See G. Smith, History of the Comstock Lode (1943); G. Lyman, The Saga of the Comstock Lode (1934, repr. 1971); L. Beebe and C. Clegg, Legends of the Comstock Lode (4th ed. 1956).
The Comstock Lode was the first major U.S. deposit of silver ore, discovered under what is now Virginia City, Nevada on the eastern slope of Mt. Davidson, a peak in the Virginia range. After the discovery was made public in 1859, prospectors rushed to the area and scrambled to stake their claims. Mining camps soon thrived in the vicinity, which became bustling centers of fabulous wealth.
The excavations were carried to depths of more than 3200 feet (1000 m). Between 1859 and 1878, it yielded about $400 million in silver and gold.
It is notable not just for the immense fortunes it generated and the large role those fortunes had in the growth of Nevada and San Francisco, but also for the advances in mining technology that it spurred. The mines declined after 1874.
Gold was discovered in this region in the spring of 1850. It was discovered in Gold Canyon, by a company of Mormon emigrants on their way to the California Gold Rush. After arriving too early to cross the Sierra, they camped on the Carson river in the vicinity of Dayton, Nevada, to wait for the mountain snow to melt. They soon found gold along the gravel river banks by panning, but left when the mountains were passable, as they anticipated taking out more gold on reaching California. Other emigrants followed, camped on the canyon and went to work at mining. However, when the supply of water in the canyon gave out toward the end of summer, they continued across the mountains to California. The camp had no permanent population until the winter and spring of 1852–53, when there were 200 men at work along the gravel banks of the canyon with rockers, Long Toms and sluices.
The gold from Gold Canyon came from quartz veins, toward the head of the vein, in the vicinity of where Silver City and Gold Hill now stand. As the miners worked their way up the stream, they founded the town of Johntown on a plateau. In 1857, the Johntown miners found gold in Six-Mile Canyon, which is about five miles (8 km) north of Gold Canyon. Both of these canyons are on what is now known as the Comstock Lode. The early miners never thought of going up to the head of the ravines to prospect the quartz veins, spending their time on the "free" gold in the lower elevation surface deposits of earth and gravel.
Credit for the discovery of the Comstock Lode is disputed. It is said to have been discovered, in 1857, by Ethan Allen Grosh and Hosea Ballou Grosh, sons of a Pennsylvania clergyman, trained mineralogists and veterans of the California gold fields. Hosea injured his foot and died of septicaemia in 1857. In an effort to raise funds, Allen, accompanied by an associate Richard Maurice Bucke, set out on a trek to California with samples and maps of his claim. Henry Tompkins Paige Comstock was left in their stead to care for the Grosch cabin and a locked chest containing silver and gold ore samples and documents of the discovery. Grosch and Bucke never made it to California, getting lost and suffering the fate of severe hardship while crossing the Sierran trails. The two suffered from gangrene and at the hands of a minor-surgeon lost limbs through amputation, a last ditch effort to save the lives of the pair. Allen Grosch died on December 19, 1857. R.M. Bucke lived, but upon his recovery returned to his home in Canada.
When Henry T. P. Comstock learned of the death of the Grosch brothers, he claimed the cabin and the lands as his own. He also examined the contents of the trunk but thought nothing of the documents as he was not an educated man. What he did know is that the gold and the silver ore samples were from the same vein. He continued to seek out diggings of local miners working in the area as he knew the Grosch brothers' find was still unclaimed. Upon learning of a strike on Gold Hill which uncovered some bluish rock (silver ore), Comstock immediately filed for an unclaimed area directly adjacent to this area.
The four miners that discovered the Gold Hill outcropping were James Fennimore ("Old Virginny"), John Bishop ("Big French John"), Aleck Henderson and Jack Yount. Their discovery was actually part of the Comstock Lode, but not a main vein. The four men are therefore credited with the rediscovery of the mine previously found by the Grosch brothers.
In the Spring of 1859, two miners, Peter O'Riley and Patrick McLaughlin, finding all the paying ground already claimed went to the head of the canyon and began prospecting with a rocker on the slope of the mountain near a small stream fed from a neighboring spring. They had poor results in the top dirt as there was no washed gravel, and they were about to abandon their claim when they made the great discovery. They sunk a small, deeper pit in which to collect water to use in their rockers. In the bottom of this hole there was material of a different appearance. When rocked out, they knew they had made their "strike" as the bottom apron was covered with a layer of gold.
