- Gold mining in the United States
Gold mining in the United States has taken place since the discovery of gold at the Reed farm in
North Carolinain 1799.
In 2006 the
United Statesproduced approximately 8.360 million troy ounces (260 tonnes) of gold, making it the second- or third-largest gold-producing nation, in a virtual tie with Australia( South Africawas number one). [http://minerals.er.usgs.gov/minerals/pubs/commodity/gold/gold_mcs07.pdf USGS] Most gold produced today in the US comes from large open-pit heap leach mines in the state of Nevada. The US produces about as much gold as it uses; the nation was a net importer of gold in 2004 and 2005, but a net exporter of gold in 2006.Mining review, Mining Engineering, May 2007, p.28.]
Gold was discovered in
Alabamaabout 1830, shortly following the Georgia Gold Rush. The principal districts were the Arbacoochee district in Cleburne County, mostly from placer deposits, and the Hog Mountain district in Talapoosa County, which produced 24 thousand troy ounces (750 kg) from veins in schist. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.6-8.]
See main article "
Gold mining in Alaska". Russian explorers discovered placer gold in the Kenai Riverin 1848, but no gold was produced. Gold mining started in 1870 from placers southeast of Juneau. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.8.] Today, most gold production in Alaskais from the Fort Knox minein the Fairbanks mining district. The Fort Knox produced 333 thousand troy ounces (10.3 tonnes) of gold in 2006.
Arizonahas produced more than 16 million troy ounces (498 tonnes) of gold.
The gold-bearing quartz veins of the
Vulture Mine, southwest of Wickenburg, in Maricopa County were discovered in 1863. The mine produced 366 thousand ounces of gold through 1959. [A. H. Koschmann and M. H. Bergendahl, "Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.40.]
The San Francisco district, which includes the towns of Oatman and Katherine in Mohave County was discovered in 1863 or 1864, but saw little activity until a rush to the distruct occurred in 1902. The district produced 2.0 million ounces of gold through 1959. [A. H. Koschmann and M. H. Bergendahl, "Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.40-41.] The last gold mine to operate in Arizona was the Gold Road mine at Oatman, which shut down in 1998. Patriot Gold is exploration drilling at the Moss mine at Oatman. [http://www.admmr.state.az.us/Publications/ofr07-24.pdf]
In 2006, all of Arizona's gold production came as a byproduct of copper mining. Columbus Gold is currently doing exploration drilling for gold at four prospects in western Arizona.
Spanish prospectors discovered gold in the Potholes district between 1775 and 1780, along the
Colorado River, in present Imperial County, California, about ten miles northeast from Yuma, Arizona. The gold was recovered from dry placers. Other placer deposits on the west bank of the Colorado Riverwere quickly discovered, including the Picacho and Cargo Muchacho districts.
Major gold mining in California started in 1848 during the
California Gold Rush. Gold production in Californiapeaked in 1852, at 3.9 million troy ounces (121 tonnes) produced in that year. But the placer deposits worked in the early years were quickly exhausted, and production crashed. Hardrock mining (in California called "quartz mining") began in 1849, and placer mining by hydraulic mining began in 1852. Despite the new mining methods, by 1865 production was 867 thousand troy ounces (27 tonnes), less than one-quarter of peak production.
Production sank to 412 thousand troy ounces (12.8 tonnes) in 1929, but then soared to more than 1.4 million troy ounces (43.5 tonnes) for each year 1939 through 1941, after the price was raised from $20.67 to $35 per ounce. However, the federal government, in
War Production BoardOrder L-208, ordered gold mines closed, to free up resources for the war effort during World War II, and production fell to 148 thousand troy ounces (4.6 tonnes) in 1943. Post-war gold production never reached the peak of the early 1940s, as inflation and the fixed price of gold eroded its value. [William B. Clark (1970) Gold districts of California, California Division of Mines and Geology, Bulletin 193, p.4.]
The largest gold-mining district in California is the famous "
Mother Lode" of the Sierra Nevada. Discovered in the early 1850s, the lode is a zone one to four miles wide and running 120 miles northwest-southeast from El Dorado County in the north, through Amador, Calaveras, and Tuolumne counties, to Mariposa County in the south. The gold of the Mother Lodeis in quartz veins within phyllite, schist, slate, and greenstone. Through 1959, the Mother Lodeproduced about 13.3 million troy ounces (414 tonnes) of gold. [A.H. Koschmann and M.H. Bergendahl (1968)"Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.55-56.]
