The advantages and necessity of a deep drain tunnel for the great Comstock ledge

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BANCROFT
LIBRARY

THE LIBRARY

OF

THE UNIVERSITY

OF CALIFORNIA

S^^ — =^95

THE

ADVANTAGES AND NECESSITY

OF A

DEEP DRAIN TUNNEL

i'UK llll*,

aHE^T

COMSTOCK LEDGE,

BY A. SUTRO.

.^AiN l^UA.NCibUU, i^ElJKUAKY, 1^05.

^^ ^ ^

i

THE

ADVANTAGES AND NECESSITY

OF A

DEEP DRim TUNNEL,

FOR THE

GRE^T

COMSTOCK LEDGE,

BY Ar. SUTKO.

//

SAN FKANCISCO, FEBRUARY, 1865.

F ^ 4-t>

CONTENTS.

Proposition to Mining Companies

Introductory Remarks

The Great Obstacle in Mining — and its Remedy

Necessity of a Grand Drain Tunnel

The Tunnell at Gittelde, Brunswick

Cost of Pumping in England

Cost of Pumping in Nevada

Evils of Pumping

Advantages of a Drain Tunnel .

The Value of the Mines will be Largely Increased

Great Depth which Can be Attained Hereafter

Report of Baron Richthofen

Opinion of Mining Superintendents and Others

BANCROFT
LIBRARY

TO

MINING COMPANIES.

Tlie undersinrned convinced of the necessity of constructing a
deep drain Tunnel to the Comstock ledge, and desirous of seeing
this great work speedily carried out, begs leave to lay the fol-
lowing proposition before the different Companies of the Com-
stock ledge, and is of the opinion that its acceptance will insure
the carrying out of this important enterprise.

The proposition would be about as follows :
i.v,.uo trcfc ihutiexs ui juct, anu no wonaer mat lau «iiierprising

American people, particularly the adventurous portion of Cali-
fornians, became excited over visions of great wealth and pic-
tures of the immense amounts of precious metals produced hy
the Spanish-American mines for the last three centuries. The
natural consequence was, a great influx of people to these
newly discovered regions, and a vigorous prosecution of work,
which shortly established the fact that the great Comstock ledge
not only contains ores of great value, but that the same ex-
tends for miles in length, and r>rnmigfirLtruJL.^--..^t^- ^

The Companies will by these means secure to the Tunnel
Company a small interest on the capital Invested. They have to
pay out nothing until they derive benefit from the drainage of their
mines, and then pay nothing, should they have no ore. Should they
have ore, the amount to be paid to the Tunnel Company is so
small compared to the advantages they will derive, that they will
save the amount to be paid per ton, alone in the advantages they
would enjoy in extracting the ore from the mines.

If the following pages are studied carefully, it will be found
that the cost of erecting the necessary pumping machinery, and
the cost of maintaining the steam engines, is so immense, that the
advantages offered by the tunnel company, must strike the mining
companies to be of vital importance to their own interests.

The Tunnel Company will have to take all the risk as to the
future yield of these mines. They have to embark in an under-
taking which involves the outlay of millions for a number of
years, before any benefit can be derived from it, and after they
complete the work, they only ask a low interest on the capital
invested, from those parties who can afford to pay, by being
enabled, through their agency, to extract ores from their veins.

It may as well be stated here, that some parties are fearful of
getting into litigation, by having an outside company construct
this tunnel, and striking the Comstock at this great depth ; on
this point we would state, that the objects of this Tunnel Com-
Danv beins for the purpose of draining: these mines, they would
The Tunnell at Gittelde, Brunswick

Cost of Pumping in England

Cost of Pumping in Nevada

Evils of Pumping

Advantages of a Drain Tunnel

The Value of the Mines will be Largely Increased

Great Depth which Can be Attained Hereafter

"^j ' "J '^ir-;Ramn Richthofen

people at large of the Pacific states, oy st^cuiiu^ mo pciuiaucut
working of the Comstock ledge, which in our opinion would be
accomplished by constructing a deep drain tunnel, we most
cheerfully endorse Mr. Sutro's proposition to the Companies,
and shall do all in our power to assist him in carrying out his
project.

San Francisco ^ March 1, 1865.

JOHN PARROTT,
LOUIS McLANE,
W. C. RALSTON.

THE COMSTOCK imES.

INTRODUCTORY REMARKS.
Over five years have now elapsed since the news of rich silver
mines, having been discovered on the eastern slope of the Sierra
Nevada mountains, first attracted the attention of the people of
California.

At first, {he reports of fabulous wealth contained in these
mines, were received with some doubt and incredulity, but soon
it became patent to the miijds of thinking men, ihat these re-
ports were matters of fact, and no wonder that the enterprising
American people, particularly the adventurous portion of Cali-
fornians, became excited over visions of great wealth and pic-
tures of the immense amounts of precious metals produced by
the Spanish-American mines for the last three centuries. The
natural consequence was, a great influx of people to these
newly discovered regions, and a vigorous prosecution of work,
which shortly established the fact that the great Comstock ledge
not only contains ores of great value, but that the same ex-
tends for miles in length, and promised to be of a permanent
character. This conclusion has proven correct by experience,
and we now have a range of mines which, in all likelihood, will
be worked long after our present generation has passed away.

