The Problem of Water
Mine Drainage at Bodie
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 feet with each stroke. Pivoted counterbalances called “balance bobs” attached at points along the rod’s length overcome the rod’s enormous mass. Bobs were permanently mounted in excavated “bob stations.” Underground components, comprising pumps, pipes, bobs, and the reciprocating rod, were called “pitwork” from an old English word “pit” that meant mine. The weight of the parts moving below ground in a Cornish system could be immense, especially if the shaft were deep. Overcoming the inertia of such an assembly and moving it up and down required a powerful engine operating at laboriously slow speeds.
Engine. Steam engines that placed Cornish pumping
machinery into motion during the early 1800s were another development of
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
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