BANCROFT
LIBRARY
<»
THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
THE RUSSELL PROCESS
AT THE YEDRAS MILL.
BY ROBERT F. LETTS,
LATE SUPERINTENDENT OF MILL.
The Russell Process was introduced at the Yedras Mill (Anglo-
Mexican Mining Company) in November, 1887, and has been in con-
tinuous use since then, having superseded the old leaching process
which had been previously employed in the treatment of this ore.
The object of this article is to compare these two processes, as well as
to give such statistics on mill work, results obtained and expenses, as
will be of general interest, without going too much into the technical
details of the two processes.
The statistics here given have been accumulated during my con-
nection with the Anglo-Mexican Company, extending over a period
of six years, both before and after the introduction of the Russell
Process, and the results here given cover not only the treatment of
Yedras ore by that process, but also the re-treatment of all the old
tailings which had previously been produced by the old leaching pro-
cess.
The metallurgical history of the Yedras mill is as follows :
Smelting being economically and metallurgically out of the
question, it was originally intended to work Yedras ore by roasting
in Bruckner furnaces (four of which were erected at the mill) and
treatment by amalgamation.
But it was soon discovered that neither these furnaces nor the
amalgamation process would work on this ore. Not only was it im-
possible to obtain sufficiently good roasting results in the Bruckners,
but then the ore was not in suitable condition for the subsequent treat-
ment. Long reverberatory furnaces were therefore adopted for roasting
and the old leaching process for the extraction of the silver.
This course was pursued for about three years, during which
time I suppose the extraction of silver did not average over 65 per
cent, of the value of the roasted ore.
In order to increase the extraction the Russell Process was intro-
duced. The result, the first three months, as shown by the report of
the superintendent of the mill, was a saving at the rate of $100,560
U. S. coin per year,* the gain in extraction by the use of the Russell
Process being 17.47 per cent, of the value of the ore more than could
be obtained by the old leaching process. These comparative results
* NOTE — In this and subsequent statements the royalty for use of process ''s omitted.
were obtained by running the two processes side by side on the same
ore for three months. Subsequent tests showed similar results, and
are given in the superintendent's reports at the end of this article.
The property of the Anglo-Mexican Mining Company is situated
on an eastern spur of the Sierra Madre mountains in the state of Sin-
aloa, Mexico, and can be reached from Jimenez, in Chihuahua, by
stage to Parral, and then by mule for eight to ten days over a moun-
tainous trail to Yedras.
The mill plant consists of
2 rock breakers,
2 shelf ore dryers,
1 shelf salt dryer,
40 ore stamps,
5 salt stamps,
8 reverberatory furnaces,
14 ore leaching vats, n ft, 8 in. diameter, by 5 ft. 2 in. highr
2 wash water precipitating tanks, 21 ft. diameter, by 5 ft. high,
2 solution precipitating tanks, 14^ x pX,
3 solution precipitating tanks, io}4 * 9/4,
1 solution storage tank, n x 8X,
2 solution storage tanks, 9 x 42/3,
i sulphide sump tank, 7^ x 4^3,
1 sodium sulphide mixing tank (iron) 3x7,
2 sodium sulphide storage tanks (iron) 3^ x 5.
The variations in size of the tanks and vats is explained by the
fact that the leaching department was made to suit existing circum-
stances as to grade and area, otherwise the ore vats would have been
made larger and the tanks generally of more uniform size.
The leaching department at Yedras has a capacity of about 60
tons per day, occupying a building 60x100 feet.
The following are two analyses of Yedras ore, representing the
averages of the ore treated at different periods :
No. i. No. 2.
Carbonate of lime 33.78 46.50
Silica 15.13 25.00
Iron 17.33 9.80
Sulphur 13.31 12.50
Arsenic 9.82 2.50
Zinc 4.92
Lead 1.78
Magnesia 2.58
Alumina 1.35
No. 2 is an analysis of the average battery sample for one month.
The composition of the ore varies greatly. A couple of months after
the above analysis No. 2 was made, the battery samples for several
weeks had 4 per cent, zinc, and two months later contained great quan-
tities of antimony.
Table I. gives general mill statistics, representing the average for
five years.
TABLE I.
CRUSHING AND ROASTING.
Year.
Mesh of Screen
on Battery.
Rate of Crush-
ing per Stamp
per Day.
Per Cent, of Salt
used in Roast-
ing
Wood used
per Ton in
Roasting.
Mesh.
Tons.
Per Cent.
Cords.
Nov. 1888, to Sept. 1892
22
2.8^
Ql/2. to 7
0.23
The rate of crushing per stamp given in the above table is for
twenty-four hours, but the battery is not usually run at night.
TABLE II.