But raining for silver was a new thing for our people. "We
had no experience at it ; hardly had any idea about the opening
and working of such mines, and not the slightest knowledge
about the reduction of silver ores. A few persons amongst us^
who had acquired experience at foreign silver mines, readily

6

gave their advice, and work fairly comraeuced. But soon it was
found that the methods employed in older countries for reducing
ores, would not apply here, for various reasons, such as the cli-
mate, expense of labor, fuel, etc., etc. ; and it became a matter of
serious doubt, whether these mines could be profitably worked on
account of these obstacles. To ship the ores to other countries,
could only apply to rich ores, the supply of which w^as limited.
To smelt the same was out of question, on account of scarcity
of fuel. To roast, by the Freyberg method, was expensive,
and the bulk of the ores could not stand the expense. To work
them by patio was difficult on account of cold weather the largest
portion of the year. These were the only methods known in the
world — none of them applicable to our mines. What was to be
done ? The inventive genius of the American people soon found
a remedy ; a trial was made to work these ores in iron pans, and
it was a success. We must admit that considerable loss is occa-
sioned in this style of working, but without it our mines could
not be worked to any advantage, and it is now generally admit-
ted, that this is the only and most profitable method to be em-
ployed for average ores, which abound in these mines. From the
day of introducing these pans, which, it may be stated, have since
been vastly improved, the country commenced to flourish. Cities
were built, roads constructed, large reduction works erected, in
short, from a state of wilderness, in a few years, a flourishing
country sprang up, many millions of bullion are produced an-
nually, and many thousands of people find employment.

But not only here do we see the eflccts of this new wealth.
California, and particularly San Francisco, are directly benefited
by it. Every branch of commerce derives benefit from our
mines, we being entirely dependent on our sister State for
supplies.

But will this prosperous state continue ? And how long ?
No one doubts the permanency of these mines. One particular
claim may run out of its chimney of good ore ; one may have
very rich ore at present, next year its neighbor will have it.

Thig is the nature of silver mines ; they contain bunches, or
chimneys of ore, sometimes producing many millions, but these
chimneys are distributed throughout the length of the whole
range, horizontally and perpendicularly. For this reason, any
particular locality on a mining range like the Comstock, may
prove of great value ; but the expense of exploration, and the
difficulties to be encountered in prospecting, make many shrink
from the undertaking, and give up all hopes of realizing their
wishes.

As long as mining was carried on comparatively near the sur-
face, everything went on well enough ; a small engine of 10, 20,
or thirty horse power was erected, at a trifling cost, a shaft sunk.
a few galleries opened, plenty of ore extracted, sent to the mills,
and silver bars produced, as if by magic. But we are a go ahead
people. What takes ten years to accomplish in Mexico or South
America, we do in one year ; and, as a natural consequence,
after five years' labor, we have attained an average depth in our
mines of four hundred feet.

And what questions do present themselves to the thinking
mind, now ? How long will it take to attain a depth of one
thousand, fifteen hundred or two thousand feet ? What obstacles
are encountered, at present, and what will be the obstacles to be
met at this greater depth ? These are serious questions to he con-
sidered by the owners of the Comstock ledge, and the people at large
of this State, who are entirely dependent on the prosperity of these
mines.

And these questions, more particularly we intend to answer,
with a view of providing means to avoid a calamity which
would befall us in a very short number of years, if we do not at
once take the matter in hand, and provide timely measures, the
nature of which we intend iu this paper further to explain :

THE GREAT OBSTACLE IN MINING— AND ITS

REMEDY.

The great obtade to he enconntered in mines, is vxUer ; this is the
fatal agent J which makes it only a question of time, when a mine
will have to be abandoned, no matter how rich, on account of
the obtacles its removal presents.

In every instance, the time must com£ when the cost of drainage
will be greater than the produce of the mine ; this may take five,
ten, twenty or fifty years, according to the value of the ores and
the quantity of the water to be encountered.

Now let us examine into our particular instance ; as stated
above, the average depth of our mines is about 400 feet ; hardly
any water of consequence has been encountered heretofore ; but
within the last twelve months, it has become a serious obstacle.
The Ophir mine, at present, is flooded in such a manner that
their small engine and pump cannot free the mine from water.
A new and more powerful engine and pumps are being erected,
which, no doubt, will accomplish this desirable result. But how
long will this machinery answer the purpose ? Competent engi-
neers will tell you, that the power of your machinery will have
to be increased by the square, as the depth and quantity of water
increases, and that in the course of not many years, at the rate
we are progressing, our mines will be worked at a depth where
the cost of pumping will nearly, or entirely, consume the net
profits derived from them, basing our calculations on the yield
et the present time.

These are serious reflections and forbode a gloomy future for our
young State ; but we will show conclusively, that a work, entirely feasi-
ble, practicable, and though of gigantic proportions, can be con-
structed without any difficulty, provided all parties inter-
ested will cooperate, which will not only remove all anxiety for
our future welfare, but which will place our mines into such a
position that they may be worked profit-ably, economically and exten-
sively for a centvry to come.

NECESSITY OF A GRAND DRAIN TUNNEL.

This work is the construction of a Grand Drain Tunnel, com-
mencing at a point in the foot hills of Carson River Yalley. a
little less than four miles or about 20,000 feet from the Corastock
ledge, and which Tunnel would strike the Comstock ledge at a
depth of 1800 feet below the surface.

Works of this kind have by experience been found to be a matter
of necessity, and have been carried out wherever nature favored
such an undertaking.

Now let us see what has been done in other parts of the world
in order to obtain drainage in mines. A late writer, speaking of
the completion of the great dr-iin tunnel in the Harz mountains
in Germany, says :

" Already in the beginning of the sixteenth century, the me-
chanical appliances for raising water were found to be insufficient,
and it was found to be a matter of necessity to construct drain
tunnels. The first one, called the Seventy-eight feet Tunnel, was
completed in 1525, the Frankensharner Tunnel in 1548, the One
Hundred and Fourteen feet Tunnel in 1551 and the Raven Tunnel
in 1573. By means of these Tunnels, which were connected with
all parts of the mines, it was found possible to work them for
about 200 years ; but towards the end of last century it became
impossible to master the water, and in consequence it was con-
cluded, in the year 1771, to run a still deeper tunnel ; work was
commenced in 1777 and the same was completed in 1799. It was
called the Deep George Tunnel, and its length, including cross
cuts, is 57,000 feet ; it drains the mines under Clausthal to a
depth of 900 feet.

This relieved the mines from water for a while, but as work
progressed and greater depth was attained, the flow of water
increased so rapidly that the grandest pump works were found
to be insufficient.

