The Comstock Lode, Nevada (Part 1)*

history
The Comstock Lode, Nevada (Part 1)*
by R.J. “Bob” Cathro
Chemainus, British Columbia
There was now (after the Cariboo
Gold Rush) an end to all mining excitement.
It would never again happen … all morbid appetite
for sudden wealth was now gone forever.
But softly, good friends! What rumor is this?
Whence come these silvery strains that are wafted
to our ears from the passes of the Sierra Nevada?
… As I live, it is a cry of Silver! Silver in Washoe!
Not gold now, you silly men of Gold Bluff. You
Kern-Riverites, you daring explorers of British
Columbia! But Silver - solid, pure Silver! Beds of
it ten thousand feet deep! Acres of it! - miles of it!
- hundreds of millions of dollars poking their backs
up out of the earth waiting to be pocketed!
“Sir,” said my informant to me, in strict confidence,
no later than this morning, “you may rely upon it,
for I am personally acquainted with the brother of
a gentleman whose most intimate friend saw the
man whose partner has just come over the mountains, and he says there never was the like on the
face of the earth! … Let us be off! Now is the
time! … Hurrah for Washoe!”
(BROWNE, 1860)
* This information on the history of the Comstock Lode
is mostly derived from Lord (1883), Rickard (1932),
Smith (1943), Paul (1963) and Watkins (1971).
Following the initial excitement, activity in the California Goldfield declined
significantly as many of the newcomers returned home or dispersed in the
search for the next Mother Lode. New gold placers were discovered near
Spokane and Yakima, Washington, in 1850, and the Rogue River valley and
Coos Bay, Oregon, in 1851. In 1856, old Spanish silver mines were reopened at
Tubac, Arizona, and there were small rushes to the South Platte River, Colorado,
and the Gila River, Arizona, in 1858. However, the most important rush, which
occurred later that year to the Cariboo Goldfield (in what is now British
Columbia), attracted 23,000 prospectors from the United States as well as many
more from elsewhere.
The next discovery that had a
major impact on the history of economic geology and the development
of new mining methods and
machinery was the 1859 discovery
of an unusually large and rich silver-gold deposit located about 280
kilometres east of San Francisco and
30 kilometres south of Reno. It was
situated within western Utah
Territory at the time, but became
part of Nevada when the new state
was created in 1864. The new mining district became known as
Washoe, named after the local
native people.
The first Europeans to pass
through the Comstock were appar- Square-set timbering (from Lord, 1883).
ently a party of Mormons enroute to
California in 1849. The first recorded prospecting was conducted the following
year by a group of Mexicans, who found small quantities of placer gold in two
tributaries of the Carson River, Gold Canyon and Six Mile Canyon, which both
had their headwaters on Gold Hill. Results weren’t sufficiently encouraging to
attract a permanent population until 1852-1853. The Grosch brothers, Ethan
and Hosea, who had obtained mining experience in California, performed the
first professional prospecting between 1854 and 1857 and appeared to make
good progress until they were both killed in separate accidents.
A placer paystreak was discovered in Gold Canyon in 1858-1859 by four
prospectors led by James (Old Virginia) Fennimore. They were soon persuaded
to share their claims with a local scoundrel named Henry Comstock, whose main
contribution was to bequeath his name to the lode. The paystreak was produced
by the weathering of small gold-quartz veins at the south end of the Comstock
Lode, situated about five kilometres farther upstream. Over the height of land, at
the head of Six Mile Canyon, Patrick McLaughlin and Peter O’Riley found a similar weak placer gold concentration in Spanish Ravine that was derived from the
Ophir mine, at the north end of the lode. Progress in mining the gold-bearing
gravel in both creeks was slow because the sluice boxes kept plugging up with a
heavy mud the miners called “the damned blue stuff.” This would become a classic example of poor prospecting.
March/April 2008 | 61
economic geology
Location map of the Comstock Lode at Virginia
City, Nevada (from Rickard, 1932).
Map of the region between San Francisco and Virginia City, Nevada (from Rickard, 1932).
Having become intrigued by the stories of the strange
blue material, rancher B.A. Harrison and trader B.F. Stone
sent samples to Nevada City and Grass Valley for assay in
June 1859. The results were spectacular — $875 in gold but
an unexpected $3,000 in silver per ton. It turned out that
the ‘blue stuff’ was mainly a mixture of argentite, other silver minerals, and fine free gold in clay. Together with Judge
James Walsh and Joseph Woodward, they rushed to the
Comstock and bought the claims from the placer miners for
far more than they were thought to be worth, precipitating
a wild staking rush and speculative flurry. All the early
claim owners sold too early and died in poverty. George
Hearst, who had been tipped off about the new discovery,
arrived early and bought a one-sixth interest in the Ophir
claim with borrowed money.
