Abstracts of papers dealing with rock and rock products, presented at the third annual Mineral Industries Conference of Illinois, May 17-18, 1935

URBANA

ILLINOIS STATE GEOLOGICAL SURVEY

3 3051 00004 2246

State of Illinois
Henry Horner, Governor
Department of Registration and Education
Division of the
STATE GEOLOGICAL SURVEY
M. M. L eight on, Chief
Urbana

INFORMATION CIRCULAR NO. 12

ABSTRACTS OF PAPERS DEALING WITH
ROCK AND 'ROCK PRODUCTS

Presented at the

THIRD ANNUAL MINERAL INDUSTRIES CONFERENCE

OF ILLINOIS
May 17~lg, 1935

Illinois' Position as the Keystone Mineral State of the Upper
Mississippi Valley - M. M. Leighton

Technologic Trends in the Production and Utilization of Rock and
Rock Products - N. 0. Rockwood

The Viewpoint of Science Regarding the Production and Utilization
of Non-metallic Minerals - C. W. Parmelee and J. E. Lamar

The Viewpoint of Science Regarding Chemical Engineering Problems
Relating to the Mineral Resources of the State - Donald B.
Keyes

Building Stone Possibilities of Illinois Limestone - J. E. Lamar

Factors in the Development of a Rock Wool Industry - Charles F.
Fryling and Orval White

Concentration of Nonmetallics by Tabling of Agglomerated Materials -
W. H. Coghill

Significance of Accelerated Soundness Tests of Stone and Gravel -
A. T. Goldbeck

Flotation Processing of Limestone - Benjamin L. Miller and C. H.
Breerwood (Presented by D. R. Mitchell)

Progress Report on the Study of the Utilization of Novaculite -
C. W. Parmelee

Trends in the Utilization of Lime and Lime Products - Lee S. Trainor

August, 1935

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INTRODUCTORY NOTE

The Third Annual Mineral Industries Conference, sponsored
by the Illinois State G-eological Survey of the Department of
Registration and Education, and the Engineering Experiment
Station of the University of Illinois, in cooperation with 35
interested organizations, was held in Urbana, May 17 and 18,
1935. The keynote of the conference was "Trends in the
utilization of mineral products." The following abstracts of
papers have been prepared in order that members of the rock
and rock products industry who were unable to attend the con-
ference may be acquainted with the information presented at the
conference bearing on their industry. Publication of papers
in full is planned at a later date. The Survey does not
assume responsibility for the statements here presented.

GENERAL SESSION

Addressing the G-eneral Session on the subject, "Illinois '
Position as the Keystone Mineral State of the Upper Mississippi
Valley," Dr. M. M. Leighton, Chief of the Illinois State
G-eological Survey, stated that for many years Illinois has
been the leading mineral producing state of the Upper Mississippi
Valley. Will it continue this leadership on a scale which will
be reasonably profitable to investors? Illinois' nonmetallic
resources are enormous and diverse including a variety of clays
and shales for cley products, limestone and shale for cement
manufacture, stone for exterior and interior construction, sand,
gravel, and crushed stone for concrete aggregate and surfacing
for farm-to-market roads, glass sand, and woolrock for making
of insulating materials. The processing minerals include lime-
stone and dolomite of many varieties, silica sand, tripoli,
fluorspar, fuller's earth, and other types of clays and sands
not already mentioned. Although largely lacking in metallifer-
ous deposits, many of these are readily at hand in other states
of the Upper Mississippi Valley.

The ansxver to the question appears to be that although
there are adverse factors which seriously threaten the position
of Illinois as a leading mineral producing State in the Upper
Mississippi Valley, the light of science is dawning on the
horizon for the mineral industries of the State and her trans-
formations are likely to be as beneficial and as sweeping as
they have been for other industries of our complex civilization.
The mineral industry, therefore, should keep in close contact
with science in order to take full advantage of its findings,
intelligently and profitably, for the sake of the future of the
industry* To do this the man with large investments in mineral
industries must either take time to school himself in science
or be associated with a man so trained.