The topographical features of the country are fcuch that no
2

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deeper drainage could be obtained, except at an apparently im-
practicable distance, and in consequence the danger was imminent,
that these mines, which had supported thou-ands of persons for
centuries, would shortly have to be abandoned entirely.

THE TUNNEL AT GITTELDE, BRUNSWICK.
In the year 1850, C. Borchers, a celebrated mining engineer^
first conceived the plan to commence a Tunnel in the Dukedom
of Brunswick, at a place called Gittelde, which would give a
deeper drainage, of about 300 feet, below the deep George
Tunnel, or a depth under the cliurch of Clausthal, of
about 1200 feet. Surveys were made and the distance found to
be 72,000 feet or about fourteen miles, and the time estimated to
complete it, was twenty-two years. On the 2l8t July, 1851 work
on this great tunnel called the " Ernst August Tunnel" was com-
menced, and on the 22d of June 1864, the last connection was
made ; It therefore only took twelve years and eleven months to
complete this, the greatest of all mining works."

It may as well be stated here, that the mines of the Harz pro-
duce about $500,000 in precious metals per annum, an amount
taken from the Comstock every fortnight. Now, if they found
it a matter of nercessity. and economy to run a tunnel fourteen
miles long in the Harz mountains, in order to obtain an addi.
tional drainage of 800 feet, in a country where fuel is cheap, how
evident must it appear, that a tunnel into the Comstock, less than
four miles in length, which will give drainage to a depth of 1800
feet, and which would secure the future working of the richest
mine in the world, would not only prove of great benefit, but
ought to be commenced and completed without delay.

At the place selected for a starting |K)int, the hills form a semi-
circle, which brings the distance from the valley within four miles
of the Comstock. The formation of the hills on the selected
tunnel route, is such that deep ravines exist, from which shafts
can be sunk at a comparatively small depth. The formation of

11

rock has been examined by Baron Richthofen, a well known
Prussian geologist, who was formerly engaged at the geological
survey of Austria, and lately attached as geologist to a Prussian
naval expedition to eastern Asia, and who is a European authority
in geological matters. This report is annexed, and will be an
interestitg document in mining circles.

It is proposed to sink four shafts on the tunnel route, which
will be about 500, 800, 1,100 and 1,£00 feet deep to the level of
the tunnel, on which powerful steam engines and pumps will have
to be erected, and from each, two drifts will be run — one towards
the mouth of the tunnel, the other towards the Comstock ledge.
This would give nine points to work from, and calculating the
distance, including shafts, at about 24,000 feet, the distance to be
sunk and run, would give an average of 2,666 feet from each
point.

Work of this kind can be pushed on with great rapidity, pro-
vided, short and double shifts of men are employed ; the tunnel
will be wide enough to allow three men to work abreast, and it
is proposed to employ double that number, so that the moment
the men at work with their picks get tired, the other three step
in their places, and in this manner change off every fifteen or
twenty minutes ; the whole shift to be changed every six or eight
hours. A foreman would be employed with each gang, whose
duty it would be to see that work is carried on without any
interruption, and to discharge all hands who do not perform their
task properly. In this manner work can be pushed with consid
erable speed, and it is the opinion of competent mining engi
neers, that at least an average of three feet per day can be made
It would therefore require 888 .days to do the whole work
Allowing en extra year to sink partly the deepest of the pro
posed shafts, the tunnel can be finished in 3. J years. The shafts
will be located in such a manner that the deeper ones will come
nearer together, in order to accomplish a connection at as nearly
the same time as possible ; with that view, a working survey is

being made now, which will require about one month to com-
plete. The proposed size of the tunnel will be about 12 feet
wide, by 10 in hight, so as to allow of a good sized rail road
track,— one to run cars in. the other to run them out.

Wherever hard rock is encountered, drilling machinery will
be employed, which is at the present time used quite successfully
in Europe, and particularly at Mount Ceni?, in the Alps. This
drilling machinery is propelled by condensed air, which being
discharged at every revolution, replenishes the air in the tunnel.

The above facts will at once explain the feasibility of the en-
terprise, and in order to more fully understand the difficulties to
be encountered in pumping and the advantages to be derived
from a drain tunnel, we will more carefully examine into the
merits of each.

COST OF PUMPING IN ENGLAND.

In order that we may get a correct idea of the cost of pumping
from a great depth, and the machinery required to do so, we will
take the statistics of a celebrated mine in Europe, the "Consoli-
dated United Copper Mines," of Cornwall :

They employ nine steam engines ; three of 90 inch cylinder ;
three of 85 ; one of 80 ; and two of 65 ; and a water wheel 48
feet in diamater, all employed in pumping ; the water discharged
per minute is from 2,000 to 3,000 gallons. The water is raised
at an average of 170 fathoms. The average cost for drainage in
ten^ears, has been, per year, £12,700 sterling.

The stream of water, which would be encountered at a depth
of 1,800 feet, draining the Comstock ledge from the Siena Ne-
vada Mine to the Uncle Sam, has been variously estimated at
8, 4, 5, and as high as 10 square feet, and the rapidity with
which it would flow out of the tunnel, at from 5 to 6 miles per
hour. Now let us take the lowest figures 3 square feet, and the
stream to flow 6 miles per hour ; that is to say, the stream would

13

fill a trough or canal 2 feet wide, and li feet high, and the
water would flow 5 miles per hour. We would then get the
following figures : 5 miles contain 26,300 feet ; each foot in
length would give 3 cubic feet or 78,900 cubic feet of water per
hour. This amount reduced to minutes gives 1,315 cubic feet of
water per minute, or 8,195 imperial gallons. The cost of
draining the "C. U. Copper Mines," of Cornwall, per annum,
is $63,500, at a depth of 1,020 feet; at 1,450 feet, (allowing
for tunnels in existence now,) the cost would be at least one-half
more, or $95,250. Now the quantity of water to be raised here,
according to the above estimate, is 3.28 times as much, which
would give an annual cost of performing this work in England,
of $312,420.