Over 17,000 claims were eventually recorded but only
the first ones staked over the Comstock Lode, which is
about five kilometres long, proved valuable. Virginia City,
derived from James Fennimore’s nickname, sprang up on
top of the lode almost immediately. Access was provided by
the 185 kilometre Carson toll road, completed in 1858 from
Placerville, in the Mother Lode, over the Sierra Nevada
Mountains and around the south end of Lake Tahoe.
Enormous amounts of water and timber would be needed,
which was obtained from the eastern slopes of the Sierra
Nevada. For example, 80 million boardfeet of lumber and
250,000 cords of firewood were consumed annually during
the boom years.
Silver mining was unknown in the western states and
most of the Comstock pioneers had little knowledge of the
metallurgical art required to extract silver from the ore, or
even about lode mining. The potential of the new deposit
soon attracted experts with experience in the silver districts
of Mexico and Europe. The first attempts to treat the
62 | CIM Magazine | Vol. 2,
3, No. 72
Comstock ore used the patio process, invented by
Bartolomene Medina in Mexico in 1557. It consisted initially of a Mexican grinding mill (arrastra), in which mules
or horses were used to drag flat boulders over a paved patio
to stir a mixture of ore, water, mercury, and a bit of salt and
copper filings or sulphate into a mud-like slurry. Tobacco
juice and sagebrush tea were also added to the mix with
negligible results. The moistened pulp was worked until the
sulphides were reduced to chlorides and then to the metallic state, when the silver and gold united with the mercury
to form amalgam. Later, a heated copper kettle (cazo) was
used to speed up the process. The mercury used at
Comstock was obtained from the New Almaden mine,
about 20 kilometres southeast of San Jose, which was discovered in 1824.
At the Ophir mine, the first to begin production, George
Hearst and his partners managed to grind and concentrate
about 35 tonnes of ore in one of the first arrastras and haul
it to San Francisco late in 1860, before snow closed the
trail. It was smelted there by Joseph Mosheim and yielded a
net return of $114,000, an average of $3,400 per tonne.
Costs per tonne after mining were $450 for smelting and
$155 for freighting. The bars of bullion were displayed in a
bank window to demonstrate the potential of the Washoe
district and guarantee a huge influx of miners, promoters
and investors in 1861.
The Comstock camp is noteworthy for its pioneering
adaptation or invention of new milling and mining methods
that influenced industry practice worldwide. Although the
sulphide content of the ore presented recovery challenges
for the silver and gold, nearly 50 arrastras were built to
treat the highest grade surface ore. A recovery of about 50
per cent was only possible because most of the sulphide
minerals had been oxidized, the silver occurred as argentite
economic geology
and silver-rich sulphosalt minerals, and the gold was presthe mine was becoming too dangerous to work in. George
ent as fine free grains. The first milling improvement was
Hearst invited a German mining engineer educated at the
the replacement of the arrastras with jaw crushers and the
Freiberg Mining Academy, Philip Deidesheimer, to come
use of the Freiberg process, which involved dry crushing
from California, where he was managing a mine, and
with California stamps, roasting (chloridization) in ovens
attempt to solve the problem. According to legend, he
and amalgamation in revolving barrels. When that proved
designed a new timbering method within six weeks, called
too slow, intricate and costly, a great deal of testing and
square-setting, that was based on the structure of a beeresearch was performed. Much of it was based on the work
hive. Rigid cubes were created by sawing mortise-andof Almarin B. Paul, a friend of Hearst’s,
tenon joints on the ends of heavy timbers,
who experimented for over two years to
which allowed adjoining timbers to
increase efficiency.
snugly interlock. Each set consisted of a
The resulting flow sheet, named the
vertical post about two metres high and
Washoe milling process, accomplished in
two horizontal members (called caps and
six hours what had previously required
girts) about 1.5 metres long. This resulted
four to six weeks. It remained the statein a strong honeycomb structure with
of-the-art until cyaniding was introduced
adequate internal working space that
in the mid-1890s. In 1862, 20 mills were
could be expanded to fit any irregular
operating at Comstock and there were 66
opening. If waste rock was available, it
by 1866, with 1,226 stamps and 919
was used to fill the cubes (squares). This
pans, representing an investment of over
timbering technique became popular
$6 million. Mark Twain (1872) described
around the world for supporting wide
the milling process in the early 1860s as
stopes in weak ground.
