State has all tended to prove the fact that the longitudinal extension of these
veins is generally very limited, and that the metalliferous portion is always
considerably less in length than that of the quartz itself. This remark applies
equally to the niimerous copper-bearing veins which have been recently dis-
covered, some few of which are valuable, w^iile their " extensions" are almost
invariably worthless.

The outcrop of these mines is a very marked and noticeable feature in the
landscape. They form part of what is known as the great quartz vein of
California; which can be traced by its prominent outcrops about seventy miles
. north from Mariposa county, in nearly a straight line, continuing through Tuo-
lumne, Calaveras, and Amador. It cannot be proved positively that this is one
and the same vein, on account of the many breaks and interruptions which oc-
cur in its course, but certain it is that throughout this distance it preserves its
distinguishing characteristics, both geologically and lithologically in a most re-
markable manner. It furnishes some of the best gold mines in California, which
are conspicuous for the great regularity of their yield, and the depth which they
have attained. Along its course and in its immediate vicinity are some of the
most extensive placers, which, although now for the most part exhausted, have
in times gone by produced so largely that while worked they were regarded as
being among the richest deposits in California. It must not be presumed that



WEST OF THE ROCKY MOUNTAINS. 43

tliis great vein is gold-bearing throughout its whole course, or that even a nota-
ble proportion of the quartz which rises .into peaks and mountains between
Mariposa and Amador counties is auriferous. It is only here and there at wide
intervals that mines can be found which can be worked with a profit. Mr. Re-
mond enumerates twenty as being found in the region which he examined,
many of which are undoubtedly still experimental enterprises, and may yet be
abandoned.

The yield of the quartz from the mines situated on this great vein is gene-
rally low and somewhat under the average of the Calif >rnia quartz, but the gold-
bearing portion of the vein is always of greater width than elsewhere, and the
quartz can be mined at less expense than in those veins which are narrow and
encased in the harder varieties of metamorphic rock.

The gross production of the Pine Tree and Josephine mines has been, un-
doubtedly, very large, though it is utterly impossible to state, with any degree
of approximation, what it was previous to 1860. Since June, I860, the quartz
from these two mines lias been treated at the Benton mills, on the Merced river,
and from the time they commenced running until March of the following year the
gross yield was about $ 1 55,000. The quartz near the surface paid much better than
that which has been worked at the Benton mills. Not only does it appear to have
been absolutely somewhat richer, but, owing to the decomposition of the sulphurets
which existed in the Josephine, rock in large proportions, it lent itself to a more
ready amalgamation. Also, as it was worked in a ten-stamp mill, of compara-
tively email capacity to the Benton mills, which have sixty-four stamps, the
miiiipg superintendent was able to select his quartz with much more ease, and
send only the better quality to the mill.. The quartz from these mines in 1860
averaged about $9 per ton, and gradually grew poorer as the richer portions of
the vein were, worked out. The cost of mining, milling, and transportation
amounted to about $5 50 per ton. This amount of $9 per ton is what was
actually obtained in the mill, although there seems every reason to suppose that
much more gold than that was really contained in the quartz, and, in fact, more
has been lost and allowed to run to waste than has been secured. On several
occasions attempts have been made to ascertain what proportion was lost and
what saved, and it would appear that in the case of this quartz not more than
forty per cent, of the gold actually contained in it was saved in the process of
milling. The cause of this appears to be almost entirely owing to the very fine
state of subdivision in which it exists, for very few specimens show any gold
visible to the naked eye. Experiments are now being conducted on the Mari-
posa estate which seem to confirm this view, for on treating the quartz which
formerly only returned $10 or $15 per ton, by more careful methods of amal-
gamation, it has been made to yield between $40 and $50. It is not to be presumed
from this statement that all the vein consists of quartz of this richness; but
there is a large amount which will certainly yield, by improved processes of
treatment, much more than it has ever been possible to obtain from it by the ordi-
nary rough method.

