holdings consist of 12 unpatented claims
under lease from Sherwood Owens covering the
Carlota/Cactus ore body, and 23 patented and 252
unpatented claims owned by the Carlota Copper
Company covering the Carlota/Cactus pit and
surrounding area.
The project area covers approximately 3,050 acres
(4.8 square miles) and is located in the Globe Ranger
District of the Tonto National Forest. The project area
is dissected by two principal drainages. Pinto Creek,
the larger of the two, is on the east side of the area,
and Powers Gulch is on the west side. The total area
affected by all of the project features is approximately
1 ,428 acres.
3.8. 1.2 Land Use Plans
Given the large percentage of federal lands in Pinal
and Gila Counties, federal management programs,
particularly those administered by the Forest Service,
significantly influence land use in the area. In
addition, since the Carlota Copper Project includes
unpatented mining claims on lands administered by
Carlota Copper Project Final EIS
3-271
3.0 Affected Environment and Environmental Consequences - Land Use
the Tonto National Forest, and is dependent upon
those lands for implementation of the project, Forest
Service land use plans, policies, and regulations have
primary jurisdiction over land use activities on these
parcels. The Forest Service has developed the Tonto
National Forest Plan to guide the long-term manage-
ment of these lands.
The Carlota Copper Project is located in Management
Area 2F, v\/hich consists of over 385,840 acres. The
emphasis placed on land management within this
area is to promote a variety of renewable resources,
such as wildlife habitat improvement, water quality
maintenance, livestock forage production, and
dispersed recreation. The management direction in
the Forest Service management plan is to allow uses
of available National Forest lands for appropriate
public or private interests consistent with National
Forest policies. One of the goals of the management
direction that the Tonto National Forest has identified
is to support environmentally sound energy and
minerals development. The Tonto National Forest
Plan (USDA Forest Service 1985) states that
“...minerals activities will be managed through Plans
of Operation to ensure environmental and other
resource needs are provided for while also develop-
ing the National Forest potential for contributing to the
nation's mineral resource needs.”
Gila and Pinal Counties have limited jurisdiction over
the proposed Carlota Copper Project; Carlota will
be subject to Gila County ordinances on the private
land within the project boundary. The Forest Service
also will require that Carlota meets any applicable
County requirements for drinking water systems,
wastewater treatment systems, solid waste disposal,
and building codes. The Arizona Revised Statutes
(ARS 11-830 Paragraph A, Sub 2) state that nothing
will “...prevent, restrict, or otherwise regulate the use
or occupation of land or improvements for railroad,
mining, metallurgical, grazing, or general agricultural
purposes, if tract is five or more contiguous acres.”
This statute was incorporated verbatim into the Gila
County and Pinal County zoning ordinances.
3.8.1. 3 Land Use
Land use in the vicinity of the project area reflects
typical land use patterns throughout the Globe-Miami
area, and primarily consists of copper and other
mining, dispersed recreation (i.e., horseback riding.
hunting, trapping, hiking), and livestock grazing. The
project area is characterized by mountainous terrain
covered with chaparral vegetation common to the
high desert.
Adjacent land use includes residential uses at the
Top-of-the-World area. Pinal County zoning at Top-
of-the-World includes mobile home parks, mobile
home subdivisions, suburban 2-acre homesteads,
local business CB-1, and general business CB-2.
Mining
The Globe-Miami Mining District is one of the
oldest and largest in the State of Arizona. Valid
claims under the U.S. Mining Laws establish private
rights to the ore, and those rights are essentially
property rights. Currently, two major mines operate
in the vicinity of the proposed project: the Pinto
Valley Mine adjacent to the project site and Miami
Mine. The Superior Mine went on stand-by and
shut-down status in 1996. Other operating mines
in the region include the ASARCO Ray complex and
other small mining interests throughout the area.
There are other proposals and exploration activities
for small copper or gold operations throughout the
study area.
Currently, there are some expansion plans for the
area. Cyprus-Miami has proposed an expansion
of its leach facilities at the Miami Mine with a
planned start-up of 1997. In addition, BMP
Copper has proposed an expansion of its facilities
with a planned start-up of 1997. Also, ASARCO
completed a major expansion of its Ray Mine in
1992.
Magma Copper Company (now BMP Copper)
proposed a land exchange with the Forest Service
that would involve BMP acquiring through the
exchange process eight selected parcels in the
vicinity of the Pinto Valley Mine operations. Over 50
percent of the selected 1 ,200 acres of land is under a
mining plan of operations or has previously been
affected by mining operations, primarily with tailings
and overburden piles. It is reasonably foreseeable
that the acquired lands would be used to expand
mine facilities, such as mine rock disposal areas,
tailings impoundments, or sediment collection ponds.
The land being offered to the Forest Service is
located in the Apache-Sitgreaves National Forest, in
3-272
Carlota Copper Project Final EIS
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-33
Land Ownership and Use
3-273
R13E^R14E
. *
3.0 Affected Environment and Environmental Consequences - Land Use
Coconino County, Arizona; approximately 465 acres
is being offered. The offered lands are generally
forested lands, primarily ponderosa pine, with
meadows and riparian areas highly suitable for
wildlife habitat. According to the Forest Service, this
land exchange would be consistent with the Tonto
National Forest Plan (USDA Forest Service 1985).
Grazing
There are portions of three grazing allotments located
within the project area in the Globe Ranger District.
• The Bellevue allotment has 17,539 acres and
three permittees (one of the permittees is Cyprus
Miami Mining Corporation). It is a year-round
yearling and cow/calf operation for a total of
1,388 animal unit months (AUMs).
• The permittee on the Bohme allotment is Cyprus
Miami Mining Corporation with 1,576 AUMs as a
year-round cow/calf operation. The allotment has
a total of 5,740 forest administered acres, as well
as a large portion of private land.
• The Pinto Creek allotment has 31 ,063 Forest-
administered acres and 1 permittee. However,
only the well field will be within this allotment.
Six grazing allotments are located in the Pinto Creek
watershed adjacent to the project area: Bohme,
Bellevue, Devils Canyon, Pinto Creek, and Brushiest,
and Hobbs {Figure 3-34). Current allotment
management plans are in place for the Devil’s
Canyon, Pinto Creek, and Brushiest allotments. The
Brushiest allotment is currently ungrazed by livestock
and is not scheduled to be grazed until such time as
further analysis is completed to determine future
feasibility. The Forest Service completed an Allotment
Management Plan for the Bellevue allotment in 1996
and is scheduled to develop an Allotment
Management Plan for the Bohme allotment in the
near future. The Bellevue Allotment Management
Plan now includes a rest-rotation method of grazing.
In addition, three grazing allotments occur within the
Tonto Basin Ranger District in the downstream
portion of the Pinto Creek drainage. The Havens
allotment has 4,345 acres and has been ungrazed by
the permittee for the past several years. In the past, it
has been a yearling operation with 100 yearlings for a
5-month period. The Poison Springs allotment is
31 ,275 acres and is currently active. It is a year-
round, cow/calf operation with 340 AUMs. The
Campaign/Bar V Bar allotment has 34,158 acres and
operates as a year-round cow/calf operation with 575
AUMs.
Recreation
Activity within the project area includes dispersed
recreational uses, such as hiking, hunting,
sightseeing, and horseback riding. The Superstition
Wilderness is near to the project area boundary;
Section 3.9, Recreation, describes existing recrea-
tional use in more detail.
Utilities
There are currently four transmission lines
that traverse the project site: two existing 1 15-kv
Salt River Project transmission lines near U.S.
Highway 60, a 500-kv Salt River line, and a 500-kv
Arizona Public Service line (Adams 1993). The
two 500-kv lines are within the same corridor
{Figure 3-33).
Timber
The land within and adjacent to the project site is not
suitable for timber harvesting; however, the project
areas does contain harvestable amounts of fuel wood
for local area residents. Fuel wood demand in the
Globe area generally exceeds supply.
3.8.2 Environmental Consequences
The issues identified for land use include the impacts
of the proposed project on existing land ownership
status, easements, rights-of-way, permits, and the
subsequent need for the issuance of new permits or
authorizations for land use. The evaluation criteria
used to evaluate land use impacts for the proposed
project included:
• The project's compatibility or consistency with the
existing land use plans, regulations, or controls
adopted by the federal, state, or local government
• Impacts on the continuance of existing permits or
other authorizations and the need for issuance of
new permits or authorizations
Carlota Copper Project Final EIS
3-275
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Miles
Riverside Technoiogy, inc.
CARLOTA COPPER PROJECT
Figure 3-34
Locations of
Grazing Allotments
i
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3-276
i
3.0 Affected Environment and Environmental Consequences - Land Use
3.8.2. 1 Proposed Action
Land Status and Ownership
The proposed action would affect both private land
and unpatented mining and mill site claims. The
majority of the project would be located on
unpatented mining and mill site claims administered
by the Forest Service pursuant to 36 CFR 228, the
Forest Service's regulations governing mining on
public lands. Carlota currently maintains lode mining
and/or mill site claims on approximately 5,900 acres
of National Forest system lands in the general project
area. The proposed action would not change the land
status or ownership in the project area. However,
patenting of land by Carlota, under a separate legal
process, could affect the land status.
Land Use Plans
The proposed action would be consistent with the
Tonto National Forest Plan. The Plan is required by
the Forest and Rangeland Renewable Resources
Planning Act (RPA), as amended by the National
Forest Management Act (NFMA). It describes
management direction, prescriptions for management
areas, and standards and guidelines for those
activities for which the Forest Service has
management authority. One of the goals for the Tonto
National Forest is to support environmentally sound
energy and minerals development. The management
prescription for all areas is to process operating plans
filed under the U.S. Mining Laws, as amended, and
federal regulations. Management Area 2F of the Plan,
within which the project is located, has a
management emphasis on wildlife habitat
improvement, water quality maintenance, livestock
forage production, and dispersed recreation. The
Forest Service must therefore respond to the
operating plan and, where feasible, require mitigation
that would minimize adverse environmental impacts
on Forest Sen/ice surface resources, with specific
emphasis on those resources identified in the
management prescription. The proposed action
meets standards established by regulation and policy,
and the appropriate guidelines were considered in
developing alternatives and mitigation.
However, the proposed action is expected to require
the amendment of an existing special use permit to
the Salt River Project for a power line and substation;
new permits for water and power facilities sites or
corridors as appropriate to Carlota; amendments
to existing grazing permits because of loss or
relocation of range structural improvements and
maintenance responsibilities; permit(s) for fuel wood
salvage; possible state permits for the salvage and
relocation of state-protected species, such as cacti;
and a commercial road-use agreement with the
Forest Service or Gila County for Forest Service
Road 287.
Gila and Pinal Counties have limited jurisdiction over
the proposed Carlota Copper Project. The proposed
action conforms with the Arizona Revised Statute
11-830 Paragraph A, Sub 2, regarding mining
purposes. The proposed project is not anticipated to
require additional permits or authorizations for the
existing land uses (i.e., grazing permits or
modifications to the Tonto National Forest Plan).
Land Use
The principal land uses in the immediate vicinity of
the Carlota Copper Project include copper and other
mining, and dispersed recreational activities and
grazing. Historical uses of the project area, other than
mining uses (e.g., grazing, wildlife habitat, open
space, dispersed recreation, particularly horseback
riding and hunting) would be limited or eliminated
over the life of the project and possibly beyond.
Mining. The proposed action would result in the
expansion of the current area affected by mining
activity. The project area encompasses an estimated
3,050 acres, with an estimated disturbed acreage of
1,428. The immediate mining area would generally
preclude public use of the affected lands. For both
safety and security reasons, public access to the
active mining and processing areas within the project
area would be precluded to the maximum extent
permitted by law during the life of the project. In
addition, the closed area would affect currently used
access routes into areas that would not be closed.
The construction of the waste rock disposal areas
and leach pad could also inhibit or preclude future
surface mining of other mineral resources, if any were
discovered, that are located beneath or adjacent to
such facilities. However, condemnation drilling was
performed, and it was determined that potentially
commercial ore reserves are not likely to be found
beneath project facilities.
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Grazing. The proposed action would affect portions
of the Bellevue and Bohme allotments. The primary
effect would be from clearing forage from areas of
disturbance. An estimated 920 acres of the Bellevue
allotment (5 percent) would be affected by the
proposed action, which equates to approximately
73 AUMs. An estimated 580 acres of the Bohme
allotment (10 percent of the Forest acres) would
be affected. This cannot be directly equated to
loss of AUMs since a considerable amount of
private land is also grazed, and the cattle are
used for reclamation purposes on the private
land. However, the effect on grazing is not limited
to areas of disturbance. If the pits and leach pad were
excluded from grazing, the affected area would be
greater than the disturbance area because areas of
the allotments would be inaccessible or implementing
management would not be practicable. Lowering
livestock numbers in their term grazing permits would
result in economic losses to the permittees. Structural
range facilities, including fences, water developments,
and possibly corrals would need to be relocated in
order for permittees to effectively graze the remaining
portions of their allotments. Grazing permits would
also have to be amended, as needed. As a result,
additional mitigation is recommended in Section
3.8.4.
Recreation. Horseback riding along Powers Gulch to
access the Haunted Canyon Trail, which leads to the
Superstition Wilderness, would be affected by the
proposed action. An analysis of this impact can
be found in Section 3.9.2, Recreation - Environmental
Consequences. Dispersed recreational uses
within the project area would be curtailed. Access
to additional recreational areas would also be
affected.
Forest Service Trail 203 would be impacted by
Carlota's proposed well field. Continued use of this
road as a mine facility would likely degrade the
recreational experience of hikers and horseback
riders and would encourage vehicular use.
Utilities. The Forest Service would amend the
existing permit to the Salt River Project to include the
new substation.
Timber. The proposed action would result in the
removal of trees and down material desirable as
fuelwood and would limit public access to fuelwood
collection. To address demand for fuelwood,
mitigation is recommended in Section 3.8.4.
3.S.2.2 Alternatives
The alternative component locations would result in
some similar impacts to the existing land status and
ownership, land use plans, and land use as described
for the proposed action. The following sections
describe several potential differences in impacts from
the various facility location alternatives in terms of
areas disturbed and type of impact.
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. This
alternative would increase the total disturbed area
affected by the project by an additional 44 acres. One
of the 22-acre mine rock disposal sites would be
located on National Forest land; the other 22-acre site
would be located on private land. Other than
increasing the total amount of disturbed acreage, this
alternative would not change the land use patterns
suggested in the proposed action.
Additional Backfill of the Carlota/Cactus Pit. This
alternative would result in an increase in reclaimed
areas to approximately 194 acres for the Carlota/
Cactus pit and 177 acres for the Main mine rock area.
Additional Backfill of the Eder South Pit. This
alternative would also result in an increase in
reclaimed areas by creating more flat or gently
sloping areas than described for the proposed action.
The reclaimed area for the Eder South pit would
increase by 16 acres to approximately 42 acres. The
reclaimed area for the Eder mine rock disposal area
would increase from approximately 40 acres to 73
acres.
Eder Side-Hill Leach Pad Alternative
The impacts associated with the Eder side-hill leach
pad alternative include an additional total disturbance
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of approximately 134 acres near the Powers Gulch
drainage channel. The land use impacts would
be similar to those described for the proposed
action except for a decrease of 134 acres for
dispersed recreational uses, compared to the
proposed action.
Water Supply Alternative
This alternative would potentially impact the land use
in the area, depending upon the level of disturbance
associated with pipelines, pumping stations, access
roads, and power lines necessary for this alternative.
Most of the pipelines would be located in an existing
corridor adjacent to the BHP Copper pipeline to the
Pinto Valley Mine.
Alternative Water Supply Well Field Access
Roads
The land use impacts associated with the alternative
water supply well access roads would be similar to
the access road component of the proposed action.
Use of the Alternative A access road would preclude
access during periods of high flow in Pinto Creek.
No Action Alternative
Under the no action alternative, Carlota would not
disturb the 1,428 acres associated with the Carlota
Copper Project. Access to the 3,050-acre project area
would be preserved. The existing land uses would be
maintained, including grazing on the Bohme and
Bellevue allotments and horseback access to
Haunted Canyon through Powers Gulch.
3.8.3 Cumulative Impacts
The interrelated actions discussed in Section 1.6,
Interrelated Actions, would potentially affect land use
in the project area. The potential impacts would be
associated with disturbing land for mining, energy and
transmission systems, commercial and residential
land development, highway improvements, land
exchanges, dam modifications, and recreational
facilities.
These interrelated actions would change existing
land uses to alternate uses, or preclude the future
development of the land for any future alternate use.
In the case of the Coolidge Dam improvements,
safety is the primary purpose for this project, which
will ensure future protection for downstream land
uses, and may actually stimulate alternate uses of
land downstream.
Cumulative effects of changes in grazing manage-
ment practices, as well as the potential designation of
a segment of Pinto Creek downstream of the project
site as a Scenic river, would have an indirect land use
effect. Such changes could result in some existing
land uses being restricted and/or redirected in order
to maintain and preserve the natural ecological
condition of the land. Land use throughout the area
will continue to be affected by interrelated projects
associated with increased economic activity, resource
development, and population growth.
3.8.4 Monitoring and Mitigation Measures
A mitigation measure for land use would involve
alternate access for horseback riding in Powers
Gulch. This measure (R-1) is discussed in Section
3.9.4, Recreation - Monitoring and Mitigation
Measures.
Suggested mitigation includes the following:
LU-1: Relocate allotment boundary fences and imple-
ment range structural improvements within the project
boundary according to a plan developed by Carlota,
the affected permittees, and the Forest Service to
reflect adjusted allotment boundaries (see also
mitigation measure TB-6 in Section 3.5.4 relative to
biological impacts). Consider using wells developed
by Carlota to satisfy structural improvement needs
both during operation and at closure.
LU-2: Construct fences to exclude livestock from
active mining and processing areas [part of above
plan(s)].
LU-3: Develop a plan with the Forest Service to
salvage fuel wood from disturbed areas.
LU-4: Work with Bellevue and Bohme grazing
permittees to develop a plan to minimize economic
losses to their existing permits.
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3.0 Affected Environment and Environmental Consequences - Recreation
3.9 Recreation
3.9.1 Affected Environment
In general, the Carlota Copper Project area has not
been developed or improved for recreational activity
except for Forest Service Trail 203, which accesses
the Haunted Canyon portion of the Superstition
Wilderness from Forest Service Road 287. Virtually
all of the landscape modifications are related to
resource development, primarily mining activity in the
Globe-Miami Mining District, and grazing.
The following information summarizes the Forest
Service management directives and recreational
activities that occur in the project area.
3.9. 1. 1 Forest Management Directives
The recreational character of the area can be defined
by the Recreation Opportunity Spectrum (ROS)
system discussed in the Tonto National Forest Plan
(USDA Forest Service 1985). The land within, as well
as surrounding, the Carlota Copper Project area is
classified using four primary ROS classes, which are
defined below, in declining order from most natural to
most modified, by human activity.
Semi-Primitive Non-Motorized (SPNM)
These areas are characterized by an environment
that appears predominately natural. Evidence of other
users is present, but there is little interaction.
Motorized use is not permitted. SPNM areas differ
from primitive areas only in the degree and type of
recreational experience users enjoy. The probability
of experiencing isolation, independence, closeness to
nature, tranquillity, and self-reliance in an environ-
ment of challenge and risk is high, although not as
high as in a primitive area.
Semi-Primitive Motorized fSPM)
The character of these areas includes a
predominately natural-appearing environment within
roaded areas and moderate evidence of other users.
Access by motor vehicles is permitted on roads and
trails. The areas are managed in such a way that
minimum on-site controls and restrictions may be
present, but they are subtle. User expectations are
similar to those for SPNM areas, but the probability of
experiencing isolation and related backwoods senses
is reduced by the increased accessibility for motor
vehicles. The opportunity for interaction with the
natural environment remains high, and the
opportunity to use motorized equipment is available.
Roaded Natural (RNA)
The characteristics of this classification include a
natural-appearing environment within roaded areas,
prevalent evidence of other users, and evidence of
past resource management activities. RNA areas are
predominately natural in appearance, but they are
readily accessible to vehicles.
Urban lli)
Characteristics of this classification include a setting
that is strongly dominated by structures and/or
resource development. Natural-appearing elements
may be present but are subordinate. There is strong
evidence of designed roads and human activity both
on the sites and in nearby areas. Motorized access to
the areas is available.
The project area is classified under two ROS ratings:
U and RNA. Existing mining activity is classified U
because of the extreme change to the natural setting.
Table 3-82 shows the current project area ROS
classification.
Table 3-82. Existing ROS Classification - Carlota
Copper Project Area
ROS Class r
Acres
Percent of
Project Area
RNA
2,854
94
U
196
6
TOTAL
3,050
100
The project area is located in Management Area 2F of
the Tonto National Forest Plan. As stated in Section
3.8, Land Use, Management Area 2F contains
approximately 385,843 acres, which represents over
85 percent of the total 450,863 acres in the Globe
Ranger District. The management objective for Area
2F is to manage for a variety of renewable natural
resources, with the primary emphasis on wildlife
habitat, water quality maintenance, livestock forage
production, and dispersed recreation. Watersheds will
be managed so as to maintain or improve their quality
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3.0 Affected Environment and Environmental Consequences - Recreation
to a satisfactory or better condition. Riparian areas
will be improved and managed (as defined by Forest
Service Manual 2526) to benefit riparian-dependent
resources. Wildfires will be managed to improve
livestock forage production and wildlife habitat, as
well as to achieve the desired resource condition,
which includes a mixture of vegetation successional
stages (USDA Forest Service 1985).
3.9.1. 2 Recreation Activities
The area surrounding the Carlota Copper Project
attracts a variety of recreational uses. Essentially all
of the area's recreational use is undeveloped and
dispersed in nature. This type of recreational use
attracts relatively few participants compared to
developed areas, but is preferred by hunters, many
horseback riders, and others. The majority of the
dispersed recreational activities that take place in the
vicinity of the project area includes horseback riding;
sight-seeing; picnicking; birdwatching; small game
(quail), javelina, and deer hunting; and hiking.
Horseback riders use the Powers Gulch Haunted
Canyon areas. Oak Flat Campground, on U.S.
Highway 60 between Miami and Superior, is the only
developed recreation site in the project vicinity.
There are no designated trails located within the mine
area, although Forest Trail 203 passes through the
well field area along Pinto Creek and Haunted
Canyon. This trail provides access to the Superstition
Wilderness. There are a number of four-wheel-drive
roads within or passing through the project area that
were constructed primarily for mineral exploration or
power line construction access. These roads are
used by four-wheel drivers and sightseers.