Exemplifying the type of benefits industry may expect
from science may be cited the researches now in progress by
the Illinois State G-eological Survey on the constitution of
clays and shales which promise to be of much significance to

the clay and clay products industry in lighting the way to. improve-
ment of existing products and finding new products. Similarly
promising results may be anticipated from researches under way in
the fields of the rock and rock products, fluorspar, end silica
industries. Recently the Survey has discovered large deposits of
woolrock in Illinois, close to transportation and markets, and
suitable for the manufacture of high grade rock wool for the in-
sulating industry.

A paper, "Technologic Trends in the Production and Utiliza-
tion of Rock and Rock Products," by kr . N , C . Rockwo od , Pre si-dent ,
Rock Products, Chicago, indicated a present trend in quarrying of
consolidated rocks towards the use of more flexible equipment and
safer high explosives, and in the case of unconsolidated rock de-
posits, such as sand and gravel, towards a constant perfection of
standard pieces of equipment. In the sand and gravel industry of
the mid-west, a pronounced trend is toward smaller, movable plants.

Many developments are to be noted in the equipment used for
preparing rock materials for use* Improvements have been made in
crushers, particularly reduction crushers. Roll type crushers are
increasing in popularity for the production of small sized aggre-
gates for surfacing of various types of highways. The use of
vibrating screens for the preparation of many of the finer sized
aggregates is now almost universal. Most recent additions to the
processing of aggregates are various types of hydraulic classifiers.

Trends in utilization of rock products involve an increased
use of aggregates, Including both crushed stone and crushed gravel,
for the construction of secondary highways and for resurfacing of
older prved highways, a more extensive use of washed and classified
fine fragments of rock as stone sand, and closer control of molding
sand bonds with special attention to bonding clays for use with
washed sand.

In the field of chemically prepared rock products, the lime
industry is giving more ' attention to details of burning and cooling
processes, recognizing that quality is more under their control
than they formerly believed. The possibility that the future may
witness the production of the metals calcium and magnesium from
lime, limestone, or dolomite was suggested. Trends in the manu-
facture of Portland cement -re distinctly toward truer chemical
control. Recent application of oil flotation of raw cement rock,
to increase the calcium carbonate content, points the way to a
better control of the raw mix, to making special cements, and to
a really standard Portland cement.

The most important market trends, which affect the business
of the aggregate producer, have been induced by the attitude of
government officials which has tended to overlook the great in-
vestment in commercial plants and the years of experience of
commercial producers in perfecting their operations and products
and to turn to new local production of untried and unproved quality,
using relief labor in most instances.

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The "Viewpoint of Science Regarding the Production and
Utilization of Nonmetallic Minerals" was discussed "by Professor
0. W. Parmelee, Head, Department of Ceramic Engineering, Uni-
versity of Illinois, and J. E. Lamar, Head of the Non-fuels
Division, Illinois State Geological Survey, who "believe that
the future will witness the continuance of many of the existing
uses for nonmetallic minerals in their raw state and as manu-
factured products together with a continuous development of
new products and uses, with increasing emphasis on the produc-
tion of raw materials or products having definite physical,
chemical and mineralogical characteristics, and a gradual
tightening of specifications. Looking ahead, science defin-
itely stands on the premise that chance will not be the major
governing factor in the development of the nonmetallic s indus-
try, althoiogh it may play a part, but rather that science has
a specific assignment, namely, to anticipate new needs or meet
existing needs for nonmetallic mineral products on the basis
of controlled and directed studies of possible combinations
and modifications of the basic nonmetallic mineral resources
of Illinois and of methods by which such combinations and
modifications can be effected.

Professor Donald B. Keyes, Head of Chemical Engineering
Division, University of Illinois, discussing the topic, "The
Viewpoint of Science Regarding Chemical Engineering Problems
Relating to the Mineral Resources of the State," called atten-
tion, in the nonmetallic field, to the development of synthetic
stone and the possibility that further work in this field may
mean the production of a, superior type of stone. Silica
aerogel recently developed in the laboratories of the Chemical
Engineering Division of the University of Illinois is said to
be one of the finest heat insulators ever produced and can be
made from the mineral resources of Illinois. This product
should be thoroughly studied in order to determine its practical
feasibility.

