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The 2015 Gold King Mine waste water spill is a 2015 environmental disaster at the Gold King Mine near Silverton, Colorado. On August 5, 2015, EPA personnel along with workers for Environmental Restoration LLC (a Fenton, Missouri, company under EPA contract to mitigate pollutants from the closed mine) caused the release of toxic wastewater when attempting to add a tap to the tailing pond for the mine. Before the incident, the local jurisdictions refused Superfund money to cleanup the regions' derelict mines due to a fear of lost tourism. Following the spill, the local government of Silverton decided to accept Superfund money to fully remediate the mine. Workers accidentally destroyed the dam holding back the pond, spilling of mine waste water and tailings, including heavy metals such as cadmium and lead, and other toxic elements, such as arsenic,〔 into Cement Creek, a tributary of the Animas River in Colorado. The EPA was criticized for not warning Colorado and New Mexico until the day after the waste water spilled. The EPA has taken responsibility for the incident, and the governor of Colorado, John Hickenlooper, declared the affected area a disaster zone. The spill affects waterways of municipalities in the states of Colorado, New Mexico, and Utah as well as the Navajo Nation. As of August 11, acidic water continued to spill at a rate of while remediation efforts were underway.〔("E.P.A. Treating Toxic Water From Abandoned Colorado Mine After Accident" ), ''NY Times'', August 11, 2015〕 ==Background== Gold mining in the hills around Gold King was the primary income and economy for the region until the last closure of a mine around Silverton in 1991.〔 The Gold King Mine itself was abandoned in 1923. Prior to the spill, the Upper Animas water basin had become devoid of fish, because of the environmental impact of regional mines such as Gold King. Other plant and animal species were adversely affected in the watershed before the Gold King Mine breach, as well.〔 In the 1990s, sections of the Animas had been nominated by the EPA as a Superfund site for clean-up of pollutants from the Gold King Mine and other mining operations along the river, but lack of community support prevented its listing, thus only allowing the EPA to do minor work to abate environmental impacts of the mine.〔 Locals had feared that the label of a Superfund site would reduce the tourism in the area, the largest remaining source of income left in the region after the closure of the metal mines.〔〔("Colorado now faults EPA for mine spill after decades of pushing away federal Superfund help" ), ''Star Tribune'', August 11, 2015〕 Officials have noted that the mine is only one of 22,000 abandoned mines in the state.〔 Many abandoned mines throughout Colorado are also known to have problems with acid mine drainage.〔"Bibliography, Watershed Contamination from Hard-Rock Mining — Hardrock Mining in Rocky Mountain Terrain — Upper Arkansas River, Colorado " (U.S. Geological Survey, Toxic Substances Hydrology Program ) URL accessed 2015-08-12.〕 At the time of the accident, the EPA was working at the Gold King Mine to stem the leaking mine water going into Cement Creek. They were building a concrete bulkhead to plug the leak, and planned to add pipes that would allow the slow release and treatment of the water. The crew's machinery breached a wall that was holding back the waste water. The mustard-yellow color of the water is caused by the oxidation of the iron, according to Ron Cohen, a professor of civil and environmental engineering at the Colorado School of Mines.〔("How are they going to clean up that Colorado mine spill?" ), ''The Christian Science Monitor'', August 13, 2015〕 The chemical processes involved in acid mine drainage are common around the world where subsurface mining exposes metal sulfide minerals such as pyrite to water and air. As of August 14, a question had arisen about whether the waste water released by the EPA operation had actually originally come from the neighboring Sunnyside Mine. Gold King Mine owner Todd Hennis said before work had been done at Sunnyside to plug a section of the mine called the American Tunnel in the mid-1990s, Gold King was discharging waste water at a rate of seven gallons per minute. After the work, he said the discharge rate had increased to 250 gallons per minute. In 2014, the EPA began investigating to determine the source of the water discharging from Gold King, but the project ran out of time before it was completed. The mine was sealed with a plan to return in 2015. A representative for Sunnyside Mine said the two mines are not linked. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「2015 Gold King Mine waste water spill」の詳細全文を読む スポンサード リンク
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