Most of the recreationists that come to the project
area are from the local area or the Phoenix
metropolitan area. The Superstition Horseman's
Association uses the Powers Gulch access to
Haunted Canyon and the Superstition Wilderness two
to three times per year, but individuals use the access
more often (Kilpatrick 1993).
Overall, recreational use within the project area is
low; however, the east side of the Superstition
Wilderness is experiencing increased use from the
Phoenix metropolitan area. The popular dispersed
recreational activities include prime white-tail deer
hunting, birdwatching, and wildlife viewing. In 1992,
the estimated total recreational visitor days (RVDs)
for the Globe Ranger District was 1.1 million. An RVD
is one 12-hour period of recreational activity by one or
more persons. Recreational visitors in the Globe
Ranger District increased from approximately
485,000 annual visitors to over 1 million RVDs from
1989 to 1992, which is an average annual increase of
32 percent. Most of the increase occurred in the
automobile sightseeing category. Other recreational
activities occur outside the immediate project area.
Roosevelt Lake, located approximately 26 miles
northwest of Globe, is in the Tonto Basin Ranger
District and provides water sport activities year-round
to area residents and visitors. Of the more than 1.1
million RVDs in the District in 1992, over 75 percent
were tied to activities at Roosevelt Lake. The U.S.
Bureau of Reclamation, Plan 6 - Arizona Project, is
currently completing a major expansion at Roosevelt
Lake. The expansion includes raising Roosevelt Dam,
which will influence the use of Roosevelt Lake. Two
new large campgrounds — a group campground and a
family campground with 206 campsites — are open;
four more campgrounds are planned. The Forest
Service operates and manages the campgrounds.
Other recreation locations in the surrounding area
include Pinal Mountain Recreation Area, San Carlos
Lake on the San Carlos Indian Reservation, Apache
Lake, the Salt River, Sierra Ancha Wilderness, Salt
River Canyon Wilderness, and Superstition Wilder-
ness. Urban recreational facilities and programs are
discussed in Section 3.7, Socioeconomics.
3.9.2 Environmental Consequences
The proposed action and alternatives could
potentially affect the dispersed recreational use and
enjoyment of the area. The potential effects are
centered around three issues: (1) temporary and
permanent loss of dispersed recreational
opportunities in the project area, (2) decreased
access to adjacent areas, and (3) increased demand
for recreational opportunities caused by the loss of
land area and population growth associated with the
project.
The evaluation criteria used to analyze the recreation
impacts for the proposed Carlota Copper Project are
listed below:
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3.0 Affected Environment and Environmental Consequences - Recreation
• Changes in ROS classification (in acres) during
and after project operations
• Decrease in recreational activities caused by a
decrease in acres, game populations, aesthetic
experience, increased demand, or other reasons
• Increase in total recreation demand in RVDs in
the project area based on predicted change in
population
The project area contains a range of recreational
opportunities. The quality of visitors' experiences can
be affected by changes to the characteristics of the
area and the land. As described in Section 3.9.1,
Recreation - Affected Environment, the primary
recreation uses within the project area include
dispersed recreational activities, such as horseback
riding, sightseeing, picnicking, hunting, and hiking.
Recreation impacts are defined in terms of the acre-
age affected by the proposed action and the alterna-
tives, access limitations, and changes to the quality of
the recreational experience. The impact analysis also
identifies the areas that would undergo a change in
ROS class because of the proposed action and
alternatives.
ROS is used to define outdoor recreation settings,
activities, and experiences through defined classes.
The ROS classes related to the project area are
described in Section 3. 9. 1.1, Recreation - Forest
Management Directives. ROS classifications were
determined for the proposed action and alternatives
to analyze changes in recreation opportunities. The
existing ROS classes of the project area are shown in
Table 3-83.
3.9.2. 1 Proposed Action
The proposed action would result in the development
of the Carlota Copper Project, which includes an
overall project area of approximately 3,050 acres and
affected acreage of approximately 1 ,428 acres. Most
of the project area would not be available for
recreation activities during mining operations, and
portions may not be available for recreation after
closure.
The dispersed recreational activities described in
Section 3.9.1, Recreation - Affected Environment
would be adversely affected by the proposed action in
a major portion of the project area. The most
significant impact would be from the loss of favorite
areas for horseback riding, hunting, four-wheel
driving, and sightseeing. This impact would primarily
affect local residents from Top-of-the-World and the
Globe-Miami area. However, existing use in the area
of the proposed project is relatively low. There is
more than adequate public land available throughout
the surrounding area to provide terrain for these
activities. The Globe Ranger District has abundant
open space acreage and designated wilderness
areas within the general vicinity. Over 59 percent of
the area in Gila County is publicly owned, primarily as
part of the Tonto National Forest (2,661 square
miles). Therefore, the impacts would not be
considered significant. However, to address the
localized impacts, mitigation is recommended in
Section 3.9.4-Monitoring and Mitigation Measures.
The majority of users access the Superstition
Wilderness trailheads via Forest Service Roads 287
and 287A. Other users access the Wilderness via
Forest Service Trail 203. Another alternate horseback
route to Haunted Canyon and the Superstition
Wilderness is from the Top-of-the-World along
Powers Gulch. Although the horseback use through
this access point is relatively low, the proposed
project would alter the access, which
could indirectly affect recreational use in the Super-
stition Wilderness. It is unclear how many horseback
riders currently use the Top-of-the-World access to
Haunted Canyon. Another alternate access route to
the Haunted Canyon trail could be developed from
Forest Service Route 898 near Top-of-the-World.
This route is just west of Powers Gulch. It would
cross private property on which the Forest Service
currently does not have right-of-way. The route
would subsequently reconnect with the existing
route to Haunted Canyon outside the project
boundary. Access to this trail would be from U.S.
Highway 60 (Section 14, T1S, R13E). Please see
Section 3.9.4 regarding mitigation relative to
recreational access.
A more detailed analysis of wilderness impacts is
provided in Section 3.10, Wilderness and Wild and
Scenic Rivers. Visual and noise impacts related to
mine activities in the Superstition Wilderness are
discussed in Sections 3.11, Visual Resources, and
3.12, Noise.
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3.0 Affected Environment and Environmental Consequences - Recreation
Table 3-83. Change in ROS Class Acreage - Proposed Action
'fsROS
iS Class'
Existing
ROS Acres
Area Change
(acres) ii
Project-Related ROS
„ Change (acres)
Percent of
Project Area
Percent^ .
Change ’
RNA
2,854
-1,892
962
31.5
-66
U
196
+1,892
2,088
68.5
+965
TOTAL
3,050
0
3,050
100.0
0
No Forest Service campsites, developed recreation
sites, or picnic areas would be affected by the
proposed action. Forest Service Trail 203 would be
impacted by Carlota’s proposed well field. The
continued use of this road as a mine facility would
likely degrade the recreational experience of hikers
and horseback riders and would encourage vehicular
use.
The projected increase in population from the
proposed action is between 161 for the low-impact
scenario and 323 for the high-impact scenario
(see Section 3.7.2, Socioeconomics - Environmental
Consequences), with the majority expected to live
in the Globe-Miami area. This population rise
would cause an increase in RVDs in the Globe-Miami
area and the Pinto Creek area, but it would not
put undue pressure on the recreation areas
given the dispersed nature of the recreational
activities.
The high-impact scenario would represent a 2.7
percent increase in the areawide population, which
would not be considered adverse from a recreational
standpoint. This population would also increase
demand on local community recreational facilities
and programs: this issue is discussed in Section
3. 7.2.1, Socioeconomics - Public Facilities and
Services.
The direct and indirect effects of the proposed action
include changes in the ROS classifications of affected
areas. Changes from RNA to U would occur because
of mining activity, which is considered an urban
setting within the ROS standards. Table 3-83 shows
the changes in acres by ROS class and the percent
of change in ROS acreage.
As reclamation is completed for project lands, some
of the area would remain unusable for recreational
purposes (e.g., the open pits), and the area may be
less desirable for recreational use. Public access for
recreational use would depend on the status of other
mining activity in the vicinity of the project area at that
time.
3.9.2.2 Alternatives
The following discussion explains the potential impact
of each alternative and describes the change in
character of the area if the alternatives were
implemented. The alternative component locations
would generally result in the same type of impacts to
the existing recreational use as discussed for the
proposed action.
Mine Rock Disposal Alternatives
The recreational impacts associated with the mine
rock disposal alternatives, including the additional
mine rock disposal sites, additional backfill of the
Carlota/Cactus pit, and additional backfill of the Eder
South pit, would be the same as the recreational
impacts discussed for the disposal and backfill
components of the proposed action.
Eder Side-Hill Leach Pad Alternative
The recreational impacts associated with the Eder
side-hill leach pad alternative would include a
decrease in dispersed recreational activities in the
disturbed area near Powers Gulch (approximately
134 acres).
Water Supply Alternative
The impacts associated with the water supply
alternative would be the same as the impacts
discussed for the water supply components of the
proposed action.
Alternative Water SuddIv Well Field Access
Roads
The alternative water supply well field access roads
would result in the improvement of slightly different
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3.0 Affected Environment and Environmental Consequences - Recreation
access routes within the Forest. The well field access
roads would increase access, particularly by four-
wheel drive vehicles, to a segment of Pinto Creek and
to Haunted Canyon. Increased access would result in
a well-defined and maintained segment of Forest
Sen/ice Trail 203, but would also result in poor
experiences for hikers and horseback riders. Visual
impacts, as discussed in Section 3.11, Visual
Resources, would potentially affect the recreational
experience, but only to a minor degree.
The ROS designation of RNA would not change for
these alternatives.
No Action Alternative
Under the no action alternative, Carlota Copper
Company would not disturb the approximately 1 ,428
acres associated with the Carlota Copper Project.
Nearly all of the roads within the project area have
been identified for closure in the Tonto National
Forest’s Resource Access Travel Management Plan.
Roads under Carlota’s current Plan of Operations
would be reclaimed and other roads, many of which
are poorly located and contribute to erosion, would be
closed in the future. The existing recreational
opportunities would be maintained, including
horseback access to Haunted Canyon through
Powers Gulch and other dispersed recreational
activities, such as hunting, hiking, and sightseeing.
3.9.3 Cumulative Impacts
The interrelated actions discussed in Section 1 .6,
Interrelated Actions, would potentially affect
recreational opportunities in the project area. The
potential impacts would be associated with
constraints placed on recreation access caused by
mining and land exchanges, or improved access or
opportunity caused by highway improvements, dam
modifications, and new recreational facilities. These
interrelated actions would change the existing
recreational patterns; in some cases, recreational
opportunities would improve, in others, they would be
more limited after completion of the projects. In
addition, the cumulative impacts of changes in the
grazing management practice and the potential
designation of Pinto Creek as a Wild and Scenic
River would represent an indirect effect on recreation,
because the future condition of some existing
recreational areas would improve from the potential
implementation of restrictions affecting future land
uses. In these cases, the natural environment would
be preserved for low-impact use, which generally
would include dispersed recreation.
Recreational opportunities throughout the area will
continue to be affected by interrelated actions
associated with increased economic activity, resource
development, and population growth.
3.9.4 Monitoring and Mitigation Measures
The following mitigation measure is proposed for
recreation:
R-1: Develop, in coordination with the Forest Service,
an access management plan. The plan would
address recreational access during all phases of the
operation when it is legally and practicably feasible.
Refer to Section 3.13.4, Transportation-Monitoring
and Mitigation Measures, for mitigation of impacts to
Forest Service Trail 203.
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3.10 Wilderness and Wild and
Scenic Rivers
3.10.1 Affected Environment
3.10.1.1. Wilderness
The Tonto National Forest Plan (USDA Forest
Service 1 985) reports a total of 585,990 wilderness
acres within the Forest. The Superstition Wilderness
has over 160,000 acres, with an estimated 23,819
acres within the Globe Ranger District.
Several wilderness areas occur in the general vicinity
of the project area, including the Superstition
Wilderness (approximately 3 miles west-north-west of
the well field), the Salt River Canyon Wilderness
(approximately 12 miles north and east of the project
area), and the Salome and Sierra Ancha Wilder-
nesses (25 miles north-northwest and 25 miles north-
northeast of the project area, respectively). The
Superstition Wilderness is the only area that would
potentially be affected by the Carlota Copper Project
because of its proximity.
The Superstition Wilderness is characterized by
desert, chaparral, and woodland vegetation types
with some ponderosa pine and desert grassland. The
management concerns stated in the Tonto National
Forest Plan are to protect the wilderness resource
and enhance the visitor experience. The manage-
ment emphasis for the portion of the Superstition
Wilderness in the Globe Ranger District
(Management Area 2A) is to manage for wilderness
values while providing livestock grazing and
recreational opportunities that are compatible with
maintaining wilderness values and protecting
resources.
Current use in the area consists of dispersed
recreation, including hiking, horseback riding, some
camping, and some hunting. The primary access to
the Wilderness is via Forest Service Roads 287 and
287A and the Miles Ranch Trailhead. The primary
access to Haunted Canyon is Forest Service Trail
203 from Forest Service Road 287. Haunted Canyon
is a popular horseback riding area for local and
regional riders, with additional access from U.S.
Highway 60 and mining roads in Powers Gulch.
Mining is no longer allowed in the wilderness, except
on valid mining claims.
Recreation visitation in the Globe Ranger District is
estimated using the sample observation survey
technique. Although the statistical basis is limited, this
method still provides a general estimate of recrea-
tional use in the Forest. In 1992, the estimated
wilderness use in the Globe Ranger District was
21,100 RVDs; one RVD equals one 12-hour period of
recreational activity by one or more persons. It is
estimated that 75 percent (15,000 RVDs) of this use
was in the Salt River Canyon Wilderness; the
remaining 25 percent (5,300 RVDs) occurred in the
Superstition Wilderness (Killebrew 1993, USDA
Forest Service 1992b). Visitor use in the eastern
portion of the Superstition Wilderness is believed to
be increasing because of the increasing population in
the Phoenix metropolitan area. Estimated wilderness
RVDs in the Globe Ranger District have increased
from 1 7,400 in 1 989 to 21 ,1 00 in 1 992, an average
annual increase of 6.6 percent.
The eastern portion of the Superstition Wilderness, in
the Globe Ranger District, is within the Brushiest and
Pinto Creek grazing allotments. Both have approved
allotment management plans, but the Brushiest
allotment is currently ungrazed pending further
feasibility analysis.
3. 10. 1.2 Wild and Scenic Rivers
Pinto Creek in the vicinity of the project area is an
intermittent stream with short stretches of perennial
flows over bedrock channel. However, approximately
5 miles downstream from the confluence of Pinto
Creek and Haunted Canyon, Pinto Creek becomes
perennial for approximately the next 8 to 9 miles
(Lewis 1977). This segment of the stream was
included in a study of rivers and streams potentially
eligible for inclusion in the National Wild and Scenic
Rivers System. The inventory was conducted by the
six Arizona National Forests at the request of the
Arizona Congressional delegation.
To be eligible for inclusion in the National Wild and
Scenic Rivers System, a stream must be free flowing
and must possess one or more outstandingly
remarkable values. The values to be considered
include scenic, recreational, geologic, fish, wildlife.
Carlota Copper Project Final EIS
3-287
3.0 Affected Environment and Environmental Consequences - Wilderness and Wild and Scenic Rivers
historic, cultural, riparian, and ecological. If a stream
is judged to be eligible, the second test and analysis
on classification is carried out: determining the stream
to be Wild, Scenic, or Recreational. To determine
classification, the stream is analyzed using the
impoundment test, the accessibility test, the
primitiveness test, the development test, and the
water pollution test. The final test for possible
designation is suitability; this test has not been
completed for Pinto Creek. Based on an informal
preliminary analysis, the perennial segment of the
stream was considered eligible based on
“outstandingly remarkable” scenic, riparian, and
ecological values, and was determined by the Forest
Service to be potentially eligible for classification as
Scenic. The Forest Service has made no proposal for
designation of the stream segment, but will consider a
proposal at the next revision of the Tonto National
Forest Plan.
The segment of Pinto Creek that was studied for
potential designation is approximately 5 miles down-
stream from the project area's northern boundary
(Figure 3-35). The segment being considered is 8.8
miles long, 8.2 miles of which are on Tonto National
Forest lands. The Forest Service currently has an
instream flow water right permit for most of the
eligible segment of the stream. This right ranges from
1 .0 to 2.69 cfs depending upon the month, and has a
priority date of 1 983.
3.10.2 Environmental Consequences
Issues identified for wilderness and wild and scenic
rivers included (1) possible effects on the Superstition
and Sierra Ancha Wildernesses from changes in air
quality, noise and light, visual qualities, social
experience, and access; and (2) potential indirect
impacts to the segment of Pinto Creek under
consideration for Wild or Scenic river designation.
Evaluation criteria used to analyze impacts on these
resources are listed below:
• Predicted changes in resources in the Super-
stition Wilderness compared to the Limits of
Acceptable Change as identified in the
Superstition Wilderness Plan
• Change in eligibility and classification status of
the Pinto Creek segment as a Wild or Scenic
river because of adverse changes in associated
resources (e.g., water quality, riparian, biological,
and scenic values)
3. 1 0.2. 1 Proposed Action
Wilderness
Impacts to a wilderness can rarely be quantified. In
the case of the proposed Carlota Copper Project,
there are a number of factors that could potentially
affect the wilderness experience, even though the
project is over 2 miles from the Superstition
Wilderness boundary.
The potential impacts of a mining operation on
wilderness activities include air quality, visual, noise,
and access. Based on information contained in the
Visual Resources, Noise, and Air Quality sections
(Sections 3.11, 3.12, and 3.1, respectively), it
appears that there would be some adverse impacts to
the wilderness associated with the proposed project.
See the respective sections for a discussion of these
impacts.
The wilderness is also situated in proximity to
the Pinto Valley Mine, which is adjacent to the
proposed Carlota Copper Project. This mine
exhibits extensive existing land disturbance,
which is visible from the wilderness. The visual
impacts from the proposed action, as discussed
in Section 3.11, Visual Resources, would not
change dramatically from the existing views from
the wilderness. Designated Forest Service Trail
203 would remain open, but the segment outside
of the wilderness would be used as a road for
access to the well field; access to this trail would be
limited. Horseback access along Powers Gulch would
be cut off after operations begin on the Eder pits. As
indicated in Section 3.12, Noise, noise emissions
from the proposed project would result in noticeable
adverse noise impacts at the eastern edge of the
Superstition Wilderness.
Since the east side of the Superstition Wilderness
does not receive as much recreational use as the
west side, it is not anticipated that the increased
population associated with the proposed project
would affect the recreational opportunities in the
wilderness. There would likely be an increase in use
from the project-related population; however, the
3-288
Carlota Copper Project Final EIS
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CARLOTA COPPER PROJECT
Figure 3-35
Section of Pinto Creek
Inventoried for Potential Wild
and Scenic River Designation
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3-289
3.0 Affected Environment and Environmental Consequences • Wilderness and Wild and Scenic Rivers
increase would not adversely influence the wilderness
experience.
The Sierra Ancha Wilderness would also likely
experience additional recreational use and increased
visitor days, but the increase is not expected to be
detrimental to the wilderness experience. The Sierra
Ancha Wilderness would not be directly affected by
the proposed action.
Wild and Scenic Rivers
The existing Pinto Creek drainage runs in a northerly
direction through the middle of the proposed
Carlota/Cactus pit. Because the ultimate pit would
span Pinto Creek, a diversion channel would be
constructed to convey both flood waters and
sediment around the east and north side of the
Cactus portion of the pit.
The outstandingly remarkable values identified for
Pinto Creek include scenic, riparian, and ecological
values. The values that could be affected by fluctua-
tions in streamflow include potential impacts to
riparian and ecological values, particularly the
cottonwood-willow community that is prevalent along
the 8.8-mile segment.
It is anticipated that the segment of Pinto Creek being
considered for Wild or Scenic designation would not
be significantly affected by ground water withdrawal
from the well field, since the relevant segment of
Pinto Creek is located below the Pinto Valley weir
approximately 5 miles north and downstream of the
confluence of Pinto Creek and Haunted Canyon and
below the drainages of Horrel Creek and West Pinto
Creek. The major source of perennial baseflow in
Pinto Creek below Horrel Creek and West Pinto
Creek appears to be near-surface ground water flow
surfacing from alluvial deposits. A small portion of the
baseflow in Haunted Canyon could contribute to the
perennial baseflow observed downstream in Pinto
Creek at the Pinto Valley weir. However, there are
insufficient data to quantify this potential contribution.
Well field pumping and pit dewatering could result in a
small potential reduction in surface water flow along
the 8.8-mile segment of Pinto Creek being considered
for Wild or Scenic designation; at this time, the
potential impact cannot be quantified. Therefore,
monitoring and mitigation measures are
recommended in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures.
Water quality would also be a factor influencing the
potential Wild or Scenic designation of the stream. If
current water quality conditions change, Pinto Creek
could become ineligible for Wild or Scenic desig-
nation. It is anticipated that water quality within the
8.8-mile segment of Pinto Creek would not be
adversely affected by mine operations (Section 3.3.2,
Water Resources - Environmental Consequences):
however, a catastrophic event could affect water
quality along this portion of the creek, as discussed in
Section 3.3.2. Monitoring and mitigation strategies are
discussed in Section 3.3.4, Water Resources -
Monitoring and Mitigation Measures.
3.10.2.2 Alternatives
The project alternatives would generally result in
similar impacts to the wilderness and to the potential
designation of the Wild or Scenic segment of Pinto
Creek as the proposed action. The following sections
describe potential differences in impacts associated
with the project alternatives.
Mine Rock Disposal Alternatives
The impacts associated with the mine rock disposal
alternatives, including the alternative mine rock
disposal sites, additional backfill of the Carlota/Cactus
pits, and the additional backfill of the Eder South pit,
would be similar to the impacts discussed for the
disposal and backfill components of the proposed
action.
Eder Side-Hill Leach Pad Alternative
Impacts associated with the Eder Side-Hill Leach Pad
alternative would be similar to the leach pad
component of the proposed action, although there
would be a greater risk of catastrophic impacts to
downstream water quality.
Water Supply Alternative
The use of low-quality water from other mines or from
remediation efforts may diminish the impacts to Pinto
Creek associated with well field development.
Alternative sources of water may decrease the
3-290
Carlota Copper Project Final EIS
3.0 Affected Environmental and Environmental Consequences - Wilderness and Wild and Scenic Rivers
likelihood of reduced baseflow and alluvial underflow
in Pinto Creek as a result of ground water withdrawal.
