Study details slope stability

The rate of rise of water levels in the Berkeley Pit and connected monitoring points is affected by many factors, including rain and snowfall and occasional ‘sloughs’ or ‘slumps’ of material from the Pit’s sidewall slopes. The most recent slough occurred on February 8, 2013. An estimated 820,000 tons of material from the southeast wall collapsed into the Pit. Montana […]

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Throughout 2010, the EPA interviewed local citizens and reviewed the status of Butte area Superfund sites, including the Berkeley, as part of a five-year review. The final review report, released in 2011, is available to the public and can be downloaded at the EPA Butte/Silver Bow Creek website. The sections of the report relating to the Butte Mine Flooding Operable […]

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What is ‘Superfund’?

Butte has the dubious distinction of being at the upper end of the largest complex of federal Superfund sites in the U.S. This Superfund complex extends from Butte and Anaconda 120 miles down the Clark Fork River to Missoula. The word “Superfund” is tossed around a lot by local and state officials working in the Clark Fork Basin, but, to […]

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Under a clear EPA order, both Montana Resources and BP-ARCO are responsible for treating Berkeley Pit water. Under the Superfund law, if one company is unable to pay its share, the other company must pay all the costs of cleanup. The company paying the full cleanup costs would likely take some legal actions to recover a fair share of those […]

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What is an ‘Operable Unit’?

An operable unit is a subsection of a larger EPA Federal Superfund site. There are four Operable Units (OUs) in the Butte mining district.  The Butte Mine Flooding Operable Unit, which includes the Berkeley Pit, the hydraulically-connected underground mine workings associated with the historic East Camp and West Camp tunnel systems, associated bedrock, and alluvial aquifers. The area covers approximately […]

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