The second-largest gold-mining district in California was Grass Valley-Nevada City district in Nevada County. Gold in
Holocenegravels was discovered in 1850, followed a few years later by hydraulic miningof Tertiarygravels. By 1880, most of the mining had shifted to lode deposits, such as the Empire Mine. Through 1959, the district produced 10.4 million troy ounces (323 tonnes) of lode gold, and 2.2 million troy ounces (68.4 tonnes) of placer gold. [A.H. Koschmann and M.H. Bergendahl (1968)"Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.70-71.]
The rich placer deposits of the Columbia Basin-Jamestown-Sonora district were discovered in 1853. Almost all the gold was found at the base of
Quaternarygravels, but some drift mines were worked in Tertiarygravels. Total production was about 5.9 million troy ounces (183 tonnes) of gold. [A.H. Koschmann and M.H. Bergendahl (1968)"Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.82-83.]
In 2007, California produced 9,400 ounces (1603 kg) of gold from two mines. The
Mesquite minein Imperial County restarted active mining in 2007, having been inactive since 2001. The only other gold producer in the state, the Briggs minein Inyo County stopped mining in 2004, but continues to produce small amounts of gold from the leach pads, from previously mined ore. [S. Kohler, "California", Mining Engineering, May 2008, p.78.]
Emgold Mining is going through the permitting process to reopen the Idaho Maryland gold mine at Grass Valley, Nevada County.
* [http://www.conservation.ca.gov/cgs/geologic_resources/mineral_production/Documents/Big_AUMap.pdf California Department of Mines and Geology: "Map of Historic Gold Mines"]
* [http://www.consrv.ca.gov/cgs/minerals/images/YellowAu.pdf California Department of Mines and Geology: "Map of California Active Gold Mines 2000-2001"]
* [http://www.consrv.ca.gov/cgs/geologic_resources/gold/CA_GoldDiscovery_files/GoldDiscovery.htm California Department of Mines and Geology: "The Discovery of Gold in California"]
See main article "
Gold mining in Colorado"
Gold was discovered in 1858 during the
Pike's Peak Gold Rushin the vicinity of present-day Denver in 1858, but the deposits were small. The first important gold discoveries in Colorado were in the Central City-Idaho Springs district in January 1859. Three Colorado mines continue to produce gold. The Cripple Creek & Victor mineat Victor, an open-pit heap leach operation owned by AngloGold Ashanti, is the leading producer, with 283 thousand troy ounces (8.8 tonnes) of gold in 2006. Other active gold mines in the state are underground Golden Wonder minenear Lake City, and the Cash and Rex mines in the Gold Hill mining district in Boulder County, Colorado. [J. Burnell and others, "Colorado", Mining Engineering, May 2007, p.76-77.]
For main articles, see
Georgia Gold Rush, and Georgia Gold Belt
Georgia is credited with a total historical production of 871 thousand ounces of gold from 1830 through 1959. [A. H. Koschmann and M. H. Bergendahl, 1968, "Principal Gold-Producing Districts of the United States", US Geological Survey, Professional paper 610, p.119.] Although a historically important gold producer, the state does not presently produce any gold.
Battle Branch Mine
Free Jim Mine
Gold was first discovered in Idaho in 1860, at Pierce.
The leading historical gold-producing district is the Boise Basin in Boise County, which was discovered in 1862 and produced 2.9 million troy ounces (90.2 tonnes), mostly from placers. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.124-125.]
The French Creek-Florence district in Idaho County began in the 1860s, and has produced about 1 million troy ounces (31 tonnes) from placers.
The Coeur d’Alene district in Shoshone County has made 440 thousand troy ounces (13.7 tonnes) of gold as byproduct to silver mining. [M. H. Bergendahl (1964) "Gold", in "Mineral and Water Resources of Idaho", Idaho Bureau of Mines and Geology, Special Report No. 1, p.93-101.]
In 2006, active gold mines in
Idahoincluded the Silver Strand mine and the Bond mine. [V. S. Gillerman and others, "Idaho", Mining Engineering, May 2007, p.83.]