In that hole, silver mining in America as we know it was born. In the rocker along with the gold was a large quantity of heavy blue-black material which clogged the rocker and interfered with the washing out of the fine gold. When assayed however, it was determined to be almost pure sulphuret of silver.
In June of the year O'Riley and McLaughlin made their find, Henry T. P. Comstock learned of the two men working on land that Comstock allegely had already claimed for "grazing purposes". Unhappy with his current claim on Gold Hill, Comstock made threats and managed to work himself and his partner, Emanual "Manny" Penrod, into a deal that granted them interest on the claim.
The geographic accounts on the location of the Comstock Lode were muddled and inconsistent. In one report, the gold strike was "on the Eastern fork of Walker's river" and the silver strike "about halfway up the Eastern slope of the Sierra Nevada" and "nine miles West of Carson River."
Patrick McLaughlin sold his interest in the Ophir claim for $3,500 which he soon lost. He then worked as a cook at the Green mine in California. He died working at odd jobs.
Emanuel Penrod sold his share of the interest for $8,500 .
Peter O'Riley held on to his interests collecting dividends, until selling for about $40,000. He erected a stone hotel on B Street in Virginia City called the Virginia House, and became a dealer of mining stocks. He began a tunnel into the Sierras near Genoa, Nevada, expecting to strike a richer vein than the Comstock. He lost everything, went insane and died in a private asylum in Woodbridge, California.
Comstock traded an old blind horse and a bottle of whiskey for a one-tenth share formerly owned by James Fennimore ("Old Virginny"), but later sold all of his holdings to Judge James Walsh for $11,000 . He opened trade good stores in Carson City and Silver City. Having no education and no business experience, he went broke. After losing all his property and possessions in Nevada, Comstock prospected for some years in Idaho and Montana without success. In September 1870, while prospecting in Big Horn country, near Bozeman, Montana, he committed suicide with his revolver.
The ore was first extracted through surface diggings, but these were quickly exhausted and miners had to tunnel underground to reach ore bodies. Unlike most silver ore deposits, which occur in long thin veins, those of the Comstock Lode occurred in discrete masses often hundreds of feet thick. The ore was so soft it could be removed by shovel. Although this allowed the ore to be easily excavated, the weakness of the surrounding material resulted in frequent and deadly cave-ins.
The cave-in problem was solved by the method of square-set timbering invented by Philip Deidesheimer, a German who had been appointed superintendent of the Ophir mine. Previously timber sets consisting of vertical members on either side of the diggings capped by a third horizontal member used to support the excavation. However, the Comstock ore bodies were too large for this method. Instead, as ore was removed it was replaced by timbers set as a cube six feet on a side. Thus, the ore body would be progressively replaced with a timber lattice. Often these voids would be re-filled with waste rock from other diggings after ore removal was complete. By this method of building up squares of framed timbers, an ore vein of any width may be safely worked to any height or depth.
Early in the history of Comstock mining, there were heavy flows of water to contend with. This called for pumping machinery and apparatus, and as greater depth was attained, larger pumps were demanded. All the inventive genius of the Pacific Coast was called into play, and this resulted in construction of some of the most powerful and effective steam and hydraulic pumping equipment to be found anywhere in the world. Initially, the water was cold, but the deeper workings cut into parts of the vein where there were heavy flows of hot water. This water was hot enough to cook an egg or scald a man to death almost instantly. Lives were lost by falling into sumps of this water hot from the vein. The hot water called for fans, blowers and various kinds of ventilation apparatus, as miners working in heated drifts had to have a supply of cool air.
Compressed air for running power drills and for driving fans and small hoisting engines was adopted in the Comstock mines. Diamond drills for drilling long distances through solid rock were also in general use, but were discarded for prospecting purposes, being found unreliable. Several new forms of explosives for blasting were also developed.
Great improvements were also made in the hoisting cages used to extract ore and transport the miners to their work. As the depth of the diggings increased, the hemp ropes used to haul ore to the surface became impractical, as their self-weight became a significant fraction of their breaking load. The solution to this problem came from A. S. Hallidie in 1864 when he developed a flat woven wire rope. This wire rope went on to be used in San Francisco's famous cable cars.