3. NORTHERN MINING DISTRICTS.

As we proceed northward from Mariposa county, the next most interesting
mine we meet with, situated upon the "Great Vein," is the App, near James-
town, a few miles from Soriora, the county seat of Tuolumne. This mine has
been worked almost uninterruptedly for nine years. The average yield of the
quartz has been at the rate of $ 15 52 per ton, and the expenses of mining and
milling have not exceeded $7 47 per ton. The yearly yield during this period
has varied from $13 26 to $19 47 per ton, and the lowest monthly return was
at the rate of $12 15; but even then a considerable profit was realized over and
above the expenses. The lower works of this mine now present as fine an



44 RESOURCES OF STATES AND TERRITORIES

appearance as they have ever done, and when we regard the length of time
during which it has been successfully worked, the great regularity of the yield
of the quartz, and the various characters of permanency which the vein pre-
serves, we have strong reasons for arguing that it will prove as persistent in
depth as almost any other mine in California. In its external characters the
quartz from this mine resembles very much that taken from the Pine Tree mine.
The greater proportion, however, of the gold which it contains is in such a fine
state of subdivision that it rarely happens that any of it is visible to the naked
eye, and undoubtedly a great deal escapes amalgamation and is lost. By more
thorough treatment in the mill, there seems every reason to suppose that the
yield could be largely increased. Experiments have been lately instituted and
they would appear to confirm this statement most fully showing that by more
careful amalgamation the quartz, in some instances, can be made to yield from
50 per cent, to 140 per cent, more gold without a corresponding increase
in the expense of treatment. Attention is now being given to this important
matter throughout California, and experiments are being made in several mills
to ascertain to what extent the gold is lost in the process of treatment, and how
far it will be economical to erect new machinery for the purpose of saving it.
The gold which is contained in the auriferous quartz exists either in such minute
particles as to be quite invisible, and not distinguishable from the quartz itself,
else in pieces of larger size, which can be readily seen and separated by pul-
verization and washing, or by the simplest forms of amalgamation, or else com-
bined, probably mechanically, with the sulphurets of iron, zinc, and* lead. In
the first and last cases it is amalgamated with great difficulty, and it rarely hap-
pens in any of the mills of California that more than a small proportion of the
gold is saved. When, however, it is in the state of free gold, as in the second
instance, a notable proportion is secured by the most simple methods, and it is
not likely that additional machinery would increase the yield sufficiently to pay
for its cost. In the quartz from a vein upon the Mariposa estate, known as the
"Mariposa," there are but comparatively few sulphurets present, and from
repeated assays made from the tailings from the mill it would appear that
almost 90 per cent, of the gold contained in the quartz was secured, while at
the Benton mills, working upon Pine Tree quartz, only between 30 or 40
per cent, was saved. In this connection it may not be uninteresting to show
what has been done in this direction in other countries, and how far it is possi-
ble to increase the yield of very refractory gold-bearing ores by careful working
and skilful treatment. One of the oldest, and, when we consider the rebellious
character of the ores, one of the most successful gold mines in the world is
that of St. John Del Key, in Brazil. The company now in possession has
been in operation thirty-six years, and though, like nearly every other mining
compan}', it has had its full share of ups and downs, the general results
obtained have been most satisfactory to the shareholders, and it was only
through the most careful, economical management of both the mining and
milling departments that this end has been arrived at. There is no quartz
mine in California which has ores in any quantity of so complex a nature or
of so difficult a treatment as those of St. John Del Key. They consist prin-
cipally of specular iron mixed with sulphuret of iron, magnetic pyrites and
quartz. The auriferous mass at this mine is about forty-four feet in width, and,
like most of the gold-bearing veins of California, dips with the rocks in the
vicinity at an angle of about 45 to the southeast. *

The vertical depth upon which this deposit has been worked is now 1,068
feet. Before the present company came into possession it had been worked
for a hundred years, and was considered exhausted.

A recent number of the London Mining Journal gives some interesting details

* Whitney's Metallic Wealth of tlie United States, p 1J2.



