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August 2006
The Problem of Water
Mine Drainage at Bodie
By
Michael H. Piatt
Any hole in the ground, if dug deep enough, will strike water. This is as true for wells as it is for mineshafts. Water in a mine, however, must be removed so men can work. Bodie’s mining companies employed four methods to remove water from their shafts: bailing, pumping with steam pumps, pumping with Cornish pumping systems, and driving tunnels. Very often, several methods were used together.
Bailing Tanks. The most expedient
and inexpensive method of clearing water from a mine, in terms of initial cost,
was bailing, which required only a watertight bucket-like container and the
mine’s hoisting machinery. Bailing was
simple. The hoist lowered the container
into the mine for filling, then emptied it at the
surface. Water usually appeared first at
the bottom of a shaft, where men worked to sink it deeper. Bailing at Bodie commenced about February
1879, when mineshafts along the ridge began striking water at depths of 400 to 500
feet. Miners cleared their dank work
areas by hand pumping water into the ore bucket, which the hoist raised and
dumped it at the surface.
An entire mine comprising crosscuts, drifts, and stopes
could also be bailed after the shaft had been excavated 20 or 30 feet beyond
the lowest level. The added depth served
as a “sump,” where water collected from the upper levels.
Dumping hundreds of gallons at the
surface without spilling water down the shaft tested the ingenuity of workers,
who rigged devices to safely empty a tank as quickly as possible. One simple mechanism overturned the tank when
it reached the surface, like dumping rocks from an ore bucket. A worker hooked a chain to the tank’s bottom,
then the tank upended when the hoist reversed.
A “discharge sluice” or “launder” carried cast off water away from the
open shaft and directed the flow toward the nearest ravine. Another mechanism required an inlet valve
with a downward projecting stem that pushed the valve open as the hoist lowered
the tank into the discharge sluice. Yet
another method utilized linkage to open a side valve the moment an ascending
tank cleared the surface.
Although readily deployed, bailing
tied up the shaft and hoist, becoming intolerable when water removal interrupted
mining. Efficiency could be improved by
suspending a tank beneath a cage, allowing the hoist to transport rock, men, or
tools between loads of water. Skips
equipped with inlet valves also removed water amid ore deliveries.
As Bodie’s mines expanded in depth
and breadth, ever-increasing inflow forced superintendents who believed pay
rock lay beneath the water line to abandon bailing and purchase steam-powered
pumps. Still, they kept their tanks
handy. Seasonal fluctuations in
groundwater often overwhelmed the pumps, prompting one nineteenth-century
expert to advise: “Bailing appliances
should be in readiness for immediate use at every mine operated through shafts
or inclines, to relieve or aid pumps.”
(Behr 1896, 150) Demonstrating
bailing’s practicality, from high atop Bodie Bluff the
Tioga Mine sank the district’s second deepest shaft to 1,100 feet with only
hand pumps and a bailing tank.
Steam Pumps. When bailing became futile or
prohibitive, pumps were the next option.
Bodie’s mine superintendents had two choices--steam pumps or Cornish
pumps. Compact “steam pumps” had long
fulfilled a wide variety of industrial needs.
Their 1840s inventor, Henry R. Worthington of
Although practical, steam pumps were
plagued with deficiencies. Most
important, they wasted power. Each unit
also required a power and discharge pipe to the surface. Heat and exhaust vapor released inside a mine
made conditions rough on men, machinery, and timbers, calling for an exhaust
pipe as well. Another crucial
disadvantage became painfully apparent when the pumps were needed most--they
would not run under water. Nevertheless,
steam pumps were popular. Between June
1879 and mid-1880 seven companies at Bodie installed them to extend their
shafts below the water line. Purchased
during the frenzy when only a few mines had demonstrated wealth, steam pumps
controlled water in the Mono (first pumps in the district), Bodie, Noonday,
Mining companies also installed
steam pumps on the surface where steam engines were at work. The pumps forced water into boilers and
safeguarded hoisting works and stamp mills against fire. Equipped with hoses and supplied by storage
tanks filled with water from the mine, steam pumps protected Bodie’s essential
wooden structures. The pumps also fought
fires downtown. Before early 1880, when
hydrants were installed, merchants reduced their insurance costs by digging
wells, usually at the rear of their establishments, and equipping each with a
steam pump and hose.