The difference in cost of fuel, labor, etc., between the state of
Nevada and Cornwall, has variously been estimated to be from
ten to fifteen times as much here, but taking the lower figures,
we would get an annual cost of draining these mines here, of
$3,124,200.

The number of engines required at theabove][mines named in
Cornwall is nine, of an average diameter of cylinder of 82
inches ; we would require 3.28 times as many on account of the
greater quantity of water and again one half as many more on
account the greater depth ; we would therefore require 4.92
times as many engines, or say 44 of 82 inch cylinder. The cost
of engines of this size, including setting up, pumps, pipes, etc.,
has been estimated to be from $100,000 to $150,000 each. Let us
base our calculations on the first named estimate : Forty -four
engines at $100,000 would give a total cost of $4,400,000. The
additional interest, current here above that in England, would be
say 1 J per cent, per month, or on the whole outlay for machinery
$66,000 per month.

We have now the following amounts :

Cost of pumping per month, $260,350

Interest on capital invested, 66,000

Or a monthly expense of $326,350

for drainage by pumping.

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Estimating the number of tons produced by these mines to be
1000 tons per day, or 30,000 tons per month, the cost of drainage
per ton of ore raised, would be $10.88.

COST OF PUMPING IN NEVADA.

In making the above estimate, we have taken estimates of an
English mine as our basis. Now let us figure the cost of
pumping, taking the quantity of water as above stated and make
our calculations from the statements made by pumping works
and mills in Nevada.

Most estimates are made that the cost of running a steam engine
for twenty-four hours is from $2,00 to $2,50 per horse power.
Some are made as low as $1,50. We will again take the lower
figures.

The ordinary way of calculating, is to count 33,000 pounds, to
be lifted one foot high per minute, as one horse power.

We have 8195 gallons, or 1315 cubic feet, at 62.32 pounds
per cubic foot, we get 81,950 lbs to be lifted per minute ; divided
by 33,000, this would give 27.80 horse powers, to lift the given
quantity one foot high ; in order to lift it 1450 feet, we
have to multiply by that number, which would give 4039 horse
powers. Now it takes just double the given power, to overcome
the friction of water in pipes, the friction of engine, etc., etc.,
which would give 8078 horse powers, to raise the given quantity
of water 1450 feet. Calculating the cost of running the pump-
ing machinery, as stated above at $1,50 per day per horse power,
we would have an expense of $12,117 per day, or $363,510 per
month, or on every ton of ore raised an expense of $12,12.

Some statistics have been furnished by Capt. Taylor of the
Best <fe Belcher mine whose pumping works, are among the best

y/^ irc^ f

15

and most economically conducted in Nevada. He gives the
followino^ account of daily expenses in pumpino; :

In consequence of these accidents, the mine will be flooded
frequently, and delays occasioned of days, weeks, or even months,
throwing the miners out of employ, stopping the mills, and cut-
ting ofi" looked for dividends ; thus creating great hardships in
all quarters.

But this is not the only evil arising therefrom : the filling of
The engineers and pitmens wages would be considerably less in
large pumping works, but not having brought into account any
allowance for wear and tear, this will be nearly balanced.

He raises the water 270 feet and discharges 253 gallons per
minute. At 1450 feet, the water would be raised 5.37 times
as high, which would give a daily expense of $472,56. The
quantity of water, from the whole length of the Comstock ledge
at 1800 feet, would be 32.39 times as much, making a daily
cost of $15,306,21, or an expenditure per month of $459,186,30,
or per ton of ore $15,36.

RECAPITULATION.

Cost of pumping the estimated water from a depth of 1,800
feet under the surface :

Cu&t per lou taking:
the yield at 30,000
tons per month.

Coat per day.

Cost per month. Cost per annum.

CalculatiooB based «)n the
cost at the Connolidated
United Copper Mines of
C .rnwall.

$10.83. $10,878.

$326,360.

$3,916,S0O.

Calcuiutioiia based on cost
of running 8team en-
frines in Nevada.

$12.12. $12,117.

$363,510.

$4,362,120.

CalculaiionH based on the
cost of pumping at the
Best & Belcher Mine,
Nevada.

$15.36.

$15,306.

$459,186.

$5,600,232.

These are astonishing figures, but they are nevertheless correct;
but even one half, one third, or one quarter of these amounts will
give sums, so immensely large, that a system of drainage by tun-
nelling must appear to be a matter of necessity.

16

Many persons not acquainted with mechanics and engineering,
will be at a loss to understand why it costs so much to pump from

COST OF PUMPING IN NEVADA.

In making the above estimate, we have taken estimates of an
English mine as our basis. Now let us figure the cost of
pmnpiog, taking the quantity of water as above stated and make
feet, it would require nine such engines and pumps to lift the
same quantity of water from a depth of 1,800 feet. The water
is raised by the first pump 200 feet high, from the lowest point, and
discharged into a reservoir ; from thence it is lifted by another
pump to a point 200 feet higher, and so on until it reaches the
surface. We must therefore have nine engines to do this work ;
and, if we calculate the quantity of water, which would be met
at 1,800 feet, to be three limes the quantity met at 200 feet, we
would require twenty-seven engines, of fifty-horse power, to pump
out a single mine at that depth, where only one is required now.

The above estimates, give simply the cost of pumping out the
continuous flow of water. It must be borne in mind though,
tliat the body of accumulated water at present contained in the ledge^
where large subterreanean reservoirs or lakes are known to exists is
very large. In order to remove this great body of water, at least
twelve months would be required, employing all the above
enumerated engines, at a cost of running them, for that length of
time, of from $3,000,000 to $4,000,000.

EVILS OF PUMPING.

Independant of the actual cost of pumping, there are other dis-
advantages connected with the same, which must not be lost sight
of. Enginesj boilers, pumps, etc., etc., rapidly wear out, and new
ones have to take their places in the course of time : pumps are
liable to get out of order at any time, and they being placed at
the very lowest point in the mine, if not instantly repaired, the

17

water will rise above them and then it is impossible to reach the
pump in order to lepair it.