WEST OF THE ROCKY MOUNTAINS. 45

with regard to the present financial position of this company, and as these favor-
able results were only obtained by economy in the management and skilful
treatment of the ores, which yield far less than the average of California quartz,
I will give a condensed statement of their operations for the last thirty-six years.
The effective capital of the company is < 129,000, divided into 1,100 shares, and
there has been paid in dividends d756,245, or ,68 15*. per share. There is on
hand a reserve fund of c41,506, and the value of the property of the mine is
estimated at c209,743, showing a total profit during the thirty-six years' work-
ing of < 1,007, 494. The produce of the mine during this period has been
,2,902,480, and the expenses cl, 894,986, or 653 per cent, of the gross re-
ceipts. The average yield of the ore raised and treated has been at the rate of
4 oitavas per ton of 2,240 pounds. This is equivalent to about $S 50, or
$7 59 reduced to the usual Califorinia ton of 2,000 pounds. The yield for the
last three years has been as follows : '

1863, 5,787 oitavas per ton, at $1 89 per oitava, $10 94; 1864, 4,827 oitavas
per ton, at $1 89 per oitava, $9 12 ; 1865, 5,479 oitavas per ton, at $1 89 per
ton, $10 36.

During this period of the total amount of gold contained in the ore there was
extracted the following percentage :

1863, 72.35 per cent. ; 1864, 75.52 per cent. ; 1865, 77,95 per cent.

The various processes heretofore employed in California for amalgamating
gold have been of the simplest possible description, and, although probably in a
majority of instances where the gold was clean, free and uncombined with the
sulphurets of iron, lead, copper, and zinc with which it is so frequently associ-
ated, these methods worked well, and the erection of expensive machinery,
which would necessitate slower working 1 , would not be warranted by the facts
of the case. Yet it has often happened, particularly in those mines situated
upon the course of the " Great Vein," that quartz which has been known to con-
tain gold in paying quantities has not yielded when treated in the mill more
than sufficient to pay expenses, and sometimes has been worked at a loss. This
would appear to be chiefly owing to the inefficiency of the apparatus employed
to collect and save the gold, which may have been in a very fine state of sub-
division, or coated with a thin film of oxide of iron arising from the decomposi-
tion of pyrites, which prevents the mercury from adhering to it without the use
of more vigorous mechanical or chemical means than are usually employed.

At and near Sutter creek, in Amador county, there are several very excel-
lent mines situated upon the course of the " Great Vein." The most noted of
these is that belonging to Messrs. Hay ward & Co., and known as the Eureka.
This mine has been worked for about eleven years, and has produced probably nearly
as much gold as any other in California. The quartz has never averaged very
high, and the principal production has been from ores of a low grade, not yield-
ing probably more than from $10 to $15 per ton. The mine is situated at the
junction of the slates and greenstone, the hanging or eastern wall of the vein
being of the latter material, hard and compact, while the foot-wall is of a dark
and soft argillaceous slate. The depth of the lowest workings is now 1,213 feet
on the incline of the vein, which makes this shaft the deepest in the United
States. The length of the underground workings is about 600 feet, and at the
north and south extremities the vein thins out rapidly. The richest portion
of this vein appeared to be at a depth of between 1,000 and 1,100 feet, where
the quartz is said to have yielded nearly $30 a t-n. The great depth attained
in this mine shows conclusively that we cannot draw any general conclusions
with regard to exhaustion of quartz veins at an inconsiderable depth. It is true
that in nearly every quartz mine of California the outcrop has been found to be
much richer than the main body of the vein at even a short distance from the
surface, but it must be borne in mind that many of the veins, and in fact a
majority of them, contained gold associated with various mineral sulphurets,