GENERAL LIXIVIATION STATISTICS.
Year.
Net Weight
of
Vat Charges
Depth of
Charges
before
Leaching.
Depth of
Charges
after
Leaching.
Filtering
Rate
per Hour.
Strength
of Stock
Solution in
Hypo.
Strength of
Extra
Solution in
Blue Stone.
Temper-
ature of all
Solutions.
Tons.
Inches.
Inches.
Inches.
Per Cent.
Per Cent.
0 Fah.
1888
1889
1890
16 to 18 y2
16 to 18 K
16 to 18 y2
62
62
62
53
53
53
4.38
3.34
3.63
1.89
1.43
1.40
0.69
0.69
0.69
»H O
o«o
-d o
SI
The mill solutions at Yedras are never used warm, cold solutions
giving equally good results.
TABLE III.
LIXIVIATION STATISTICS.
DEPTHS AND VOLUMES OF WATER AND SOLUTIONS, AND TIME OF LEACHING.
Year.
ist Wash Water.
ist Ordinary Solution.
Extra Solution of the Russell Process
Time.
Depth
Volume
per Ton
Time.
Depth.
Volume
per Ton
Time.
Depth.
Volume
per Ton.
Hrs.
In.
Cub. ft.
Hrs.
In.
Cu. ft.
Hrs.
In.
Cu. ft.
1888
1889
1890
10.72
12.52
12.24
43.24
41.81
40.25
23.2
22.5
21.6
25.63
32.09
43.50
95.37
93.45
149.20
51.3
50.3
86.0
19.02
20.77
19.07
24
24
24
13
13
13
The twenty hours time given for ' 'extra solution" includes twelve
hours during which the solution stands in the ore. In the case of the
wash waters and ordinary solutions the liquid is continually running
through the charge.
TABLE III.— CONTINUED.
LIXIVIATION STATISTICS.
DEPTHS AND VOLUMES OF WASH WATERS AND SOLUTIONS,
AND TIME OF LEACHING.
Second Ordinary Solution
2d Wash Water, j Total Times .Depths & Volumes.
•
c
jj
o
H
H
o
^H
fin
1
o
6
S3
PH
6
If
ll
^ o
«d
rt
1
V
3
"o
6
1
15
|j
ll
o J2
IH
>
H
Q
H
Q
H
H
Hw
H
Hours.
Inches.
Cu. Ft.
Hours.
In. [CuFt
Hours.
Inches.
Cu. Ft.
Cu.Ft
1888
54.20
212.27
114.1
7.34
24
13
116.91
331.6
178.4
36.2
1889
57.17
176.41
94.3
10.38
24
13
132.91
293.9
157.6
35.5
1890
54.27
193.40
140.0
8.72
24
13
137.80
366.6
203.0
34.6
The volume of water per ton, referred to in the last column of
the above table, represents the total quantity used per ton in leach-
ing. The solutions being used over and over again indefinitely, no
water is required for them except at the first starting of a mill, when
they are made up once for all. If the rate of leaching at Yedras
were faster, as at the Aspen mill in Colorado, where, I understand, the
leaching rate is about 14 inches per hour, instead of three as at
"Yedras, the time occupied in treating a charge would be much re-
duced. Just so much solution must pass through the ore to accom-
plish the work, but, with the exception of the extra solution which is
allowed to stand twelve hours, all the wash waters and solutions do
just as good work running rapidly through the charge as slowly.
For a four times as rapid rate of leaching the time of treatment
£>f a charge would be reduced about two-thirds.
TABLE IV.
CHEMICALS USED PER TON OF ORE.
Year.
Hyposulphite.
Blue Stone. -
Caustic Soda.
Sulphur.
Total Chemicals
per Ton.
Ibs.
Ibs.
Ibs
Ibs.
Ibs.
1888
1889
1890
18.^1
1892
1.07
0.82
0.74
1.31
0.85
7.02
5.62
3.85
6.02
6.16
5.12
3.13
2.69
4.23
3.64
3.97
2.69
1.86
2.92
2.50
17.18
12.26
9.14
14.48
13.15
Average 0.96
5.73
3.76
2.79
13.24
Owing to distance from railroad the price of chemicals per pound
at Yedras is, of course, considerably greater than at any place in the
United States or at most localities in Mexico.
In the following table, and throughout this article, United States
money is used, as the value of Mexican silver coin varies according
to the price of silver.
The average cost of chemicals per pound at Yedras for the last
three years is as follows :
Hyposulphite of soda 8.0 cents.
Blue stone 10.0 cents.
Caustic soda 9.1 cents.
Sulphur 7.1 cents.
No soda ash (sodium carbonate) is used at Yedras, as there is
usually no lead in the ore.