follows:
Other notable advances in mining
“This mill was a six-stamp affair, driven Philip Deidesheimer (1832-1916), inventor of the were adopted quickly at Comstock,
by steam. Six tall, upright rods of iron, as square-set timbering method at the Comstock
including the Burleigh mechanical rock
large as a man’s ankle, and heavily shod Lode, Nevada, in 1861.
drill, powered by compressed air.
with a mass of iron and steel at their lower
Developed between 1866 and 1870 by
ends, were framed together like a gate, and these rose and fell,
Charles Burleigh for the Hoosac railway tunnel in
one after the other, in a ponderous dance, in an iron box called
Massachusetts, it was the first successful rock drill built
a battery. Each of these rods or stamps weighed 600 pounds. …
in the United States. The first model weighed 170 kiloThe ceaseless dance of the stamps pulverized the rock to powgrams. It was introduced at Comstock in 1872 to drive
der, and a stream of water that trickled into the battery turned
the six kilometres long Sutro drainage tunnel. Even after
it into a creamy paste. The minutest particles were driven
Ingersoll and Rand drills replaced the Burleigh model
through a fine wire screen … and were washed into great tubs
later, older miners still referred to piston-style rock drills
warmed by superheated steam - amalgamating pans, they are
as ‘burleys’ (Hoffman, 1999). Another noteworthy milecalled. The mass of pulp in the pans was kept constantly stirred
stone was the use of flat, woven-wire shaft cable (rope),
by revolving ‘mullers’. A quantity of quicksilver was kept
invented by A.C. Hallidie of California about 1867. CIM
always in the battery, and this seized some of the liberated gold
and silver particles and held on to them. … Quantities of
coarse salt and sulfate of copper were added from time to time
References
to assist the amalgamation by destroying the base metals
Browne, J.R. (1860). Peep at the Washoe. Harper’s New Monthly Magazine, 22, 127. New York:
which coated the gold and silver and would not let it unite with
Harper & Bros. Available at http://cdl.library.cornell.edu/cgi-bin/moa/moacgi?notisid=ABK4014-0022-3. Accessed on October 11, 2007.
the quicksilver. …”
Hoffman, L.C. (1999). The rock drill and civilization. Available at http:
There is nothing so aggravating as silver mining. There
www.americanheritage.com. Accessed on November 1, 2007.
never was any idle time in that mill. There was always someLord, E. (1883). Comstock Mining and Miners. Washington: United States Geological Survey.
thing to do. It is a pity that Adam could not have gone straight
Reprinted in 1959 by Howell-North Books Publishers, San Diego.
out of Eden into a quartz mill, in order to understand the full
Paul, R.W. (1963). Mining Frontiers of the Far West, 1848-1880. New York: Holt, Rinehart and
Winston.
force of his doom to ‘earn his bread by the sweat of his brow’.”
Even more challenging problems had to be overcome
Rickard, T.A. (1932). A History of American Mining. New York: McGraw-Hill Book Company, Inc.
underground because the oreshoots became very wide, the
Smith, G.H. (1943). The History of the Comstock Lode: 1850-1920. Reno: University of Nevada
Bulletin, Geology and Mining Series No. 37. Reprinted in 1966 by the Nevada State Bureau of
ore was quite soft and friable, and the mines were
Mines and the Mackay School of Mines, Reno.
extremely wet and unbearably hot at depth. By late 1860,
Twain, M. (1872). Roughing It. Hartford: American Publishing Company. [Mark Twain was the
when the Ophir mine reached a depth of almost 60 metres
pen name of Samuel Langhorne Clemens (1835-1910).]
and had exposed an ore zone about 15 metres wide, conWatkins, T.H. (1971). Gold and Silver in the West: the Illustrated History of an American Dream.
Palo Alto: America West Publishing Company.
ventional timbering was unable to support the walls and
March/April 2008 | 63
history
The Comstock Lode, Nevada (Part 2)*
by R.J. “Bob” Cathro
Chemainus, British Columbia
The great “Comstock lode” stretched
its opulent length straight through town from north
to south, and every mine on it was in diligent
process of development. The (Gould and Curry)
mine alone employed six hundred and seventy-five
men … The “city” of Virginia roosted royally
midway up the side of Mount Davidson, seven
thousand two hundred feet above the level of the
sea, and in the clear Nevada atmosphere was
visible from a distance of fifty miles! It claimed a
population of fifteen thousand to eighteen
thousand, and all day long half of this little army
swarmed the streets like bees and the other half
swarmed among the drifts and tunnels … Often
we felt our chairs jar, and heard the faint boom of
a blast down in the bowels of the earth …
(TWAIN, 1872).