In 1859 the Americans knew nothing about silver mining. In the California placer mines there were a number of Mexicans who had worked silver mines in their own country. Initially, the Comstock miners endeavored to partner with Mexicans, or at least hire a Mexican foreman to take charge of the mine. The Mexicans adopted their methods of arastras, patios and adobe smelting furnaces to process silver ore. These methods proved to be too slow for the Americans and could not process the quantities of ore being extracted. The Americans introduced stamp mills for crushing the ore, and pans to hasten the process of amalgamation. Some of the German miners, who had been educated at the mining academy of Freiberg, were regarded as the best then existing to work with argentiferous ores. They introduced the barrel process of amalgamation and the roasting of ores. While the barrel process was an improvement on the patio, it was found not to be well adapted to the rapid working of the Comstock ores as pan amalgamation. The Comstock eventually developed the Washoe process of using steam-heated iron pans, which reduced the days required by the patio process to hours.
In the early days of pan processing of ores, there were tremendous losses in precious metals and quicksilver (mercury). Almost every millman was experimenting with some secret process for the amalgamation of ore. They tried all manner of trash, both mineral and vegetable, including concoctions of cedar bark and sagebrush tea. At that time, untold millions in gold, silver and quicksilver were swept away into the rivers with the tailings. Although many patterns and forms of amalgamating pans were invented and patented, there was much room for improvement. Improvements were made from time to time, resulting in reductions in losses of metals, but none of the apparatus in use on the Comstock was perfect.
Before railroads were built, all freight and passengers were transported by teams of from 10 to 16 horses or mules. Ore was hauled to the mills by these teams, which also brought to the mines all the wood, lumber and timber required. Teams also hauled over the Sierras all the mining machinery, all supplies required by both mines and mills, and goods and merchandise needed by the stores and businesses. Each team hauled trains of from two to four loaded wagons. When the large reduction works of the Ophir Mining Company were in peak operation, lines of teams from one to three miles (5 km) in length moved along the wagon roads, and sometimes blocked Virginia City streets for hours.
In 1859, 1860 and 1861, great quantities of goods were transported across the Sierras to and from California on the backs of mules. When the Central Pacific Railroad line was completed, this hauling was from Virginia City to Reno via the Geiger grade wagon road, for transfer to rail for delivery to points east and west.
Ground was broken on the Virginia and Truckee Railroad on February 19, 1869 and eight months thereafter, the most difficult section from Virginia City to Carson City was completed. Rails were extended North across the Washoe valley, from Carson City to Reno, where it connects with the Central Pacific. Between Virginia City and Carson City, at Mound House, the railroad also connects with the Carson and Colorado Railroad.
When silver was first discovered on the Comstock, the flow of water from natural springs was adequate to supply the needs of the miners and small towns of Virginia City and Gold Hill, Nevada. As population increased wells were dug for domestic needs, and the water within several mine tunnels was added to the available supply. As the mills and hoisting works multiplied, the demand for water for use in steam boilers became so great that it was impossible to supply it without creating a water shortage among the residents, now thousands in number. In this need, the Virginia City and Gold Hill Water Company was formed, being the first non-mining incorporation on the Comstock Lode.
Water from wells and tunnels in the surrounding mountains was soon exhausted. It became imperative to look toward the main range of the Sierra Nevada mountains, where there was an inexhaustible supply. Between the Sierra and the Virginia ranges lay the Washoe Valley, a great trough nearly in depth. Herman Schussler, a Swiss trained engineer of great repute who had planned water works in San Francisco, was brought to the Comstock to plan and design the new works. Surveys were made in 1872, the first sections of pipe laid June 11, 1873 and the last on July 25 the same year.
The initial pipe was made of wrought iron, a total length of over , with an interior diameter of and a capacity of 92,000 gallons per hour. The pipe traversed the Washoe Valley in the form of an inverted siphon, and at the lowest point having a pressure of of water, or 800 pounds per square inch. The inlet being above the outlet, the water is forced through the pipe at tremendous pressure. Water was brought to the inlet in the Sierra Nevada range from sources of supply in two large covered flumes, and at the outlet end of the pipe was delivered in two large flumes a distance of to Virginia City. The pipe was constructed of sheets of wrought iron riveted together, each section fastened with three rows of rivets. Lead was used to secure the joints between each pipe section. The first flow of water reached Gold Hill and Virginia City on August 1, 1873 with great fanfare. This accomplishment was the greatest pressurized water system in operation in the world, having superseded the water system at Cherokee Flat also designed by Schussler.