If adequate water is supplied from alternate sources,
the potential for diminished flows in Haunted Canyon
and Pinto Creek would be reduced; therefore,
potential impacts to the potential Wild or Scenic
segment of Pinto Creek would decrease.
Alternative Water Supply Well Field Access
Roads
The impacts associated with Access Road
Alternatives A and B would be similar to the access
road component of the proposed action.
No Action Alternative
Under the no action alternative, the existing
horseback access to Haunted Canyon and the
Superstition Wilderness through Powers Gulch would
be maintained. Impacts to the wilderness (visual,
noise, air quality, and increased use) from mine
development and operations would not occur. The
potential for diminished streamflows and water quality
degradation on the potential Wild or Scenic segment
of Pinto Creek would be avoided.
3.10.3 Cumulative Impacts
The interrelated actions discussed in Section 1 .6,
Interrelated Actions, could potentially affect the
wilderness experience in the Superstition Wilderness.
Potential direct impacts would be associated with air
quality, noise, and visual degradation. Potential
indirect impacts would be associated with increased
recreational use from an influx of new population. The
interrelated actions could change existing wilderness
recreational patterns. In some cases, recreational
opportunities would improve; in other cases, they
would be limited.
The cumulative impact on the potential designation of
a segment of Pinto Creek as a Wild or Scenic river
would be associated with an indirect recreation effect;
that is, the future condition of some existing recrea-
tional areas will improve because of restrictions
affecting future potential land uses. In these cases,
the natural environment would be preserved for low-
impact use. Cumulative impacts may also result from
the Pinto Valley Mine's impacts to both the quantity
and quality of water in the downstream segment.
These impacts could result from activities such as at
the Pinto Valley Mine ground water pumping and
accidental contaminant discharges from project
facilities.
3.10.4 Monitoring and Mitigation
Measures
Recommended air quality monitoring and mitigation
measures are addressed in Section 3.1 .4, Air
Resources - Monitoring and Mitigation Measures.
Recommended monitoring and mitigation measures
for potential streamflow and water quality impacts to
Pinto Creek are presented in Section 3.3.4, Water
Resources - Monitoring and Mitigation Measures. A
recommended mitigation measure for the preserva-
tion of access to the Superstition Wilderness is
presented in Section 3.9.4, Recreation - Monitoring
and Mitigation Measures. Recommended mitigation
measures for noise impacts to the Superstition
Wilderness are identified in Section 3.12.4, Noise -
Monitoring and Mitigation Measures.
Carlota Copper Project Final EIS
3-291
3.0 Affected Environment and Environmental Consequences - Wilderness and Wild and Scenic Rivers
3-292
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Visual Resources
3.11 Visual Resources
3.11.1 Affected Environment
The project area represents a visually diverse and
interesting setting from the perspective of both natural
and man-made features. Two well-defined north-
south-trending drainages bisect the area. The larger
of these is Pinto Creek, which is an intermittent
stream throughout much of the project area, with
areas of perennial flows downstream. The other
major drainage is Powers Gulch, which lies to the
west of Pinto Creek and is an intermittent stream
throughout the project area. Each of these drainages
contains a number of smaller, but often deep and
well-defined, side drainages.
Haunted Canyon is perennial downstream of Powers
Gulch and contains a riparian area with a dense
vegetative canopy. The northern and eastern slopes
of this drainage complex are generally heavily
vegetated by a mixture of pihon-juniper and chaparral
plant species. The relatively high plant diversity that
occurs here is evident on close examination, but from
a casual or distant perspective these slopes appear
to be more uniform than they actually are.
Within the lower portions of the Pinto Creek drainage
there is a well-developed and visually interesting
riparian zone, which contains an overstory canopy of
sycamore, ash, walnut, and other tree species. Many
of the south- and west-facing slopes are less
vegetated and, in some locations, are dominated by
rock outcrops and boulder fields within a desert
grassland community. In particular, the southern
portion of the project area between the Pinto Creek
and Powers Gulch drainages is characterized by very
large, rounded granitic boulders and rock formations,
with scattered juniper trees and typical chaparral and
desert grassland species. In the northern portion of
the project area near Grizzly Mountain, several
prominent rock formations jut above the surrounding
vegetated ridges and serve as visual focal points.
The most extensive and visually evident modification
in the vicinity of the project area is the Pinto Valley
Mine. This existing copper mine lies just to the east
and north of the proposed project site, extending over
an area of more than 3 miles from north to south. It
includes a central open pit, various mine rock
disposal areas and tailings impoundments, and
support and processing facilities. This mine is the
westernmost of a number of existing copper mines,
which extend north and eastward past the commu-
nities of Miami and Globe {Figure 1-2). An existing
steel-lattice 115-kv transmission line runs from east to
west across the southern portion of the project area.
The line loops in and out of the Pinto Valley Mine
near the mine access road. A power line corridor
containing the 500 kv transmission lines crosses the
northern portion of the project area from east to west.
Some four-wheel-drive recreation and mine
exploration roads also traverse the area. Top-of-the-
World, a small residential community, is located along
U.S. Highway 60 southwest of the proposed project.
U.S. Highway 60 traverses to the south of the project
area across the upper reaches of the Pinto Creek
drainage just to the south of the Powers Gulch
headwaters and through the rounded, granitic boulder
formations that separate these two drainages at this
point. This highway provides elevated views of
portions of the project area to the north, particularly to
portions of the Pinto Creek drainage and the existing
Magma Pinto Valley Mine. Elevated views are also
possible from near Top-of-the-World. Within a short
walk of several residences within this community, an
overview of Powers Gulch and lands to the north can
be obsen/ed. The Magma Pinto Valley Mine Road
provides access to both the Magma Pinto Valley Mine
and to Forest Service managed lands beyond the
mine to the north and west. Throughout the majority
of its length, this road is in the proximity of various
features and facilities associated with the existing
Magma Pinto Valley Mine. This area is also visible
from various back-country viewpoints within the
Superstition Wilderness, the boundary of which lies
approximately 3 miles to the west.
The Tonto National Forest has inventoried and
classified the lands within the project area for visual
resources at a planning level of detail. The
management objectives that are described in the
Tonto National Forest Plan (USDA Forest Service
1985) are designed to provide a general indication of
landscape values and viewer sensitivity. The majority
of lands within the project area has been designated
as a Partial Retention visual quality objective. This
objective essentially states that changes to the
landscape should remain visually subordinate to the
characteristic landscape. A portion of the project area
in Powers Gulch, which is unseen from the identified
Carlota Copper Project Final EIS
3-293
3.0 Affected Environment and Environmental Consequences - Visual Resources
sensitive viewpoints, has been classified as a
Maximum Modification visual quality objective. This
management designation states that with some
qualifications, landscape modifications may dominate
the characteristic landscape. An approximately 0.5-
mile-wide corridor centered on U.S. Highway 60 and
the Pinto Valley Mine access road (Forest Service
Road 287) has been designated as a Retention visual
quality objective. This objective states that landscape
modifications should not be visually evident and may
only repeat the form, line, color, and texture qualities
that are frequently found in the characteristic
landscape.
3.11.2 Environmental Consequences
Visual resource issues identified for the proposed
Carlota Copper Project include (1) the impacts of
open pits, mine rock disposal areas, leach pads,
roads, and associated project facilities on the existing
visual landscape to sensitive viewpoints, including
U.S. Highway 60, the Superstition Wilderness, and
Top-of-the-World; and (2) deterioration of the
remoteness experience within the Superstition
Wilderness and of the rural setting for Top-of-the-
World residents because of project night lighting.
Evaluation criteria for the assessment of visual
resource impacts include the following:
• Ability to meet the assigned Visual Quality
Objectives (VQOs) that have been established for
the project area
• Potential increase in night light spill and glare
from the project area to the Superstition
Wilderness and residents of Top-of-the-World
The ability to meet the assigned VQO levels has been
deter-mined through a systematic process composed
of the following steps:
• Identification of the nature and extent of physical
modifications to the landscape anticipated from
the proposed action and alternatives (specifically,
how the landscape would be altered)
• Identification of important viewing conditions from
the key observation points (KOPs) potentially
affected by the project (i.e., distance, duration,
screening, etc.)
• Identification of the context of the view from
KOPs (character and condition of the surrounding
landscape)
• Identification of visual contrast levels for each
KOP (the degree of contrast created between
the proposed project/alternatives and the
surrounding landscape as seen from each
KOP)
• Identification of visual contrast levels affected by
the alternatives including the proposed action
3.11.2.1 Proposed Action
Based on computer-generated seen-area (visibility)
plots, three KOPs were identified as being affected to
some degree by views of the proposed Carlota
Copper Project. These include relatively short and
intermittent segments of U.S. Highway 60 in the
vicinity of Pinto Creek, a ridge behind the community
of Top-of-the-World, and scattered high points within
the Superstition Wilderness. Figures 3-36a, 3-37a,
and 3-38a are photographs looking toward the
Carlota mine area from these three viewpoints. The
U.S. Highway 60 viewpoint photograph was taken
from a small pullout approximately 0.75 mile west of
the Pinto Creek crossing. The Top-of-the-World
viewpoint photograph was taken from a slightly
elevated ridge behind the residential area. No project
elements would be visible from any of the residences
at Top-of-the-World; however, there would be limited
visibility from a commercial building. The Superstition
Wilderness viewpoint photograph was taken from
near Government Hill.
Figures 3-36b and 3-37b are computer-generated
photo simulations from the U.S. Highway 60 and
near Top-of-the-World viewpoints that illustrate
the height-of-mining stage of development. Figure
3-38b is the view from the Superstition Wilderness
viewpoint with the computer-generated outline of
the main mine features overlaid. Figure 3-39a
illustrates the proposed project following
reclamation from the view-point near Top-of-the-
World.
3-294
Carlota Copper Project Final EIS
Figure 3-36a. Existing Condition Photograph Looking Northwest
from a Road Pullout Approximately Three-Quarters of a Mile
West of the Pinto Creek Bridge
Figure 3-36b. Photosimulation of Proposed Cariota Copper Project
Looking Northwest from Highway Pullout
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figures 3-36 a&b
Views from
U.S. Highway 60 KOP
3-295
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Figure 3-37a. Existing Condition Photograph Looking North from an
Overiook North of the Top-of-the Worid Residentiai Area
Figure 3-37b. Photosimuiation of Proposed Cariota Copper Project Looking
North from an Overiook North of the Top-of-the-Worid Residentiai Area
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figures 3-37 a&b
Views from the KOP near
Ti”» h o-\A/r* r I H
3-297
Figure 3-38a. Existing Condition Photograph Looking Southwest
from near Government Hill
Figure 3-38b. Photosimulation of Proposed Carlota Copper Project
Looking Southwest from near Government Hill
^ Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figures 3-38 a&b
Views from the Superstition
Wilderness KOP
-
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Figure 3-39a. Photosimulation of Proposed Post-Mining Reclamation Conditions as
Seen from KOP near Top-of-the-World
Figure 3-39b. Photosimulation of Post-Mining Heap-Leach Reclamation Alternative
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figures 3-39 a&b
Views of Reclamation Alternatives
from the KOP near Top-of-the-World
3.0 Affected Environment and Environmental Consequences - Visual Resources
Table 3-84 illustrates the primary variables
involved in determining impacts for the three
KOPs. The proposed project would result in a
strong degree of modification to the existing
landform and vegetation patterns. Proposed
structures would represent a lesser (moderate)
contrast because of the large scale and complex
nature of the existing landscape features. The
remaining impact variables are unique to each
viewpoint.
The U.S. Highway 60 viewpoint is over a mile from
the nearest element of the proposed project. From
this KOP, views are generally open to the Carlota/
Cactus pit and the Main mine rock area; the Cactus
Southwest mine rock area is mostly screened from
view, and all other primary mine features are entirely
screened from view, as shown in Figure 3-36b.
Because of the intermittent and short viewing oppor-
tunities, as well as the speed of highway traffic, the
Table 3-84. Visual Resource Impact Summary for the Proposed Action
im'iiact Variables
KOPs
U.S. Highway : | Near Top-oMhe-
60/70 1 ‘ World
Superstition
VV^ilderness
Physical Modification
(at mine site):
Landform
Strong form, line, color, and textural modifications to the landscape
Vegetation
Strong form and color, moderate line and textural modifications to the landscape
Structures
Moderate form, line, color, and textural modifications to the landscape
Assigned VQO from
Management Prescription
Distance
1.1+ miles
0.8+ mile
3.6+ miles
Screening
Generally open views
to Carlota/Cactus pit
and Main mine rock
area: Cactus
Southwest mine rock
area mostly
screened; all other
major features
entirely screened
Generally open views to
Eder pits and mine rock
areas; partially screened
to Cactus Southwest mine
rock area, leach pad, and
Main mine rock area;
Carlota/Cactus pit entirely
screened
All major project features
partially screened, but
generally open visibility
Duration
Very brief (seconds)
Moderate (minutes-hours)
Moderate (minutes-hours)
Overall Visibility Level
Low
High
Moderate
Context of View
Heayily influenced by
existing Magma Pinto
Valley Mine
Generally natural;
portions of Magma Pinto
Valley Mine visible in
background
Heavily influenced by
existing Magma Pinto Valley
Mine in views to the east
Visual Contrast (physical
conditions modified by
viewing conditions and
context)
Moderate (evident
but not dominant)
High (dominant)
Low (visible but not
evident — would appear as a
continuation of existing
disturbance)
VQO (visual management
prescription)
Partial Retention
Primarily Maximum
Modification with some
Partial Retention
Partial Retention and
Maximum Modification
Short-Term Impacts (during
mining)
Moderate
Moderate-High
Low
Long-Term Impacts (post-
reclamation
Revegetation efforts would soften the form, line, color, and texture modifications
to some degree, but contrast levels would remain high overall, and impacts would
remain near short-term levels.
Carlota Copper Project Final EIS
3-303
3.0 Affected Environment and Environmental Consequences - Visual Resources
duration of view would be very brief. The overall level
of visibility of the proposed project would therefore be
low, as seen from this viewpoint. The context of these
views is strongly influenced by the presence of the
adjacent Pinto Valley Mine. Overall visual contrast, or
the visible degree of landscape modification as
influenced by viewing conditions, from this viewpoint
would be moderate. This means that the proposed
modifications would be evident, but not dominant.
With a Partial Retention VQO, short-term visual
impacts (during active mining) would be moderate
(i.e., at, but not exceeding, the management
guidelines).
The viewpoint near Top-of-the-World is approximately
0.8 mile from the nearest project element. Views are
generally open to the Eder pits and mine rock area,
and partially screened to the Cactus Southwest mine
rock area, leach pad, and Main mine rock area. The
Carlota/Cactus pit is entirely screened from view
{Figure 3-37b). The duration of the visual impact
would be moderate (i.e., a few minutes to an hour or
more): the overall visibility would be high. The
landscape in view is generally in a natural-appearing
condition, with the exception of a portion of the
background that is influenced by the existing Pinto
Valley Mine. Visual contrast levels are high (the
proposed project would appear as the dominating
element in views from this viewpoint). VQO desig-
nations on project lands within view are primarily
Maximum Modification with some Partial Retention,
resulting in short-term impact levels of moderate and
high, respectively (at Maximum Modification levels
and exceeding Partial Retention levels).
The Superstition Wilderness viewpoint is beyond 3.5
miles from the nearest project features. All major
project features are partially screened but generally
visible {Figure 3-38b). Duration of view would be
moderate (i.e., a few minutes to several hours). The
overall visibility level would be moderate. The existing
Pinto Valley Mine stretches for a long distance across
the cone of vision in views to the southeast, strongly
influencing the character of the landscape in view.
Overall visual contrast is low; the proposed project
would appear as an extension of the existing
disturbance. The affected lands in view are
designated as a combination of Partial Retention and
Maximum Modification, which would result in low,
short-term visual impacts.
The long-term (postreclamation) impacts from each of
these viewpoints would remain essentially the same
as those identified above. While revegetation efforts
would soften the form, line, color, and texture
modifications to some degree, overall contrast levels
would not be substantially reduced, primarily because
of the scale and extent of modifications proposed and
the limitations on the amount of this disturbance that
can be effectively reclaimed.
The Carlota Copper Project would cause an
increase in night light and glare because of project
night lighting for operational, security, and safety
needs. Considering the existing night lighting from the
adjacent Pinto Valley Mine, the degree of increased
night glow would be minor. However, to address
potential impacts to Superstition Wilderness users
and Top-of-the-World residents, additional mitigation
is recommended in Section 3.1 1.4 - Monitoring and
Mitigation Measures.
3. 1 1.2.2 Alternatives
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. The
alternative sites would not be visible from the
viewpoint near Top-of-the-World and would be
minimally visible from the U.S. Highway 60 and
Superstition Wilderness viewpoints. The reduction in
the height of the Main mine rock area is expected to
be visually insignificant as seen from any of these
viewpoints. This alternative would be very similar to
the proposed action.
Additional Backfill of the Carlota/Cactus Pit. The
additional mine rock added to the Carlota/Cactus pit
would be visible from the U.S. Highway 60 viewpoint,
and to a lesser degree from the Superstition Wilder-
ness viewpoint. The primary advantage from a visual
resource perspective would be the reduction in the
height of the Main mine rock area. This would be
most evident in views from the viewpoint near Top-of-
the-World, where the middle-ground ridgeline near
Grizzly Peak would be eliminated from view under the
proposed action. Under this alternative, the top of this
middle-ground ridgeline would remain visible above
the rock dump, defining the extent of the project.
Despite this advantage, substantial portions of the
project would remain highly visible, and impact levels
3-304
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Visual Resources
would not be measurably reduced. Figure 3-39b
illustrates the view of a modified reclamation
alternative (see the discussion of the heap-leach
reclamation alternative below) that includes aspects
of the Carlota/Cactus pit backfill alternative, including
the height reduction and reclamation of the Main mine
rock area as it would appear from the Top-of-the-
World viewpoint. This figure also includes reclamation
of the heap-leach pad and the Eder pits and mine
rock area, which are not part of the Carlota/Cactus pit
backfill alternative.
Additional Backfill of the Eder South Pit. Additional
backfill of the Eder South pit would be evident only
from the viewpoint near Top-of-the-World. The
primary benefit would be the removal of the Eder
mine rock area. The removal of the mine rock dispos-
al area would not only reduce the visible extent of the
disturbed area, but it would also have the benefit of
opening up views of the undisturbed background.
Figure 3-39b illustrates the view of a modified
reclamation alternative (see the discussion of the
heap-leach reclamation alternative below) that
includes aspects of the Eder South pit backfill alterna-
tive, including the height reduction and reclamation of
the Eder mine rock area as it would appear from the
Top-of-the-World viewpoint. This figure also includes
reclamation of the heap-leach pad and the Main mine
rock area, which are not part of the Eder South pit
backfill alternative.
Eder Side-Hill Leach Pad Alternative
The alternative leach pad configuration would not be
visible from the U.S. Highway 60 viewpoint. It would
be visible from the Superstition Wilderness viewpoint;
however, at a distance of over 3.5 miles, the change
in configuration would be similar to the visual contrast
from the proposed action.
The differences in the heap-leach facility under this
alternative would result in substantially greater visual
contrast as seen from the viewpoint near Top-of-the-
World. A portion of the heap-leach facility on the east
side of Powers Gulch would be approximately 135
feet lower than the proposed heap-leach facility and
would be smaller in area. However, the portion of the
alternative heap-leach facility on the west side of
Powers Gulch would be approximately 135 feet
higher than the proposed Eder mine rock area.
Therefore, there would be minor advantages and
disadvantages to the relocated heap-leach facility
from a visual contrast/scale perspective.
The greater visual contrast of this alternative would
come from the relocated Eder mine rock area, which
would be within 0.4 mile of the viewpoint near Top-of-
the-World. The closest facility under the proposed
action would be the Eder South pit at a distance of
approximately 0.8 mile. The top elevation of the re-
located Eder mine rock area would be 4,480 ft-amsi,
which is 140 feet higher that the proposed Eder rock
dump and 280 feet higher than the proposed heap-
leach facility. The greater height and closer proximity
of the Eder mine rock area under this alternative
would result in a substantially greater scale of
disturbance, both short- and long-term, as seen from
this viewpoint. Visual impacts would be high.
Water Supply Alternative
The use of low-quality water from off-site sources
would have visual effects similar to the proposed
action. The size of the pipelines would be relatively
small (8-inch diameter) and would follow the power
line route through an area of existing and proposed
mining disturbance. The degree of visual contrast
would therefore be relatively low; in fact, it would not
be visible from any of the three KOPs. Visual
resource impacts would be minor from this
alternative.
Alternative Water Supply Well Field Access
Roads
Access Road Alternative A. This alternative would
involve substantially less disturbance than the
proposed access road because it would be located
along an existing road in the bottom of the drainage
rather than requiring new construction on the higher,
steep side slopes. This area would not be visible from
any of the three KOPs previously identified, but it
would be highly visible to back-country recreationists
who visit the lower Pinto Creek drainage. Therefore,
this alternative would represent a substantial
improvement over the proposed access road. Both
visual contrast and visual impacts would be
measurably reduced.
Access Road Alternative B. Except for a small
portion near the confluence of Haunted Canyon and
Carlota Copper Project Final EIS
3-305
3.0 Affected Environment and Environmental Consequences - Visual Resources
Powers Gulch, this alternative would be in an area
that is not visible from any commonly used view-
points. The visual impacts would be low because the
modifications to the landscape would essentially be
unseen.
No Action Alternative
Under the no action alternative, the visual condition of
the project area lands would remain nearly in their
current condition, allowing for natural ecological
change and other unforeseen future minor actions.
Because views from U.S. Highway 60 and the
Superstition Wilderness into the upper Pinto Creek
drainage are already heavily influenced by the
existing Pinto Valley Mine, this alternative would have
measurable, but not overriding, advantages from a
visual perspective. Powers Gulch, on the other hand,
is less disturbed and substantially less influenced by
the Pinto Valley Mine. This area, while visible from
the Superstition Wilderness, is not seen as a distinct
part of the overall project area. The primary
advantage of the no action alternative, therefore, is
the elimination of disturbance within the Powers
Gulch area as seen from the viewpoint near Top-of-
the-World. In this area, visual impacts would be
reduced from moderate-high to none.
Reclamation Alternative
A separate reclamation alternative was evaluated as
part of the visual resource analysis to determine if
substantial benefits could be realized by implement-
ing specific reclamation measures. The variations
described here were analyzed only from a visual
perspective.
