Plan for treatment technology assessment

The guiding documents for Pit management require ongoing assessment and evaluation of the Horseshoe Bend Water Treatment Plant and the technology used to treat contaminated Pit water until several years prior to full-scale implementation. That implementation is required when water levels at any monitoring compliance point reach the Critical Level of 5,410 feet above sea level. A review of treatment […]

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In 2010 EPA interviewed local citizens and reviewed the status of Butte area Superfund sites as part of a required five-year review (the full review report is available here). Five-year reviews determine whether remedies or other response actions are protective of human health and the environment in compliance with a site’s decision documents. Methods, findings, and conclusions are documented in […]

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1982-2013: 31 years since pumps stopped

Over 31 years ago economic factors led the Atlantic-Richfield Corporation, or ARCO, now a subsidiary of British Petroleum, to cease mining operations at the Berkeley Pit in Butte, Montana. Underground mining had come to an end seven years earlier, but the underground pumps had continued to operate, pumping groundwater out from the mines and the Berkeley Pit. The 1982 suspension […]

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1955-1982: Berkeley Pit history

Over the active lifespan of the Berkeley, approximately 320 million tons of ore and over 700 million tons of waste rock were mined from the Pit. Put another way, “The Richest Hill on Earth” produced enough copper to pave a four-lane highway four inches thick from Butte to Salt Lake City and 30 miles beyond. In 1955, mining in Butte […]

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Could the Berkeley Pit ever overflow?

The Berkeley Pit will never overflow. In 1994 the EPA established the Critical Water Level (the maximum level the water will be allowed to reach) at 5,410 feet above sea level, which is one hundred feet below the rim. Water levels are regularly monitored at the Pit, in historic underground mines, and in wells surrounding the Pit. Failure to keep […]

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