| Anaconda Mine | |
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Anaconda Copper Mine. Inactive since 1978, the pit has flooded. |
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| Location | |
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Anaconda Mine
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| Location | Lyon County |
| State | Nevada |
| Country | United States |
| Owner | |
| Company | ARCO (current) Anaconda Copper (when in operation) |
| Year of acquisition | 1953 (by Anaconda Copper) |
| Production | |
| Products | Copper |
| Production | 360 million tons Combined ore and waste |
| Financial year | Life of Mine |
| History | |
| Opened | 1918 (as Empire Mine) 1953 (as Anaconda Copper Mine) |
| Closed | 1978 |
The Anaconda Copper Mine is an open pit copper mine in Lyon County, Nevada that was owned and operated by the Anaconda Mining Company. It is located adjacent to the town of Yerington. The company town of Weed Heights was built to support the mining operation which ran until 1978.[1]
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The Anaconda Mine first opened in 1918 as the Empire Nevada Mine. In 1953 the property was acquired by the Anaconda Copper Company,which ran the mine until Anaconda was taken over by Atlantic Richfield Company.[1] Atlantic Richfield ceased operations in 1978 due to a low copper prices, lower priced foreign imports of copper and declining grade and resources in the pit.[2] The property was sold in 1982 to Don Tibbals,[2] a Lyon County commissioner.[3] The land was subsequently resold to Arimetco, with the exception of Weed Heights.[1]
The Anaconda mine operated for 25 years and produced approximately 360 million tons of material from the pit. Most of the material remains in tailings or in leach heap piles. The copper was processed from the extracted ore using two processes. Copper oxide ore (from the upper portion of the pit) was processed by heap leaching, either directly with sulfuric acid in vats to produce a copper solution precipitated by passing it over scrap iron, or by leaching successively in acid and kerosene solutions, subsequently electroplating onto stainless steel sheets. Copper sulfide ore from the lower portion of the pit was processed by crushing, and flotation with calcium oxide added to the solution to maintain an alkaline pH.[1]
The mining wastes at the closed mining site have been investigated by the US Environmental Protection Agency. Since 2000, it has spent approximately $6 million addressing this issue and ARCO has spent $2.7 million to clean the site.[2] In 2009 ARCO committed to spending $10.2 million for future and past cleanup work. Of the $10.2 million, $8 million is for future work and $2.2 million is to reimburse the EPA for past work completed. In 2008 ARCO reimbursed the EPA $2.7 million.[4]