Figure 3-39b illustrates the visual appearance of
additional reclamation of specific components of the
proposed action as seen from the viewpoint near
Top-of-the-World. Under this reclamation scenario, all
pits would be backfilled, resulting in reduced heights
to the Main and Eder mine rock areas and the elimi-
nation of the Cactus Southwest mine rock area.
The tops of the Main and Eder mine rock areas
would be reclaimed as well as the top and
southwest side of the proposed heap-leach pad.
While these measures would noticeably improve
the long-term visual contrast as seen from the
viewpoint near Top-of-the-World and would
improve, to some degree, the visual contrast of
the mine and heap-leach areas as seen from the
U.S. Highway 60 and Superstition Wilderness
viewpoints, the scale of the overall disturbance
is such that long-term visual impacts would
remain.
3.11.3 Cumulative impacts
Table 3-85 lists the actions that have been identified
for consideration of visual resources. As the first
column in this table indicates, a majority of these
proposed projects represent either visually minor
modifications or are of low contrast within the
context of the surrounding landscape. Examples
of these two conditions include the transmission
line upgrade, which will involve only minor
maintenance modifications that are visually
insignificant, and the Cyprus Miami Mine, which
will not be visually insignificant in its own right but
will involve relatively minor modifications in light
of the substantial disturbance that already exists
in this location.
Table 3-85 also identifies some projects that are
located a considerable distance from the proposed
Carlota Copper Project. The memory people have
about a particular area is in direct proportion to either
the significance/familiarity of the place, the distinctive-
ness (good or bad) of the landscape features there,
or the time that has passed since they visited the
area. The second column of Table 3-85 identifies
projects that, because of considerations of distance
(time) or distinctiveness, have little residual effect on
judgment of the overall visual quality of the project
area.
The Pinto Valley Mine represents a visually
interrelated action. This project is of an actual or
potential size/scale to be memorable within the
travel time from this mine to the Carlota Copper site.
The Pinto Valley Mine expansions are relatively
minor in relation to the existing disturbed area.
Nevertheless, they are close to the Carlota Copper
Project and may have a cumulative interaction. The
Gibson mine is a relatively small historic underground
mine located on private land; as such, it is of interest
to the few people who do see it.
3-306
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Visual Resources
Table 3-85. Summary of Visual Resource Impacts from Interrelated Actions
•
Proposals
^dnofKcilonatU^ll
Mining Projects
Old Carlota Mine
X
Gibson Mine
X
Copper Cities
X
Miami Unit
X
Cyprus Miami Mine
X
Pinto Valley Mine
X
Ray Mine
X
Superior Underground Mine
X
Placer Mining
X
Copper Florence
X
Energy and Transmission
Projects
X
Water Resource Projects
Pinto Creek (w/s River)
X
Coolidge Dam Project
X
X
Roosevelt Dam Project
X
Transportation Projects
Highway 60/70 Improvements
X
Highway 88 Improvements
X
Private Land Development
Projects (Commercial and
Residential Development in the
Globe-Miami Area)
X
Visually minor actions, or actions that represent a relatively minor addition to an already altered landscape
Of more significance in determining the cumulative
effect of this project on the visual character and
quality of the region are the extensive, large-scale
past and existing mining operations that exist within a
few miles of the proposed project. With little
exception, this activity visually dominates the land-
scape to the east from the existing Pinto Valley Mine,
immediately adjacent to the proposed Carlota Copper
Project, through the Miami-Globe area. Within this
context, the proposed Carlota Copper Project
represents only a relatively minor addition. Its
greatest adverse impact from a cumulative visual
perspective is that it expands the extent of large-scale
mining activity by one drainage to the west.
3.11.4 Monitoring and Mitigation
Measures
Through the course of this analysis various reclama-
tion scenarios were simulated to assess their effec-
tiveness. The reduction in the mine rock areas
through backfilling the pits would have a noticeable
positive influence. However, even these actions, as
costly and intensive as they are, would not mitigate
the overall adverse visual impacts associated with the
proposed project. This is primarily because they
would affect a relatively small portion of the overall
disturbed area.
During active mining, little can be done to reduce
the strong form and color contrasts without unduly
interfering with mine operations. Measures to
curtail dust are discussed in Section 3.1, Air
Resources. Other possible options for reducing
visual impacts during active mining include the
following:
VR-1: Colors for buildings and field facilities would be
selected to blend with the surroundings and to reduce
reflectivity to the greatest degree possible.
Carlota Copper Project Final EIS
3-307
3.0 Affected Environment and Environmental Consequences - Visual Resources
Specifications would be submitted to the Forest
Service for review.
VR-2: Permanent night-lighting would be shielded and
directed downward to avoid night spill and glare.
Mobile lighting would be positioned to minimize glare
off of the property, consistent with safety
considerations.
VR-3: Revegetation would be implemented where
feasible to reduce the long-term (postmining) form
and color contrasts that would be created by mining.
Of greatest priority for revegetation are roads and the
southern and western portions of mine rock areas
and the heap-leach pad, which are most visible from
the viewpoint near Top-of-the-World.
VR-4: Top portions of the Eder pits would be
treated, particularly the south-facing slopes, to
reduce the visual impacts of the open pit slopes if
there is a large light or color contrast with the
surrounding area. This would be accomplished using
chemical darkening agents, rounding or warping
benches, and/or rubblizing slopes. Final mitigation
design would be approved prior to the Eder phase of
mining.
3-308
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Noise
3.12 Noise
3.12.1 Affected Environment
The principal issue associated with the noise analysis
is the potential increase in sound levels above the
levels that currently exist in the project vicinity,
sometimes referred to as the ambient or background
level (see Table 3-86 ior noise definitions). While
increased sound levels are not inherently objection-
able, sound becomes noise when it is unwanted or
disagreeable. Noise presents a problem when it
interferes with the performance or enjoyment of other
activities.
Estimating the likelihood that the proposed Carlota
Copper Project would cause adverse increases
in noise levels requires that the character of the
existing noise environment be established as a
baseline for the analysis. Important features of the
existing noise environment include the locations and
types of noise-sensitive receptors, terrain features
that would affect noise propagation from project-
related activities, sources of existing noise near the
project site, and existing ambient noise levels in the
vicinity.
Certain human activities are commonly more sus-
ceptible than others to noise interference. Such
activities or land uses, termed sensitive receptors,
include residential areas, schools, hospitals, libraries,
and certain outdoor gathering places, such as parks,
particularly when they are primarily used for passive
types of recreation. Two areas have been identified
as potential noise-sensitive receptors in the vicinity of
the proposed Carlota Copper Project: the Superstition
Wilderness and the Top-of-the-World community.
The Superstition Wilderness contains 159,780 acres,
stretching approximately 24 miles east to west and 16
miles north to south. The southeastern edge of the
wilderness is approximately 2.5 miles west of the
western site boundary of the project. The nearest
proposed project facility, the Main mine rock disposal
area, is approximately 2,500 feet farther inside the
site boundary. Top-of-the-World is a small,
unincorporated residential community containing
approximately 200 homes and 500 to 600 people.
The nearest residence is approximately 600 to 800
feet from the project site boundary and 4,200 feet
south-southeast from the nearest proposed project
facility, the Eder South pit.
Terrain can affect noise either as a barrier or as a
reflector of sound energy. Terrain acts as a barrier
when an earth mound breaks the line of sight
between a noise source and a receptor. The degree
of effect on noise propagation depends on several
factors, but projective calculations typically focus on
the height and continuity of the barrier. Generally, the
higher the barrier projects into the line of site, the
greater the noise reduction; a relatively long, contin-
uous barrier is noticeably more effective than a
broken barrier. The reflector effect typically occurs
where a noise source is located between a raised
topographic feature and a receptor. A reflector effect
is generally more pronounced where the topographic
incline is steep, hard surfaced, and smooth, such as a
building or a flat-faced rock cliff.
Topography in the vicinity of the proposed Carlota
Copper Project is extremely complex, dissecting the
area into several named drainages with numerous
minor tributaries. The primary ridge dividing the north-
flowing Pinto Creek basin from the south-flowing
Devil's Canyon basin crosses the study area in a
generally east-west direction. The ridge runs
northwesterly from Five Point Mountain, 1 mile south
of the project site, crossing U.S. Highway 60 at the
Gila/Pinal County line just east of Top-of-the-World.
North of the highway, the ridge turns westerly, closely
tracking the southern boundary of the project site. It
continues to the west for several miles before twisting
northwesterly into the Superstition Wilderness. The
low point of the ridge is approximately 4,615 ft-amsi,
where it is crossed by the highway. Northwest of the
highway, the ridge varies from just over 4,600 ft-amsI
to more than 5,400 ft-amsI. Several secondary ridges
branch off the primary ridge. The proposed project
site includes parts of the Powers Gulch and Pinto
Creek drainages, straddling one of these secondary
ridges. Another ridge forms part of the western
boundary of the site.
The elevation of the project site varies from below
3,450 ft-amsI in the Powers Gulch and Pinto Creek
drainage bottoms along the northern site boundary to
over 5,000 ft-amsI in places along the southwesterly
site boundary. Top-of-the-World is at approximately
4,600 ft-amsI. The southeastern boundary of the
Carlota Copper Project Final EIS
3-309
3.0 Affected Environment and Environmental Consequences - Noise
Table 3-86. Noise Terminology and Symbols
Symbol
Term
' Peflnitlon
dBA
A-weighting
The most commonly used frequency-weighting measure; simulates human sound |
perception and correlates well with human perception of the annoying aspects of noise, i
Ambient Noise
Total, all-encompassing noise associated with a given environment and time. I
Background Noise
Noise from all sources other than a particular sound of interest (e.g., other than mining
noise if mining noise was being measured.
dB
Decibel
Unit of measure of sound pressure and sound power levels; expresses relative
difference in power between two signals equal to 10 times the logarithm (base 10) of
the ratio of the two levels. Because of the logarithmic scale, the noise level doubles with
each increase of lOdB.
LEVELS
CNEL
Community Noise
Equivalent Level
Leg for a 24-hour, midnight-to-midnight period with 5 dBA added to the sound levels
from 7 p.m. to 10 p.m. and 10 dBA added to the sound levels between 10 p.m. and 7
a.m.
Ld
Day Average
Sound Level
Leg for the daytime period from 7 a.m. to 10 p.m.
i-dn
Day-Night Average
Sound Level
Leg for a 24-hour, midnight-to-midnight period with 10 dBA added to the sound levels
from 10 p.m. to 7 a.m.
Leg
Equivalent
Continuous Sound
Level
Level of steady state sound that, in a specific time period, has an equal amount of
sound energy as the time-varying sound. The time period varies depending on the
application; it is commonly a 24-hour day unless otherwise specified
l-max
Maximum Sound
Level
The greatest sound level measured on a sound level meter during a designated time
interval or event using fast time averaging on the meter.
l-n
Night Average
Sound Level
Leg for the nighttime period from midnight to 7 a.m. and from 10 p.m. to midnight.
i-Dk
Peak Sound Level
Maximum instantaneous sound level during a specified time interval or event.
Li
Percentile Level 1
Sound level exceeded 1 percent of the time during a given period. In other words, the
sound level would be at or below the Li level for 59 minutes and 24 seconds per hour
measured.
•-10
Percentile Level 10
Sound level exceeded 10 percent of the time during a given period; often represents a
short-term noise associated with passing vehicles or airplanes flying over.
L50
Percentile Level 50
Sound level exceeded 50 percent of the time during a given period; the median sound
level.
I-90
Percentile Level 90
Sound level exceeded 90 percent of the time during a given period; sometimes used as
an approximation for background noise.
Noise
Unwanted sound; one that interferes with one's hearing of something; a sound that
lacks agreeable musical quality or is noticeably unpleasant.
Superstition Wilderness ranges in elevation from
3,800 ft-amsi in Haunted Canyon to nearly 5,100
ft-amsi on several promontories.
Elevations in the interior of the Wilderness range
from below 2,000 to 6,266 ft-amsI at Mound
Mountain.
Existing noise sources near the proposed project are
important because they influence existing noise levels
and, consequently, may affect the likelihood that
project- related noise would be audible at sensitive
receptors. Noise sources in the vicinity of the
proposed project include highway traffic on U.S.
Highway 60, ongoing operations at the Pinto Valley
Mine, frequent overflights by military jet-fighter air-
craft, and natural noise sources, such as wind, birds,
and insects.
A series of noise measurements was taken in the
vicinity of the proposed Carlota Copper Project to
provide a sense of existing noise levels. Measure-
ment results illustrated in Table 3-87, and weather
conditions illustrated in Table 3-88 indicate that
3-310
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Noise
Table 3-87. Ambient Noise Survey Data
^ * t " 1 Sound Pres
Duration fdE
pate 1 Time* 1 (minutes) 1 L„ |
sure Lg
iA)
!=«
yels .
•
.| a
Notes
Superstition Wilderness
Location A
12/15/92
15:00
20
31.5
27.5
26.0
29.1
Streamflow noise
Location B
12/16/92
12:38
2
28.0
19.5
18.5
26.3
Slight, sporadic breeze
12/16/92
12:50
2
28.5
21.5
19.5
24.5
Slight, sporadic breeze
12/16/92
13:12
2
22.0
18.5
18.5
20.4
Faint mine hum
12/16/92
13:24
2
28.5
20.5
19.0
25.8
12/16/92
13:36
5
53.0
42.0
23.5
47.8
Two jet fighters'*
12/16/92
13:48
10
27.0
21.0
19.5
25.9
12/16/92
14:00
NA
3
3
3
18.2
Faint mine hum
12/16/92
14:10
NA
3
3
3
26.2
Slight breeze
12/16/92
14:20
NA
3
3
3
22.1
Top-of-the-World
Location C
12/15/92
17:15
20
51.5
47.0
42.5
49.6
Traffic, dogs, airplane
12/15/92
22:45
15
43.0
36.0
29.5
39.1
Light traffic, dogs
Location D
12/15/92
18:35
20
45.5
37.5
27.0
45.5
Traffic, dogs
Location E
12/15/92
19:06
10
42.0
35.5
26.0
38.0
Light traffic, dogs
12/15/92
23:55
15
36.5
28.0
22.5
32.2
Light traffic
' See Figure 3-40.
^ Approximate time.
Octave band measurements taken to characterize the sound frequencies represented in the ambient noise. A different
measurement technique was used than for the other measurements in this table, so useable information on L,o, Lso, or L90
was not generated.
‘Lp, = 73.1 dBA.
Table 3-88. Weather Conditions During Noise Survey
Tim?* 1
5 Temperature
1 i m i
r Wind ' ' -
Spied (mph) and
■ M Direction, ■ ■ ■ ..
*■
12/15/92
14:50
44
0-5
SW
26
17:15
36
0-3
SW
29
18:35
34
0
—
25
19:06
34
0
—
19
22:45
30
0
—
46
12/16/92
12:38
54
0-2
SE
28
’ Mountain Standard Time
Carlota Copper Project Final EIS
3-311
2000 4000
Scale in Feet
■one
■mile
Riverside Technology, inc.
CARLOTA COPPER PROJECT
Figure 3-40
Noise Monitoring Sites
I
*!■»
/PINTO \
01
1
Tt*tf Ttt\ik . i
4i*a ■
.. r \
. \ , at >:> ■■
>v*» VfHey
'-A
\
r*v7
Superstition
Wilderness .
Boundary if<h^
/fJ'tJiif
\ r ' \
•-;• I ’;'v-V.r - ^ ■
'J ...' S .' . -
3-312
3.0 Affected Environment and Environmental Consequences - Noise
existing noise levels in the area range from very quiet
in the back country when the wind is calm to moder-
ate near the Top-of-the-World community with some
highway traffic present.
The noise measurements were taken at two locations
in the Superstition Wilderness and at three locations
in and near Top-of-the-World (see Figure 3-40).
Wilderness monitoring locations were (A) near the
trailhead of Forest Service Trail 203 and (B) on the
ridge forming the eastern boundary of the Superstition
Wilderness northeast of Government Hill. Top-of-the-
World monitoring locations were (C) approximately
300 feet north of U.S. Highway 60 on the northern
edge of Top-of-the-World, (D) approximately 0.5 mile
north of Top-of-the-World on Forest Service Road
898, and (E) approximately 800 feet north of Top-of-
the-World on the same road.
The average equivalent continuous sound level (Leq)
at the edge of the Superstition Wilderness without the
aircraft noise or the stream noise was 24.6 dBA; Lgo
was 19.0 dBA. These readings are below most
wilderness noise measurements cited in literature
sources (ERA 1971a, NPS 1990). The low levels are
likely attributable to the lack of wind at the time of the
monitoring; wind is an important determinant of back
country noise, as noted by Bommer and Bruce
(1992), among others. The daytime Leq measured at
Top-of-the-World was 49.6 dBA. This level is approxi-
mately equivalent to typical measurements reported
by the ERA (1971a) for suburban and small town
neighborhoods.
Subjective observations from the field monitoring
effort indicate existing noise levels in the Superstition
Wilderness varied greatly with weather conditions,
especially with wind speeds {Table 3-88). The
measurements recorded at site B were taken with
almost no air movement and no discernible animal or
insect noise. Under those circumstances, operations
at the Rinto Valley Mine were perceived as a very
low-level hum. Even the slightest breeze through
grasses, shrubs, and trees raised sound pressure
levels by 3 to 6 dBA, completely obliterating any
perception of the Rinto Valley Mine noise. Measure-
ments taken at site A, approximately 50 yards from
the stream, were dominated by water noise such that
only high-level external sources, like aircraft
overflights or strong breezes, would be perceptible
above the background levels.
Noise at the Top-of-the-World site was dominated by
traffic noise from U.S. Highway 60. This was not
surprising since traffic noise is almost invariably the
dominant noise source affecting existing ambient
noise levels near a major highway or street. It held
true even with light traffic in the early evening and late
at night, suggesting that other sources contributed
very little to the overall background noise.
Traffic flow data from the ADOT and methodology
documented in Noise Assessment Guidelines (U.S.
Department of Housing and Urban Development
1984) were used to check the field measurement data
for representativeness. Similarly, for existing noise
levels in the Superstition Wilderness, measured noise
levels were compared with ERA (1971a) data based
on land use and density and with other file data and
literature sources. Again, the comparison was made
to check the short-term measurement data for
representativeness of the ambient condition. Based
on these comparisons, the noise measurements are
considered representative of ambient conditions in
similar environments.
3.12.2 Environmental Consequences
The noise issues associated with the proposed
Carlota Copper Rroject include adverse noise impacts
to (1) residents of Top-of-the-World and (2) recrea-
tional users of Forest Service lands, specifically the
Superstition Wilderness.
Noise impacts are commonly judged according to two
general criteria: the extent to which a project would
exceed federal, state, or local noise regulations, and
the estimated degree of disturbance to people or
wildlife. For the Carlota Copper Rroject site, there are
no specific governing noise regulations. Conse-
quently, the degree of disturbance becomes the key
factor in evaluating noise effects. In this case, the
sensitivity considerations are focused on residents of
Top-of-the-World and on the Superstition Wilderness.
Specific evaluation criteria are (1) the degree of
project-related increase in average sound levels (Lgq)
in the Superstition Wilderness relative to an Lgo
reference level and (2) project-related changes in
Carlota Copper Project Final EIS
3-313
3.0 Affected Environment and Environmental Consequences - Noise
noise levels at Top-of-the-World relative to the U.S.
Department of Housing and Urban Development
acceptable noise standard of 65 dBA (L^n) in
residential areas. These criteria comprise a
quantifiable method to evaluate the concept of human
disturbance, which is known to vary with a number of
interrelated factors, including the change in noise
level; the presence of other, non-project-related noise
sources in the vicinity: people's attitudes toward the
project: the number of people exposed; and the type
of human activity affected (e.g., sleep or quiet conver-
sation as compared to physical work or active
recreation).
In preparing the analysis, guidance was taken from
Guidelines for Preparing Environmental Impact
Statements on Noise (CHABA 1977). Noise impacts
were projected using NOISECALC, a sound
propagation model developed for analyzing large-
scale industrial-type development projects.
NOISECALC provides for evaluation of atmospheric
attenuation, barrier attenuation, source directionality,
and path-specific or non-path-specific excess
attenuation at the analyst’s discretion. NOISECALC
employs noise analysis methodology adopted by
American National Standards Institute (ANSI).
3.12.2.1 Proposed Action
Major sources of noise from the Carlota Copper
Project would include crushing ore, drilling rock,
blasting, loading trucks hauling rock and ore, and
handling and distributing crushed ore. The types and
numbers of equipment planned for use are listed in
Table 3-89.
Total noise emissions were estimated for the
anticipated activities based on the equipment roster in
Table 3-89 using noise emission factors obtained
from EPA data (EPA 1971b), from file data, and from
field measurements of other mining projects with
similar characteristics. Because the distances from
project activities to sensitive receptors would be large
relative to the distances between operating equip-
ment involved, noise sources were grouped for
analysis purposes into four noise emission centroids,
or major composite noise sources, representing the
major activity areas (See Figure 3-41). The four
centroids are (A) the Carlota/Cactus pit. Main mine
rock area, and primary and secondary crushers; (B)
the Eder South pit and mine rock area; (C) the Eder
North pit and mine rock area; and (D) the leach pad.
Two high-activity time periods were analyzed: Years
8 and 14. Year 8 represents maximum activity in the
Carlota/Cactus pit with the largest number of trucks
running and the highest activity level on the Main
mine rock disposal area. Year 14 represents the
maximum activity level in the Eder pits area.
The projected noise levels were estimated with
all equipment operating simultaneously and no
barriers intervening in the line of sight between the
equipment and the listener. These are considered to
be very conservative conditions because, in the
actual operating conditions of a mine, equipment use
varies in time and location. As development of a mine
proceeds, pit activities recede progressively deeper
into the earth such that the pit wall becomes a higher
and higher barrier, blocking transmission of an
increasing percentage of the noise generated.
Similarly, as rock dumps increase in size they
become progressively larger above ground barriers to
noise transmission. Also, mine trucks and other
vehicles move about through the varying terrain of a
mine site, sometimes moving behind natural or man-
made barriers, sometimes stopping and idling or
shutting off their engines, and sometimes moving
down grade with engines throttled back. Stationary
equipment, such as crushers and conveyors, may
operate steadily throughout a day, but they may also
be shut down for fairly long periods of time. The noise
emissions thus vary dramatically as mine activities
ebb and flow. It is not feasible or even possible to
model all of the variations. Consequently, a high level
of activity was modeled under the assumption that
resultant project-related noise levels would rarely, if
ever, exceed the estimated levels.