EXHIBITS AND DEMONSTRATIONS

Blowing of Rock Wool from Illinois Rock, Charles F.
Fryling, Chemist, State Geological Survey. Following the gen-
eral session an opportunity to witness the blowing of rock
wool was afforded in one of the laboratories where impure
limestone was transformed into a white, fibrous, wool-like
material. The process is as follows:- Crushed rock of suitable
chemical composition, widely prevalent in Illinois, is melted
to a fluid glass in a small induction furnace. The furnace is
then tilted to allow the white-hot liquid to pour in a steady
stream into a high pressure steam blast issuing from a "steam
gun" held at a right angle to the flow of glass. The melting
of the steam and the molten material effects the transformation
of the latter into wool. A bombardment proceeds from the point
of meeting, consisting of thousands of minute, white-hot par-
ticles being propelled through the air at a high velocity,
dragging out hair-like threads of glass in their wake. Toward
the far end of the chamber, at a distance of about twenty to
thirty feet from the blowing nozzle, masses of wool settle to
the floor.

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Rock wool has properties which stamp it as an ideal heat and
sound insulation material, the market for which is growing at a
rapid rate. Mineral operators of Illinois would do well to investi-
gate in further detail factors relative to the rock wool industry.
It has been fully demonstrated that the physical "set-up" is ex-
ceedingly favorable to the industry in our State. For those parties
who are sufficiently interested in the development to investigate
further, a thorough perusal of the State G-eological Survey's
Bulletin No. 61, "Rock Wool from Illinois Mineral Resources," is
recommended.

Exhibit of Novaculite Refractories, C. W. Parmelee, Head of
the Department of Ceramic Engineering, University of Illinois. The
exhibit of the researches on the use of Southern Illinois novaculite
included a large number of small fired specimens which had been
prepared with the use of various bonding agents and accelerators.
An important phase of the study of this problem had been the proper
sizing of the crushed material. These specimens demonstrated that
with a proper sizing of grain and choice of the bonding agent,
excellent results could be obtained since the appearance and the
compressive strength equalled that of commercial silica brick. A
few specimens of standard size novaculite brick prepared in a
similar manner were exhibited.

EVENING ADDRESS

One of the high points of the meetings was the address by
Dr. John W. Finch, Director of the U. S. Bureau of Mines, which
followed the annual Conference dinner. Dr. Finch pointed out that
minerals are more necessary to the life and well-being of people
than most persons realize. Not only are minerals necessary for
progress and for comfortable human existence, but mining carries a
large burden of responsibility for the welfare of the community.
He said that the chief cause of trouble in the mineral industry
today, over-production and unemployment, have their seeds in the
World War and not in the depression. The period of inflation and
over-production following the war necessitated a period of readjust-
ment that has not yet been accomplished. According to Dr. Finch,
the committee appointed by the President to study causes of malad-
justment and unemployment in the industry and to recommend means of
improvement had recommended that the government allow the various
groups in the industry to attempt to work out their own affairs,
and that all other expedients would be tried before that of
government control.

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SYMPOSIUM ON ROCK AND. ROCK PRODUCTS

On Saturday morning, May 18, a symposium of seven timely
papers on rock and rock products was presented before an
audience including representatives of the various nonmetallic
industries of the State.

Little known building stone resources of Illinois were
described in a paper entitled "The Building Stone Possibilities
of Illinois Limestones," by J. E. Lamar, Geologist and Head,
Non-fuels Division, Illinois State Geological Survey, This
paper, based on a preliminary study made by the Illinois
Geological Survey, pointed out the presence of deposits con-
taining beds more than three feet thick of pink, gray-white,
cloudy gray, buff, mottled gray, gray oolitic, dark gray almost
black, and breccia marbles suited to interior use. The deposits
occur in the north, west and south parts of Illinois. Gray
travertine occurs as a part of the Niagaran formation in the
Chicago area and also in the LaSalle limestone of the LaSalle
region. Buff travertine is available from dolomite formations
in northwestern Illinois. Stone for exterior construction
purposes is to be had at many places in north, west and southern
Illinois and includes a variety of grays, buffs, and browns
and in southern Illinois also oolitic limestone resembling the
well known Bedford stone.