IP
46 RESOURCES OF STATES AND TERRITORIES

which were decomposed and the gold infiltrated down for some distance below
the suiface of the ground, causing the upper portion to appear abnormally rich.
Thus the gold contained in the first few feet of the vein may be the result of
the degradation of many tons of quartz ajpd the decomposition of a large quan-
tity of sulphurets. It is only by taking the results afforded by the treatment
of quartz during a series of months that anything like a correct average of the
value of the ore can be obtained, and although this Eureka mine has probably
yielded as regularly as any other prominent mine in California, it has been sub-
ject to great irregularities, and frequently the quartz has barely paid expenses.
The popular idea that mineral -bearing veins grow richer as they are worked
upon in depth, is a fallacy, and has no truth either in theory or fact ; nor can
we say that true veins, as distinct from veins of segregation and mineral deposits,
grow poorer as we proceed downwards. I do not suppose there is a metalli-
ferous vein in the world that is equally rich for any considerable distance, either
lengthwise or up and down, and the valuable portion is almost always very
limitel in extent compared with the main body of the vein. Some of the silver
veins of Mexico, which have produced such enormous sums, have been traced
for miles, and on their course have furnished many valuable mines, but by far
the greater proportion of the vein has been barren and unproductive. The Oom-
stock vein of Nevada, which has already produced upwards of $60,000,000
worth of bullion, has been productive only over about one-seventh of its explored
length.

These remarks apply with great force to the gold quartz veins of this coast.
The ore exists iii bunches or else in shoots or chimneys which cut the axis of
the vein at every conceivable angle between the horizontal and the vertical, and
these are always less than the length of the vein itself and sometimes than its
width also.

It frequently happens, that these ore-shoots have distinct terminal lines, and
in these cases the experienced miner is enabled to select his ore and avoid ex-
tracting that which he knows is too poor to pay. On other occasions, however,
it would appear that the gold is distributed without any regularity and appa-
rently in the most capricious manner. When we consider the richness of the
veins, the length of time that some of the mines have been worked, and the
amount of gold annually produced, the most important quartz mining region of
California is without any doubt that of Grass valley, in Nevada county. Here
mines have been worked uninterruptedly since 1851. It is true there have been
periods when the interest jvas more than usually depressed and several of the
mines, which are now regarded as being among the best, were thought to be ex-
hausted, and abandoned for the time being, but in many instances when work
was resumed new bodies of gold-bearing quartz were opened up which proved
rich and valuable. The veins in this district, and particularly those which have
been the most productive, are noted for their narrowness as well as for the rich-
ness of the quartz. They are incased in a hard metamorphic rock, and the ex-
penses of mining are, as a general thing, higher here than anywhere else in
California, amounting, as they do in some instances, to from $20 to $26 per ton.
Within the last fourteen years the total production from the quartz mines of the
Grass Valley district has not been far from $23,000,000. The most prolific
vein has been that situated upon Massachusetts and Gold Hill, which alone has
produced more than $7,000,000 worth of gold during this time from a lode which
will only average a foot or fourteen inches in width.

The " Eureka" is another prominent and leading mine in this vicinity. One
great feature of interest connected with it is the gradual improvement of the
quartz as greater depth has been attained upon the vein, which varies in width
from three to four feet. This mine was first worked in 1854, and more or less
ever since that period. About one year ago the property changed hands, and
since that time the yield of the mine has been greater than at any previous



WEST OF THE EOCKY MOUNTAINS. 47

time. When this vein was. first worked and down to a depth of about thirty-
five feet from the surface, the yield of the quartz was from $6 to $12 per
ton, which but little more than paid expenses. Below this level the value of
the quartz rapidly increased from 814 to $21, and at the one hundred foot
level the quartz paid at the rate of $28 ; at the two hundred foot level the
average was about $37, and now, between the second, and third levels or three
hundred feet from the surface the .average yield has been during the last four
months at the rate of over $60 per ton. The quartz contains from two to
three per cent, of sulplmrcts of iron, which are said to assay generally about
$300 per ton,- and are regarded as being amang the richest in Grass valley.
These sul,.hun.-rrf are-worked by parties in the neighborhood, who charge $50
per ton and n:;uni whatever gold id extracted to the proprietors pf the mine.
During the f'nur months which preceded the first of October the mine produced
42,227 x- tons of quartz, which yielded $255,072 55. and the expenses of mining
and milling were $67,320 83, leaving as profit $187,751 72. The average
yield of the quartz during the period Avas at the rate of $60 33 per ton. Dur-
ing the whole year the amount of quartz worked was 11.375JJ tons, which pro-
duced $526,431 41, at an expense of $168,389 23, leaving as profit for the whole
year $368,042 IS The average yield per ton was $47 15, and the average cost
of mining and milling was $13 75, leaving a profit of $33 40 per ton.