* The geological information in this chapter is mostly
derived from Berger, Tingley, and Drew (2003) and
Hudson (2003), except where noted. Background
historical information is mainly from Lord (1883),
Paul (1963), Rickard (1932), Smith (1943), and
Watkins (1971). In addition, ‘Barney’ Berger provided invaluable assistance, including two figures
from his paper.
72 | CIM Magazine | Vol. 3, No. 3
Nevada is called ‘The Silver State’ because it was founded while the Comstock
silver-gold mines were being developed. The establishment of the state capital at
Carson City, 19 kilometres southwest, reflected the influence of the mining district, which produced intermittently between 1859 and 1996. Using the prevailing metal prices during its boom years between 1860 and 1880, silver accounted
for about 55 per cent (Rickard, 1932) to 60 per cent (Lindgren, 1913) of the total
value of the ore, with the balance contributed by its gold output. If the value of
its production was calculated today using November 2007 metal prices of
$800/oz for gold and $15/oz for silver, the situation would be reversed. The value
of the production would now be about 70 per cent from gold and the remainder
from silver, Comstock would be called a gold-silver lode and the state might have
a different nickname.
In terms of contained metal, the Comstock Lode ranks among the top 10
per cent of world epithermal districts and can be classified as world class. It
was one of the first epithermal districts described in North America. Exact
production records for the camp are unknown because record-keeping in the
early years was incomplete. In addition, the unfortunate custom at that time
of quoting the amount of silver and gold produced by dollar value, rather than
by tonnage and grade, requires many assumptions to be made. The best available estimate of total production is about 257 tonnes (8.26 million ounces) of
gold and 6,000 tonnes (193 million ounces) of silver from 16.35 million
tonnes (18 million tons) of ore (Hudson, 2003). This equates to a relatively
rich average grade of approximately 15.7 g/t (0.46 oz/ton) gold and 367 g/t
(10.7 oz/ton) silver, a gold equivalent grade of about 22.5 g/t (0.66 oz/ton) at
present metal prices.
Eighty per cent of the dividends paid from the camp came from just two pairs
of adjacent mines — Con Virginia (California) and Crown Point-Belcher (Paul,
1963). The Con Virginia (California) oreshoot alone produced 1,131,900 tonnes
of ore that averaged 87.4 g/t (2.55 oz/ton) gold and 1,834 g/t (53.5 oz/ton) silver
(R.E. Kendall in Hudson, 2003). That is approximately 35 per cent of the gold
and 31.5 per cent of the silver produced in the entire camp.
Two Mexican words commonly used in the Comstock camp to describe
ore grades were adopted into the American lexicon — bonanza, meaning fair
weather, was used to describe an especially rich precious metal lode and borrasca, meaning storm, was applied to an unproductive vein, mine or claim.
Miners, promoters and investors spoke frequently about mine workings
being in either bonanza or borrasca, and the richest orebody in the camp,
the Con Virginia (California), was called the Big Bonanza. The promotional
name ‘bonanza’ was subsequently given to deposits, claims or geographic
features in almost every mining camp in North America. For example, it was
given to one of the richest creeks in the Klondike Gold Field (Yukon
Territory) in 1896.
Modern studies of the geology of the Comstock Lode are more difficult
because the bulk of the mining took place before current research tools were
developed, and the unstable ground conditions prevented later access to the richest and deepest parts of the lode. As a result, part of the research has, by necessity, been restricted to specimens collected by early mine foremen and/or is based
on contemporary descriptions. The principal challenge throughout almost 150
years of study has been the complex structural deformation history, which is still
economic geology
Comstock Lode, Virginia City, Nevada
ELEVATION
Feet
7000
Meters
2000
South
North
5000
1000
3000
Longitudinal projection of stoped orebodies (black) along the Comstock Lode. The individual claims are identified at the bottom (from Berger et al., 2003; modified from Becker, 1882).
Yellow Jacket
East Yellow Jacket
partially unresolved. The main
gyrite, were identified within the
Shaft
Shaft
B'
B
points of remaining controversy
zone of oxidation, which
relate to the timing of mineralizaextended to depths of 100 to 160
623'
tion with respect to transpresmetres. No base metals were
793'
Yellow Jacket Mine
sional deformation, regional
recovered from the Comstock ores
983'
Cross Section
extension and the local displacebecause of the limitations of the
Black
1461'
To
ment gradient, and the localizatreatment processes available at
Sutro
Dike
<50%
Tunnel
1763'
tion of bonanza ore within a zone
the time. Bastin (1922) reported
Quartz Vein
Bonanza
of strike-slip faulting linked by
that the ores were characteristi2165'
Ore
normal faults.
cally fine grained, with individual
2465'
0
400 feet
>50%
The Comstock fault zone, the
grains commonly less than one
Quartz Vein 2833'
200 meters
0
main structure in the district, is
millimetre in diameter and only
traceable for more than 15 kilorarely attaining diameters of 5 to
Cross-section looking north through the Yellow Jacket mine,
metres along strike and bounded
10 millimetres.