The popularity of mineral wool insulation indicates future
expansion of the industry, according to Charles F. Fryling,
Chemist, Illinois State Geological Survey, and Orval White,
President, Mineral Insulation Company, Chicago Ridge, in a
paper entitled "Factors in the Development - of a Rock Wool
Industry. " Factors, of importance in establishing a plant, are:
(a) There are about 30 plants, 8 in Indiana, the remainder
scattered from Vermont to California; (b) freight rates are
high, ranging from $0,70 to $50.00 per ton depending on dis-
tance; (c) woolrock deposits are widespread, some have recently
been found in Illinois, southern Indiana, and Ontario; (d)
patents on blowing insulation into dwellings are held jointly
by six companies; (e) an estimated cost of a two-cupola plant,
exclusive of land and quarry equipment, is ^38, 000; (f) it
should be possible to produce rock wool at 420.00 per ton.
The present trend seems to be toward decentralization in order
to supply local needs more economically. The beginnings of
the rock wool industry in Indiana, together with present
plant practice, were described. Suggestions based on similar-
ities in the manufacture of rock wool and Portland cement were
advanced for overcoEiing production difficulties at present
encountered. Semi-plant scale development work is advocated.

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Mr. W. H. Coghill, Supervising Engineer, Mississippi Valley-
Station, U. S. Bureau of Mines, Holla, Missouri, presented a
paper, "Concentration of Nonmetallics by Tabling of Agglomerated
Materials," which drew attention to the fact that methods of ore
dressing generally considered applicable only to metallic ores
have been shown in recent years to be important in the beneficia-
tion of many nonmetallic products. The use of concentrating
tables, agglomeration, and flotation have all been shown to have
special application in separating constituents not readily separ-
able by the conventional methods of washing and screening. Where
the constituents have sufficiently different specific gravities,
shapes, or sizes, separation can be made on concentrating tables
as shown recently at a gravel plant where a notable quantity of
coal is removed from river gravel by tabling. Certain nonmetallic
ores are suitable for separation by selective oiling or agglom-
eration. By this method two minerals, which may have about the
same specific gravity are subjected to crude oil and one of
several organic reagents such as fatty acids or fatty acid soaps,
which form a film on one of the minerals. The mineral coated is
easily floated and separated by tabling. This method is now used
in improving the grade of phosphate ore concentrates and has been
shown to be applicable to the separation of certain ores composed
of KOI and NaOl. It is thought that the field of nonmetallics is
a fertile one for application of these methods.

"The Significance of Accelerated Soundness Tests on Stone
and Gravel" was the title of a paper presented by Mr. A. T.
Goldbeck, Director, Bureau of Engineering, National Crushed
Stone Association, Washington, D. C, who pointed out that in
considering the materials for use in any structure the dura-
bility of those materials for the component parts of the struc-
ture with their different exposure conditions should be con-
sidered just as carefully as the stress-resisting properties of
those materials. Although unsound aggregates are known to be a
possible source of trouble in concrete, the durability of con-
crete is mostly determined by the durability of the mortar, and
most lack of durability can be traced to the presence of too
much water in the concrete before it has hardened. H0wever,
aggregates do cause trouble, and in recognition of this fact
accelerated methods for detecting unsound aggregates have been
devised. The tests commonly employed are the sodium sulfate or
magnesium sulfate soundness tests and the freezing and thawing
tests. A critical examination of these tests would seem to lead
to the following conclusions:

(l) That the results obtained in the sodium sulfate
soundness test may vary because of the use of the same sieve
for preparing the sample as for measuring the per cent of
loss and because of slight variations in the temperature of
the solution or to other unexplained variations in the
method.

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(3) The freezing and thawing accelerated soundness tests
will give different percentages of loss for a given number of
cycles, depending entirely upon the rate at which freezing
takes place.

The results obtained with the sodium sulfate test and
the freezing and thawing test are only in fair agreement with
one another and there have been some notable examples of lack
of agreement. An accelerated soundness test does not with
certainty determine the soundness of an aggregate unless it
is known that the results of that test agree with service
behavior. Failure in an accelerated soundness test should
be taken as r danger signal, but final judgment of an aggregate
should be based on the performance of the aggregate in actual
use.

