Silver mining in the United States

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 "Crime of 73," but silver mining continues today.

The United States produced 1,200 metric tons of silver in 2007, 35% of the silver it used. The remaining 65% was imported from Mexico, Canada, Peru, and Chile. Thirty-six US mines reported silver production. Interest in silver mining has increased in recent years because of increased price of the metal: the average silver price increased from $4.39 per ounce for the year 2001, to $13.45 per ounce for 2007. ["Mining review," "Mining Engineering", May 2007, p.37-47.]

Alaska

In 2006, Alaska was the nation's leading silver-producing state. [http://minerals.er.usgs.gov/minerals/pubs/commodity/silver/silvemcs07.pdf] Two Alaska polymetallic mines were significant silver producers. The Red Dog mine, the world’s largest source of zinc, also produced 75 metric tons (2.4 million troy ounces) of silver. The Greens Creek mine produced 280 metric tons (8.9 million ounces) of silver. [D.J. Szumigala, "Alaska", Mining Engineering May 2007, p.66.]

External links

* [http://www.kennecottminerals.com/mines/greens.html Kennecott Minerals: "Greens Creek Mine"]
* [http://www.greenscreek.com/default.html Greens Creek Mining Company]

Arizona

More than 80% of the state's silver was a byproduct of copper mining; other silver came as a byproduct of lead, zinc, and gold mining. [Melissa Keane and A. E. Rogge (1992) "Gold & Silver Mining in Arizona 1848-1945", Arizona State Historic Preservation Office, p.14.] The most productive silver district in Arizona that was mined primarily for silver was Tombstone in Cochise County, discovered in 1877. [Melissa Keane and A. E. Rogge (1992) "Gold & Silver Mining in Arizona 1848-1945", Arizona State Historic Preservation Office, p.14.] In 2006, all the silver mined in Arizona came as a byproduct of copper mining.

California

Most of the silver produced in California has been a byproduct of mining other metals, such as copper (Copperopolis), tungsten (Pine Creek mine in Inyo County), or gold (Randsburg). [H.K. Stager (1966) "Silver", in "Mineral Resources of California", California Division of Mines and Geology, Bulletin 191, p.381-385.] However, there have been mines where silver was the principal product.

Silver mines at Panamint in Inyo County produced silver from 1873 until the town was destroyed by a flash flood in 1876. [Robert M. Norris and Robert W. Webb (1990) "Geology of California", New York: Wiley, p.212.]

The Cerro Gordo Mines in Inyo County started producing lead and silver in 1860. Ore bodies were replacements and fissure fillings in Paleozoic limestone. In the 20th century zinc became the principal product. [Robert M. Norris and Robert W. Webb (1990) "Geology of California", New York: Wiley, p.211.]

Silver was discovered at Calico in San Bernardino County in 1881, and mining was prosecuted strongly there until 1896. [Robert M. Norris and Robert W. Webb (1990) "Geology of California", New York: Wiley, p.248.]

Silver was discovered in 1919 in the eastern Rand district, near Randsburg and Johannesburg, in San Bernardino County . The Rand district had already been an established gold district. The Kelly Rand mine produced silver from miargyrite and pyrargyrite ores from 1919 to 1928. [Robert M. Norris and Robert W. Webb (1990) "Geology of California", New York: Wiley, p.246.]

Colorado

See main article, "Silver mining in Colorado"

Silver veins were first discovered in the Montezuma district of Summit County in 1864. Despite the early silver discoveries, Colorado’s largest silver district, Leadville was not discovered until 1874. The discovery at Leadville and started the Colorado Silver Boom.

The largest current source of silver in Colorado is as a byproduct of gold mining at the Cripple Creek & Victor mine, a large open-pit heap leach operation owned by AngloGold Ashanti at Victor, Colorado. In 2006, the mine produced 4.0 metric tons (130,000 ounces) of silver. [. Burnell and others, "Colorado", Mining Engineering, May 2007, p.76.>]

Idaho

The Coeur d’Alene district of Shoshone County in northern Idaho has produced more silver than any other mining district in the United States, and is historically one of the top three silver districts in the world in total silver produced. (It competes with Potosi in Bolivia and Pachuca-Real del Monte in Mexico for the title of greatest silver district, each having produced more than a billion troy ounces of silver). Through 2006, the Coeur d’Alene district has produced a total of more than 37,000 metric tons (1.2 billion ounces) of silver.