In consequence of these accidents, the mine will be flooded
frequentl.v, and delays occasioned of days, weeks, or even months,
throwing the miners out of employ, stopping the mills, and cut-
ting oft' looked for dividends ; thus creating great hardships in
all quarters.

But this is not the only evil arising therefrom : the filling of
the chambers and galleries with water swells the ground and
timbers, which after the water is removed shrinks, and conse-
qaenily leaves the mine in an insecure state, making it liable to cave
in. The timbers, undergoing these changes, decay sooner, and
must be renewed oftener in consequence. Miners in distant
parts of the mine remain in a constant state of anxiety, fearing
some accident to the pumps ; they certainly do not work with
that feeling of security they would otherwise posess.

Another objectionable feature of pumping is, the fact that the
mine which reaches the greatest depth is compelled to do all the
pumping, not only for itself, but also for its neighbors, thus drain-
ing them without receiving any remuneration. This will retard
mining operation? to a large extent, as many companies would
prefer to suspend the working of their mines until the adjoining
claims have reached the same level, in order to bring them to
equitable terms. A drain tunnel will avoid all these difficulties.

ADVANTAGES OF A DRAIN TUNNEL.

As to the advantages derived from a drain tunnel, at this great
depth, we will enumerate a few :

Shafts can at once be sunk the whole depth connecting with
the tunnel, thus insuring the most thorough ventilation ; this is
a matter of great importance in deep mines ; the health of the
miners is thereby secured and they can work along with vigor
and energy, not being stifled with fumes of powder and foul air j
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18

and it is a fact, ascertained by experience, that they will per-
form one-half more work, which reduced to dollars and cents
will make an immence saving in the course of the year.

THE VALUE OF THE IMINES WILL BE LARGELY
IXCKEASED.

At present the value of a mine is estimated, to a large extent,
by the body of ore actually in sijrht, and very few of them have
explored their pay ore to more than one hundred feet in depth.
After this drain tunnel is completed, nothing will prevent the
mines from being opened at once to the whole depth of 1,800
feet, shotving the different bodUs of ore contained in the surne,
exposing milUmis of dollars to the eye, and thus increasing their
value in proportion. Having thus thousands of tons of ore Id
Fight, preparation? can be made to work the same in an econom-
ical manner, nnd mills can be creeled with perfect security.

Many advantages would arise from the more perfect system of
mining and timbering, which could be adopted ; it could bedono
more systematically and economically than at present.

Hauling being ver) expensive, quite a considerable saving
would arise from the fact that the ore in a well drained mine is
nearly dry. At present about 10 per cent, of water is contained
in the ore as hauled to the mills, and calculating the average cost
of hauling at $4 per ton, this would save 40 cents on every ton, or
$400 per day, or the large sum of $144,000 per annum.

Particular advantages would arise to those claims on the Corn-
stock ledge, who never have found any ore yd, or who have run out
of it. They are tired of paying assessments, and their mines
will probably not bo prosi)ected for many yeai-H to come. This
drain tunnel will enable them to explore their claims at a great
depth, atjout a small expense ; and there is every reason to think
that many of them will prove of great value.

19

GREAT DEPTH WHICH WILL BE ATTAINED HERE-

AFTER.

The mines can be worked a great depth below the level of this
tunnel by pumping the water into the same. This is accom-
plished in Europe, in a very ingenious manner, at comparatively
small expense, by collecting the water in the upper parts of the
mine in reservoirs and conducting it in pipes to hydraulic
engines placed at the level of the tunnel ; thus using a portion of the
very water which causes all the obstacles at present, as a most useful and
economical motive power to propel pumps ; tohich, in their turn
raise the wafer f. am ^reat depths below. It may safely be stated,
therefore, that by means of this tunnel the Comstock ledge can
profitably be worked to a depth of at least 3,000 feet.

The necessity of completing this tunnel, without delay, must be
apparent to every one who reads these pages attentively, and
gives this important subject the attention it deserves. No time
ought to be lost to commence operations at once, and to push the
same with the greatest energy, day and night, until completed.
By the time this work can possibly be finished, the decline of our
mining interests^ and all other interests in JVevada, will fairly have
commenced. If this matter is delayed until the mines cannot be
worked any deeper by machinery, the country will go to ruin,
waiting for a drain tunnel to be completed.

Much has been spoken and written about the importance of a
railroad across the mountains ; it has been the subject of dis-
cussion in the newspapers, in the Halls of the Legislature, and in
Congress, for a number of years past. It is certainly a subject
of great interest to the people of Nevada and California. But
this tunnel is of still greater im,portance, for we venture to say, that
but few people would be in JYevada by the time a railroad is finished,
if this tunnel is not constructed.

Every person owning in the Comstock ledge is deeply inter-
ested in the carrying out of this enterprise, and so is every resi-
dent of the State of Nevada ; whether miner, merchant, farmer,

20

banker, teamster, millman, or of any other occupation. But the
people of California, and particularly San Franci?co, are not the
less interested ; every dollar produced by these mines finds its
way to California, in exchange for its produce.

It is a gratifying fact to the undersigned that this important
undertaking is commencing to be appreciated by all intelligent^
persons who go to the trouble to investigate its merits. He has
for several years past endeavored to explain its importance, but
could find no encouragement whatever to carry it out.

But it is apparent that the proper time has now arrived to carry
out this great work. Persons who never dreamed of the difficul-
ties to be encountered from water in (working) mines, commence to
realize the importance of drainage and have become enthusiastic
friends of this enterprise.

The attention of many has been drawn towards this under-
taking, by the fact that the Nevada Legislature has of late granted
the undersigned the exclusive privilege for fifty years, to construct
a tunnel from the valley of Carson river ; he is fully determined
to overcome all obstacles, should any present themselves, and feels
satisfied that with the assistance of the many friends of this enter-
prise, the day will soon arrive when work will fairly be commenced*

A. SUTRO.
San Francisco, February 24. 1865.

REPORT OF BARON RICHTHOFEN.