It should also be noted that the sensitive receptor
locations identified for the Superstition Wilderness
are on the very easterly edge of the area on topo-
graphic high ground. Designated trails nearest these
receptor points receive relatively light use, estimated
at less than 1 percent of trail use in the Wilderness
(USDA Forest Service 1986). The farther into the
interior of the Wilderness one would go, the lower the
project-related noise levels would be. Also, noise
levels in valleys below the ridge tops would be lower
than those presented because the ridges act
as barriers to noise, providing increasingly greater
noise sheltering the farther one is below the ridge
top.
3-314
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Noise
Table 3-89. Carlota Copper Project Equipment Roster
r TV^tba! Sound tevels fdBil) for Mln'e and Riant Eqd1pment"^^"^.:l:S#. -
Eauipmenttype
No.
Units
Operating
Operating
Schedule
«(7days/week)
^ Distance from "
I Receptor
(feet) ...
Blasthole Drill (type 75,000-lb pulldown)
2
3 shifts/day
75
50
Hydraulic Shoyel (typ 13-16 cu yd)
3
3 shifts/day
85
50
Road Grader
2
3 shifts/day,
50% utilization
82
50
Track Dozer
2
3 shifts/day,
50% utilization
88
50
Rubber-Tire Dozer
1
3 shifts/day,
75% utilization
81
50
Leach Pad Dozer
1
2 shifts/day,
50% utilization
82
50
Front-End Loader (backup and stockpile)
(tyo 13.5 cu yd)
1
1 shift/day ayg
85
50
Haul Truck (typ 90-120 ton)^
16
3 shifts/day
77-80
50
Haul Truck on Leach Pad (typ 90 ton)
2
2 shifts/day
70-75
50
Water Truck (typ 50 ton)
2
2 shifts/day
70-75
50
Crushers, Chutes, Feeders, Screens,
etc.
3 shifts/day
90-105
50
Primary Blasting
—
1 blast/day
70-120
1,000
IT ibU-ion naui iruc;Kt> wuuiu uc uocu, me —
below emission levels for crushers, dozers, etc., which are the dominating noise sources. . . ^ ^ enn
Note- There would also be two diesel powered, back-up generators on the site, a 350-hp unit at the leach pad, and a 600-hp
unit at the plant site. They were not specifically included in the noise analysis, however, because they would only operate in
upset conditions when the notably noisier crushers were shut down.
Source; BLM (1992) (Section 4.9.1 - Equipment Manufacturer’s Specifications)
Noise emissions from Year 8 would emanate mainly
from activities at centroids A and D, reflecting mining
at the Carlota/Cactus pit and related processing
activity; pre-strip activity at the Eder South pit would
have begun, but at a relatively low level according to
the equipment assignment. The resulting noise levels
at the four sensitive receptor locations are presented
in Table 3-90. Although the analysis was very
conservative and fully accounted for pit noise with no
barrier attenuation, these levels would be well above
ambient at the high ground on the eastern edge of
the Superstition Wilderness. This would be
considered a noticeable adverse effect. The 49.5 dBA
level at Top-of-the-World would exceed ambient
levels and would be discernible above background
noise, but it would be well within the 65 dBA
evaluation criterion.
Blasting would be disturbing to some residents and
visitors. The effects would approximate a clap of
thunder, shorter in duration and generally less
disturbing than low-level flyovers by military fighter
aircraft. Noise from blasting is expected to peak at a
level similar to, or perhaps higher than, the level of
military aircraft. However, the duration would be more
in the range of 1 to 2 seconds compared with 2 to 4
minutes for the flyovers, so the perception would be
of less disturbance to human activity and, in fact, the
total sound energy generated by blasting would be
much less than that from aircraft.
Residents would be less disturbed if blasting would
occur at a consistent time every day and be limited to
daytime hours. Also, warning sirens would be used as
a safety measure in the mine prior to every blast.
Carlota Copper Project Final EIS
3-315
Qrihi^
5^0.=. .^~•t•'S!fti=;
' •Kf'v ■-. ' ' 't.-,
MAIN MINE
ROCK AREA
CENTROID A
CARLOTA/CACTUS PIT
CENTROID D
EDER NORTH PIT
LEACH PAD
CACTUS
SOUTHWEST^
MINE ROCK?^
■■%-vAREA la
CENTROID C
EDER MINE
ROCK AREA
CENTROID B
C>!'merLt
\ ’ , : ‘Tank
EDER SOUTH PIT
East Fork
>. Taiik
•V..V - ^ ^ . ' • '
Scale in Feet
Riverside Technoiogy, inc.
CARLOTA COPPER PROJECT
Figure 3-41
Noise Emission Centroids
3-316
3.0 Affected Environment and Environmental Consequences - Noise
Table 3-90. Project-Generated Noise Levels at Sensitive Receptors - Year 8
<1fe»P‘or
Slgnlfi^isnce
Noise Lev
Estimated
mm
Superstition Wilderness Valley
26 dBA'
43.2
49.6
Superstition Wilderness Ridge
19 dBA'
43.4
49.8
Tony Ranch Ridge
19 dBA'
45.2
51.6
Top-of-the-World
65 dBA*
49.5
55.9
’See Section 3.12.2, Noise - Environmental Consequences, above.
'Threshold based on L90 reference level measured at location A (see Table 3-87 and Figure 3-40).
'Threshold based on L90 reference level measured at location B (see Table 3-87 and Figure 3-40).
‘Source: HUD 1984
The same sirens, occurring at a consistent time each
day, would notify nearby residents of an impending
blast and would thus further reduce the startle factor
of blasting noise. If properly managed, the effects are
so brief that they would not be considered a major
adverse impact. Mitigation measures presented in
Section 3.12.4 would constrain the noise effects of
blasting to a reasonable level at residences in Top-of-
the-World. (See Section 3.12-4, Noise, Monitoring
and Mitigation Measures, for specific mitigation
requirements.)
Blasting noise and some equipment noise would
decrease somewhat over time because, as the depth
of the pit increases, the pit walls would function as a
noise barrier.
Noise emissions from the project would vary over
time. The variation could occur in the course of a
single day, and would certainly occur over weeks and
months in the life of the project as activities shift from
place to place on the site and as various types of
equipment are turned on or off to support the current
activities. The noise impact levels noted in Tables
3-90 and 3-91 are considered to be very con-
servative. Variations in the noise levels would be of a
lower magnitude in any reasonably foreseeable set of
circumstances during operation of the proposed
project.
Activity in Year 14 would be almost entirely shifted to
the Eder South and North pits, centroids B and C, still
including the leach pad, centroid D. Noise level
effects of Year 14 activities at the four sensitive
receptor locations are presented in Table 3-91. As
they were for Year 8, noise levels at Year 14 are
projected to exceed the stringent evaluation criterion
at the edge of the Superstition Wilderness, but not the
less stringent standard in Top-of-the-World.
To add perspective to the noise effects presented in
Tables 3-90 and 3-91, the conservative estimated L„,
levels at the edge of the Superstition Wilderness,
ranging from 43 dBA to 45 dBA in Year 8 and 45 dBA
to 47 dBA in Year 14, are in the range variously
described as “quiet suburban residential” to “normal
suburban residential” (ERA 1971b) or as “quiet
residential” (Beranek 1971). The Year 8 estimated
level in Top-of-the-World falls between “quiet
residential” and “average residential” while the Year
14 level coincides with “average residential” (Beranek
1971).
3. 12.2.2 Alternatives
Mine Rock Disposal Alternatives
Alternative Mine Rock Disposal Sites. The
alternative mine rock disposal sites would reduce the
adverse noise effects by moving a portion of the mine
rock disposal activity farther from the Superstition
Wilderness into a location with better screening from
Top-of-the-World. The noise advantages would be
modest, however, because high activity mining,
crushing, ore transport, and leach pad areas would
not be moved from their proposed locations.
Additional Backfill of the Carlota/Cactus Pit.
This alternative would generate more overall noise
over the life of the project because of the additional
Carlota Copper Project Final EIS
3-317
3.0 Affected Environment and Environmental Consequences - Noise
Table 3-91. Project-Generated Noise Levels at Sensitive Receptors - Year 14
1 ijceirtoi
Si.. 1 ,
significance
threshold’
: i : — . .
Noise te
Estimated L^
vel(dBA)
Superstition Wilderness Valley
26 dBA=
44.8
51.2
Superstition Wilderness Ridge
19dBA’
45.1
51.5
Tony Ranch Ridge
19dBA’
47.3
53.7
Top-of-the-World
65 dBA^
55.0
61.4
'See Section 3.12.2, Noise - Environmental Consequences, above.
^Threshold based on L90 reference level measured at location A (see Table 3-87 and Figure 3-40).
^Threshold based on L90 reference level measured at location B (see Table 3-87 and Figure 3-40).
^Source; HUD 1984
material handled and transported. It would be unlikely
to greatly raise the maximum noise levels currently
projected because a portion of the hauling and
grading activity would take place within the mine,
where the pit would effectively screen some of the
noise from reaching sensitive receptors.
Additional Backfill of the Eder South Pit. The Eder
South pit backfill alternative would have similar effects
on noise as those described above; however, the
noise would occur much closer to Top-of-the-World.
Higher noise levels at the Eder South pit would
increase the noise effects at Top-of-the-World,
although the threshold would not be exceeded.
Eder Side-Hill Leach Pad Alternative
From a noise perspective, the Eder side-hill leach pad
alternative would be impossible to distinguish from
the proposed project leach pad location. The general
locations are very similar, and the activity levels
would be similar such that at a distance of more than
a mile at the nearest receptor, no noise difference
would be apparent.
Water Supply Alternative
The use of the low-quality water from off-site sources
would have minimal effects on noise levels in the
project vicinity. Noise emissions would result from
constructing this alternative, but the magnitude would
be small and short-term in duration, ending with
construction.
Alternative Water Supply Well Field Access
Roads
The construction and use of the two alternative
well field access roads would result in minor effects
on noise levels in the project vicinity. The noise
levels associated with these alternatives would be
considered relatively small and would be similar
to the access road component of the proposed
action.
No Action Alternative
The no action alternative would effectively continue
noise levels as they currently exist.
3.12.3 Cumulative Impacts
Past and present actions that may interact with
the proposed Carlota Copper Project from a noise
standpoint are already included by virtue of the
field measurement and evaluation of existing
ambient noise in the project vicinity. Most of the
mining projects cited fall into this category, although
only a few within close proximity are likely to generate
noise that can be heard in the noiseshed of the
project site. It appears, from the information available,
that major adverse cumulative noise effects are
unlikely.
Grazing management changes would have no
substantive, cumulative effects on noise in the project
vicinity.
3-318
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Noise
The proposed transmission line upgrade would have
no substantive cumulative effects on noise near the
proposed Carlota Copper Project, nor would any of
the water resources projects. The Pinto Creek
Wild/Scenic River designation, should it occur, would
produce minimal, if any, additional noise. The dam
projects are far too distant to be interactive.
Proposed highway improvements near the project site
would produce construction noise levels that could
impact Top-of-the-World; however, the effects would
be transient, limited to the short duration of the
highway construction, and likely limited to daylight
hours.
Although the designated military training route over
the project area was deleted in the Department of
Defense's Flight Information Publication AP-1B
following the closure of Williams Air Force Base,
another route is immediately to the north of the
project area, and low-level military flyovers are likely
to occur in the future.
Potential additional development at Top-of-the-World
would be the only private land development near
enough to generate interactive noise effects.
Construction may generate some objectionable noise;
however, the typically short time span of the activity
would not be likely to produce major adverse effects.
3.12.4 Monitoring and Mitigation
Measures
Mitigation potential for major adverse mining noise
effects is somewhat limited by the nature of ore body
locations and the scale of operations involved.
Nevertheless, certain measures listed below can be
implemented to minimize adverse effects.
N-1: All equipment would use state-of-the-art mufflers
and would be maintained in good operating condition
at all times.
N-2: A blasting schedule would be implemented that
would avoid nighttime hours and would establish a
consistent time of blasting.
N-3: The Forest Service would review final stationary
facility (e.g., crushers and screens) design for noise
considerations (for example, mitigation of noise
impacts to the Superstition Wilderness and Top-of-
the-World would be considered as part of facility
sitings, or berm construction would be required if
predicted levels of noise generation could not be
met).
N-4: Occasional monitoring would be conducted to
verify the model and determine operational noise.
This monitoring would consist of monitoring for 1 day
annually (selected randomly) until a reasonable level
of model verification was obtained for the Superstition
Wilderness and at Top-of-the-World.
N-5: Carlota would submit changes in equipment
types or size to the Forest Service together with the
manufacturer’s noise specifications. The Forest
Service would determine whether additional modeling
or mitigation would be required to address noise
impacts.
Carlota Copper Project Final EIS
3-319
3.0 Affected Environment and Environmental Consequences - Noise
3-320
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Transportation
3,13 Transportation
3.13.1 Affected Environment
3. 13. 1. 1 Highways and Roads
The proposed project area is served by a somewhat
sparse network of roadways, typical of much of rural
Arizona. Interstate 10 (I-10) is the primary east-west
traffic artery across southern Arizona, connecting the
region with Las Cruces, New Mexico, and El Paso,
Texas, to the east and the Los Angeles basin to the
west. 1-10 passes approximately 65 road miles west
of the project site at its nearest point and runs
through both Phoenix, 65 miles west of the site, and
Tucson, 80 miles to the south. 1-8 originates near
Casa Grande, halfway between Phoenix and Tucson,
connecting 1-10 west with San Diego. Major north-
south routes are 1-17 north from Phoenix and 1-19
south from Tucson.
U.S. Highway 60 forms the southeast boundary of the
project site and provides the primary access route
connecting the site with Phoenix to the west and the
Miami-Globe area to the east. U.S. Highway 60
continues northeast from Globe providing access to
northern New Mexico. U.S. Highway 70 runs south-
east from Globe providing access to southern New
Mexico. Arizona State Routes 88 and 77 provide
access to the northwest and south, respectively, from
the Miami-Globe area. County and Forest Service
roads serve as collector roads for the major state and
federal routes.
Access to the project site is proposed to come from
the existing Forest Service Road 287, a paved road
running north from U.S. Highway 60 to the Pinto
Valley Mine operation. The road is maintained by
BHP Copper Company. An existing dirt road would be
improved to provide access from the Forest Service
road to Carlota Copper Project facilities.
U.S. and state highways in the project vicinity are
typically paved, all weather, two-way rural highways
with 1 1- to 12-foot-wide travel lanes in generally good
condition. U.S. Highway 60 in the immediate project
vicinity has a third lane. At the intersection with the
Pinto Valley Mine Road, the third lane is reserved for
left turns. Farther west, where U.S. Highway 60 abuts
the project site, the third lane is a passing lane.
Shoulders on U.S. Highway 60 are typically paved for
2 feet beyond the delineated lanes and graded but
unpaved for 3 to 6 feet beyond the pavement;
however, this width varies with terrain. Immediately
west of the Pinto Valley Mine Road, shoulders are
only 2 feet wide, stopped on the south side by a rock
face and on the north side by a guard rail protecting a
drop-off. The north shoulder is approximately 3 feet
wide adjacent to the project site, stopped again by a
rock outcrop.
Forest Service and county roads are more varied in
quality and condition than state and federal highways.
They range from very rough jeep tracks to well main-
tained, graded roads with full two-lane cross sections
to paved, striped highways. Back country roads follow
terrain rather than survey lines and are virtually all
indigenous dirt and rock with no imported surface
material applied.
The Pinto Valley Mine Road, designated Road 287 on
Forest Service maps, is paved from U.S. Highway 60
to the Pinto Valley Mine entrance gate, with the
pavement generally wider than 24 feet. Pinto Valley
Mine Road widens near its intersection with U.S.
Highway 60, spreading from approximately 35 feet at
the cattle guard to well over 100 feet at the edge of
U.S. Highway 60 pavement. This widened road neck
accommodates a relatively high-speed, right-turn
movement from westbound U.S. Highway 60
northbound on the road. It also has two lanes
southbound to separate left-turning traffic from
right-turning traffic. Another road. Forest Service 349,
extends south from the U.S. Highway 60 intersection,
but it receives very little traffic.
Forest Service Road 287 continues northwesterly
from the mine gate, through and among Pinto Valley
Mine facilities, to Pinto Creek. This segment of the
road is dirt and gravel surfaced in generally good to
excellent condition, although in a few places it can
become slick with clay mud in wet weather. West of
Pinto Creek, Forest Service Road 287 continues
northerly. Forest Service Road 287A branches off to
the west for 4 to 5 miles, ending at Miles Ranch on
the boundary of the Superstition Wilderness. Forest
Service Road 287A provides access to the
Superstition Wilderness via several trailheads. The
road is in generally fair to good condition, although it
is surfaced entirely with native materials.
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3.0 Affected Environment and Environmental Consequences - Transportation
Highway 88, north of Miami, are operating at LOS E,
indicating traffic volumes on those roadway segments
are reaching capacity in peak periods.
Streets in the communities of Miami and Globe
generally have sufficient capacity to accommodate
current traffic with no major trouble spots. Traffic
volumes are highest during shift changes at area
mines, but traffic continues to flow at acceptable
levels (Stratton 1993).
3. 13. 1.2 Commercial Transportation
Local public transportation is generally not available
in the Miami-Globe area. Interstate bus service is
provided by Greyhound Bus Lines eastbound and
westbound through Globe. The Globe-San Carlos
Regional Airport, located east of town, is a general
aviation field with a lighted 4,750-foot runway. The
nearest scheduled commercial air service is 70 miles
away in Phoenix. Both Superior and Globe-San
Carlos have limited service and fixed base operators;
charter service is available. The Arizona Eastern
Railroad provides freight rail service to the area.
Table 3-92. 1991 Major Highway Traffic Volumes in the Carlota Copper Project Area
- ■ \ ■ 1
Segment
AADT‘
Peak 1 V/C |
Houf^ 1 Ratlo^ 1 tOS^
U.S. Highway 60
AZ 177 to Bluebird
4,800
576
0.30
C
Northeast of U.S. Highway 70 Junction
3,200
384
0.20
C
U.S. Highway 70
East of U.S. Highway 60 Junction
9,500
1,140
0.60
E
West of AZ 77 Junction
5,000
600
0.32
C
East of AZ 77 Junction
3,500
420
0.22
C
AZ 77
South of U.S. Highway 60 Junction
1,000
120
0.06
A
AZ 88
North of U.S. Highway 60 Junction
8,500
1,020
0.54 E
AZ 177
South of U.S. Highway 60 Junction
2,600 312
0.16 B
’AADT - Annual Average Daily Traffic
^Estimated at 12 percent of AADT
\/C - Volume/Capacity Ratio
“LOS (Transportation Research Board 1985)
Traffic count data for project area highways indicate
diverse patterns of change in traffic flows. This
suggests the variations result from localized condi-
tions rather than any identifiable, area-wide trend.
Counts for U.S. Highway 60 in the project vicinity
indicate only moderate variation in recent years.
Traffic volumes increased 6 percent from 5,100
vehicles per day in 1 989 to 5,400 in 1 990, but
then declined 11 percent to 4,800 in 1991. In addition,
the volume of traffic on Highway 60 has probably
decreased somewhat with the shut-down of this
Superior Mine in 1996. Although this pattern was not
unique to U.S. Highway 60, there was no discernible
pattern that was typical of traffic variations on
highways in the project area.
Current traffic volumes are at or below capacity on all
major highways in the project area {Table 3-92). U.S.
Highway 60 is operating at a C level of service (LOS)
in the vicinity of the project site, indicating traffic flows
are stable with some restrictions on drivers' choice of
speed, lane changing, and passing. This is an accept-
able LOS, often used as an appropriate design
criterion. U.S. Highway 70, east of Globe, and State
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3.0 Affected Environment and Environmental Consequences - Transportation
3.13.2 Environmental Consequences
Transportation issues associated with the Carlota
Copper Project include (A) impacts to traffic flow and
safety on U.S. Highway 60 and (B) impacts on
existing roads and trails within the project area.
Transportation effects were evaluated relative to four
criteria; (A-1) increase in Average Daily Traffic (ADT)
count on access routes; (A-2) compliance with appli-
cable LOS criteria, (A-3) protection of safety condi-
tions for the traveling public, and (B-1) number of
miles of roads and trails on the Resource Access
Travel Management Plan (USDA Forest Service
1990a) removed from public access.
In the Carlota Copper Project context, the relevant
LOS standard is the ADOT criterion of LOS C for
peak periods. At LOS C, traffic flows are in the stable
range, but most drivers are becoming restricted in
their freedom to select speed, change lanes, or pass.
Intersection capacity is often a potentially key limiting
factor in traffic analysis. This is certainly the case for
the project site, as U.S. Highway 60 is the only major
artery tunneling traffic to the site from all origins, and
there would be only one intersection access point
connecting the proposed project to the highway. The
LOS approach was also used to evaluate intersection
operations, though it is commonly applied separately
to individual traffic movements through the intersec-
tion, rather than to total intersection capacity and
LOS, because service levels of different movements
in a single intersection can vary dramatically from one
another.
Safety is a less well defined concept as a significance
criterion. Many different factors affect highway safety,
including sight distances, road conditions, roadway
geometry, and even weather conditions. Particular
factors of interest are those that might be modified by
developing a mining project, such as the mix of
different types of vehicles in the traffic stream, the
availability of gaps in the dominant traffic flow to
accommodate traffic entering the highway from a side
road, and the introduction of unusually large numbers
of oversized vehicles.
The Resource Access Travel Management Plan is
the result of a Forest Service process developed to
identify desired future roadway and trail access
conditions. The plan establishes target objectives to
aid in decision-making for maintenance activity
programming and for project and management
activity review. As an evaluation criterion, the plan is
useful for defining the priority roads and trails that
may be affected by the proposed project or alter-
natives.
3. 13.2. 1 Proposed Action
Two major categories of traffic would be generated by
the proposed action; worker commuting traffic (mainly
automobiles and pickup trucks) and material deliver-
ies (mainly heavy trucks and tractor-trailer rigs).
Commuting traffic is estimated at approximately 50
vehicles inbound to the site and 50 outbound at major
shift change hours. The basis for this estimate is 301
workers operating 3 shifts per day, 7 days per week.
Four approximately equal sized crews were assumed
necessary to cover the resulting 21 shifts per week.
Commuting traffic was further assumed to average
1 .5 persons per vehicle. For purposes of the analysis,
shift changes were assumed to occur concurrently
with morning and afternoon peak traffic flow hours.
Delivery truck traffic was estimated at 18 heavy
delivery trucks and 5 light delivery trucks per day,
making one inbound and one outbound trip each
(Carlota 1993a). As a worst case estimate,
1 5 percent of the deliveries (7 trips) was assumed to
occur during the peak hours.
