Editing Summitville mine (section)

==History==
Charles Baker's group of prospectors found traces of placer gold in the [[San Juan Mountains]] in 1860 at [[Eureka, Colorado]]. The group was forced out in 1861 by the Ute Tribe, who had been awarded the area in a US treaty.  [[Gold]] was discovered in Wightman Fork, on South Mountain, which is the same location of present-day Summitville. More prospectors returned in 1871, when lode gold was found in the Little Giant vein at Arrasta Gulch, near [[Silverton, Colorado]]. The miners were allowed to stay after the Brunot Treaty of 13 Sept. 1873. In exchange for giving up 4 million acres, the [[Southern Ute Indian Reservation]] received $25,000 per year. Gold veins were found at 11,500 feet on South Mountain in 1873 and the town was founded when stamp and amalgamation mills were built.<ref name=Voynick>Voynick, S.M., 1992, Colorado Gold, Missoula: Mountain Press Publishing Company, {{ISBN|0878424555}}</ref>{{rp|49–50}}

By 1885 there were more than 250 individual claims in operation. The site was soon mined out, with the weather of the 3,500 m high site adding to difficulties. The site was re-opened on a number of occasions for gold or other metals but with little success, and prior to the site's acquisition in 1984 the last survey was in the early 1970s for [[copper]]. The total amount of gold extracted from the site from 1873 until 1959 was around {{convert|257,600|ozt|kg}}.

In 1984 an area of {{convert|1230|acre|km2|1}} was acquired by the Canadian-based [[Galactic Resources Ltd.]] subsidiary Summitville Consolidated Mining Company, Inc. (SCMCI). They began a new large-scale open pit operation covering {{convert|550|acre|km2|1}}. New techniques were used to extract gold from otherwise uneconomic [[ore]].

The mining involved the treatment of [[pyrite|pyritic]] ore with a [[sodium cyanide]] solution to leach the gold out of the ore&mdash;heap leaching (see also [[cyanide process]]). The solution ([[leachate]]) was then removed from the ore and the valuable metals extracted using [[activated carbon]]. SCMCI leached around 10 million tons of ore on a {{convert|73|acre|km2|1|adj=on}} heap leach pad. The mining operations were finished in October 1991 with the leaching continuing until March 1992, when Galactic Resources filed for bankruptcy. A total of {{convert|294,365|ozt|kg}} of gold and {{convert|319,814|ozt|kg}} of silver were recovered. SCMCI then closed the site and converted on-site equipment for the detoxification process, with around 160 million U.S. gallons (610,000 m<sup>3</sup>)  of stored water needing treatment. After the company insolvency proceedings were completed in a British Columbia court, the US Government declared the site a superfund cleanup site and spent $155,000,000 of public funds cleaning up the site.