The total cost of all chemicals at Yedras in 1890 was 3.6 cents
per ounce of silver produced. Of the copper used in the form of blue
stone, about 50 per cent, remains in the ore.
TABLE V.
COST OF CHEMICALS PER TQN OF ORE.
Year.
Hyposulphite.
Blue Stone.
Caustic Soda.
Sulphur.
Total Cost of
Chemicals per
Ton of Ore.
Cents.
Cents.
Cents.
Cents.
Dollars.
1888
1889
1890
1891
1892
8.7
6.6
6.0
11.1
7.6
70.2
56.0
38.5
63.2
70.8
46.5
28.5
24.5
402
383
28.2
19.1
13.2
21.9
21.2
1.54
1.10
0.85
1.36
1.38
Average
8.0
59.7
35.6
20.7
1.25
In the following table are given the assay office results by both the
old leaching process and the Russell Process, and the mill results ob-
tained by the latter during the past year. The assay office results are,
of course, the standard up to which each of these processes is expected
to work in the mill. As shown in the tables the Russell Process in the
mill is a little above its standard. On each charge of ore the old
process is used first, extracting what it can, and then the Russell
Process follows it. But, except when a comparative mill run between
the two processes is made, the results of which are given further on,
the tailings are not sampled after the old process and before the
Russell Process, but only when each charge is entirely finished.
Consequently the mill results by the old leaching process are not
given in this table.
TABLE VI.
ASSAY OFFICE AND MILL RESULTS FOR
Month.
Extraction by
Old Process
in Assay Office.
Extraction by
Russell Process
in Assay Office.
Extraction by
Russell Process
in Mill.
Russell Process in Mill
compared with same
Process inAssay Office.
Per Cent.
Per Cent.
Per Cent.
Per Cent
January ....
February . . .
March
71.28
77.73
78.26
84.75
85.77
85.96
80.45
84.25
8633
-4.30
-1.52
+ 037
April
78.72
87.01
87.94
+ 0.93
May
75.62
86.98
88.53
+ 1.55
Tune
69.52
87.30
8861
+ 1.31
July..
70.29
85.61
86.26
+ 0.65
Au£TUSt
69.51
86.88
89.65
+ 2.77
September .
October
November . .
December . .
69.43
61.87
61.44
62.42
87.55
86.32
87.24
84.68
90.55
89.88
87.61
91.24
+ 3.00
+ 3.56
+ 0.37
+ 6.56
Average . .
70.50
86.30
87.57
+ 1.27
In Table VI the — and + signs indicate by how much the Russell
Process in the mill fell below or exceeded its standard, i. e. the re-
sults by that process in the assay office. So far, this year, the results of
the process in the mill exceed the assay office results by 1.27 per
cent.
The mill extraction at Yedras, as given in Table VI, is not
as high as at most other mills using the process. This is due
to the fact that the roasting in the reverberatories, owing to the large
loss of silver, which may then take place, if it is too long continued,
or at too high a temperature, must be conducted with reference to
this loss as well as to the subsequent extraction by lixiviation. The
roasting might be so conducted as to yield 92 or 93 per cent, of the
value of the roasted ore by lixiviation, but such a roasting would cause
a greater loss of silver by volatilization. Also, if more salt were used
the per cent, of extraction from the roasted ore would be higher. But
salt costs at Yedras about twelve times as much as at Park City, Utah.
With seven per cent, salt and the roasting as at present conducted,
the loss by volatilization is 6 to 8 per cent., and the extraction from
the roasted ore 87 per cent. This is better economically than to use
a larger per cent, of salt or roast longer, even with 92 per cent, ex-
traction from the roasted ore as a result.
NOTE.— The statistics for 1892 are furnished by H. H. Hughes, Superintendent of the Anglo-
Mexican Mining Company at Yedras.
TABLE VII.
DIFFERENCE BETWEEN ASSAY OFFICE AND MILL RESULTS
FOR FIVE YEARS.
Year.
Russell Process in Mill
over Old Process in
Assay Office.
Russell Process in Mill
over Old Process in Mill.
(See Table A.)
Russell Process in Mill
over ( + ) or below ( — )
Russell Process in Assay
Office.
Per Cent.
Per Cent.
Per Cent.
1888
1889
1890
1891
1892
11.13
8.47
9.17
11.62
17.07
O5 £-
•* _{.C5
^' T*5
i— i
+ 0.02
-0.29
+ 0.54
-4.75
+ 1.27
Av6rasf6
11 49
16 46
-0 64
As shown in above Table VII, the Russell Process during the past
five years has extracted in the mill 16.46 per cent, of the value of the
ore more than could be extracted by the Old Process in the mill.