Sump Pumps. Manufacturers produced two steam pump types
specifically for mining. Units deployed
at the bottom of a shaft, known as “lift” or “sinking” pumps, raised water from
below then pushed it upward--the first stage in delivering water to the
surface. Vertically configured and
slender for the confined work area at the bottom of a shaft, the combined steam
engine and pump drew water through a hose, allowing miners to place the intake
where needed. Readily repositioned, a
sinking pump descended with the shaft, becoming a permanent installation at the
bottom of a mine, where it drew water from the sump to keep the upper levels
dry.
Station Pumps.
Usually larger and more powerful than sinking pumps, horizontally-configured
engine and pump units moved water up the discharge pipe in stages, from one
pump to the next, to discharge it at the surface. Permanently mounted on sturdy foundations in
excavated “pump stations” adjoining the mineshaft, the pumps drew water from
nearby supply tanks that received water from the pump below and seepage from
levels above. A float automatically
started and stopped the pump to maintain water at the proper level.
One popular style joined two steam
pumps side by side, forming a “duplex pump.”
Four pumps powered by two steam engines maintained a steady stream of
water and minimized damaging impulses inside the vertical discharge pipe. Duplex pumps became an industry standard,
receiving praise as “one of the most ingenious, effective and certainly one of
the most largely applied advances in modern engineering.” (Hunter 1991, 474)
Cornish Pumps. Another pumping
system at Bodie originated in the tin and copper mining region of
Mine managers were willing to bear
the cost of pumping if they believed rich ore lay below. This was never more true
than during Bodie’s frenetic mining boom, when over-optimistic directors
squandered capital to push downward.
Beginning in July 1879, five Bodie mines installed Cornish pumps: the Booker (first in the district), Standard,
Champion, South Standard, and Jupiter.
Two monumental Cornish pumps installed at the Red Cloud and Lent shafts
in July and December 1880 respectively became the district’s last. Possessing Bodie’s largest and most powerful
steam engines, these two centrally-located shafts were equipped to raise water
more than 2,500 feet (though neither shaft extended deeper than 1,200
feet). Their energy requirements were
astronomical. Boilers at the Lent Shaft
consumed 23 to 24 cords every 24 hours in 1889 so miners could reach the
1,200-foot level.
To the dismay of stockholders,
Bodie’s ore grew poorer the deeper the mines went, and the lower levels rarely
yielded enough to pay expenses. Added to
mining and milling costs, the enormous cost of water removal repeatedly forced
miners back to the upper levels. The Red
Cloud ceased pumping in 1882, the Lent Shaft in 1883, and the Standard in
1884. By the time these principal
companies stopped pumping, every other mine in the district had abandoned its
watery levels. Pumping resumed at the
Lent Shaft 1885, but ended in 1890 after an attempt to find pay ore below the
water line proved futile. Even
technological advances in the 1890s, resulting in less expensive
electric-powered pumps, failed to excite interest in Bodie’s flooded levels
until 1928, when electric pumps drained the reopened Red Cloud. In the absence of profitable ore, that
venture failed within four years.
A Cornish pump comprised three major
components: pumps placed at intervals in
the mineshaft, a pump rod moving up and down to operate the pumps, and a steam
engine on the surface to set the pump rod in motion. Cornish pumps raised water in stages, similar
to steam pumps, except that steam was not piped down the shaft to deliver
power. Instead, lift pumps and station
pumps received power from the timber rod moving up and down in the shaft’s
pumping compartment. Each pump overcame
only a small head as it forced water upward to the next storage tank, and so
on, until the water reached the surface.
Lift Pumps. The pump at the shaft’s bottom pulled water
through a suction hose and pushed it through a pipe to a supply tank
above. Cornish “lift pumps” or “sinking
pumps” drew water in and forced it upward during the pump rod’s upstroke. Extensions added to the pump rod and
discharge pipe allowed the pump to follow the shaft downward and remain close
to the work area. After a mine had been
fully developed, a lift pump raised water from the sump, draining the workings
above.
Station Pumps. Placed in stations at intervals 200 to 300
feet apart along a mineshaft, “force pumps” or “plunger pumps” were generally
larger and more powerful than sinking pumps, requiring permanent installations
with supply tanks that received water pumped from below and seepage from
workings above. Water from each supply
tank flowed by gravity into the adjacent pump, which forced it up the pipe
column as the pump rod moved downward.