The water company laid an additional pipe alongside the first in 1875, and a third pipe in 1877. These pipes of lap welded joints delivered more water, there being less friction of rivet heads upon the water. Additional flumes were also constructed to diversify and improve reliability of supply.
While there was a scarcity of water on the surface, there was an excess of water underground in all the mines. Floods in the mines were sudden and miners narrowly escaped being drowned by vast underground reservoirs that were unexpectedly tapped. Intrusion of scalding-hot water into the mines was a large problem, and the expense of water removal increased as depths increased. To overcome these troubles, Adolph Sutro conceived the idea of running a drain tunnel under the Comstock Lode from the lowest possible point. A survey was made by Schussler and work commenced in October 1869. The Sutro Tunnel was completed from the valley near Dayton through nearly four miles of solid rock to meet the Comstock mines approximately beneath the surface. From the main tunnel, branches were run north and south along the vein a distance of over two miles (3 km), connecting to various mines. The tunnel was wide and high. Drain flumes were sunk in the floor and over these were two tracks for horse carts. It required over eight years to complete construction. The tunnel provided drainage and ventilation for the mines as well as gravity-assisted ore removal. However, by the time the tunnel reached the Comstock area mines, most of the ore above had already been removed and the lower workings were deeper still. Although virtually no ore was removed through the tunnel, the drainage it provided greatly decreased the operating costs of the mines served. The ventilation problems were solved at about the same time by the use of pneumatic drills.
Peak production from the Comstock occurred in 1877, with the mines producing over $14,000,000 of gold and $21,000,000 of silver that year. Production decreased rapidly thereafter, and, by 1880, the Comstock was considered to be played out. The deepest depth was struck, in 1884, in the Mexican winze at below the surface. Underground mining continued sporadically until 1922, when the last of the pumps was shut off causing the mines to flood. Re-processing of mill tailings continued through the 1920s, and exploration in the area continued through the 1950s.
Comstock's silver mines were criticised for the way that their share prices were manipulated on the San Francisco stock exchanges, and for the way that insiders skimmed the profits to the detriment of the common shareholders. Insiders used rumors or assessments to drive share prices down, buy up the cheap shares, then spread rumors of large new silver finds to increase prices once more so that they could sell their shares at a profit. Mining company managers also issued contracts to themselves for timber, and water. Ore from the mines was commonly processed by ore mills owned by the company insiders, who were accused of keeping part of the silver they extracted for themselves, and refusing to make an accounting.
Nevada is commonly called the "Silver State" because of the silver produced from the Comstock Lode. However, since 1878, Nevada has been a relatively minor silver producer, with most subsequent bonanzas consisting of more gold than silver.
George Hearst, a highly successful California prospector, became head of Hearst, Haggin, Tevis and Co., the largest private mining firm in the United States, owned and operated the Ophir mine, on the Comstock Lode, as well as other gold and silver mining interests in California, Nevada, Utah, South Dakota and Peru. Hearst was a member of the California State Assembly and became a United States Senator from California. George Hearst was the father of the famed newspaperman, William Randolph Hearst.
William Chapman Ralston, founder of the Bank of California, financed a number of mining operations, repossessed some of those mines as their owners defaulted, and ultimately made enormous profits from the Comstock Lode.
William Sharon, a business partner of William Chapman Ralston, was the Nevada agent for the Bank of California, and acquired Ralston's assets when his financial empire collapsed. William Sharon became the second United States Senator from Nevada.
William M. Stewart, who abandoned mining to become an attorney in Virginia City, Nevada, participated in mining litigation and the development of mining on the Comstock Lode. As Nevada became a state in 1864, Stewart assisted in developing the state constitution and became the first United States Senator from Nevada.
Silver baron Alvinza Hayward, known in his lifetime as "California's first millionaire", held a significant interest in the Comstock lode after 1864.