Also, the extraction by the Russell Process in the mill averaged only
64-100 of one per cent, less than the highest extraction obtainable
by that Process in the assay office.
TABLE VIII.
VALUES OF PRODUCTS AND DISTRIBUTION OF VALUES IN PRODUCTS.
Year.
1890
Per Cent. Silver in each Product.
Distribution of Silver in the Products.
Wash Water
and Weak
Solution
Sulphides.
Sulphides
from
"Ordinary
Solution."
Sulphides
from
"Extra
Solution."
Average
Value of
Total
Product.
Per Cent, of
Total Pro-
duct in Wash
Water and
Weak Solu-
tion Sul-
phides .
Per Cent, of
Total Pro-
duct in Sul-
phides from
Ordinary
Solutions.
Per Cent, ot
Total Pro-
duct in Sul-
phides from
Extra
Solution.
Per Cent.
Silver.
Per Cent.
Silver.
Per Cent.
Silver.
Per Cent.
Silver.
Per Cent.
Per Cent.
Per Cent.
46.47
69.10
24.79
60.2
10.0
75.0
15.0
TREATMENT OF OLD TAILINGS
BY THE RUSSELL PROCESS.
All the tailings which had been produced at the Yedras mill by
the old leaching process, before the introduction of the Russell Pro-
cess in 1887, have now been re-treated by the latter. The manipula-
tions of the solutions for tailings is practically the same as in the treat-
ment of ore.
The tailings are brought from the old dumps, where they had
been thrown out in former years, and are charged directly to the
leaching vats without any drying, roasting or other preliminary treat-
ment. Like the charges of ore, they are leached first with water in
order to remove the small per cent, of soluble salts which is present,
this washing requiring about four hours. A small amount of ordi-
nary hypo-sulphite solution is then applied, not because this solution
extracts anything, as it extracts absolutely nothing. But, as the vol-
ume of the "extra solution" is only enough to saturate the charge, and
it would become diluted to some extent with the wash water if it fol-
lowed that, the small volume of ordinary solution is interposed be-
tween them.
As in treating ore, the "extra solution" amounts to 13 cubic feet
per ton. It is followed by more of the ordinary hyposulphite solu-
tion to extract any silver which has been made soluble by the "extra
solution" but which has not passed out of the charge with that solu-
tion, but remains mechanically held in the pulp.
The total amount of tailings from the old leaching process at
Yedras which have been re-treated by the Russell Process is about
30,000 tons.
Table IX gives the assay office and mill results on the tailings
re-treated in 1889.
TABLE IX.
TREATMENT OF OLD TAILINGS BY RUSSELL PROCESS— l88o.
MONTH.
Value
Per
Ton.
Per Cent, by
Old Process in
Assay Office.
Per Cent, by
Russell Process
in Assay Office.
Per Cent,
by Old
Process
in Mill.
Actual "Clean
Up" by Russell
Process in Mill.
Ounces.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
January
February...
March
April
18.49
18.40
17.45
1639
33.60
35.49
28.60
3063
62.30
59.30
56.39
5827
b«
8J
aid
70.46
63.43
56.13
6693
May .
17,92
36.72
61.22
Vs
7407
June.. .
16.14
31.11
5663
1-1*
5350
July
16.00
33.75
5675
o~.S
55.90
August
September..
14.68
18.26
31.00
37.03
56.68
58.60
£ 2
H^
<u
64.87
52.51
Averages . .
17.23
32.17
57.20
0.0
60.14
9
No tailings were treated in October, November or December of
1889, nor in June, July, August, September or December, 1890.
Table X gives the results on tailings for 1890.
TABLE X.
TREATMENT OF OLD TAILINGS BY THE RUSSELL PROCESS — 1890.
MONTH.
Value
Per
Ton.
Per Cent, by Old
Process in
Assay Office.
Per Cent, by
Russell Process
in Assay Office.
Per Cent .
by Old
Process
in Mill.
Actual "Clean
Up" by Russell
Process in Mill.
Ounces.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
January. . . •
February. . .
March ....
13.02
15.24
1548
24.35
36.62
36.12
39.56
50.20
53.88
JLti
2£a
O.U--
? fcuo •
34.09
47.95
55.00
Apri]
13 03
32.00
5380
2 ~ S3
45.28
May
10.93
30.38
45.29
0$-B g
59.73
October
November..
10.41
11.50
26.50
31.83
35.50
43.57
D (/> O
£% G
H o
34.28
43.91
Averages . .
13.46
34.48
49.26
0.0
46.84
In both the foregoing tables it will be noticed that the old leach-
ing process in the mill fails to extract anything from the tailings which,
had been previously produced by it, although in the assay office the
extraction from these tailings by that process is 32.0 to 34.0 per
cent.