Comstock fault zone, showing the relationship between bonanza
by nearly parallel faults for
A large variation in character
and stockwork ore and the local reverse dip near surface (from
Berger et al., 2003).
almost its entire length. The orewas exhibited within and between
bearing part of the lode is about
orebodies, with some lacking pre4.2 kilometres long. The lode is comprised of about 50
cious metals, others containing intergrowths of base and
small to large, lenticular oreshoots of irregular shape that
precious metal minerals, and still others that essentially
occur within the fault zone. Two of the orebodies dipped
lacked base metals. The Ophir mine, for example, had a
70° west near the surface, whereas the rest had easterly to
western vein rich in base metals and an eastern vein rich in
near vertical dips. Mined widths were mostly in the 10 to 17
both precious and base metals. Gold/silver ratios generally
metre range. Individual orebodies rarely extended more
decreased with depth but varied widely in some oreshoots.
than 150 metres vertically and most were less than 150
Most of the richest ores reportedly contained appreciable
metres long. The margins of the orebodies were commonly
chalcopyrite and were relatively poor in sphalerite. Massive
marked by a narrowing and feathering into thin veins concalcite was deposited just below and in the lower parts of
taining less sulphide minerals, or were sometimes cut off
orebodies.
abruptly by clay seams.
Pliocene to Holocene reactivation of faults disrupted the
In decreasing order of abundance, the major ore minerlode and affected the relative positions of many of the oreals were sphalerite, chalcopyrite, galena, pyrite, acanthite
bodies and alteration assemblages. Detailed studies have
and electrum. Acanthite is a low-temperature polymorph of
shown that the best (bonanza) mineralization resulted from
argentite and is the mineral that forms the tarnish on sterthe focusing of hydrothermal fluid flow into spatially
ling silver. Stephanite was reportedly the main silver minrestricted networks of interconnected fractures. These coneral in the Con Virginia orebody and was abundant in the
fined zones of high vertical permeability and hydraulic conOphir. At least 12 other silver and copper minerals, includnectivity are interpreted as the result of complex deformaing native silver, amalgam, covellite, chalcocite and chlorartional processes.
May 2008 | 73
economic geology
The orebodies are scattered within a quartz gangue
composed of weakly mineralized massive veins, breccias
and stockwork veins that have been complexly rearranged
by post-mineral faulting. Stockwork veins were the most
common, comprising up to 90 per cent of the lode, but
usually 10 to 50 per cent. The next most abundant gangue
material was white, massive to stockwork quartz, called
‘red quartz’ or ‘bastard quartz’ by the miners. It was usually mosaic and/or comb-textured, unbanded or poorly
banded, and contained multiple generations of quartz
breccia fragments containing crosscutting veins cemented
by quartz. Massive quartz was found to the deepest
explored depths, where it was hard, locally contained base
metals, and consistently contained precious metals at subore grades.
Early workers quickly recognized the difference between
rich, ore-bearing quartz and barren, massive quartz. The
ore-bearing quartz was milky white, very friable and apparently anhedral, with a sandy texture resembling sugar or
table salt. The ‘sugar’ quartz was loose and crumbly except
where it was cemented by ore minerals or later quartz.
Some of the orebodies were completely shattered and broken, possibly by post-mineral faulting. The sandy texture
and shattering contributed to the difficult mining conditions described in the previous chapter.
The Comstock Lode is an adularia-sericite epithermal
system that can be divided into early and bonanza stages.
Extensive studies over more than a century have identified
12 hydrothermal alteration assemblages or sub-assemblages. The main stage of Au-Ag-Zn-Cu-Pb mineralization
was deposited towards the end of a late stage of deep, lowsulphidation alteration. The other type is intermediatedepth high-sulphidation alteration. The superposition of
the two styles tends to obscure and conceal the low-sulphidation alteration within the much more obvious highsulphidation alteration. A close spatial relationship
between these two epithermal environments is quite
unusual globally.
Richthofen (1868) first applied the term ‘propylite’ to
certain rock units in the Comstock district. Becker (1882)
realized that it was altered andesite, and this assemblage
was later recognized as one of the most common hydrothermal alterations worldwide. Three sub-assemblages of
propylite have been mapped, based mainly on the presence
or absence of epidote. They form halos around the hightemperature parts of the lodes.