Gold was reported in
Marylandas early as 1830, but no production resulted. Placer gold was discovered at Great Falls near Washington, DCin 1861 during the American Civil Warby Union soldiers from California. After the war a number of mines were opened on gold-bearing quartzveins in Montgomery County. No gold production has been reported since 1951. Total production was about 6 thousand troy ounces (190 kg). [Emery T. Cleaves (1964) "Mineral resources of Montgomery and Howard Counties", in Howard and Montgomery Counties, Maryland Geological Survey, p.264-266.]
[http://www.mgs.md.gov/esic/brochures/gold.html Maryland Geological Survey: "Gold in Maryland"]
Approximately 29 thousand troy ounces (900 kg) of gold were produced from the Ropes gold mine northeast of Ishpeming in
Marquette County, Michigan. The underground mine, originally operated from 1880 to 1897, and reopened from 1975-1989, extracted gold from quartzveins in peridotite. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.141-142.]
Gold was first discovered in
Montanain 1852, but mining did not begin until 1862, when gold placers were discovered at Bannack, Montanain 1862. The resulting gold rush resulted in more placer discoveries, including those at Virginia City in 1863, and at Helena and Butte in 1864. [A. H. Koschman and M. H. Bergendahl (1968) "Principal gold-Producing Districts of the United States", US Geological Survey, Professional Paper 610, p.143.] In 1867, the Atlantic Cable Quartz Lodewas located.
Current active hardrock gold mines include the Montana Tunnels mine, and the Golden Sunlight mine. Active gold placers include the Browns Gulch placer and the Confederate Gulch placer. Gold is also produced from three platinum mines in the
Stillwater igneous complex: The Stillwater mine, the Lodestar mine, and the East Boulder Project. [R. McCullough, "Montana", Mining Engineering, May 2007, p.95.]
See main article: "
Gold mining in Nevada" Nevadais now the leading gold-producing state in the nation, currently producing 82% of all the gold mined in the United States. Almost all the gold in Nevada comes from large open pit miningand cyanide heap leachingrecovery. A number of major mining companies, such as Newmont Mining, operate gold mines in the state. Active gold mines include Jerritt Canyon and the Getchell Mine.
Gold was first discovered in New Mexico in 1828 in the “Old Placers” district in the
Ortiz Mountains, Santa Fe County, New Mexico. The placer gold discovery was followed by discovery of a nearby lode deposit. [Fayette Jones (1905) "New Mexico Mines and Minerals", reprinted as "Old Gold Mines and Ghost Camps of New Mexico", Fort Davis, Tex.: Frontier Book Co., p.21-23.]
In 2007 all gold production in New Mexico (13 thousand troy ounces) came as a byproduct of
coppermining from two large open pitmines in Grant County. However, two primary gold mines are being readied for production: the Northstar mine in Rio Arriba County, and the San Lorenzo Claims mine in Socorro County. [S.A. Lucas Kamat, "New Mexico," "Mining Engineering", May 2008, p.111.]
North Carolinawas the site of the first gold rush in the United States, following the discovery of a 17 pound (7.7 kg) gold nugget by 12-year old Conrad Reed in a creek at his father’s farm in 1799. The Reed Gold Mine, south of Georgeville in Cabarrus County, North Carolinaproduced about 50 thousand troy ounces (1.6 tonnes) of gold from lode and placer deposits. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.212.]
Gold was produced from 15 districts, almost all in the Piedmont region of the state. Total gold production is estimated at 1.2 million troy ounces (37.3 tonnes).
Although gold mines are spread over much of
Oregon, almost all of the gold produced has come from two principal areas: the Klamath Mountainsin southwest Oregon, including Coos, Curry, Douglas, Jackson and Josephine counties; and the Blue Mountains in northeast Oregon, mostly in Baker and Grant counties.
Illinoisdiscovered placer gold in the Klamath Mountains of southwest Oregon in 1850, starting a rush to the area. Lode gold deposits were also discovered.
Travellers along the
Oregon Trailbound for the Willamette Valleyare said to have discovered gold in northeastern Oregon in 1845, but no production resulted. Mining in earnest did not begin until 1861. [Howard C. Brooks and Len Ramp (1968) "Gold and Silver in Oregon", Oregon Department of Geology and Mineral Industries, Bulletin 61.]
About 37 thousand troy ounces (1.2 tonnes) of gold was produced from the Cornwall iron mine five miles south of Lebanon,
Lebanon County, Pennsylvania. Although the deposit produced iron since 1742, no gold was reported from the mine until 1908. [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.231.]