Tables XI and XII give the chemicals consumed in leaching for
the months corresponding to those of . Tables IX and X.
TABLE XI.
TREATMENT OF OLD TAILINGS BY THE RUSSELL PROCESS.
CHEMICALS USED PER TON — 1889.
Month.
Hyposulphite.
Blue Stone.
Caustic Soda.
Sulphur.
Total
Chemicals .
Per Ton.
Ibs.
Ibs.
Ibs.
Ibs.
Ibs.
January
February
1.07
1.33
5.70
571
4.82
4.00
3.21
2.66
14.80
13.70
March
1.50
582
*14.21
*7.10
*28.63
April
246
600
431
2.86
15.63
May
286
610
389
2.59
15.44
June
1.65
531
321
2.14
12.31
July
1.94
512
2.68
1.78
11.52
J j
August
1.13
503
2.84
1.89
10.89
September
131
462
350
2.33
11.76
Averages . .
1.62
5.11
3.13
2.69
12.55
* Caustic lime, as during March "calcium sulphide" was used as a precipitant for silver
sulphide. As a result the cost of precipitating was increased about 25 per cent, instead of sodium,
for that month .
10
TABLE XII.
TREATMENT OF OLD TAILINGS BY THE RUSSELL PROCESS.
CHEMICALS USED PER TON — l8gO.
MONTH .
Sulphite.
Bluestone.
Caustic
Soda.
Sulphur.
Total
Chemicals
Per Ton.
Ibs.
Ibs.
Ibs.
Ibs.
Ibs.
January
0.85
3.80
2.21
1.47
833
February . .
1.08
3.84
2.45
1.69
9.06
March
2 85
427
1.74
1.20
1006
April
1 89
426
2.48
1.72
1035
May
0.77
3.69
2.54
1.76
8.76
October
002
417
2.29
1.57
8.05
November
004
4.43
3.67
2.53
10.67
Averages
107
406
248
1.71
9.33
Tables XIII and XIV give a summary of statistics on the treat-
ment of the old tailings at Yedras for three years. Naturally
the richest of these old tailings were treated first, which accounts
for their decreasing value.
TABLE XIII.
TREATMENT OF OLD TAILINGS BY THE RUSSELL PROCESS AT YEDRAS.
SUMMARY.
Year.
Value
per Ton.
Per Cent, by
Old Process
in Assay
Office.
Per Cent,
by Russell
Process in
\ssay Office
Per Cent,
by Old
Process
in Mill.
Apparent
per Cent, by
Russell
Process in
Mill.
Apparent by
Russell Pro-
cess in Mill
below that
Process in
AssayOffice.
Actual
Extraction
by Russell
Process
in Mill.
Ozs.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
1888
1889
1890
19.49
17.23
13.46
37.40
32.17
38.48
62.70
57.20
49.26
Old Process
extracts
nothing in
Mill.
60.14
55.95
48.37
-2.55
—1.25
—0.89
62.74
60.14
46.84
Av'ges
16.73
36.02
56.39
00.00
54.82
—1.57
56.57
In the above table ' 'apparent" extraction in mill is obtained by
-comparing the value per ton of the final tailings with the old tailings as
11
charged to the leaching vats (taking into account any soluble salts
also).
"Actual extraction" in mill isobtained by comparing the "clean
up" in silver with the silver actually charged to leaching vats.
The "actual " extraction averages ify Per cent- above the "ap-
parent " for the three years.
TABLE XIV.
TREATMENT OF OLD TAILINGS BY THE RUSSELL PROCESS AT YEDRAS.
SUMMARY — CONTINUED.
CHEMICALS USED PER TON, ETC.
Year.
Hypo-
sulphite.
Blue Stone.
Caustic
Soda.
Sulphur.
Total
Chemicals
per Ton.
Cost of
Chemicals
per Ton.
Ounces
Silver
Extracted
per Ton.
Ibs.
Ibs.
Ibs.
Ibs.
Ibs.
Dollars.
Ozs.
1888
1889
1890
2.08 .
1.62
1.07
6.32
5.11
4.06
4.54
3.13
2.48
3.30
2.69
1.71
16.24
12.55
9.33
1.45
1.12
0.84
12.23
9.75
6.30
Ar'ges
1.59
5.10
3.38
2.57
12.64
1.13
9.43
The value of the product from the treatment of old tailings at
Yedras, by the Russell Process, averages about 25 per cent, in silver,
or approximately 7,000 ounces per ton.
12
SUMMARY.
Tables IV and XIV give the chemicals on both ore and tailings
for the years 1888, 1889 and 1890, as follows:
YEAR.
Total Chemicals Per Ton
for Ore.
Total Chemicals Per Ton
. for Tailings.