Tertiary volcanic activity centred in the vicinity of the
Comstock district began at about 18.2 Ma with the eruption of andesitic lavas, and at least four superimposed
Miocene hydrothermal events have been recognized. The
oldest volcanic rocks are a suite of lavas, breccias, dacitic
intrusions and minor sediments that were intruded by
the 15.2 Ma Davidson diorite. The largest Davidson body
forms the footwall of the Comstock fault zone and
numerous dykes that are present in the hangingwall. The
74 | CIM Magazine | Vol. 3, No. 3
hydrothermal alteration and ore deposits have been
dated at 14 Ma.
Mining at Comstock reached a depth of almost 1,000
metres and was exceeded only by the Adelbert shaft in the
Pr̆íbram silver mine, Czech Republic, which became the
deepest in the world in 1875, at 1,000 metres (see CIM
Magazine, March/April, 2006, p. 65). The Pr̆íbram
deposit, which consisted of relatively narrow veins hosted
by strong wall rocks, encountered very little water and
was completely dry below 800 metres, and reached an
ultimate depth of almost 1,600 metres. Comstock, on the
other hand, attempted to mine wide, soft oreshoots in
unstable wallrocks and was extremely wet and unusually
hot. These conditions required more extensive timbering
than had been encountered in most mines in the world,
as well as continuous pumping with the largest pumps
available. To make matters worse, the mines required
strong ventilation and were even cooled with ice because
the inflowing water was so hot it made the working conditions at depth almost unbearable. The water temperature increased 3°F for every 100 feet of depth and reached
170°F (about 77°C) at a depth of 968 metres in the Yellow
Jacket mine, where the rock temperature was measured as
167°F. Even with abundant ice, miners could only work
alternate hours and, in some cases, only 15 minutes at a
time. These adverse conditions eventually restricted further exploration when miners refused to work in such
conditions.
The source of the hot water, and the impact of Comstock
and the California Gold Field on American mining and
exploration practice, and their effect on economic geology,
will be discussed in the next chapter. CIM
References
Bastin, E.S. (1922). Bonanza ores of the Comstock Lode, Virginia City, Nevada. United States
Geological Survey Bulletin, 735-C, 41-63.
Becker, G.F. (1882). Geology of the Comstock Lode and the Washoe district. U.S. Geological
Survey Monograph, 3.
Berger, B.R., Tingley, J.V., & Drew, L.J. (2003). Structural localization and origin of compartmentalized fluid flow, Comstock Lode, Virginia City, Nevada. Economic Geology, 98, 387-407.
Hudson, D.M. (2003). Epithermal alteration and mineralization in the Comstock District,
Nevada. Economic Geology, 98, 367-385.
Lindgren, W. (1913). Mineral Deposits. New York: McGraw-Hill Book Company, Inc.
Lord, E. (1883). Comstock Mining and Miners. Washington: United States Geological Survey.
(Reprinted in 1959 by Howell-North Books Publishers, San Diego).
Paul, R.W. (1963). Mining Frontiers of the Far West, 1848-1880. New York: Holt, Rinehart and
Winston.
Richthofen, F. (1868). The Natural System of Volcanic Rocks. San Francisco: California
Academy of Sciences.
Rickard, T.A. (1932). A History of American Mining. New York: McGraw-Hill Book Company, Inc.
Smith, G.H. (1943). The history of the Comstock Lode: 1850-1920. University of Nevada
Bulletin, Geology and Mining Series, 37. (Reprinted in 1966 by the Nevada State Bureau of
Mines and the Mackay School of Mines, Reno).
Twain, M. (1872). Roughing It. Hartford: American Publishing Company. [Mark Twain was the
pen name of Samuel Langhorne Clemens (1835-1910).]
Watkins, T.H. (1971). Gold and Silver in the West: The Illustrated History of an American
Dream. Palo Alto: America West Publishing Company.
history
The Comstock Lode, Nevada (Part 3)*
by R.J. “Bob” Cathro
Chemainus, British Columbia
The number of men on the payrolls of
the Comstock mines increased from perhaps 1,500
in the 1860s to more than twice that in the 1870s,
with possibly two-thirds of the men classified as
“miners,” the rest occupying nearly 40 categories
of skilled and unskilled labour. One of the bigger
mines might have 500 to 700 employees… The
census of 1880 showed that while native
Americans formed more than half of the total
population, in the mining labour force they were
greatly outnumbered, only 770 of 2,770 being
American-born. Of the 1966 listed in the special
category of “miners,” 691 were Irish, 543 English
(including Cornishmen but excluding Welshmen),
394 Americans, 132 Canadians and the rest
scattered among very small national groups. By
contrast, Americans had pre-empted jobs that
required operating or maintaining machinery. … A
“Miners Protective Association” was formed at
Virginia City in 1863 … to maintain the existing
standard wage of $4 per day, in coin, for all work
done underground.