Each pump forced water up to the next supply tank, and so on, to the
surface. Since the length of the stroke
and pump diameter remained constant, the frequency of strokes regulated the
volume of water pumped.
Pump Rod. The rod that delivered power to the pumps
consisted of timbers, 6 to 18 inches square, spliced end to end with bolts and
iron strapping. Suspended in the shaft’s
pumping compartment, this ponderous connecting rod moved up and down
Engine. Steam engines that placed Cornish pumping
machinery into motion during the early 1800s were another development of
Subterranean pumps
powered by a reciprocating rod were known in the American West as “Cornish
Pumps.” While Cornish Pumps were
employed in western mining, Cornish engines were not. Instead, mine superintendents preferred
smaller, less expensive high-pressure steam engines of American design and
manufacture. Although not necessarily
more efficient or more powerful than their Cornish counterparts, modern engines
were more easily adapted to fluctuating water volumes and increasing mine
depths. These engines resulted from a
revolution in engine design initiated simultaneously by Richard Trevithick of
Pumping engines at Bodie ran under high boiler pressures (80-120 psi) and delivered power on both strokes of the piston, requiring balanced pitwork that equalized the workload in both directions. They ran at only about 6 or 7 strokes per minute, with a maximum of fewer than 15. Although the Booker’s pumping engine resembled a Cornish engine by deriving power from a vertical cylinder that transmitted motion through a walking beam, it was not a true Cornish engine. There is no doubt about Bodie’s other engines. The Corliss engine at the Standard Mine converted rotational to reciprocating motion through gears and an enormous toothed “spur-wheel” weighing 16,425 pounds. A connecting rod and bob transferred power from the large wheel to the pump rod. Bodie’s largest and most powerful engines, those at the Red Cloud and Lent shafts, employed horizontal cylinders that allowed one engine to drive two pump rods and double the amount of water delivered to the surface. The Red Cloud’s mighty compound pumping engine, by far Bodie’s largest, required steam from four boilers. Its 27-inch diameter high-pressure cylinder adjoined a low-pressure cylinder 48 inches in diameter. Placed end to end, the two cylinders with 8-foot strokes could raise 2,000,000 gallons of water every 24 hours, but the mine shut down before full capacity was needed. The Lent Shaft’s engine, possessing a single 40-inch diameter cylinder with an 8-foot stroke, received a second line of pumps in 1887 to sustain a costly 200 foot drive to the 1,200-foot level, where high-grade ore was anticipated but not found. After 1890, when the effort to open deeper levels ended, the Lent’s pumps held groundwater below the 700-foot level until 1893, the last time a Cornish pump operated at Bodie.
Tunnels. The oldest and
most direct method of draining a mine was tunneling to provide a drainage
outlet. Tunnels conveyed water from
underground workings without machinery.
The concept is simple, but initial costs were high. Tunnels, however, furnished natural drainage
forever with only occasional maintenance and also provided ventilation and a
convenient route for transporting ore and waste rock. By the strictest definition, a “tunnel” must
pass completely through a mountain and have openings at each end, like railroad
tunnels. A horizontal passageway that
penetrates only part way is said to be an “adit.” Despite these lexical distinctions, a
near-horizontal passageway driven into an American mountain for mining was
called a “tunnel,” whether it went all the way through or not. Presumably intended to reach an ore body,
tunnels driven at a slight upward angle conveyed water by gravity. Covered wooden troughs, known as “boxes” (as
in sluice boxes), carried water through the tunnel. Buried alongside or sometimes under a track,
boxes allowed men, mules, and mine cars to pass without interference from
flowing water.
Bodie boasted three major
tunnels: the Bulwer, Bodie Tunnel, and
Syndicate. Each was roughly 2,000 feet
long, but none of them provided natural drainage. Driven from
BIBLIOGRAPHY
Barton, D. B.
The Cornish Beam
Engine.
Behr, Hans C.
Mine Drainage, Pumps, Etc. In
Collins, Henry F.
“Cornish Pumps and Pumping Engines.” Mining
and Scientific Press (
de Laval, Carl George P.
“Pumping on the Comstock.” Engineering
and Mining Journal (
Hunter, Louis C.
A History of Industrial Power in
the
_______ and
Ihlseng, M. C.
A Manual of
Mining.
Moore, Joseph, and George W.
Dickie. Pumping and Hoisting Works for Gold and Silver Mines.
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