Virginia, February 16, 1865.
A. SuTRO, Esq., Dayton :

Dear Sir :

I learned with great interest of your magnificent project to
run a deep drain tunnel to the Comstock vein, from a place near
the mouth of Webber Canon, three and a third miles north of
Dayton, and I cheerfully comply with your request to state to
you my views about the importance and feasibility of this enter-

•21

prise. Its value will, of course, chiefly depend upon the question
whether these mines will ever be worked to considerable depth ;
that is, whether the Comstock vein will extend far down, and
whether it will retain its metallifferous character in depth. Both
questions have to be decided from the stud}^ of the structure and
nature of the Comstock vein, and from comparing the results
with the observations at such mines in other countries, which
have already been worked to great depth. My experience on
the Comstock vein is based on close and repeated examinations
of! nearly all the mines on its course. I believe, to concur with
almost everybody, who has equal experience about them, in the
opinion, that it is a true fissure vein, of extraordinary length, and
extending downward much farther than any mining works will
ever be able to be carried on. It would be too lengthy to
enumerate the various reasons which lead most positively to this
conclusion. It is now assumed almost universally as a fact, and
the number of those who consider it as a gash vein, or a system
of gash veins, is fost diminishing.

As to the downward continuance of the ore bearing character,
every instance goes to show that the average yield in precious
metals remains about equal at every depth. Some mines had
accumulations of ore near the surface (Ophir, Mexican, Gold
Hill), in others they commenced very near under the surface
(Gould & Curry, Potosi, Yellow Jacket, Belcher), at others,
again, considerable work had to be done before bodies of ore of
any amount were struck (Chollar, the southern part of Gold
Hill, Uncle Sam, and others), and some which had no ore hereto-
fore, appear to have good prospects to find it soon. The fact
that some rich bodies of ore, which were found near the surface,
gave out. at the depth of a few hundred feet, induced the com-
mon belief, that the Comstock vein was becoming poorer in its
lower parts. But the explorations of the last months have
entirely defeated this opinion. On the contrary, the enormous
amount of bullion, which is being produced by the mines at

22

present, may almost appear to prove that the vein is improving
in depth. But this conclusion is probably equally fallacious, as
it must be borne iu mind that many mines have been developed
at different levels, and ore is being extracted from several of
those. Hoisting works, and the mode of extracting the ore,
have also been improved, and, of course, help to increase the
daily produce. This average equality of the produce of the
vein at every different level, is not only true for the amount of
ore extracted, but also for ils yield. The rich body of ore in the
Ophir and Mexican mines, forms the only exception to this rule,
as none of equal average percentage in silver and gold has been
found again. Even the relative proportion of gold and silver in
the ore has not undergone any material change, though the
bullion, on account of the more imperfect processes of reduction,
contained at first proportionally more gold than at pre-
sent. The ore found in the Uncle Sam mine, at the depth
of 414 feet, is as rich in gold as any found in other parts within
100 feet from the surface.

There is no reason to doubt that this equality of average pro
duce and yield thoughout the entire le^ngth of the vein, will con-
tinue downward to any depth. Besides, the very obvious
theoretical conclusion that vast amounts of silver could not be
carried into the fissure from the overlying or the enclosing rocks,
but naturally had to rise from unknown depth, through the chan-
nel of tiie fissure itself, to be deposited in it wherever the condi-
tions for sublimation or precipitation were given in its open
space. Experience in other countries by no means shows of a
regular decrease or an increase in yield as of common occurrence,
though either of them may happen. More commonly, the pro-
duce of true fissure veins in precious metals, has been found to
be about constant.

It is, notwithstanding, a well known fact, that the profits of
silver and gold mining decrease rapidly in reacliing deeper
levels. The magnificent silver veins in the Karpathians, for in-

23

stance, which are the only ones in Europe, closely resembling the
Comstock vein, have been worked formerly with great profit, and
pay now but little above their expenses. But this is principally
due to the increased expense in working them. Drainage is the
heaviest item, mostly where the water has to be raised to a great
hight. It devours so much of the produce, that, with increasing
depth, the net profits will be diminished, then totally absorbed,
and, finally, exceeded by the cost of raising the water. Drain
tunnels have, therefore, been constructed wherever it could be
done with a reasonable expense, provided the veins could be
struck at a considerable depth. It appears that, for the Com-
stock vein, the day is not far distant when the expenses of rais-
ing water will be so large, that a great quantity of those middle
class ores, which are the principal source of wealth of these
mines, will no more yield any profits, and the benefits from the
richer ores will also be diniinished ; and, if mining in this fast
country proceeds as rapidly towards lower levels as it did here-
tofore, it will have to be abandoned after some years, if the
difficulty is not met with by the means proposed by you. It is
useless for me to dwell upon the great benefits which the mines
would derive from the construction of a deep drain tunnel.
Calculations on a very moderate basis show the advantages by
plain figures so ohviously as to strike every thinking mind.

The second subject about which you requested me to state my
views, is the practical feasibility of your project. The best
starting point of the drain tunnel will of course be at such a
place, where the greatest possible depth on the vein can be
reached by the shortest possible route. Besides, it has to be
taken into consideration, which qualities of rock the tunnel
would have to run through, and which are the facilities for sink-
ing air shafts. I will try to argue these different points, as my
numerous geological examinations and rambles over the country
of Washoe have made me pretty familiar with its physical out-
lines and its geological structure.