(PAUL, 1963)
All the information in this chapter on stock markets
has been derived from Sears (1973) unless otherwise
noted.
74 | CIM Magazine | Vol. 3, No. 4
The unusually hot water encountered in the Comstock mines played an
important role in pointing geologists and miners to the link between hot
springs, hydrothermal fluids and mineralization. Similar hot water occurred in
a large geyser field at Steamboat Springs, 11 kilometres northwest of Comstock
and 16 kilometres south of Reno, Nevada. A period of intense fumarolic activity between 1984 and 1987, before the installation of a geothermal power
plant, showed that up to 21 springs are present, making it either the fourth or
fifth largest geyser field in the world. Whereas the geysers had reached heights
of up to 15 metres previously, the power plant lowered the water table to about
10 metres below surface (GOSA, 1989).
The Steamboat Springs geyser field lies within a small northeast-trending
belt of rhyolite domes and flows about eight kilometres long. Two of the domes
are up to one kilometre in diameter, three others are smaller and a questionable dome underlies the hot springs. Hot spring activity may have started as
long as 3 million years ago but two of the domes have been dated at only 1.21
and 1.14 Ma. The active sinter deposits include small quantities of gold, silver,
mercury, antimony, arsenic, thallium, sulphur and boron (Stone, 1990). It was
natural that early workers in the district would notice the similarities between
the hot water in the Comstock Lode and Steamboat Springs.
The mines at Comstock and in the California gold districts made vital contributions to the emerging science of economic geology and to mining technology. Future advances in economic geology would be dependent on the discovery and development of new mines that would provide the field laboratories for
studying the origin and occurrence of metals. In addition to systematic
prospecting, future discoveries were also dependent on risk capital and better
mining techniques to explore the new prospects at depth. Comstock and
California gold created the excitement that ensured that the tools would be
provided to achieve those aims. Those tools were mining stock exchanges for
raising the risk capital and a modern mining equipment manufacturing industry, neither of which existed before. Both of these became centred in San
Francisco, turning it into a world mining capital for about three decades.
The first U.S. paper currency (the ‘greenback’) was issued in 1862, near the
start of the Civil War and just as the Comstock boom was starting. The paper
dollar tended to trade at a substantial discount to gold because it was not
directly exchangeable. Speculation in gold was transacted through an exchange
in New York, where the value of the greenback fluctuated widely according to
the war news and traded as low as 40 cents. The federal government had a
strong incentive to support new mining developments in the West, since it
needed to acquire substantial reserves of gold and silver to finance the war.
Thus, the Civil War had a far-reaching influence on gold and silver mining in
California and Nevada.
Public stock companies focused on mining had already appeared at the time
of the California gold rush. Between 1850 and 1859, 432 companies were
incorporated in California, three-quarters of which were mining or water companies (see CIM Magazine, Vol. 2, No. 7, p. 102). The number of incorporations skyrocketed during the Comstock rush; 2,933 were formed in 1863
alone, 84 per cent of them gold and silver mines (Jung, 1999). That was partly
because these mines required relatively more capital for milling equipment
than the California gold mines, but also because the public became far more
economic geology
Above: Pacific Iron Works single-drum hoist, which was made in two sizes — one for
work to a depth of 130 m, and another for work to 200 m. Reproduced in the Mining
and Scientific Press, February 19, 1881 (from Bailey, 1996).
Right: Hendy ore crusher, the cheapest on the market. Only the outer jaw moved and
the shoes and dies were easy to replace. Reproduced in the Mining and Scientific
Press, November 20, 1880 (from Bailey, 1996).
involved in stock speculation. Eastern U.S. and European
investors showed scant interest in California or Nevada
until the rise of lode mining, which they recognized as a
complex, capital-intensive activity that required sophisticated machinery and scientific processes. Promoters
worked hard to convince the public that mining was no
longer a reckless adventure but rather a modern industry
conducted by sober businessmen with practical experience. They skilfully used the press to attract investors by
contributing newspaper articles, writing letters to editors
and serving as sources. The press responded with optimism. Some promoters began to produce elaborate stock
prospectuses for investors to examine (Jung, 1999).