Ibs.
Ibs.
1888
1889
1890
17.18
12.26
9.14
16.24
12.55
9.33
The above Table illustrates a fact, which, I believe, has been
observed wherever the Russell Process, has been used, viz.: . That the
amount of chemicals consumed per ton is practically independent of
the richness of the ore. For, in the above case, the amount of silver
extracted from the ore per ton is four to six times the amount extract-
ed from the tailings and yet the weight of chemicals used per ton is
almost exactly the same.
The average amount and cost of chemicals per ton used in re-
treating the old tailings at Yedras by the Russell Process, during the
above three years, has been as follows:
Hyposulphite 1.59 Ibs. at 8.0 cents 12.72 cents.
Blue Stone 5.10 " " 10.0 " 51.00 cents.
Caustic Soda 3.38 " " 9.1 " 30.76 cents,
Sulphur 2.57 " " 7.1 " 18.24 cents.
12.64 $1.1272!100
In the United States, for instance, at Park City, Aspen or Butte,
the cost of these chemicals would be about 65 cents, instead of $i. 13,
per ton of tailings.
The average actual extraction in silver from these old tailings
during these three years has been 56.57 per cent., or 9.46 ozs. per ton.
The average price of silver in the United States for this period was
97 cents per oz., making the gross extraction of silver from the tailings
equal to $9.18 per ton.
The following table gives the average expenses and profits at
Yedras arising from the treatment of these tailings by the Russell
13
Process at the rate of 50 tons per day (the usual rate being 30 to 50
tons) :
Chemicals per ton $1.13
Loading per ton 0.25
Unloading per ton 0.13
Labor in leaching per ton 0.29
Fuel and power per ton 0.13
Product and sundry expense per ton 0.50
Total expenses per ton $2.43
RECAPITULATION.
Extraction per ton (9.43 ozs. at 97 cts.) $9.18
Expenses per ton 2.43
Net profit per ton $6.75
The statistics which have just been given refer to the treatment ot
Yedras tailings only. We now come to a comparison of the Russell
Process and the old leaching process in the treatment of Yedras ore.
During the past five years the comparative efficiency of these two
processes at the Yedras mill has been tested four times. The dura-
tion of each of these tests was from one to three months.
Two of these were made by my predecessor in charge of the
mill, Mr. F. M. Johnson, and two by myself.
Two methods were pursued in making these comparative runs.
One was to divide the roasted ore equally between the two processes,
running one-half the ore vats and precipitating tanks on the old pro-
cess and the other half by the Russell Process, the products being
kept entirely separate and the tailings from each process being thrown
out. By this method, however, there is a loss of seven to ten ounces
per ton on all the ore treated by the old leaching process; as that
amount, which might be extracted by the Russell Process, if it were
used on those charges after the old process, remains in the tailings
and is lost.
In the other method of making the comparison between the
two processes, all the charges are treated first by the old process, that
is by the simple hypo-sulphite solution, until no more silver can be
extracted by that process, the sulphides being precipitated by them-
selves and kept separate. Then these same charges of ore are treated
by the Russell Process, that is by a cuprous hypo-sulphite, or "extra"
solution. The precipitates from this solution are likewise kept sep-
arate. In this way a comparison between the two processes is made
without any loss, each charge of ore having the benefit of being
treated by both processes before it is thrown out.
In fact this is the way all the ore is treated at Yedras, whether a
comparison is being made or not, all charges being first treated by
the old process and then by the Russell Process.
The first of the two comparative runs made by myself between
the two processes was in September, 1890, the test being continued
during the whole of the month.
I extract from my report to the Anglo-Mexican Company, made
at the time on this test run :
" Our intention was to give the old process every possible show.
Great care was taken to keep the precipitates separate, both at the be-
ginning and end of the month. The tons of ore in question were to-
tally leached out. During the month no experiments, or extra < clean
up,' was carrried out. In making the test we allowed the old process
to take out all it could take, /. e. , we ran the vats (by the old process)
as long as sodium sulphide would show the least trace of silver in the
solution. When the old process would not take any more silver out,
the 'extra solution' of the Russell Process was applied, and, as in the
case of the old process, was run as long as sodium sulphide showed
any trace of silver coming out."
The actual "clean ups" from the two processes were as follows:
Extracted by the old leaching process 26,361.42 ozs.
Additional extracted by the Russell Process, 5,088.76 ozs.
Total, .31,450.18 ozs.
Per cent, of total product extracted by old process 83.8
Per cent, of total product extracted by Russell process, 16.2
That is, after the old process had done its utmost work, extract-
ing 26,361.42 ozs., the Russell Process was used on the same charges
of ore and extracted 5,088.76 ounces more.