Employing the scenario described above, approxi-
mately 107 vehicles would be added to the traffic flow
on U.S. Highway 60 during the peak hours. Traffic
east of the site was estimated at 80 percent (86
vehicles), with the remaining 20 percent (21 vehicles)
assigned to the west. Traffic flows would remain at
LOS C for both legs of the major arterial with full
development of the proposed Carlota Copper Project,
despite the growth in traffic.
The principal access point for the proposed project
would be the Pinto Valley Mine Road, also known as
Forest Service Road 287. The intersection of this
road with U.S. Highway 60 was recently improved by
ADOT to provide longer sight distances, wider
shoulders, and a better alignment for the south
approach. The intersection was evaluated for LOS
using procedures set out in the Highway Capacity
Manua/ (Transportation Research Board 1985). The
left-turn movement from Pinto Valley Mine Road
southbound onto U.S. Highway 60 was found to be
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3.0 Affected Environment and Environmental Consequences - Transportation
operating at a LOS C; all other movements through
the intersection were operating at a LOS A. Adding
the estimated traffic from the proposed Carlota
Copper Project would not change the LOS ratings of
any of the movements through the intersection.
Initially, an alternative access point was considered
that would be located approximately 2.5 miles west of
the Pinto Valley Mine Road intersection. However,
this alternative was eliminated from further consider-
ation because its intersection with U.S. Highway 60
currently has severe sight restriction caused by
curves near outcroppings. The site would require
substantial improvements to address safety concerns.
T ransportation safety concerns related to the
proposed project have been largely eliminated by
recent reconstruction of the Pinto Valley Mine Road
intersection. The reconstruction was warranted by a
series of accidents in the vicinity in recent years and
by identified sight distance and stopping distance
adversities that made access to U.S. Highway 60
difficult. The new intersection layout effectively
removed the safety impediments. Development of the
proposed project would have no effect on the physical
characteristics of the intersection or the highway. The
increase in traffic would be modest, remaining well
within the roadway capacity, as noted above. The mix
of heavy vehicles in the traffic stream would not
substantially change. As such, any increase in the
risk of traffic accidents would be minor and
proportional to the overall increase in traffic. Potential
impacts associated with the transport of hazardous
materials are addressed in Section 3.14, Hazardous
Materials.
Based on the analysis described, development of the
proposed project would not cause major adverse
changes to highway traffic and safety conditions in
the site vicinity.
Commercial transportation operations would not be
adversely affected by developing the proposed
project. To some degree, commercial operations may
benefit from the increased population base and
increased business activity generated by the project.
No indication was found of capacity limitations for the
commercial transportation resources.
Portions of several existing Forest Service roads are
contained within the project area. According to the
Resource Access Travel Management Plan, all roads
but one. Forest Service Road 898, are planned for
closure. Development of the project would comply
with the Resource Access Travel Management Plan
for closing those roads. It would perhaps speed up
the actual closure in some cases, although some
roads have already been blocked by earth barriers
and are not accessible to vehicles at this time.
Forest Service Road 898 is a loop road approximately
5.5 miles long. It intersects U.S. Highway 60 on the
west edge of Top-of-the-World, heads northerly along
the west side of Powers Gulch for approximately 2.5
miles, and returns along the back (west) side of the
ridge to U.S. Highway 60 approximately 1 mile west
of the starting point and at the west base of Signal
Mountain. Development of the proposed project
would truncate approximately 2.2 miles of Forest
Service Road 898 beginning approximately 0.8 mile in
from U.S. Highway 60 on the easterly leg of the loop.
The proposed project would conflict with the
Resource Access Travel Management Plan in this
respect. From a practical standpoint, however, por-
tions of Forest Service Road 898 are washed out and
may be impassable. At best, access is limited to four-
wheel-drive vehicles. The Forest Service has no
immediate plans to upgrade the road. Consequently,
the potential conflict with the Resource Access Travel
Management is more theoretical than actual in this
case.
Forest Service Road 287, Pinto Valley Mine Road, is
also planned to remain open to public access,
according to the Resource Access Travel Manage-
ment Plan. Although the proposed project boundary
abuts Forest Service Road 287, development of the
project would not adversely affect the road or public
use of the road, so there would be no conflict with this
aspect of the Resource Access Travel Management
Plan.
The Resource Access Travel Management Plan also
addresses trail access in the Tonto National Forest.
In the project vicinity. Forest System Trail 203
through Haunted Canyon is planned to remain open
to the public to provide access to the Superstition
Wilderness via Tony Ranch. The proposed project
would affect this trail by authorizing the use of a
section of the trail (previously a road) to be main-
tained as an access road to well sites. There is
currently access to the trail from the south through
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Transportation
the project site. This access is proposed for closure in
the Resource Access Travel Management Plan;
however, regardless of the outcome of the Carlota
Copper Project, future access would come only from
the north via Forest Service Road 287. The proposed
project would thus not conflict with the Resource
Access Travel Management Plan relative to trails.
There is a portion of Forest System Trail 203 that is
coterminous with a well field road, which may be
closed to vehicle traffic not required to maintain the
well field; however, trail access would be protected so
no adverse effect is anticipated from this interaction.
There may be some conflicts between using the road
for well field access and using the trail for recreation.
3. 13.2.2 Alternatives
The on-site project alternatives, including the mine
rock disposal sites, the Eder side-hill leach pad
alternative, and the water supply alternative would
have virtually no effect on transportation off the site.
The selection of the water supply well field access
route along Pinto Creek (Alternative A) would
preclude access to the area during periods of high
flow and would affect a longer segment of Forest
Service Trail 203. The other access route (Alternative
B) would be similar to the proposed action.
The no action alternative would essentially result in a
continuation of existing traffic conditions.
3.13.3 Cumulative Impacts
Past and present activities in the project vicinity are
reflected in the affected environment discussion
presented previously. Among the mining projects
included in the list of interrelated actions (Section 1.6,
Interrelated Actions), only a few in close proximity to
the Carlota Copper Project are likely to actually
generate traffic interactions that would be considered
problematic. BMP Copper’s Florence Project is near
enough that there would be a potential for interactive
traffic effects, primarily at Top-of-the-World. The
probability level and degree of interaction is difficult to
quantify without additional information on the exact
location, the scale of the project, mining methods and
equipment proposed, and the development schedule
anticipated. It appears, from the information available,
that adverse cumulative traffic effects are unlikely.
Grazing management changes would have no sub-
stantive, cumulative effect on traffic in the project
vicinity.
The proposed transmission line upgrade would
have minimal effects, if any, on traffic near the
proposed project. Construction near or on the U.S.
Highway 60 right-of-way would cause minor traffic
flow constraints, but the effects would be short-term
and temporary and would not be expected to be
significant.
The Pinto Creek wild and scenic river designation,
should it occur, would produce minimal, if any,
additional traffic that would most likely not be focused
on the peak hour traffic periods most sensitive from a
traffic perspective.
The dam and water-based recreation projects are too
distant to result in cumulative impacts.
Proposed highway improvements near the project site
would produce construction-related traffic constraints
that could adversely interact with project traffic, but
the effects would be transient, short-term, and would
likely be managed by ADOT to minimize adverse
traffic effects.
Potential additional development at Top-of-the-
World would be the only private land development
near enough to generate cumulative traffic effects.
Construction may generate some heavy truck traffic,
though the typically short time span of the activity
would not be likely to produce major adverse effects.
Longer-term population growth in the area would
contribute proportionally to traffic growth, which
would interact with project-related traffic. In the event
of concurrent development of other large-scale
mining projects in the area, there may be a future
need to address cumulative transportation effects by
such means as modifying shift schedules or by
carefully managing deliveries of equipment and
supplies.
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3.0 Affected Environment and Environmental Consequences - Transportation
3.13.4 Monitoring and Mitigation
Measures
With no major adverse LOS or safety impacts
identified, specific traffic mitigation measures are not
considered necessary. Nonetheless, there are
opportunities to reduce traffic associated with the
Carlota Copper Project, such as encouraging
carpooling among workers.
T-1: Carlota would fund relocation of Forest Service
Road 898 or maintenance of the westerly leg of
the road to the extent that public access to the
northern end of the Eder ridge is preserved. A final
plan would be developed and completed before
Carlota’s operation restricts access to the easterly leg
of the road.
T-2: Carlota would close or obliterate (as determined
by the Forest Service) and revegetate those roads
identified on Resource Access Travel Management
Plan that are located within the project area for which
access would be cut off by project operations.
Additional measures for closing these roads are
provided in Section 3.4.4, Soils-Monitoring and
Mitigation Measures. This measure would also satisfy
some of the requirements for mitigating impacts to
upland habitat.
T-3: Carlota would participate with the Forest Service
in developing a plan to manage the section of Forest
Service Trail 203 that would be impacted by opera-
tions. The plan would ensure access by both Carlota,
for well site operation and maintenance, and the trail
users. Carlota would fund maintenance of the section
of the trail that may include, but not be limited to,
drainage, erosion control, turnarounds, gating,
signing, and revegetation. Upon closure of oper-
ations, Carlota would reclaim that section of the trail
to trail standards present before the project’s
initiation.
T-4: Carlota would acquire a Road Use Permit from
the Forest Service to use and maintain the paved
portion of Forest Service Road 287 (Pinto Valley Mine
Road). This portion of the road would continue to be
used by the general public, other Forest System Land
users, and private land owners in the area.
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Hazardous Materials
3.14 Hazardous Materials
3.14.1 Affected Environment
Small quantities of hazardous materials may exist on
the project site as a result of historic mining and
exploration activities along Pinto Creek and Powers
Gulch. An abandoned rail tanker car located in the
northwestern portion of the proposed Carlota/Cactus
pit may have been used historically to store sulfuric
acid; however, the tanker and the surrounding soil
beneath and in the vicinity of the tanker have not
been sampled for hazardous substances. Two
wooden troughs with scrap iron are also located in
the western portion of the proposed pit. These
troughs are believed to have been used to extract
copper from copper sulfate solution.
Since ore processing activities were conducted in the
past in this area, hazardous substances may be
present. Several other potential sites that may contain
hazardous materials are described in the cultural
resource survey (SWCA 1993a). Most of these sites
are associated with existing mine workings shown in
Figure 3-5. Several sites are described in the cultural
resources report as containing slag deposits
presumably left from past ore processing activities.
However, according to Carlota personnel, this
material is not slag, but actually naturally leached and
oxidized rock (known as vein gossan) composed
primarily of iron oxide minerals. The affected
environment that could potentially be affected by an
accidental release of hazardous materials during
transportation to and from the mine site and during
storage and use on the project site includes air,
water, soil, and biological resources.
3.14.2 Environmental Consequences
3. 14.2. 1 Project-Related Hazardous Materials
The Carlota Copper Project would require the trans-
portation, handling, storage, use, and disposal of
materials classified as hazardous. These hazardous
materials include (1) diesel fuel, gasoline, oils,
greases, antifreeze, and solvents used for equipment
operation and maintenance; (2) kerosene, sulfuric
acid, oxime reagent, and cobalt sulfate used in the
copper extraction process; (3) ammonium nitrate and
high explosives used for blasting in the open pits; and
(4) sludge and other by-products generated during
the copper extraction process {Table 3-93). Some
substances are listed generically (i.e., oils, greases,
lubricants, solvents, and high explosives), since the
exact chemical composition would depend on the
brand and type selected. However, the transportation,
handling, storage, use, and disposal would be the
same, regardless of the brand and type.
Table 3-93. Hazardous Substances Approximate Daily Usage, Delivery Frequency, and On-Site
Storage
Substance
Typical Daily
Usage
Nominai
Deib^ry Size
Approx. Delivery
■■
Planned On-Site Storage
Diesel Fuel
7,500 gal
7,500 gal
1/day
30,000 gal
Gasoline
100 gal
3,000 gal
1 /month
5,000 gal
Oil, Grease, Anti-
freeze, Lubricants
410 lbs
As needed
1/week
5,000 lbs
Solvents
15 gal
As needed
1 /month
300 gal
Kerosene
930 gal
7,500 gal
1/week
18,000 gal
Sulfuric Acid
403 tons
27 tons
(3,500 gal)’
1 7/day
1 ,540 tons
Oxime Reagent
700 lbs
As needed
1 /month
10,000 lbs
Cobalt Sulfate
145 lbs
As needed
1 /month
1 ,500 lbs
Ammonium Nitrate
12 tons
24 tons
3/week
126 tons
High Explosives
170 lbs
As needed
2/month
5,000 lbs
’One gallon of sulfuric acid weighs 15.3 lbs.
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3.0 Affected Environment and Environmental Consequences - Hazardous Materials
Brief descriptions, including the use and storage of
the substances listed in Table 3-94 as well as other
hazardous materials that may exist during the
operation of the project, are provided in the following
sections.
Diesel Fuel and Gasoline
These petroleum products would be used as fuel
sources for the daily operation of the mining
equipment. Fuels would be stored in covered above-
ground tanks designed for that purpose. The storage
areas would be HDPE-lined or paved and surrounded
by dikes to contain rainfall and spills. The volume of
the containments would be at least as large as the
largest tank plus 10 percent. A sump would be
provided for collecting minor spills. Signs warning
against smoking and open flames would be posted on
or near the tanks.
Fuels would be dispensed to mobile equipment and
vehicles using DOT-approved equipment. A portion of
the normal preventive maintenance program would be
devoted to detecting and eliminating fuel leaks.
Oils. Greases. Lubricants. Anti-Freeze, and
Solvents
Oils, greases, lubricants, and antifreeze would be
used for lubricating and cooling mobile and stationary
equipment. Solvents would be used for cleaning and
thinning. These materials would be stored in above-
ground tanks located in the maintenance shop. The
storage area would have a concrete slab foundation,
with a concrete curb (approximately 4 inches high)
along its perimeter. Appropriate warning signs would
be posted. Used oil would be placed in a holding tank
and shipped off the site for recycling or disposal.
Solvents would be contained and continuously
recycled in the parts-cleaning basins. As the solvents
become loaded with grease, dirt, or contaminants,
they would be periodically replaced. Spent solvent
would be collected in a storage drum for disposal or
would be removed from the site by a solvent recycling
contractor.
Mobile equipment would be fueled and lubricated in
active operating areas using separate mobile fueling
and lubrication units in order to minimize downtime
and maximize operational efficiencies. These mobile
units could contain diesel fuel, hydraulic oil, motor oil,
antifreeze, and grease. Drybreak couplings and
pressure-sensitive automatic shutoff valves would
ensure that transfer would occur without spillage.
Kerosene
Kerosene, which would be used as a diluent for
the oxime reagent in the SX process, would be
circulated in a closed-loop system within the SX
section. The kerosene would be pumped from the
kerosene tank to the SX mixer-settlers. After the initial
loading of the process tanks, additional kerosene
would be required to make up primarily for
evaporation losses.
Kerosene would be delivered by road tankers and
then unloaded into a vertical cylindrical storage tank
in the bermed area beside the sulfuric acid tank.
Table 3-94. Estimated Number of Spills Resulting from Truck Accidents (Rural Two-Lane)
Total truck
lRu|r^l|j^ad
DisSle :
" . Probability of
1 Calc^^fi|| 1 Reieasi Given /
X-:: %:
Cat^laled
t Nuiperol
Spills
Sulfuric
Acid
124,100
75
2.19
20.38 18.8
3.83
Diesel
7,300
75
2.19
1.20 18.8
0.22
’Accident rates are based on the average number of truck accidents occurring per million road miles traveled by road types.
Spill probabilities are based on statistics from accident reports that indicate the percentage of tmck accidents involving liquid
tankers that resulted in spills.
Source: Hardwood and Russell 1990, and Rhyne 1994
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Diluent would be pumped as required for make-up
(for 1 .5 hours per week) into the loaded organic
decant tank. The tank would be provided with a flame
arrestor. The storage tanks, process piping, and SX
equipment would be located within a secondary
containment structure with sumps and pumps. Spills
would be collected and sent to the process area or a
tank, as appropriate.
Sulfuric Acid
Sulfuric acid would be used to leach the copper from
the ore on the leach pad and as an electrolyte in the
EW tank house. The sulfuric acid would interact with
the kerosene and oxime reagent in the SX mixer-
settlers. Both the leaching and electrolyte solutions
would be circulated in closed-loop systems. The acid
in the leaching solution would be consumed in the
leaching process, although small amounts of acid
mist would be lost to the atmosphere from the EW
cells.
Acid solution may be sprayed or sprinkled onto the
ore in a pretreatment process before the ore is placed
on the leach pad. The ore would then be leached to
recover the copper. The leach solution that would
percolate through the ore would be collected on an
impermeable liner and would flow through lined
channels to a double-lined collection pond. It would
be pumped from the pond to the SX/EW plant, where
the copper would be extracted. The barren solution,
or raffinate, would flow to a double-lined pond, where
it would be refortified with acid and pumped back to
the leach pad to leach the ore.
Road tankers would deliver sulfuric acid (93 percent)
to the plant. The tanker pump or compressed air
would be used to unload the acid into a 201 ,500-
gallon above-ground tank near the process plant.
This tank would be located in a bermed area
containing limestone for neutralizing spills. The
containment area would be capable of containing the
volume of the largest tank plus 10 percent. A
horizontal-centrifugal pump within the berm would
deliver acid to the pretreatment area and the raffinate
spiking at the static mixer. A smaller dosing pump
would deliver acid to the electrolyte recirculation tank
to make up for acid lost in the electrolyte bleed. The
containment area would be equipped with a sump to
transfer spilled acid to the process pond or to a tank.
Appropriate warning signs would be posted.
Piping for the acid solution would be made of HOPE
or stainless steel. These materials were selected
because of their resistance to acid and their high
resistance to physical damage.
Oxime Reagent
Salicylaldoxime reagent would be the active reagent
in the SX process. It would be mixed with kerosene
and circulated within the SX section in a closed-loop
system. Small amounts of reagent would be lost
primarily to evaporation. The reagent would be
delivered in a partly diluted state either in bulk or in
55-gallon drums by flatbed truck. The reagent would
be stored either in a tank or in drums on a paved
patio adjacent to the SX plant.
Cobalt Sulfate
Small amounts of cobalt sulfate would be mixed with
the electrolyte to control anode corrosion. The
reagent would be delivered in bags and made up into
a 1 percent solution with hot water in the reagent
preparation tank. This solution would be dosed by a
positive displacement pump into the circulating
electrolyte to make up for losses in the electrolyte
bleed. The cobalt sulfate would be consumed in the
process.
Ammonium Nitrate/High Explosives
These explosives would be used for blasting in the
open pit. Boosters and detonating cord would be
transported to the blast site by pickup truck and
loaded into the holes. A mixture of ammonium-nitrate
and fuel oil (ANFO) would be used as the primary
blasting agent for Carlota’s mining operations. All of
the explosive would normally be consumed in the
blast. A blasting contractor would be employed during
operations.
The location of the ANFO storage has not yet been
determined. Because the two components are
relatively easily handled and are non-explosive prior
to mixing, they would be stored separately and mixed
only in quantities necessary for near-term blasting
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Hazardous Materials
operations. The ammonium nitrate storage facility
would consist of an ammonium nitrate bulk storage
bin and storage trailers and magazines used to store
initiators, boosters, blasting caps, and other blasting
supplies. Bulk ammonium nitrate would be discharged
to a specially designed ANFO mixing and loading
truck that would belong to the blasting contractor. The
ANFO truck, which would have a self-contained 230-
gallon fuel-oil tank, would travel to the blasting area
and mix the ammonium nitrate and fuel oil as it is
loaded into pre-drilled blastholes.
Leach and Electrolyte Solutions
These solutions would be contained within the
process vessels of the SX/EW plant.
Miscellaneous
Guartec, a natural gum derivative, would be used as
a deposit-smoothing aid in the tank house. It would be
incorporated in the cathode deposit and would require
make-up in addition to that required to compensate
for the electrolyte bleed.
Electric Power
All electrical equipment on the property would be non-
polychlorinated byphenyl (non-PCB). Non-PCB oil-
filled electrical equipment and transformers would be
inspected regularly for evidence of damage or
deterioration that could result in failure of the
transformer casing or equipment housing.
Hazardous Waste
Small quantities of hazardous waste, such as
chlorinated solvents, laboratory chemicals, or other
materials, may be generated. Carlota would most
likely be classified as a small quantity generator of
hazardous waste, and an EPA identification number
would be acquired.
3. 14.2.2 impact Analysis
Important issues related to the presence of
hazardous materials at the proposed project site are
the potential impacts to the environment in the event
of an accidental release of hazardous materials
during transportation to the project area and use or
storage of these materials at the site. The criterion for
evaluating the impacts of hazardous materials is the
risk of a potential spill to sensitive receptors along
transport routes or exposure pathways.
If some of the previously listed chemicals were to
enter the environment in an uncontrolled manner,
there could be associated direct or indirect harmful
effects. The environmental effects of a release would
depend on the substance, quantity, timing, and
location of the release. The event could potentially
range from a minor diesel fuel spill on the project site
where cleanup equipment would be readily available,
to a severe spill during transportation involving a large
volume of sulfuric acid that could be released into a
stream or populated area. Some of the chemicals
could have immediate destructive effects on soils and
vegetation, and there could also be immediate
degradation of aquatic resources and water quality if
spills were to enter streams. Spills of hazardous
materials could seep into the ground and contaminate
the ground water system. In addition, infiltration into
the subsurface could occur from beneath the leach
pads or process ponds, resulting in degradation of the
ground water. Depending on the proximity of people
to such spills or the use of degraded water for human
consumption, such accidental spills could affect
human health. In addition, some of the chemicals
have the potential to create fires or explosions if
mishandled or if an unforeseen incident occurs.
Transportation
Trucks would be used to transport a variety of
hazardous and non-hazardous materials and wastes
to and from the project site. Based on the quantity of
materials and number of deliveries, the materials of
greatest concern would be sulfuric acid and fuel
(gasoline and diesel).
The largest daily delivery to the project site would be
sulfuric acid, with an average of 17 tanker truckloads
per day (3,500 gallons/tanker). Sulfuric acid would be
supplied by the BHP Copper’s San Manual Mine
located approximately 75 miles south of the project
site near San Manual, Arizona. The most likely
transportation route for the sulfuric acid would be
north from the San Manual Mine on State Highway 77
to State Highway 70, west on State Highway 70 to
U.S. Highway 60, and then west on U.S. Highway 60
to the project access road. The route crosses the
communities of Mammoth, Dudleyville, Hayden, and
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3.0 Affected Environment and Environmental Consequences - Hazardous Materials
Miami-Globe, and the San Pedro, Aravaipa, and Gila
Rivers. Other hazardous materials would be
transported from a variety of local suppliers (i.e., from
other nearby mining companies) in the Phoenix area
(approximately 65 miles to the west) or other
locations. The main transportation route for these
hazardous materials into and out of the site would be
along U.S. Highway 60.