In contrast to stock exchanges in distant capital markets that focused on financing banks, insurance companies, railways, utilities and other major corporations, a
large number of mining stock exchanges (also called stock
boards or brokers boards) were formed in or near western
gold and silver “boom towns,” beginning in 1861. One
feature that distinguished the western mining markets was
the close connection, some said far too close, between
mining companies and banks. Ten exchanges opened in
California between 1861 and 1864, eight of which were in
San Francisco. In Nevada, seven opened in 1863 and four
in 1864, five of which were in Virginia City and three at
Gold Hill. Two more were opened in Portland in 1864 and
1865. Most of them (including the first one, called the San
Francisco Board of Brokers) were short-lived, even
“ephemeral,” partly because several were wiped out by a
local depression in the Nevada market in 1864–1865. By
1870, San Francisco was established as a major financial
centre.
Much has been written about the early California stock
exchanges, which were characterized by gambling, manipulation and fraud long before the era of regulatory over-
sight. The motivation of the early organizers was largely
self-interest. According to one 1861 anecdote, “it became
customary for large stock owners to meet in the morning,
pretend to make sales to one another and report their
transactions to brokers, who then used these prices in
making deals with their customers.” This gave legitimate
brokers a strong incentive to start the San Francisco Stock
and Exchange Board in 1862. It operated until 1967.
One particularly important function of specialized
(mining) exchanges was their assistance in the growth of
an industry of vital importance in the economic progress
of the country and the direction and speed of settlement
(Sears, 1973).
In spite of the improprieties and abuses, the better mining exchanges gradually became reputable and served a
valuable, even crucial, role in generating the risk capital
needed for exploration. At a time when the industrialization of the United States was in its early stages, the mining industry took the lead in the organization of limited
liability companies and specialized stock exchanges to
facilitate the flow of capital. The mining exchanges also
played an important role in making the mining industry a
leader in the widespread use of the corporate form of business organization and in the distribution of securities to
the public.
San Francisco was also strategically positioned, with
its large harbour and river access to the gold fields, to
develop into an important manufacturing centre to serve
the mining industry. The West Coast was relatively isolated from the great eastern industrial centres until the
transcontinental railways were built across the mountains
June/July 2008 | 75
economic geology
Above: Severance & Holt No.1 prospecting drill. An early model, portable diamond drill
with a 15 HP steam engine. Reproduced in the Mining and Scientific Press, May 7,
1870 (from Bailey, 1996).
Right: Ingersoll rock drill powered by compressed air, which was represented in San
Francisco by Parke and Lacy. Reproduced in the Mining and Scientific Press, August
19, 1882 (from Bailey, 1996).
to the Pacific Coast, starting in 1869. Local entrepreneurs
took advantage of this opportunity to develop a thriving
industry producing custom-made and locally designed
equipment. By 1864, 47 foundries and machine shops
had been established, including names such as Union
Iron Works, Pacific Iron Works, Risdon Iron and
Locomotive Works, Fulton Foundry and Iron Works,
Pelton Water-Wheel Company, Parke and Lacy, Vulcan
Foundry and Iron Works, Joshua Hendy Iron Works,
Aetna Iron Works, California Wire Rope Company and
others. Their crushers, stamp mills, hoists, headframes,
pumps, steam engines, dredges, aerial tramways and
smelter equipment could soon be found at every mine site
in western North America, as well as in Central and South
America and throughout the Eastern Hemisphere. In
1876, 2,000 workers were employed in the San Francisco
mining machinery industry, earning between $3 and $5
per day.
After the railroads reached the coast, the San Francisco
firms began to face steadily increasing competition and, by
1892, much of the mining equipment used in the West
76 | CIM Magazine | Vol. 3, No. 4
was being supplied from Chicago and Milwaukee by companies like Allis-Chalmers and Ingersoll. By 1919, the
transition was complete and the strongest of the San
Francisco companies were only able to survive by switching to shipbuilding and other new fields. CIM
References
Bailey, L.R. (1996). Supplying the mining world: the mining equipment manufacturers of San
Francisco 1850 - 1900. Tucson, Arizona: Westernlore Press.
GOSA (1989). The annual journal of the Geyser Observation and Study Association,
Transactions, Volume 1. Retrieved on October 30, 2007, at http://www.uweb.ucsb.edu/~glennon/geysers/world.htm.
Jung, M.A. (1999). Capitalism comes to the diggings: from gold-rush adventure to corporate
enterprise. In J.J. Rawls and R. Orsi (Eds.), A Golden State: mining and economic development
in gold rush California. Berkeley: University of California Press in association with the
California Historical Society.
Paul, R.W. (1963). Mining frontiers of the far west, 1848 - 1880. New York: Holt, Rinehart and
Winston.
Sears, M.V. (1973). Mining stock exchanges 1860 -1930: an historical survey. Missoula:
University of Montana Press.
Stone, D. (1990). In C.A. Wood and J. Kienle (Eds.), Volcanoes of North America: United States
and Canada (pp. 252-262). Cambridge: Cambridge University Press.