Three silver mines are currently operating in the Coeur d’Alene district: the Galena mine, owned by US Silver; the Sunshine mine, owned by Sterling Mining Co.; and the Lucky Friday mine. The Lucky Friday mine produced 89 metric tons (2.9 million ounces) of silver in 2006; the Galena mine produced 40 metric tons (1.3 million ounces) of silver in 2006. [V.S. Gillerman and others, "Idaho", Mining Engineering, May 2007, p.82.]

ee also

* Hercules Mine, Idaho

Missouri

Silver mining began in 1879 at the Einstein mine, nine miles northwest of Fredericktown in Madison County. The settlement of Silver Mine, complete with US Post Office was established to serve the miners of the Einstein, Ozark, and Apex mines. The mines closed within a few years, but reopened briefly in 1916 and again in 1927 to mine tungsten. [Carl Tolman (1933) "The geology of the Silver Mine area", in "57th Biennial Report", Appendix I, Missouri Bureau of Geology and Mines, p.5-34.]

Montana

Butte, Montana is historically the second-greatest source of silver in the United States, second only to the Coeur d’Alene district in Idaho. Butte started as a placer gold camp in 1864, and the placers were exhausted by 1867. But in 1874 prospectors discovered silver veins. Butte flourished as a silver-mining district until miners tunneled into large copper veins in 1882. From then until the 1980s, Butte was primarily a copper-mining district, but with a lot of silver as a byproduct. [Charles Meyer and others (1968) "Ore deposits at Butte, Montana", in "Ore Deposits in the United States, 1933-1967", New York: American Institute of Mining Engineers, v.2, p.1373-1416.] Over the years, Butte has produced more than 22,000 metric tons of silver.

Silver was discovered at Phillipsburg in 1864, and the district was one of the most prolific silver producers in Montana. Major mines included the Granite Mountain mine, the Bi-Metallic mine, and the Hope mine. In 1887, the district produced 2.2 million troy ounces (68 metric tons) of silver, making it the largest silver producer in the US for that year. [Lee I. Niedringhaus, "Silver rampage", Financial History, Fall 2005, p.26.] The district suffered greatly from the fall in the price of silver in 1893, and remained moribund until World War I, when the manganese deposits of the district became valuable, and Philipsburg became one of the top US producers of that metal. Silver occurs in veins filling fracture zones through Paleozoic limestone. Minerals in the silver-ore veins include polybasite, pyrargyrite, proustite, sphalerite, galena, and tennantite. Manganese occurs as replacement bodies of pyrolusite and rhodochrosite in limestone adjacent to the fracture zones. No mines are presently active in the district. [E. N. Goddard (1940) "Manganese deposits at Philipsburg, Granite County, Montana", US Geological Survey, Bulletin 922-G.]

Nevada

See main article: "Silver mining in Nevada"

The discovery of the Comstock Lode in 1858 inaugurated large-scale silver mining in the United States. The Comstock was the first important silver-mining district in the United States, and its discovery stimulated a great deal of prospecting for silver across the Great Basin area of the United States. The resulting silver rush led to many other silver discoveries in Nevada, including Austin (1862), Eureka (1864), and Pioche (1869).

New Hampshire

Silver-bearing galena was mined from three districts in New Hampshire. [Dennis P. Cox (1970) "Lead-Zinc-Silver Deposits Related to the White Mountain Plutonic Series in New Hampshire and Maine", US Geological Survey, Bulletin 1312-D.]

The Silver Lake mine near Madison in Carroll County operated intermittently from 1826 to 1918. Ore was extracted from underground workings until 1915, when a small open pit was dug.

The Mascot mine and the Shelburne mine worked veins in schist and granite on Mount Hayes, between Gorham and Shelburne in Coos County. The Shelburne mine operated intermittently from the 1830s into the 1850s; a final attempt at mining took place in 1880. The Mascot mine worked from 1881-1885 and in 1906.

The North Woodstock mine, near the town of the same name in Grafton County, apparently mined and milled lead-silver ore, although no production records are known.

New Mexico

No silver is known to have been mined in New Mexico prior to the silver discovery in 1863 near Magdalena in Socorro County. The major silver-mining area of Silver City in Grant County was discovered in 1866. [A.J. Thompson (1965) "Silver", in "Mineral and Water Resources of New Mexico", New Mexico Bureau of Mines and Geology, Bulletin 87, p.141.]

A rancher found the Lake Valley silver deposits in Sierra County in 1876. The deposits are bedded manto-type deposits in Paleozoic limestone. The mines, promoted by Whitaker Wright, produced well for a few years after miners tunneled into a silver-lined cavity they named the “bridal chamber” that alone yielded 2.5 million troy ounces (78 tonnes) of silver. But no more bridal chambers were discovered, the mines struggled and were worked periodically into the 20th century. The district produced manganese during World Wars I and II. [E. J. Young and T. G. Lovering (1966) "Jasperoids of the Lake Valley mining district, New Mexico", US Geological Survey, Bulletin 1222-D.] Total production of the Lake Valley district through 1931 was 5.8 million ounces (180 tonnes) of silver. [George Townsend Harley (1934) "The geology and ore deposits of Sierra County, New Mexico", State Bureau of Mines and Mineral Resources, Bulletin 10, p.178-179.]

