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Methods for mining silver change for every body of ore. The method that's chosen depends on the grade of the ore, the steepness and shape of the terrain, its depth, host rock, transportation availability, and other economic factors. [7] Commonly, silver ore is obtained from open pit mines, and underground drifts and shafts. [7]
Annual US mined silver production. Silver mining in the United States began on a major scale with the discovery of the Comstock Lode in Nevada in 1858. The industry suffered greatly from the demonetization of silver in 1873 by the Coinage Act of 1873, known pejoratively as the "Crime of 73", but silver mining continues today.
The patio process is a process for extracting silver from ore. Smelting, or refining, is most often necessary because silver is only infrequently found as a native element like some metals nobler than the redox couple 2 H + + 2 e − ⇌ H 2 (gold, mercury, ...). Instead, it is made up of a larger ore body.
The Crown Point-Belcher bonanza was discovered in 1870. The ore body extended from the 900 to the 1,500-foot level (275 to 460 m), having a length of 775 feet (236 m) and a width of 120 feet (37 m). The ore, the precious metal value of which was 54 percent from gold and 46 percent from silver, lasted only four years. [2]: 137–138
The government purchases of silver were subsequently nearly doubled by the 1890 Sherman Silver Purchase Act, further extending the boom into the early 1890s. The repeal of the act in 1893 resulted in a collapse of silver prices, bringing about an end to the boom. After 1893, many mining camps became ghost towns. The accompanying collapse in ...
In 1920, about ten miners still worked, mostly mining silver-lead ore. Mining had largely ceased by 1938. [ 11 ] As of 2019 [update] , a former high school teacher was the only miner; the then-70-year-old had been collecting small amounts of silver underground since 1997, selling the silver to tourists, while searching for a productive vein.
Silver ore was first discovered in west-central Arizona in 1583 by Spanish explorer Antonio de Espejo, but no mining resulted.Again in 1598, Juan de Oñate led another expedition searching for Espejo’s silver; many claims were staked, but the expeditioners returned to Santa Fe without mining any silver, and the deposits remained unexploited.
Ore occurs in the Mississippian Leadville Limestone and the lower part of the overlying Pennsylvanian Belden Formation. Ore minerals include galena, sphalerite, and native silver. Early production was almost all silver, but after 1900, lead and zinc became economically important. Major mining operations continued until 1952.