BANCROFT
LIBRARY

24

As to the starting point of the drain tunnel, you hate, with
remarkable sagacity, selected a place which so far supercedes
any other, as to be indeed the only feasible one in the country.
South of Webber Canon, the range of hills which slope into
Carson Valley, recedes in the shape of an amphitheatre, and
allows the almost level bottom of the desert to approach the
Comstock vein within less than four miles. The level of the
Carson river at Dayton, is about 1900 feet lower than the crop-
pings of the Comstock vein at the Gould & Curry office. If the
tunnel starts 100 feet above the river, at the foot of the hills,
it will strike the Comstock vein 1800 feet below those croppings.
Making no allowance for the Eastern dip of the vein, its length
would be about 19,000 feet ; thus making the proportion of depth
to length, as I to 10.65.

There is no place more suitable along the banks of Carson
river. A tunnel from the lower part of Gold Canon (below
Johntown,) would have to run 22,000 feet to the Divide, and 25,-

000 feet to the Gould & Curry cropping^ besides starting be-
tween 200 and 300 feet higher than the place selected by you.
and offering great disadvantages as to the qualities of rocks and
the sinking of air shafb^. A third place which might be selected
for starting, would be at the bottom of the canon which extends
from the Santiago Mine down to the New York House. You
would strike by such tunnel the central part of American Flat
at 11,000 feet, the Gould <fe Curry croppings at 24,000 ; but com-
paring with the place near the mouth of Webber Caiion, you
would lose about 600 feet in depth.

The disadvantages of running a tunnel from Washoe Valley
or Steamboat Springs, to the Comstock vein, are so obvious that

1 need not dwell upon them. Those places, are, respectively,
about 1300 and IfiOO feet lower than the Gould and Curry
croppings ; the distance of the former from the same croppings
is about 30,000, that of the latter about 40,000 feet. Both
places can never compete with any on the Carson river : and

25

besides their great distance and comparatively little depth, you
would have to run through extremely hard rocks, and would
never be able to sink air shafts.

The three places in Carson Valley, will compare as follows :

starting Point.

Length of tunnel to
Gould & Curry cropp.

Depth below Gould
& Curry cropp.

Proportion of depth
to length.

1. Near mouth of Webber ")
Canon, 3)^ miles north of Day- Ubout 19,000 feet,
ton. J

about 1800 feet.

1: 10.55.

2. In Gold Canon, below
John town.

J " 26,000 '•

" 1500 '•

1: 16.66.

3. In Canon from Santiago
Mine to Xew York House.

1 " 24.000 «

" 1200 "

1: 20.00.

Though these figures are but aproximations, they show plainly
the great superiority of the place selected by you.

The facilities of excavating the tunnel will mainly depend
upon the quality of the rocks through which it will pass. It is
a remarkably fortunate incidence that the route selected by you
promises, also, in this respect, to be the most advantageous.
While the tunnels, both from Gold Canon and from New York
Canon, would have to pass to great extent through quartzose
porphyry, which is the hardest, and through a certain kind
of metamorphic rock, which is the toughest rock of the country f
you will not meet either of these rocks. The first 6000 or 7000
feet will be run through trachyte and trachytic breccia which in a
broad semicircular belt of prominent hills, swing from Dayton by
the Sugarloaf to Washoe Valley. Trachytic breccia can easily
be worked by the pick, yet is ordinarily solid and dry enough to
require no timbering. You may form an idea of its excellent
qualities for tunneling, from the fact that in Hungary wine cellars,
hundreds of feet in length, are with preference excavated in this
kind of rock. The solid trachyte is an excellent blasting rock.
Its superior qualities have caused its general use in Washoe for
building material ; it was applied as such in the construction of
the solid masonry of the Gould & Curry Mill. With the use of

26

the drilling machine of Mount Cenis you will make speedy work
in this rock.

The next 2,500 feet will, to all probability, exhibit a great
variety of rock, some of which will be rather hard. This applies
chiefly to certain volcanic rocks of dark color (andesite), which
flank the trachytic range to the west; but as they occur in
dykes parallel to the same, they will retard work but slightly.

The following 10,000 feet, which bring you to the vein, will
most likely consist of the same material as is traversed by the
numerous tunnels which lead at present to the Comstock vein.
This rock (trachytic greenstone) would ofi*er serious obstacles if
it was in an undecomposed state. But from the general nature
of its decomposition, which, evidently, was performed from be-
low, by ascending steam and vapors, during a time of volcanic
action, I believe to be justified in the conclusion that you will
find it for the entire length of 10,000 feet of the same rotten na-
ture, as in the shallow tunnels at present in existence. It varies
in them constantly, some varieties being easily worked by the
pick, while others, occurring in streaks parallel to the vein, are
less decomposed, and have to be blasted. Timbering would
probably be required but to a limited degree in a small tunnel ;
but if you make it of sufficient size for a double track, you may"
have to timber almost all of the 10,000 feet.

A third requirement, though not absolutely necessary with
the present accomj)lishments of tunneling, will be the sinking of
air-shafts. Also, in regard to these, your tunnel offers greater
facilities than any other route. It passes first under a high
range of hills, which is accompanied on either side by deep
ravines. Each of them will be a suitable starting place for an
air-shaft ; the depth of the latter would be about 500 and 750
feet; The first of the two would be about 3,000 feet distant
from the mouth of the tunnel, the second about 3,600 feet from
the first. Approaching the Comstock vein, there are two more
places suitable for air-shafts, the distance from tlie second to the

27

third being 2,500 feet, that of the third to the fourth, 4,000 feet,
thus leaving about 6,000 feet distance from the fourth shaft to a
point vertically under the Gould and Curry croppings. The two
last shafts would have a depth of 1,200 and 1,300 feet. One of
them will, no doubt, be sufficient.

None of ihe prominent mining countries of the world can
boast of equal facilities for a drain-tunnel. I do not know of
any that drains mines at an equal depth, and yet, many drain-
tunnels have more than double the length of the one proposed by
you. If, in the Harz mountains, where labor and fuel are cheap,
it was considered economical to construct a drain-tunnel of
72,000 feet in length for draining the mines to the depth of
1,200 feet, all this for a product which is scarcely one-thirtieth
of that of Washoe, how much more economical must it be in the
latter country, with its enormous value of labor and fuel, to run
a drain-tunnel of but 19,000 feet in length to drain the Comstock
vein at 1,800 feet depth, for augmenting the net profits from a
pi'oduce of $15,000,000 a year!