Professor D, R. Mitchell, Assistant Professor of Mining
and Metallurgical Engineering, University of Illinois, re-
viewed a paper by Professor Benjamin L. Miller, Professor of
Geology, Lehigh University, and C. H. Breerwood, Vice-President
and General Manager, Valley Forge Cement Company, published
as Technical Publication No. 606, American Institute of Mining
and Metallurgical Engineers, entitled "Flotation Processing
of Limestone." This report describes the use of froth flota-
tion for correcting the composition of limestones poorly
adapted for cement because of low lime content or improper
ratios of silica, alumina, or iron and suggests the possibility
that by proper processing of the same type of rock, suitable
material can be produced not only for ordinary Portland cement
but for practically all kinds of special cements with only
minor amounts of foreign material, if any, for special correc-
tion. Advantages of limestone processing listed are: quarrying
costs are reduced, limestone hitherto unavailable becomes usable,
costs of grinding raw rock are reduced, coal is saved, costs
of clinker grinding are reduced, available supplies of limestone
are increased, purchase of high-grade limestone is eliminated,
quality of cement is improved, a company is enabled to produce
different products and there is the possibility of marketing
materials separated from the limestone. Disadvantages of
processing include cost of plant, cost of operation and value
of stone discarded.

A ^Preliminary Report of Tests on Small Specimens of
Silica Refractories from Novaculite," by Professor C. W.
Parmelee, Head of the Department of Ceramic Engineering,
University of Illinois, mentioned the existence in extreme
southern Illinois of large deposits of novaculite, a form of
silica which has found only a limited use for the manufacture
of silica refractories. The present investigation to determine
the little known properties which affect its use for silica
refractories is Incomplete but the following conclusions
may be drawn on the basis of the work to date: (l) Novaculite

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inverts to cristobalite more rapidly than does quartzite, the in-
version is more complete and takes place at much lower temperatures;
(2) novaculite must he inverted very slowly at a low temperature to
prevent shattering of the grains; (3) in the presence of certain
fluxes the inversion of novaculite to cristobalite has been observed
to proceed at a reasonable speed below 1000°C; (4) proper grading
of grains is of prime importance both from the standpoint of manu-
facture and use and novaculite has been found to crush easily to
the proper grrde; (5) trial specimens have been made which have the
same compressive strength as commercial silica brick.

A paper, "Trends in the Utilization of Lime and Lime Products/
by Lee S. Trainor, Chief Engineer, National Lime Association,
Washington, D. C., stated that lime is sold for a wide variety of
uses in three distinct fields - chemical and industrial processes,
agriculture, and construction. Probrbly the most important trend
in the chemical and industrial use of lime is to be found in new
and improved methods of treatment of municipal and industrial
water supplies and in the treatment and purification of domestic
and i ndu s t r i al wa s t e s .

Some of the more important agricultural uses of lime include
soil treatment, in dusts and sprays and in rations for stock.
Recent additions to our knowledge of soil correction problems
makes possible a more intelligent use of lining materials and
it is now possible to quickly measure the acidity of a soil and
to prescribe the approximate quantity of liming materials needed
to give the desired condition for optimum growth of different crops.

The use of lime for construction purposes dates back to the
earliest records of civilized man, and line was the principal bond-
ing agent in masonry mortar until the recent adoption of Portland
cement. This change was made on the assumption that increased
mortar strength guaranteed higher strength in masonry and was
accompanied by widespread dissrtisf action due to an ever increas-
ing number of leaky masonry walls. Recognizing the importance of
this situation, extensive research projects were initiated by
several organizations. The results of these studies demonstrate
that to bond uniformly, completely and permanently to different
types of building units, under a diversity of conditions a mortar
must be adaptable - that is, it must produce a good extent of bond
with all types of building units without the necessity of wetting
them before laying. The studies indicate that for all normal
masonry above grade, the proper combination of properties is
obtained in a mortar composed of two volumes of lime, one volume
of Portland cement and approximately nine volumes of sand.

Abstracts of the papers dealing with Coal and with Clay and
Clay Products may be obtained by addressing the Chief, Illinois
State Geological Survey, Urbana.

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