Almost all the silver produced today in New Mexico comes as a byproduct from the two large open-pit copper mines in southwest New Mexico.

Oklahoma

Copper and silver occur in a sandstone roll-front-type deposit in the Wellington sandstone of Permian age at Paoli, Garvin County, Oklahoma. About 1900, several wagon loads of ore were shipped from the deposit. [P.N. Shockey and others, (1974) "Copper-silver solution fronts at Paoli, Oklahoma", Economic Geology, v.69, n.2, p.266-268.]

Oregon

Most silver in Oregon was produced as a byproduct of gold and copper mining. Two mines operated primarily for their silver were the Bay Horse mine in Baker County, which produced 125,000 ounces (3.9 tonnes) of silver, and the Oregon King mine in Jefferson County, which produced 300,000 ounces (9.3 tonnes) of silver. [H.C. Brooks and Len Ramp (1969) "Gold and silver", in "Mineral and Water Resources of Oregon", Oregon Department of Geology and Mineral Industries, Bulletin 64, p.133, 136.]

Pennsylvania

The Pequea silver mine near Conestoga in Lancaster County was worked from before the Revolutionary War to 1875. A minor amount of mining was done about 1900. The ore is silver-bearing galena in the Cambrian Vintage Dolomite. Production is unknown. [Jacob Freedman (1972) "Geochemical prospecting for zinc, lead, copper, and silver, Lancaster Valley, southeastern Pennsylvania", US Geological Survey, Bulletin 1314-C, p.C34-C43]

Texas

The Allamoore-Van Horn silver-mining district in Hudspeth County and Culberson counties was discovered in 1880, and mined intermittently. Silver and copper were mined from Precambrian igneous and sedimentary rocks. No reliable production figures are available. [R.D. Sample and E.E. Gould (1945) "Geology and Ore Deposits of the Allamoore-Van Horn Copper District, Hudspeth and Culberson Counties, Texas, US Geological Survey, Open-File Report 45-22.]

Silver mineralization was discovered in 1880 or 1881 in Presidio County, Texas. Mining began in 1883 at what became the town of Shafter. [Clyde P. Ross (1943) "Geology and ore deposits of the Shafter mining district, Presidio County, Texas", US Geological Survey, Bulletin 928-B.] At least six mines were worked. The deposits are manto-type deposits in Permian limestone of the Mina Grande formation, related to an igneous intrusive. Silver minerals include argentite and native silver. Associated minerals include the lead minerals anglesite and galena, the zinc minerals sphalerite, hemimorphite, and smithsonite, and gangue minerals quartz, calcite, goethite, and dolomite. Total production to 1999 was 35 million troy ounces (1090 tonnes) of silver, along with some gold. [Douglas B. Silver, "Finding the silver lining in Shafter, Texas," "Mining Engineering", Mar. 1999, p.28-32.]

External links

* [http://www.tsha.utexas.edu/handbook/online/articles/SS/gps2.html Handbook of Texas Online: "Shafter Mining District"]

Utah

The beginning of silver mining was delayed in Utah, due to its remote location. The completion of the transcontinental railroad spurred prospecting in Utah, and led to major silver discoveries.

The first mining claim in the Park City district was staked in 1868, and the first ore shipment made in 1871. Prominent mines included the Flagstaff mine, Ontario mine, and Silver King mine. Ore occurs in veins and replacement deposits in sedimentary and igneous rocks. [Clark L. Wilson (1959) "Park City Mining District", in "Guidebook to the Geology of the Wasatch and Uinta Mountains Transition Area", Salt Lake: Intermountain Association of Petroleum Geologists, p.182-188.] Today almost all the silver produced in Utah comes from the Bingham Canyon Mine, which produces silver as a byproduct of copper mining.

Virginia

Virginia has produced about 90 thousand ounces of silver as a byproduct of mining other metals. [ [http://www.dmme.virginia.gov/DMR3/silver.shtml Virginia Division of Geology and Mineral Resources: "Silver"] ]

Washington

The Chewelah district in Stevens County produced 1.7 million troy ounces (53 tonnes) of silver and 5,000 metric tons of copper from quartz-carbonate veins. Chalcopyrite is the principal ore mineral. The deposits are hosted in shear zones in argillite of the Precambrian Belt Supergroup. [Allen V. Heyl and others, "Silver", in "United States Mineral Resources", US Geological Survey, Professional Paper 820, p.594-595]

See also

* Silver mining

References