4. MINING IN THE SIERRAS; MILLS, EXPENSES, &c.

In thus dismissing the Grass Valley district with only a brief description of
two of its leading mines, I do not intend to detract at all from its past, present,
or future importance, for there is no region in California, or probably upon the
Pacific coast, where, by a careful study of the numerous veins in this neigh-
borhood, so much information could be obtained which would throw light upon
the vexed questions relating to gold mining and the metallurgical treatment o
the quartz.

As we proceed north from Nevada county, the next most important quartz
mining district is in the mountainous region round about Downieville, the county
seat of Sierra. The placer mines in this vicinity have been exceedingly rich,
and Fin-passed only by those in Nevada county in extent and permanence.
Quartz mining, however, has received but comparatively little attention until
"within the last few years, probably owing to the rugged nature of the country
and the severity of the climate during the winter months.

The most noted mine in this county, as well as Uie one which has produced
most largely, is that known as the Sierra Buttes. This mine is about fourteen
miles from Downieville, at an elevation of probably not less than 7,000 feet
above the sea. The vein is enclosed in a hard metamorphic slate, and varies
in width from six to thirty feet. In the process of working, the whole thick-
ness of the vein is not removed, and the richer portions, which lie next the
fool-wall, are sent to the mill. The average width of this more productive
streak is about twelve feet. The. depth upon which this vein has been worked
is not far from 750 feet, and the quartz in the lower portion of the mine is said
to pay as well as that taken from the upper works. Quartz from- near the sur-
face of this vein was worked in arrastras as early as 1851, but the first mill was
erected in 1853. The present owners have been in possession of the property
since 1857, and the yield of the mine has been, during the last nine years, ap-
proximately as follows :

Gross yield. Expenses. Profits.

1857 $51,000 $15,000 $36,000

1858 55,000 15,000 40,000

1859 88 000 20,000 68,000



48 EESOURCES OF STATES AND TERRITORIES



1880


Gross yield.
$120 000


Expenses.
$37 000


Profits.
$83 000


1861


198 000


4 000


150 000


1862


166,000


54,000


112,000


1863


156,000


57,000


99,000


1864


90 000


75 000


15 000


1865.. ..


196 000


64 000


13-\000











1,120,000 385,000 735,000



The yield of the quartz varies generally from $14 to $17 per ton, and the
cause of the falling off'in the gross product during 1863-'64 was the great scarcity
of water, which necessitated the erection of a flume at an expense of $40,000.

The principal expenses attending the working of auriferous quartz are the
cost of extracting the quartz from the mine and its subsequent treatment in the
mill. With regard to the first no general data can be given, for the amount
paid for mining varies from $1 50 to $26 per ton. It is dependent upon the
hardness of the quartz ; the hardness of the country rock in which the vein is
encased ; the relation which the auriferous portion of the vein bears to that
which is barren ; the depth of the workings, and finally the amount of water in
the mine, and whether it has been drained by adits or pumping. As a general
rule, however, it may be assumed that in the case of large veins, or those which
exceed five or six feet in width, that the cost of extraction will be from $1 50
to $6, arid that the total cost of mining and milling will not be more than $7
or $8 per ton under any circumstances.

With regard to the milling expense, however, we have accurate data to fol-
low, and these are not much affected by change of locality.

The mills are generally situated in close proximity to the mines, for the differ-
ence between the cost of running a steam and a water mill is almost always less
than the cost of hauling the quartz for any distance by teams. The mills are
of nearly ail sizes and capacity, and vary from those which have only two or
three stamps to those which have forty-eight. The weight of these stamps is
from 400 Ibs. to 1,000 Ibs., and they are run at a velocity varying from 50 blows
to 80 blows per minute and fall from 10 to 14 inches. The favorite weight
would appear to be about 650 Ibs., with a fall of 12 inches and a velocity of
from 60 to 70 blows per minute. It is generally assumed that a ten-stamp mill,
with stamp of 550 Ibs., falling^! 2 inches and striking 60 blows a minute, will crush
12 J tons of ordinary quartz in the twenty-four hours.

The mills which are moved by water power alone are situated either on the