The total chemicals used per ton for both processes was:
Hyposulphite of Soda 0.0 Ibs. at 8.1 cents 0.00
Blue Stone 3.0 Ibs. at 10.0 cents .... 33.00
Caustic Soda 3.58 Ibs. at 9.1 cents .... 28.60
Sulphur 2.48 Ibs. at 9.3 cents .... 17.40
Total 9.06 $0.79.00
The total additional cost of the Russell Process, or in other
words, the extra expense of producing this 5,088.76 ozs. over the
cost of the old process was as follows:
Chemicals $632.50
Fuel 21.21
Extra help, etc 155.60
Total $809.31
15
At the then price of silver the 5,088.76 ozs. equalled $5,852.07-..
Deducting the above expenses there is left $5,042.76 as the net profit
per month due to the use of the Russell Process.
The second test made by myself on the comparative efficiency of
the two processes was carried out during the month of November,
1890.
In this run the total chemicals used per ton for both processes
were:
Hypo-sulphite 0.35 Ibs.
Blue Stone 6.40 Ibs.
Caustic Soda 2.84 Ibs.
Sulphur 1.70 Ibs.
Total 11.29 Ibs.
The total cost of these chemicals per ton was 95 cents.
Of the total ounces extracted the old process took out 80.29 per-
cent, and the Russell Process the remaining 19.71 per cent. The ad-
ditional ounces silver extracted by the Russell Process over the old
process were 7,653.7, or (with silver at $1.02.5 per oz.), $7,845.04,
making a net profit due to the use of the Russell Process of about
$7^000 per month.
Of the two comparative runs made by my predecessor in charge
of the mill, Mr. F. M. Johnson, the first was made during the first
three months of the use of the Russell Process. The following taftle-
from June to December, 1887, shows the mill extraction by the old'-
leaching process for seven months and the results by the Russell Pro-
cess for two months.
TABLE XV.
MILL RESULTS FOR SEVEN MONTHS, 1887.
Month.
Extraction in Mill by
Old Process.
Extraction in Mill by
Russell Process.
Per Cent.
Per Cent.
June
711
July
660
» J
August
660
Process not in use
September
731
until November.
October
631
November
637
81 2
December
673
822
The following is from the printed report of Mr. F. M. Johnson
on the above mentioned comparative run between the two processes.
The data on the "old process" dates from June i, 1887, up to and.
16
including January 31, 1888. The data on the "Russell Process"
dates from November i (when it was introduced), 1887, up to January
31, 1888.
TABLE A.
OLD LEACHING PROCESS. — ASSAY OFFICE AND MILL RESULTS.
Number
of Months
Run.
Value
per Ton.
Extraction
in the
Assay Office.
Extraction
in Mill.
Extraction in
Mill below
Assay Office.
Total
Leaching Time.
No.
O/s.
Per Cent.
Per Cent.
Per Cent.
Hours.
8
60.67
72.09
67.12
-4.97
92
TABLE B.
RUSSELL PROCESS. — ASSAY OFFICE AND MILL RESULTS.
Number of
Months Run.
Value
per Ton.
Extracted
by Old Pro-
cess in Assay
Office.
Extracted
by Russell
Process in
Assay
Office.
Extracted
by Russell
Process in
Mill.
Difference be-
tween Old Pro-
cess in Assay
Office and Rus-
sell Process in
Mill.
Difference
between Russell
Process in
Assay Office
and Mill.
Total
Leach-
ing
Time.
Ozs.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
Per Cent.
Hours.
3
55.3
69.94
83.62
82.44
12.5
- 1.18
76
TABLE C.
OLD LEACHING PROCESS — CHEMICALS PER TON.
Lime.
Sulphur.
Total Chemicals
Per Ton.
Total Cost
Per Ton.
Ibs.
Ibs.
Ibs.
Dollars
9.7
4.7
14.4
0.52
TABLE D.
RUSSELL PROCESS— CHEMICALS PER TON.
Hypo-Sulphite.
Eluestone.
Caustic Soda.
Sulphur.
Total Chemi-
cals Per Ton.
Total Cost
Per Ton.
Ibs.
Ibs.
Ibs.
Ihs.
Ibs.
$
1.4
9,6
5.5
3.6
20.1
2.20
NOTE i. — By referring to the above tables (A and B) it will be seen that the old process in
the assay office extracts 4.97 more than the old process in mill, and 12.05 per cent, less than the
Russell Process in the mill, which shows a net gain in extraction in favor of the Russell Process of
17.47 per cent.
NOTE -2.. — That the time for treatment is shortened by the Russell Process.