The future of Washoe, indeed, depends entirely on the execu-
tion of this magnificent enterprise. It is of vital importance for
the State of Nevada, and will have great influence on the neigh-
boring California, which chiefly derives the benelits of the mines
of Washoe. The numerous advantages will only be fully under-
stood when the work will be completed. Allow me to draw
your attention still to one among them, t^everal companies on
the Comstock vein have been very unfortunate ; they either
found no ore at all in their mines, or, if it was found at first,
it gave out. and the owners are discouraged to do any fur-
ther prospecting work. It is very probable, that in deep level^',
some of these poor mines may be among the best. But it is still
of far greater importance, that it will then be possible to deter-
mine how far north and south the Comstock vein extends, and
bow far it is ore-bearing. Notwithstanding the well defined
character and enormous width of this vein in the Uncle ?am

28

mine, and its rich ore, the vein, which is very shapeless near
the surface, has not yet been traced with certainty farther south,
and prospecting on American Flat is almost entirely abandoned.
Capital is l)eing invested very unwillingly in the exploration of
either this southern or the northern end of the vein, where
equal labor and capital invested have not been rewarded. At
the depth of 1,800 feet, all irregularities will probably have
ceased, and then these unprofitable mines on both extreme ends,
may still prove to be valuable claims.

Allow me to congratulate you to have been the first to have
taken an enterprise of such vast importance firmly in your hand.
With the sincere wish, that you may overcome the diflSculties
which you will no doubt meet in carrying out a work of such
magnitude,

I remain yours very sincerely,

FR. RICHTHOFEN.

OPINION OF MINING SUPERINTENDENTS— AND

OTHERS.

The undersigned, fully aware of the importance and urgent
necessity of providing means for draining the Comstock ledge .
by means of a deep drain tunnel, and foreseeing the difiiculties
which must present themselves, before long, in removing the
water from these mines ; and being satisfied that the best inter-
ests, of not only the owners of the Comstock ledge, but the peo-
ple at large of this State, would be seriously affected by neglect-
ing this matter : we would most earnestly recommend the imme-
diate construction of such a work, and ask the co-operation of all
parties interested, in order that this important undertaking may
speedily be carried out.

Virginia, February 15th, 18(^5.

A.. E. Davis, Gen'l Sup't Ophir S. M. Co.
Harvey Beckwith, Sup't Mexican Mine.

29

0. H. Frank, Sup't Central S. M. Co.
Pat. N. McKay, Sup't California S. M. Co.
Jas. Morgan, President Sides Co.

H. H. O'Reiley, Sup't White & Murphy Co.
Thomas G. Taylor, Sup't Best & Belcher M. Co.
Charles Bonner, Sup't Gould & Curry S. M. Co.
Sain'l F. Curtis, Sup't Savage M, Co.
Chas. L. Peck, Sup't Hale & Norcross S. M. Co.

1. Adams, Sup't Choliar S. M. Co.

Pat. N. McKay, Sup't Potosi G. & S. M. Co.

J. M. Walker, Sup't Bullion M. Co.

P. S. Buckminstcr, Sup't Imperial S. M. Co.

John II. Mills, President of Superior Co.

Robert Apple, Sup't Minerva Consolidated M. Co.

R. Graves, Sup't Empire M. & M. Co.

W. Tozer, President Challenge S. M. Co.

L. U. Colbath. Sup't Challenge S. M. Co.

L. S. Bowers, owner in Gold Hill.

Lindauer & Hi.rschman, owners in Gold Hill.

Chas. Pioda, owner in Gold Hill.

J. Woodruff, Sup't Bacon M. & M Co.

Wm. Arrington, President Confidence Co.

Robert Apple, President Apple M. & M. Co.

Winters, Kustel & Co. owners in Gold Hill.

M. A. French, owner in Gold Hill.

John B. Winters, President Yellow Jacket S. M. Co.

H. Woodcock Sup't Crown Point Co.

F. A. Tritle, President Belcher M. Co.

Wm. Arrington, President Overman Co.

C. C. Thomas, Sup't Uncle Sam Co.

Pax ton & Thornburg, Bankers.

Wm. Sharon, Ag't of Bank of California.

Jas. H. Latham, Ag't Wells, Fargo & Co.

B. F. Hastings & Co. Bankers.

30

E. Ruhling & Co. Bankers.
Almarin B. Paul & Co. "

Maynard & Flood, " _.

M. C. Hillyer, Trustee Chollar S. M. Co.

A. Meyer, Trustee Hale & Norcross S. M. Co.

D. E. Avery, Gen'l Ag't ^ew York & Washoe M. Co.
J. R. Williams Sup't Sierra Nevada S. M. Co.

W. E. Bidleman, Sup't Utah Co.

J. Neely Johnson.owner in Virginia City mines.

H. F. Rice, Ag*t Wells, Fargo & Co'8, Carson.

F. Rithshoen.
John Cradlebaugh.
Gillig, Mott & Co.

W. M. Brown, Mining Engineer.

C. V. Beseler, "

John A. Veatch, "

John White, formerly ot the United Mines, Cornwall.

S. M. Johns, formerly of the Wheal Prosper Mine, Cornwall.

J. F. Lewis, Chief Justice Supreme Court.

C. M. Brosnan, Justice of Supreme Court.

W. 0. Beatty, Justice of Supreme Court.

Richard Rising, District Judge, Storey County.

R. S. Mesick,

C. Burbank,

J. L. CrOv^sman, Lieu't Governor.

C. W. Noteware, Secretary of State.

H. W. Nightingill, Controller of State.

E. Rhoades, State Treasurer.
N. W. Winton, State Senator.
M. S. Thompson, "

J. Seely,

A. J. Lockwood, "

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