It is assumed that liquid fuels would be transported
from the Phoenix area. Carlota expects a delivery
frequency to average 1 shipment per day for diesel
fuel and 17 shipments per day for sulfuric acid over
the life of the project (3,500 gal/truck for sulfuric acid
and 7,500 gal/truck for diesel fuel). This would result
in a total of 124,100 shipments of sulfuric acid (17
shipments/day x 365 days/year x 20 years) and 7,300
shipments of diesel fuel (1 shipment/day x 365
days/year x 20 years).
The risk of a release involving deliveries of these two
substances was based on accident statistics for liquid
tankers carrying hazardous materials (Harwood and
Russell 1990). According to these statistics, the
average rate for truck accidents for two-lane rural
loads is 2.19 per million miles traveled. The statistics
also indicate that, on the average, 18.8 percent of
accidents involving liquid tankers carrying hazardous
materials resulted in a spill or release. The probability
of a spill resulting from a truck carrying sulfuric acid or
diesel is presented in Table 3-94. The probability
analysis indicates that approximately four accidents
involving a sulfuric acid release may occur over the
life of the project (3.83 releases). The probability of an
accident involving a diesel spill is less than one (0.22)
release over the life of the mine. Carlota would most
likely obtain fuels from a distributor located closer
than Phoenix, resulting in an even lower probability of
an accidental release. One spill resulting from a truck
accident for either of these substances would be
considered a significant impact.
All hazardous substances would be transported by
commercial carriers or vendors in accordance with
the requirements of Title 49 CFR and Title 28 Arizona
Revised Statutes. Title 49 CFR requires that all
shipments of hazardous substances be properly
identified and placarded. Shipping papers must be
accessible and must include information describing
the substance, immediate health hazards, fire and
explosion risks, immediate precautions, fire-fighting
information, procedures for handling leaks or spills,
first aid measures, and emergency response
telephone numbers. Carriers would be licensed and
inspected as required by the ADOT. Tanker trucks
would be inspected and would have a Certificate of
Compliance issued by the Arizona Motor Vehicle
Division. These permits, licenses, and certificates are
the responsibility of the carrier.
In the event of a release off the project site, the
transportation company would be responsible for
response and cleanup. Each transportation company
would develop a Spill Prevention, Control, and
Countermeasures (SPCC) Plan to address the
materials being transported. Local and regional law
enforcement and fire protection agencies also may be
involved initially to secure the spill site and protect
public safety. Carlota has developed a contingency
plan for transportation accidents occurring on or near
the project site (Carlota 1993a), which includes
notifying the local emergency response personnel
(law enforcement, fire fighters, and/or medical
personnel, as appropriate) and providing advice,
personnel, and equipment as appropriate to minimize
the impact of the accident. In addition, the Chemical
Manufacturer’s Association maintains the Chemical
Transportation Emergency Center (CHEMTEC),
which has a 24-hour hotline to provide information,
advice, and assistance in identifying and mitigating
chemical emergency scenes.
Title 49 CFR requires that the carrier notify local
emergency response personnel, the National
Response Center (for discharge of reportable
quantities of hazardous substances to navigable
waters), and DOT in the event of an accident
involving hazardous substances. Carlota personnel
trained in hazardous materials handling would assist
in response actions, whenever possible.
Storage and Use
The operation of the project would require the use
and storage of materials classified as hazardous.
These materials would be used in various
applications, such as mining (ANFO and high
explosives), copper extraction (sulfuric acid and
process reagents), and equipment operation (fuels,
antifreeze, and lubricants ). The general use, storage
locations, and quantities for these materials are
summarized in Tables 3-93 and 3-95.
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3.0 Affected Environment and Environmental Consequences - Hazardous Materials
Table 3-95. Use and Storage Areas for Hazardous Materials
Substance .
Operational Use
StoraoeArea^^ .
Diesel Fuel and Gasoline
Equipment Operation
Mine Maintenance Shop
Oil, Grease, Lubricants, and
Antifreeze
Equipment Operation and
Maintenance
Mine Maintenance Shop
Solvents
Parts Cleaning and Thinning
Agent
Warehouse
Sulfuric Acid
Ore Leaching and the SX/EW
Process
SX/EW Plant
Kerosene
SX/EW Process
SX/EW Plant
Oxime Reagent
SX/EW Process
SX/EW Plant
Cobalt Sulfate
SX/EW Process
SX/EW Plant
ANFO and High Explosives
Mining (blasting)
Undetermined
Over the life of the project, the probability of minor
spills of materials such as fuels or lubricants is
relatively high. These releases could occur during
such operations as haul truck refueling or as a result
of a hydraulic oil line rupture on a piece of excavating
equipment. Spills of this nature v\/ould most likely be
localized, contained, and removed. Carlota would
have the necessary spill containment and cleanup
equipment available at the site, and personnel would
be able to respond quickly.
The design of the SX/EW plant, along with the other
ore processing facilities on the site, would minimize
the potential for an upset that would result in a major
spill. The SX/EW plant site would be designed to
prevent discharge to the vadose zone (the unsatur-
ated layer above the water table) or to waters of the
U.S. Tanks would have secondary containment
sufficient to hold the volume of the largest tank and
additional freeboard. Tanks and vessels would be
positioned on an asphalt or concrete surface or on a
surface protected by a synthetic liner. Surface water
runoff and any spills from the SX/EW plant site
would drain into the double-lined raffinate and
plant/PLS ponds adjacent to the plant. The raffinate
and plant/PLS ponds are designed to contain the
largest estimated combined volume of stormwater
(resulting from the 72-hour 1/2 PMP) and antecedent
operational storage with 3 feet of remaining freeboard
(Knight Piesold 1996i). The raffinate pond would be
located directly upgradient from the lined leach pad,
and solution that overtops the pond embankment
would flow down a spillway into the leach pad.
Materials stored at the mine/maintenance facilities
would be contained in above-ground tanks located in
the maintenance shop. The storage area would have
a concrete slab foundation and would be enclosed by
a concrete curb approximately 4 inches high. Appro-
priate warning signs would be posted. Parts, supplies,
and small quantities of chemical products would be
stored in the warehouse, adjacent to the maintenance
shop. Small quantities of chemical products, such as
industrial cleaning agents, spray solvents, and water
treatment chemicals, would be stored in a special
hazardous materials storage area; incompatible
materials would be segregated.
The hazardous waste storage area would consist of a
chemical storage building in a secured area. The floor
of the building would be grating over a sump, which
could be gravity drained. The building would be
equipped with an emergency alarm, lighting, and fire
suppression equipment. Leaks or spills from drums or
waste receptacles would be limited to the contents of
one container; material would be caught in the floor
sump. Transmission fluid, shop solvents, and bulk
bins for grease would be stored in the lubricant
storage area at the warehouse. This area would also
be constructed with a concrete slab floor.
Samples would be collected and analyzed in the on-
site laboratory located near the SX/EW plant. The
laboratory facility would consist of a storage and
preparation area and the analysis laboratory. Routine
analysis procedures would involve analysis of
leaching and process solutions. Chemicals would be
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Hazardous Materials
stored in original vendor containers in a locked
cabinet when not in use. A chemical spill cleanup kit
would be stored in the laboratory. All handling,
storage, shipment, and related documentation of
laboratory wastes would be completed in accordance
with applicable regulations under the designation of
“Small Quantity Generator” (40 CFR Part 261.5).
Solution ponds associated with the heap-leach oper-
ation would have double-synthetic liners and leak
collection and recovery systems. Pipelines would
transfer PLS from PLS ponds on the west side of the
leach pad to the SX/EW plant adjacent to the east
side of the leach pad. Pipelines would originate at
each of the two PLS ponds and extend to a junction
located about midway between the ponds. The pipe-
line would be placed on top of the HOPE synthetic
liner of the leach pad. From the junction of the two
pipelines, a single pipeline would extend from the top
of the leach pad liner or the top of the leach pad to
the SX/EW plant. The pipelines would be approxi-
mately 24 inches in diameter and constructed of
HOPE, stainless steel 31 6L, or carbon steel lined with
HOPE; piping joints would be constructed as required
by design pressures. In the event of a leak or spill
from the pipeline, the fluid would be contained by the
liner underlying the leach pad and would drain to the
PLS ponds or would be contained by the asphalt or
synthetic liner underlying the SX/EW plant and drain
to the raffinate or plant PLS/SX ponds.
All hazardous substances would be handled in
accordance with applicable Mine Safety and Health
Administration (MSHA) or OSHA regulations (Titles
30 and 29 CFR). The hazardous substances to be
used at the mine (fuels, oils, lubricants, kerosene,
packaged chemicals, and ammonium nitrate) would
be handled as recommended on the manufacturer's
Material Safety Data Sheets (MSDS). High explosives
and sulfuric acid would be handled only by specially
trained personnel with appropriate protective and
handling equipment. With the above-listed design
features and operational practices in place, the prob-
ability of a major release occurring at the site would
be low.
In the event of a major or minor spill, Carlota has
prepared an SCHMM Plan (Carlota 1993b) that
addresses (1) potential contaminant sources and
planned protective measures, (2) inspections and
record keeping, and (3) incident coordination and
emergency response. All spills would be cleaned
up or neutralized and reported, if required, to the
National Response Commission, State Emergency
Response Commission, and/or Local Emergency
Planning Commission.
Disposal
Since some of the hazardous materials used in the
general operation of the facility would not be totally
consumed in the process, they would become waste
materials. These materials would include used oils
from mobile and stationary equipment and used
solvents from cleaning and thinning processes. These
substances would be temporarily stored on the site
and routinely shipped off the site by a licensed
oil/solvent recycling contractor for recycling or
disposal.
Other materials produced as by-products of the
copper extraction process that are considered
hazardous wastes include the following:
• An organic and solid mixture typically known as
“Crud” from the crud tank in the SX/EW plant
• Cell sludge from the SX/EW plant
• Slime at the bottom of the raffinate and plant
PLS/SX ponds
• Small quantities of hazardous wastes, such as
laboratory wastes or chlorinated solvents
The solid portion of the crud that accumulates in the
SX/EW plant would be routinely separated from the
liquid phase and disposed of on the leach pile. The
liquid portion would be recycled back into the
process. Cell sludge, which has a high lead content,
would be collected and transported off the site for
recycling by the vendor selected to supply the anodes
for the EW process; this vendor would also remove
and recycle the electrodes and the associated metal
residue. At closure, slimes or residual material that
would occur at the bottom of the raffinate and plant
PLS/SX ponds would be excavated and placed on the
leach pad (Carlota 1995a).
Laboratory wastes would be stored on the site for a
maximum of 180 days, and then they would be
shipped to a licensed hazardous waste disposal
Carlota Copper Project Final EIS
3-333
3.0 Affected Environment and Environmental Consequences - Hazardous Materials
facility. Laboratory waste containers would be
properly labeled, and all required papenvork, such as
hazardous waste manifests, would be completed prior
to shipping.
These materials would be produced as by-products of
the operation, and only the cell sludge and laboratory
wastes would have to be transported off the site for
recycling or disposal. Because of the small volumes
and infrequent handling of these wastes, the potential
for a spill that would greatly impact the environment
would be low. If a release were to occur, containment
and cleanup procedures outlined in the SCHMM plan
would be followed.
3.14.2.3 Alternatives
The environmental impacts associated with the
transportation, handling, storage, use, and disposal of
hazardous materials for the project alternatives would
be similar to the relevant component(s) of the
proposed action.
3.14.3 Cumulative Impacts
Large-scale mining operations occur throughout the
Globe-Miami area, all of which require shipments of
process chemicals, reagents, and various supplies
to operate the facilities. Some of the shipments
contain materials classified as hazardous. The
Carlota Copper Project would add approximately
18 truck-loads per day of hazardous materials to
the roads in the vicinity of the project. The greatest
increase would be the 17 truckloads of sulfuric acid
that would travel State Highway 77 between San
Manual and the project site. As discussed in Section
3.13, Transportation, State Highway 77 operates at
LOS A. With this low level of use, it is unlikely that the
increased truck traffic would significantly increase the
probability of an accident and a release of a hazar-
dous material. The probability of an accident with a
release would increase along U.S. Highway 60 (near
the project site), where the LOS is at a level C.
The cumulative effects of the use and storage of
hazardous materials on the project site would be
minimized by implementing spill prevention and
containment design features, along with the SCHMM
plan.
3.14.4 Monitoring and Mitigation
Measures
HM-1: Currently, Carlota's SCHMM Plan is
preliminary and is written to cover issues in general
terms. The plan would be updated as engineering
design plans for the project are finalized. BMPs for
handling hazardous materials would be included in
the final SCHMM Plan. The SCHMM Plan would be
subject to Forest Service and other appropriate
regulatory agency approval. The plan would be
reviewed on an annual basis and amended as
necessary.
HM-2: Any potential existing hazardous materials
located on the site (such as the abandoned railroad
tanker car) during construction would be tested to
determine the contents or makeup. Appropriate
cleanup and disposal actions would be taken if the
substances were found to be hazardous.
HM-3: The sulfuric acid would be offloaded from the
tanker trucks to the storage tank using a gravity flow
system to minimize the risk of a spill during this
procedure.
HM-4: The SCHMM plan necessitates 24-hour
access to the project site to ensure incident
coordination and emergency response are
implemented in the event of a spill of hazardous
materials. Since the main access road to the
site crosses Pinto Creek, the crossing must be
designed to accommodate the 100-year, 24-hour
storm event. The final SCHMM plan must include
a commitment to other means of entry if events
greater than the 100-year, 24-hour storm or other
unforeseen circumstances make the main road
inaccessible.
HM-5: At closure, any slimes and residual materials
remaining in ponds containing process solutions
(excluding the PLS ponds within the leach pad)
would be tested to evaluate the toxicity and leaching
characteristics of the material. If these materials are
toxic or have the potential to leach constituents that
could adversely affect surface or ground water
quality, the material would be disposed of in
accordance with the ADEQ Aquifer Protection Permit
and applicable state and federal regulations.
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3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
3.15 Summary of Monitoring and
Mitigation Measures
Table 3-96 summarizes the monitoring and mitigation These measures apply to the proposed action and
measures identified in Sections 3.1 through 3.14. the alternatives unless otherwise indicated.
Table 3-96. Summary of Monitoring and Mitigation Measures
1'^ ImpsH^s ^ ^ ^ iUlonItodngandMttigattoR
General
All identified environmental
impacts
Contribute funding to the Forest Service, through a collection
agreement, through project construction. The funding would be
used to expedite approvals, monitor project construction, and
implement operational monitoring programs.
Air Resources
Air quality degradation from H,SO^
emissions
AQ-1 : Design tank house ventilation system to facilitate
deposition of H,SO^ emissions as close to tank house as
possible.
Potential for perceptible plume
impacts in the Superstition
yyilderness
AQ-2: Establish a three-tier monitoring program. The first tier
would determine the existence of perceptible plume
impacts in the Superstition Wilderness due to emissions
from the Carlota Copper Project. If impacts are
detected, the second tier of the program will be
implemented to further characterize and more accurately
attribute these impacts to emissions from the Carlota
Copper Project. If necessary, the third tier involves
using the results of the monitoring program to identify
and implement additional mitigation measures to rectify
any visibility impacts.
Geology and
Minerals
• Ground subsidence associated
with shafts and adits
GM-1 ; (1 ) Remove wood, garbage, and other debris or loose
material from the openings prior to backfilling.
(2) Use large rocks (> 1 ft diameter) as backfill.
(3) Use an acid-resistant concrete mixture to fill
openings in the leach pad footprint.
GM-2: Plug all existing drill holes with acid-resistant grout prior
to heap-leach pad construction: follow Arizona
regulations for well abandonment.
• Potential slope stability
problems in the Carlota/Cactus
and Eder pits
GM-3: (1 ) Identify potentially adverse geologic conditions in the
pit walls by geologic mapping.
(2) Define potential failure planes using rock-coring.
(3) Implement slope dewatering.
(4) Detect initial signs of slope instability.
(5) Develop contingency plans.
(6) If necessary, modify final setback distance of any
potentially affected facility.
(7) Place fencing around pits beyond limits of potential
mass failures.
• Potential for induced slope
instability and increased erosion
during construction of water
supply access road
GM-4: (1 ) Get approval from Forest Service for design and
alignment of the road based on a geotechnical
investigation of existing slope conditions.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (continued)
ttrfpacis
Monitoring and MHIgatlon !
• Potential slope stability
problems for the Powers Gulch
diversion, Powers Gulch
diversion embankment
alternative, Eder side-hill leach
pad, and low-quality water
pipeline alternative
GM-5: Develop site-specific mitigation measures, if necessary,
after conducting a thorough geotechnical investigation
and analysis of slope conditions. All remaining material
from the Eder mine rock disposal area would be removed
and placed on the heap-leach pad or other designated
area.
• Potential for small avalanche-
type failures on the Main mine
rock disposal area
GM-6: Demonstrate, using slope stability analysis, that the final
rock pile design will be stable under both static and
pseudo-static conditions.
Water Resources
• Potential effects to surface
water and ground water
resources
WR-1 : Revise ground and surface water monitoring plan (GWRC
1996a) to include additional monitoring points and revise
monitoring frequency of existing monitoring points. The
plan would be submitted to and approved by the Forest
Service prior to initiation of project construction.
• Potential effects on streamflows
and alluvial ground water in
Haunted Canyon and Pinto
Creek from well field pumpage
WR-2: Conduct additional aquifer and well field testing during the
mine construction phase but prior to well field production
for operating the mine. The full-scale testing would be
designed to simulate withdrawal rates expected during
the life of the project and would concurrently monitor the
effects on surface and ground water resources.
WR-3; Implement wellfield mitigation program to offset potential
flow reductions in Haunted Canyon and Pinto Creek and
to maintain aquatic and riparian resources at pre-project
levels. Streamflow would be augmented with ground
water pumped from the well field, or with water from other
suitable source(s) approved by the Forest Service and
other appropriate agencies.
WR-4: Implement measures as necessary to ensure that the
water discharged to supplement streamflows (as required
in WR-3) meets applicable Arizona water quality
standards.
• Potential effects of pit
dewatering on Pinto Creek flows
WR-5: If necessary, implement mitigation to off-set impacts to
Pinto Creek from pit dewatering. Mitigation could
potentially include a cutoff wall on the downstream end of
the Pinto Creek diversion and/or improvements to other
nearby stream reaches, wetlands, or riparian corridors.
• Potential effects of pit
dewatering on springs
WR-6: Establish a ground water monitoring program to measure
water level changes in natural springs and seeps. Miti-
gate affected springs and seeps by;
(1 ) Supplementing or replacing flows,
(2) Improving collection or yield at existing springs,
(3) Developing or improving nearby springs, and
(4) Using a replacement water source.
WR-7: Implement a comprehensive ground water monitoring
program (GWRC 1996a) to measure the extent and rate
of ground water drawdown. Carlota has indicated its
intent to assist affected parties by deepening existing
wells, drilling new wells, or providing a replacement water
supply of equivalent yield and general quality during any
period of effect.
• Potential effects to water supply
wells from mine dewatering and
well field development
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Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (continued)
Resources
Intpacis ,,
# Monitodng said Mitiqatioiii "
• Potential reduction in stream
flows from well field pumpage
WR-8: Implement water conservation measures to reduce the
quantity of ground water required. Carlota would prepare
a water conservation plan for approval by the Forest
Service.
• Potential effects to surface and
ground water quality from an
accidental release of leachate
solution
WR-9: Install and maintain (1) automated monitoring in Powers
Gulch to provide for early detection of a release, (2) flow
shutoffs and secondary containment for piping between
components, and (3) an emergency pump system
capable of removing solution to an emergency
containment facility. Mitigate adversely affected surface
or ground water quality by identifying the potential
contaminant source, correcting the source of release
(where possible), and remediating contamination, if
necessary. Target borrow material for leach pad
subgrade with loaded permeability potential of 1x10"®
cm/sec in most critical areas.
• Potential effects from runoff or
seepage from the waste rock
facilities
WR-10: Implement a waste rock sampling plan and, if necessary,
develop and implement a materials handling plan to
prevent impacts to surface and ground water as specified
in the ADEQ Aquifer Protection Permit.
• Potential erosion and
sedimentation effects
associated with facility
WR-1 1 : Develop and implement erosion and sediment controls
and a Stormwater Protection Plan in coordination with the
Forest Service.
construction, operation, and
closure
WR-1 2: Design and maintain process solution containment
components to accommodate the peak flows and
volumes resulting from the 1/2 PMF without any
discharge of process solutions. Design the Powers
Gulch and East diversion channels to safely
accommodate the 6-hour 1/2 PMF.
WR-1 3: At closure, redesign the Pinto Creek, Powers Gulch, and
East diversions to safely convey the full PMF storm
event. Conduct periodic inspections of the diversions
postclosure to ensure diversion design is adequate for
maintenance-free operation.
• Potential impacts to water
resources from the heap-leach
pad operation and postclosure
WR-1 4: Construct an upstream access port for the central spine
drain beneath the main portion of the heap-leach pad to
provide an upstream opening that could be used for clean
out, flushing, or inspection, if necessary.
WR-1 5; Investigate and test closure methodology and provide
annual reports of findings to the Forest Service. Prepare
final heap leach closure design for approval by the Forest
Service and other regulating agencies.
WR-1 6; The main and north embankments would have a seal
zone keyed into bedrock. The need for alluvial monitoring
wells upgradient of the embankments would be evaluated
based on site conditions and depth of alluvium below the
spine drains.
Note: Additional mitigation measures for the alternatives are
identified in Section 3. 3. 4. 4.
Carlota Copper Project Final EIS
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3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (continued)
Resources
Impacts
Mdnlt^iig
Soils and
Reclamation
• Potential loss of soil resources
or reduction of soil productivity,
and potential damage to surface
resources of the National Forest
system lands
SR-1: (1) Salvage suitable soils and extend equipment
operations up to 40 percent grades.
(2) Identify alternative borrow materials for leach pad
construction.
(3) Minimize excavation and transport losses of
salvageable soil materials.
SR-2: (1) Develop and maintain an approved topsoil
management plan.
(2) Locate topsoil stockpiles in protected areas.
(3) Inspect stockpiles to determine stability and success
of reseeding and mechanical erosion controls.
