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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When the Horseshoe Bend Water Treatment Plant starts operating later this year, the contaminated waters from the Berkeley Pit and underground mines should be managed safely for years to come. In the meantime, another cleanup project – called the Butte Priority Soils Operable Unit – is just now reaching its critical decision point (i.e., the Record of Decision, scheduled by […]

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