NOTE 3.— That the cost for chemicals in the Russell Process is $1.68 more than in the old
process. (C and D)
NOTE 4. — The net gain in extract-ion of 17.47 percent. (A and B) on 60 ounce ore would be 10.48
ounces, or $10.06 per ton (with silver at 96 cents per oz.) From this take $ i .68 (the extra cost for
chemicals in the Russell Process) and there will be left a profit of $8.38 per ton. If 12,000 tons be
treated in a year the net gain in profits by using the Russell Process would be $100,560.00 per year.
17
The above is the report of Mr. Johnson, dated Feb. 7, 1888.
Being the first three months run the amount of chemicals is much
greater than afterward, and also the cost per ton, as shown by the
following table:
AMOUNT AND COST OF CHEMICALS FOR DIFFERENT PERIODS
BY RUSSELL PROCESS.
Weight of Chemicals
Cost of Chemicals
Period
per Ton of Ore.
per Ton of Ore.
Ibs.
Dollars.
First 3 months run as per
above report.
20.10
2.20
1888
17.18
1.54
1889
12.26
1.10
1890
9.14
0.85
1891
14.48
1.36
1892
13.15
1.38
The following is the report of Mr. Johnson on the second com-
parative run made by him in August, 1889, the report being dated
September 7, 1889:
"THE EFFICIENCY OF THE 'EXTRA SOLUTION' IN RUSSELL'S IMPROVED
PROCESS OF LIXIVIATION AT THE YEDRAS MILL. — REMARKS.
"To determine the actual efficiency of the extra solution of the
Russell Process, on Yedras ores, we precipitated the silver-bearing
solution of simple hypo-sulphite of soda coming from the ore in a
separate set of vats., The silver extracted by the extra solution of
the Russell Process was also precipitated in vats by itself. We aimed
to leach all the silver out of the ore that the simple hypo-sulphite
of soda solution was capable of extracting, and then the extra solu-
tion was added to the same ore to further the extraction.
TABLE NO. 1.
Ozs. Extracted as
Sulphides Without
Use ot Russell
Process.
Ounces Extracted
as Sulphides by the
Russell Process.
Amount extracted during" base metal
leaching (z. e., first wash water). . . .
Amount extracted by simple hypo-
sulphite solution . .
3,576.26
23 678 66
Amount extracted by extra solution
after the simple hyposulphite had
done its utmost work
10 115 20
Totals . . '.
27,254.92
10,115.20
Amount extracted by both methods in sulphides 37,370.12 ounces.
Per cent, of total extraction by simple hypo-sulphite
solution and wash water (old process) 72.93 per cent.
Additional extraction by extra solution (Russell Process) 27.07 per cent.
18
- TABLE INO.[2.
COST OF ADDITIONAL CHEMICALS USED IN RUSSELL PROCESS.
Hyposulphite of Soda 1687 Ibs. @ 7.7 $ 129.90
Blue Stone 8650 Ibs. @ 8.5 = 735.25
Caustic Soda 2292 Ibs. @ 6.2 = 142.10
Sulphur 1528 Ibs.. @ 5.4 - 82.51
Total cost of Chemicals for Russell Process $1,089.76
REMARKS ON TABLES I AND 2.
"The value of the silver which was further extracted by the Rus-
sell Process is $9,407.14. Subtracting the cost of the chemicals,
$1,089.76, from this leaves $8,317.38, which is the net profit due to
the use of the " extra solution" of the Russell Process over and above
the simple hypo-sulphite solution (or old process) expressed in dollars,
for the month of August.
"The extraction by the hypo-sulphite solution (old process) is
probably a little greater than it would have been if the stock solution
(of that process) had not been kept in thorough condition due to the
use of the bluestone (of the Russell Process) which was used in the
extra solution."
The net savings at Yedras due to the use of the Russell Process
over the old leaching process may be summed up as follows. (All the
old tailings have already been treated. )
Net Saving
per Year.
On tailings at rate of 1,500 tons per month $121,500.00
On ore as per 1st comparative mill run 100,560.00
On ore as per 2d comparative mill run 99,808.56
On ore as per 3d comparative mill run 60,513.12
On ore as per 4th comparative mill run 84,000.00
The amount of ore treated at Yedras varies from 1000 to 1200
tons per month.
Omitting the profits arising from the treatment of the old tail-
ings, the net profits per year, due to the use of the Russell Process,
over the old leaching process on ore, at Yedras, have averaged
$86,000.00 per year, or $6.00 to $7.00 per ton. The difference in
extraction of silver in the mill for the five years has averaged 16.5
per cent, of the value of the ore in tavor of the Russell Process and in
the treatment of old tailings 56.6 per cent, of their value, over the ex-
traction by the old leaching process.
PUBLISHED BY
RUSSELL PROCESS Co.,
PARK CITY, UTAH,
U. S. A.
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11