SR-3: (1) Review reclamation priorities with Forest Service to
determine use of excess topsoil.
(2) Improve microbial conditions using bacterial and
fungal inoculants or other seedbed amendments.
SR-4: Prevent excessive topsoil erosion by;
(1) Evaluating BMPs such as placing slope breaks along
leach pad slopes, using mulches on all areas to be
revegetated, and constructing embankments at the
toes of the Main mine rock disposal area
(2) Monitoring and maintaining these features
(3) Implementing BMPs for surface drainage, roads, and
erosion and sedimentation controls
SR-5: Evaluate reclamation after 3 years to determine if
success criteria are met.
SR-6: Implement as much concurrent reclamation and
stabilization as possible.
SR-7 Remove and dispose of all building and facility
foundations according to appropriate regulations.
SR-8 Define the bonding requirements for reclamation.
SR-9: Define the closure and reclamation schedule.
SR-10: Define the proposed revegetation testing program
(schedule and location) during project operation.
SR-1 1 : Incorporate the types and application rates for seedbed
amendments (including microbial inoculants) into the
revegetation testing program.
SR-1 2: Define the reseeding methods and locations.
SR-1 3: Define the final seed mixes and planting specifications for
reclamation.
SR-1 4: Determine additional monitoring and maintenance for the
reclamation program. Maintain firefighting capabilities
until reclamation is deemed successful.
SR-1 5: Close roads to normal vehicular traffic; restore drainages;
and approximate original contour, stabilize, and
revegetate.
SR-1 6: Reclaim the impoundment area created by the alternative
Powers Gulch diversion embankment by using suitable
waste rock and creating a drainageway for surface flows;
revegetate backfill areas.
3-338
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (continued)
Resources
liitpects
Monitoring and Mitigation
Terrestrial Biology
• Direct loss or disturbance to
occupied and potential Arizona
hedgehog cactus habitat
TB-1: Subject to the U.S. Fish and Wildlife Service Biological
Opinion, identified measures are listed below:
(1 ) Review facility sites and alignments for relocation to
avoid cacti.
(2) Protect plants in occupied areas using fencing and
stakes.
(3) Establish revegetation test plots to determine best
methodology for reestablishing vegetative cover;
where avoidance is not feasible, transplant cactus
into test plots to determine optimum re-
establishment habitat.
(4) Permanently withdraw from mineral entry a selected
parcel (186 acres) that support populations of
Arizona hedgehog cactus.
(5) Acquire a grazing permit for an area that includes
Arizona hedgehog cactus populations and preclude
grazing activity during mine operation and
reclamation.
(6) Develop a conservation plan, in coordination with the
Tonto National Forest, for protecting the Arizona
hedgehog cactus over the long term.
• Indirect water quality impacts to
bald eagles on Roosevelt Lake
TB-2: Implement water quality monitoring and mitigation
measures (Section 3.3.4) to mitigate or alleviate potential
water quality impacts to Roosevelt Lake.
• Direct and indirect disturbance
to riparian vegetation and
wetlands
TB-3: (1) As described in the CWA Section 404 permit,
improve/enhance riparian habitat in an amount and
quality greater than that disturbed by the project.
(2) Acquire grazing permits and implement non-use
during the life of the project.
(3) Construct fencing around off-site riparian areas to
protect them from grazing.
• Indirect impacts to riparian
habitats in Haunted Canyon
TB-4: Implement hydrologic and riparian habitat monitoring and
initiate water augmentation, as necessary.
• Disturbance to bat roosts
TB-5: Identify and provide for protection of alternative bat roost
sites, as necessary.
• Impacts to potential lesser long-
nosed bat foraging habitat
TB-6: Transplant agaves from disturbance areas to appropriate
undisturbed habitats in project area.
• Loss of upland vegetation and
habitats
TB-7: (1) Construct fencing of mining areas.
(2) Implement road closures.
(3) Purchase grazing permit(s), and implement non-use.
(4) Maintain existing off-site water developments.
Aquatic Biology
• Sedimentation impacts on
aquatic and fish spawning
habitat
AB-1 : Coordinate construction activities with the Forest Service
to ensure that proper mitigation measures are
implemented: schedule activities to minimize impacts
during spawning periods.
• Loss of wetland habitat
AB-2: As required by the CWA Section 404 permit, restore
wetland habitat in an amount and quality greater than that
disturbed by the project.
• Loss of waters of the U.S.
AB-3: As required by the CWA Section 404 permit, restore
waters of the U.S. in an amount and quality equal to or
greater than that disturbed by the project.
Carlota Copper Project Final EIS
3-339
3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (continued)
Resources
Impacts
MonlioilrHS mid Mitigate
Cultural
Resources
• Direct impacts to 56 cultural
sites (35 are NRHP-eligible),
and indirect impacts to 12 sites
(8 are NRHP-eligible)
CR-1 : Retrieve data at 35 directly impacted, NRHP-eligible sites
and conduct appropriate mitigation. Monitor 8 indirectly
impacted, NRHP-eligible sites regularly (by an
archaeologist), and fence sites, if necessary. This
mitigation applies to the TCPs associated with impacted
NRHP-eligible archaeological sites. For non-eligible sites,
the Forest Service may consult with concerned Tribes to
identify possible ways to alleviate potential impacts.
Socioeconomics
• In-migration of workers
SE-1 ; Provide recruitment and training opportunities for the
Native American workforce at the San Carlos Indian
Reservation and other local workers.
• Housing shortage for both
construction and operations
workforce
SE-2: Provide a schedule of project development to local
government planning agencies.
• Decrease in water availability
for Top-of-the- World residents
See measures WR-1 and WR-7 under Water Resources.
Land Use
• Disturbance and loss of grazing
allotments that would require an
amendment to the Tonto
National Forest Plan
LU-1 : Relocate allotment boundary fences and implement
range structural improvements according to a plan
developed by Carlota, the permittees, and the Forest
Service.
LU-2: Construct fences to exclude livestock from active mining
and processing areas.
• Loss of permit(s) for fuel wood
salvage that would require an
amendment to the Tonto
National Forest Plan
LU-3: Develop a plan with the Forest Service to salvage fuel
wood from disturbed areas.
• Lowering of livestock numbers
for grazing permits
LU-4: Work with Bellevue and Bohme grazing permittees to
develop plan to minimize their economic losses.
Recreation
• Reduction in dispersed
recreation activities in project
area; including elimination of
access for horseback riding in
Powers Gulch
R-1 : Develop a recreational access management plan with the
Forest Service.
Wilderness and
Wild and Scenic
Rivers
• Potential flow and water quality
impacts on the Pinto Creek
segment being considered for
Scenic designation
See measures WR-1, 3, 4, 5, 6, 7, 8, 10, and 13 underwater
Resources.
• Limited access to the
Superstition Wilderness
See measure R-1 under Recreation.
• Increased noise levels in the
Superstition Wilderness
See measures N-1 through N-5 under Noise.
Visual Resources
• Visual impacts to sensitive
viewpoints such as U.S. High-
way 60, the Superstition Wilder-
ness, and Top-of-the-World
residents
VR-1 : Select colors for buildings and project facilities that blend
with the surroundings and reduce reflectivity.
VR-2: Shield and direct night-lighting downward to avoid night
spill and glare.
VR-3: Revegetate (where feasible) to reduce the long-term
(postmining) form and color contrasts. Priority locations
would include roads, mine rock areas, and the heap-
leach pad.
3-340
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
Table 3-96. Summary of Monitoring and Mitigation Measures (Continued)
Monitoring and Mitig«Hf>n
VR-4: Treat the top portions of the Eder pits using chemical
darkening agents, rounding or warping benches, and/or
rubblizing slopes to prevent color contrast with
surrounding area.
Noise
• Noise impacts to sensitive
receptors such as the Super
stition Wilderness, Top-of-the-
World, and Tony Ranch Ridge
N-1 : Use state-of-the-art mufflers and maintain equipment in
good operating condition.
N-2; Avoid nighttime blasting.
N-3: Submit final facility design to the Forest Service for
review of noise considerations.
N-4: Conduct monitoring to verify model and determine
operational noise.
N-5: Submit changes in equipment type or size to the Forest
Service; additional modeling or mitigation may be
required to accommodate the change.
Transportation
• Restricted access to Eder Ridge
T-1: Fund relocation of Forest Service Road 898 and/or
maintenance of the westerly portion so that public access
to Eder Ridge is presen/ed.
• Planned closure of portions of
several existing Forest Service
roads
T-2: Close and revegetate those roads identified in the RATM
that would be cut off by project operations.
• Restricted access to Forest
Service Trail 203
T-3: Develop a plan with the Forest Service to manage the
section of Forest Service Trail 203 affected by project
operations. Maintenance activities may include drainage,
erosion control, turnarounds, gating, signing, and
reveqetation.
• Vehicle wear on Forest Service
Road 287 (Pinto Valley Mine
Road)
T-4: Implement a Road Use Permit between Carlota and the
Forest Service to use and maintain the paved portion of
Forest Service Road 287.
Hazardous
Materials
• Potential impacts to environ-
mental resources in the event of
an accidental release of hazard-
ous materials during transporta-
tion and use or storage at the
site
HM-1 : Update Carlota’s SCHMM Plan after engineering design
plans for the project are finalized.
HM-2: Test existing hazardous materials that are located on the
site during construction to determine their contents and
cleanup/disposal actions.
HM-3: Offload sulfuric acid from tanker trucks to storage tank
using gravity flow system.
HM-4: Revise the SCHRMM plan and modify Pinto Creek main
access road crossing design to allow access for
emergency response during flooding events.
HM-5; Test slimes and residual materials remaining in the lined
ponds containing process solutions (excluding the PLS
ponds within the leach pad) and, if necessary, dispose of
the material in accordance with the ADEQ Aquifer
Protection Permit and applicable state and federal
regulations.
Carlota Copper Project Final EIS
3-341
3.0 Affected Environment and Environmental Consequences - Monitoring and Mitigation Measures
3-342
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Unavoidable Adverse Impacts
3.16 Unavoidable Adverse
Impacts
Unavoidable adverse impacts are impacts that remain
following the implementation of mitigation measures,
or impacts for which there are no applicable mitigation
measures. Implementation of the proposed environ-
mental protection measures and the mitigation
measures identified in Chapter 3, Affected Environ-
ment and Environmental Consequences, would
eliminate most of the adverse impacts associated
with the proposed action and the alternatives. The
unavoidable adverse impacts that would remain
following mitigation are summarized below for each
resource. If specific alternatives would result in
different unavoidable adverse impacts, the impacts
associated with the alternatives are listed for the
affected resources.
The potential impacts associated with a leak or spill of
hazardous materials, including a release of material
from the heap-leach pad, are identified for the
appropriate resources; however, the nature and
severity of the impact would depend upon numerous
factors, such as the location and volume of the spill or
leak in relation to the sensitive resources, time of
year, sensitivity of the resource, and characteristics of
the pathway (e.g., surface water flow, gradient, etc.).
No unavoidable adverse impacts are anticipated for
socioeconomics, recreation, or transportation.
3.16.1 Air Resources
• Potential to cause perceptible plume impacts in
the Superstition Wilderness.
3.16.2 Geology and Minerals
• Disturbance to approximately 1,428 acres of
surficial geologic materials.
• Generation of approximately 100 million tons of
spent ore to be left in the closed and reclaimed
heap-leach pad.
. Permanent storage of approximately 1 60 million
tons of mine rock in surface disposal areas.
(This amount would be reduced by approximately
17 million tons for the agency preferred alter-
native.)
3.16.3 Water Resources
• Permanent loss of approximately 39 acres of
alluvial floodplain.
• Removal and consumption of ground water from
well field extraction and mine dewatering.
• Loss of approximately 2.4 miles of natural stream
channel.
• Permanent removal of 0.5 square mile of
contributing watershed area.
• Possible release of hazardous substances
resulting in ground water or surface water
impacts.
• The success of stream and spring mitigation is
unknown: if mitigation does not succeed,
unavoidable adverse impacts would occur.
3.16.4 Soils and Reclamation
• Long-term loss of approximately 490 acres of
soils from postmining land uses (and an addi-
tional 34 acres of soils for the Eder side-hill leach
pad alternative).
• Potential reduced soil production associated with
a spill or leak of hazardous materials.
3.16.5 Biological Resources
3. 16.5. 1 Terrestrial Biology
• Of the vegetation types in the project area
(interior chaparral, rubbleland chaparral, dry-
slope desert brush, and juniper/grassland),
approximately 490 acres would be removed and
would not be reclaimed (and an additional loss of
approximately 34 acres for the Eder side-hill
leach pad alternative).
• Loss of wildlife habitat in vegetation types listed
above.
Carlota Copper Project Final EIS
3-343
3.0 Affected Environment and Environmental Consequences - Unavoidable Adverse Impacts
• Loss of approximately 10 to 20 percent of
transplanted Arizona hedgehog cacti that
may be unsuccessfully transplanted for
the proposed action (and additional backfill
of the Eder South pit alternative or the
Eder side-hill leach pad alternative).
• Loss of occupied habitat for the Arizona
hedgehog cactus; 23.9 acres for the
proposed action (6.9 acres for the
additional backfill of the Eder South pit
alternative; 20 acres for the Eder side-hill
leach pad alternative. Agency preferred
alternative would partially restore potential
habitat in reclaimed area of Eder South pit).
• Loss of potential habitat for the Arizona
hedgehog cactus of 237.6 acres for the
proposed action; however, unoccupied
habitat is not protected under the
Endangered Species Act.
• Possible effects of a spill or leak on
vegetation and wildlife habitat, including
the Arizona hedgehog cactus.
• Possible toxic effects of a spill or leak on
populations of Arizona toad and lowland
leopard frog in Haunted Canyon and Pinto
Creek. Adverse effects on amphibian
populations would affect food sources for
common black-hawk.
3. 16.5.2 Aquatic Biology
• Possible toxic effects of a spill or leak on
aquatic biota, including the desert sucker
and longfin dace in Haunted Canyon and Pinto
Creek.
• Loss of habitat in a 7,300-foot section of
Powers Gulch caused by flow reductions
from the construction and operation of the
diversion and inlet control structure.
3.16.6 Cultural Resources
• Direct impacts to 56 cultural resource sites;
indirect impacts to 12 cultural resource sites.
• Impacts to TCPs cannot be avoided and are not
mitigable, but may be alleviated through further
consultation with the affected Tribes prior to
project implementation.
3.16.7 Land Use
• Temporary loss of approximately 1 ,500 acres of
grazing area.
• Loss of approximately 490 acres of unreclaimed
land to postmining land uses.
3.16.8 Wilderness and Wild and Scenic
Rivers
• Potential effects on ecological values because of
a release from the leach pad.
3.16.9 Visual Resources
• Moderate visual impacts from U.S. Highway 60
and moderate-to-high impacts from the Top-of-
the-World community.
• High visual impacts from the Top-of-the-World
community (Eder side-hill leach pad alternative).
3.16.10 Noise
• Noise impacts to recreationists at the eastern
edge of the Superstition Wilderness.
3.16.11 Hazardous Materials
• Potential spills or leaks of hazardous materials
may affect environmental resources. The
magnitude of the impact would depend on
numerous factors, as discussed above.
3-344
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Short-Term Uses/Long-Term Productivity
3.17 Relationship Between
Short-Term Uses of Man's
Environment and the
Maintenance and
Enhancement of
Long-Term Productivity
Short term is defined as the life of the Carlota Copper
Project through closure and reclamation. Long term is
defined as the future after reclamation is completed.
Many of the impacts associated with the Carlota
Copper Project would be short term and would no
longer be adverse after reclamation. However,
decreases in the long-term soil and vegetation
productivity on 490 acres at the pits, mine rock
disposal areas, and portions of the leach pad areas
are expected. These impacts would be partially offset
by reclaiming previously disturbed areas. The
relationship of the short-term use of the environment
and long-term productivity are identified for each
resource in Table 3-97.
Table 3-97. Irreversible, Irretrievable, Short-Term, and Long-Term Commitment of Resources - Proposed
Action
Irreversible
Impacts
Irretrievable
'-®'’*''''^’lmpactd
Reii^^lWMt®bPrt-Term Use of the Environment and
Loncpnrfc Productivity *
Air Quality
No
No
The potential for perceptible plume impacts in the Superstition
Wilderness would exist throughout the life of the project. The
potential for these impacts to occur would vary depending upon
meteoroloqical conditions and mining activity rates.
Geology and
Minerals
Yes
Yes
Approximately 900 million pounds of copper would be removed
from the mineral resource.
VVater Resources
No
No
Ground water would be consumed from well field extraction and
mine dewatering. Well field extraction and mine dewatering would
lower the ground water table and could result in the loss of some
stream and spring flows; proposed monitoring and mitigation
measures are anticipated to minimize these impacts. The ground
water levels and resources dependent on these ground water
conditions would eventually recover and approach premining
conditions.
Yes
Yes
The lake formed in the Carlota/Cactus pit after closure would
continue to be a source of ground water loss through evaporation
on the order of 480 acre-feet per year (after the pit lake water
level reaches equilibrium); however, this loss is small compared
to the overall water balance for the ground water basin.
Yes
Yes
Permanent watershed loss of 0.5 mi^
Soils and
Reclamation
Yes
Yes
Soil erosion is expected to be short-term because of the use of
reclamation measures. There would be a long-term reduction in
soil productivity on approximately 490 acres that would not be
reclaimed.
Terrestrial Biology
Yes
Yes
There would be a long-term reduction in vegetation productivity
on approximately 490 acres of land that would not be reclaimed.
Other impacts would be short-term because of reclamation and
mitigation measures.
No
No
Loss of habitat would be a short-term impact during the life of the
project.
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Short-Term Uses/Long-Term Productivity
Table 3-97. Irreversible, Irretrievable, Short-Term, and Long-Term Commitment of Resources - Proposed
Action (continued)
*
Irreversible
s. impacts
irretrievable
impacts
Relationship of Short-Teiim Use of the Entdronment and
Aquatic Biology
No
No
Loss of habitat from the diversion channels would be short-term,
since recolonization in new channels would be expected. Loss of
habitat from dewatering would be short-term because mitigation
measures would return flows to affected stream segments. Potential
effects of spills or leaks would likely be short-term, with effects
minimized by protection measures and recovery of affected
populations.
Waters of the
U.S., Including
Wetlands
No
Yes
There would be an irretrievable loss of waters of the U.S., including
wetlands, under all alternatives. Development of the Carlota/Cactus
Pit and the Pinto Creek diversion would result in the irretrievable loss
of 0.34 acre of jurisdictional wetlands and 7.28 acres of waters of the
U.S. in the Pinto Creek drainage. Construction of the heap-leach pad
and the Powers Gulch diversion would result in the irretrievable loss
of 2.18 acres of waters of the U.S. for all alternatives except the Eder
Side-hill Leach Pad Alternative.
Carlota's proposed mitigation plan, in compliance with Carlota's CWA
Section 404 permit, would replace lost wetlands at a ratio of 3 to 1 in
the Pinto Creek drainage and reconstruct waters of the U.S. in the
diversion channels at a ratio of 1 to 1 .
Threatened and
Endangered
Species
No
Yes
Loss of habitat and potential effects of dewatering and spill or leaks
would be short-term, as listed for aquatic and wildlife resources. Loss
of Arizona hedgehog cactus individuals (unsuccessful transplants)
and habitat would potentially be long-term. However, recovery of
habitat and individuals would be expected after 20 to 30 years.
Cultural
Resources
Yes
Yes
Disturbance of cultural sites would result in permanent loss of those
sites and their context, with partial mitigation by data recovery.
Socioeconomics
No
No
There would be short-term impacts to the local infrastructure. There
would be increased productivity during the life of the project including
production of copper reserves, creation of 177 construction jobs, 282
to 301 operations jobs, and revenue support for Gila and Pinal
Counties, as well as the State of Arizona.
Land Use
No
Yes
There would be a short-term loss of public land for livestock grazing
and temporary elimination of horseback riding access to the Haunted
Canyon trail via Powers Gulch. Reclamation and mitigation would
restore grazing productivity and the horseback access, respectively.
There would be a long-term loss of postmining land use on areas
within the pits and the leach pad. The project would irretrievably
devote National Forest System lands to mining uses for the 23-year
life of the project. Following completion of mining, about 490 acres of
land would not return to premining uses.
Recreation
No
No
Short-term impacts on horseback access, as identified for Land Use
would occur. There would be short-term impacts on dispersed
recreation, such as hunting.
Wilderness and
Wild and Scenic
Rivers
No
No
Potential releases from the leach pad would affect the ecological
value of the Pinto Creek Scenic river designation on a short-term
basis. Decreases in long-term productivity of natural resources would
not be expected because of recovery and mitigation measures.
3-346
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Short-Term Uses/Long-Term Productivity
Table 3-97. Irreversible, Irretrievable, Short-Term, and Long-Term Commitment of Resources - Proposed
Action (continued)
impacts
Irretrievable
impacts
Term Productivity
Visual
No
Yes
Moderate to high visual impacts would occur during the life of the
project from the Top-of-the-World community. Impacts would be
reduced through reclamation and mitigation measures.
Noise
No
No
Short-term noise impacts during construction and operation on the
Superstition Wilderness would occur. Impacts would cease after
project reclamation is completed.
Transportation
No
No
Short-term traffic impacts during construction and operation would
occur.
Hazardous
Materials
No
No
A spill or leak of hazardous materials would potentially affect
sensitive environmental resources on a short-term basis. However,
protection measures, mitigation, and expected recovery of natural
resources would result in no long-term reduction in productivity.
Carlota Copper Project Final EIS
3-347
3.0 Affected Environment and Environmental Consequences - Short-Term Uses/Long-Term Productivity
3-348
Carlota Copper Project Final EIS
3.0 Affected Environment and Environmental Consequences - Irreversible and Irretrievable Commitment of Resources
3.18 Irreversible and
Irretrievable Commitment
of Resources
The construction and operation of the Carlota Copper
Project could result in the irreversible or irretrievable
commitment of certain resources. Irreversible is
defined as the loss of future options for using
nonrenewable resources, such as minerals or cultural
resources, or factors such as soil productivity.
which would be renewable only over a very long
period. Irretrievable is a term that represents the loss
of production, harvest, or use of natural resources. In
some instances, irretrievable actions can be reversed
if the use changes after the completion of the project.
The irreversible and irretrievable impacts of the
proposed action are summarized in Table 3-97 in
Section 3.17. In general, the alternatives would result
in a similar irreversible and irretrievable loss of
resources.
Carlota Copper Project Final EIS
3-349
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