South Carolina had a number of lode gold mines along the Carolina Slate Belt. [ [http://pubs.usgs.gov/info/ayuso1/ US Geological Survey: "Carolina Slate Belt Gold Deposits"] ]
The Haile deposit was discovered in Lancaster County in 1827, and at least 275 thousand ounces of gold were extracted intermittently between then and 1942, when the gold mine was ordered closed as nonessential to the war effort. Beginning in 1951, the deposit was mined for associated sericite, which was used as a white filler. [Jeffrey C. Wynn and Robert W. Luce, "Geophysical methods as mapping tools in a strata-bound gold deposit: Haile mine, Carolina slate belt", Economic Geology, Mar.Apr. 1984, p.383-388.] Gold is associated with silicic, kaolinitic, and pyritic alteration of greenschist-grade felsic metavolcanics. [W.H. Spence and others, "Origin of the gold mineralization at the Haile mine, Lancaster County, South Carolina", Mining Engineering, Jan. 1980, p.70-73.] The mine was reopened as an open pit in the 1980s, and operated until 1992.
Kinross Gold Corporation's reclamation of the Haile site was nominated for a US Bureau of Land Management"Hardrock Mineral Environmental Award."
The Brewer mine operated from 1828 to 1995, and is now a federal
Superfundsite. [ [http://www.epa.gov/region4/waste/npl/nplsc/brwgldsc.htm Brewer Gold Mine NPL Site Summary - Land Cleanup and Wastes | Region 4 | US EPA ] ] Kennecott Mineralsoperated the Ridgeway open-pit gold mine from 1988 to 1999, and the land is now being reclaimed by Kennecott.
The Barite Hill mine operated from 1990 to 1994.
For main article, see
Black Hills Gold Rush
The only operating gold mine in
South Dakotais the Wharf mine, an open pit heap leach operation. [E. H. Holm and others, "South Dakota", Mining Engineering, May 2007, p.111.]
Placer gold was discovered on Coker Creek in
Monroe County, Tennesseein 1827. The district produced about 9 thousand troy ounces (300 kg). [A.H. Koschman and M.H. Bergendahl (1968) "Principal Gold-Producing Districts of the United States", U.S. Geological Survey, Professional Paper 610, p.240.]
About 15 thousand troy ounces (450 kg) of gold was recovered from the massive sulfide copper ores at
Some prospects have been excavated for gold on the Llano uplift of central Texas. Gold prospects include the Heath mine and the Babyhead district, both in Llano County, and the Central Texas mine in Gillespie County. Gold production, if any, is not known. [Edgar B. Heylman, "Gold in Texas", International California Mining Journal, Oct. 2001.]
[http://www.tshaonline.org/handbook/online/articles/GG/dkg1.html Handbook of Texas Online: "Gold mining"]
Most gold produced in
Utahtoday is a byproduct of the huge Bingham Canyon copper mine, southwest of Salt Lake City. Over its life, Bingham Canyon has produced more than 23 million ounces (715 tonnes) of gold.
The Barneys Canyon mine in Salt Lake County, the last primary gold mine to operate in
Utah, stopped mining in 2001, but is still recovering gold from its heap leachingpads. Utah gold production was 460 thousand troy ounces (14 tonnes) in 2006. [R.L. Bon and K.A. Krahulec, "Utah", Mining Engineering, May 2007, p.116.]
For main article, see
Virginia gold mining
* [http://www.dmme.virginia.gov/DMR3/gold.shtml Virginia Department of Mines Minerals and Energy: "Gold"]
Gold was discovered at the South Pass-Atlantic City-Sweetwater district in present Fremont County in 1842. The placers were worked intermittently until 1867, when the first important gold vein was discovered, and prospectors and miners rushed to the area.. The towns of South Pass City, Atlantic City, and Miners Delight catered to the miners. The district was nearly deserted by 1875, and was worked only intermittently afterward. Total gold production was about 300 thousand troy ounces (9.3 tonnes). In 1962, the district became the site of a major iron mine. [Richard W.Bayley (1969) "Ore deposits of the Atlantic City District, Fremont County, Wyoming", in "Ore Deposits of the United States, 1933-1967", v.1, New York: American Institute of Mining Engineers, p.589-604.]
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