Superfund Information Systems: Site Profile

Superfund Site:


Stay Updated, Get Involved

On this page:

Announcements and Key Topics

EPA Approves Conditional Discharge of Treated Water from Butte Mine Flooding Operable Unit

With conditional approval of the pilot project for the Butte Mine Flooding Operable Unit, Montana Resources, Inc. and the Atlantic Richfield Company will start pumping contaminated water at the end of September from the Berkeley Pit and treating it in the Horseshoe Bend Water Treatment Plant. Water from the Yankee Doodle Tailings Impoundment will be treated in the recently constructed pilot project treatment plant and discharged to Silver Bow Creek.

  • The pilot project begins pumping and treating water from the Berkeley Pit for the first time in decades, approximately four years ahead of the date required by the consent decree.
  • The process is intended to serve the dual purpose of maintaining or drawing down the current water level in the Berkeley Pit as well as allowing Montana Resources to reduce the water level in the Yankee Doodle Tailings Impoundment as part of their active mining operations.
  • Berkeley Pit water will be treated in the Horseshoe Bend Water Treatment Plant, and the treated water will be used in the active mining operations. The process water from Montana Resources’ active mining operations combined with Horseshoe Bend seep water will be stored in the Yankee Doodle Tailings Impoundment, from which water will be withdrawn and run through the new polishing plant to meet interim stream standards before being discharged to Silver Bow Creek.

The public comment period has concluded on the proposed plan for an amendment to the Butte Priority Soils Operable Unit Record of Decision. EPA will respond to the comments received in a responsiveness summary as part of any potential Record of Decision Amendment. This will be released in the fall of 2019.

The proposed plan and the administrative record of documents supporting it are also available for review at the following locations:

EPA MT Superfund Record Center
10 West 15th Street Suite 3200
Helena, MT 59626

Montana Tech Campus Library
1300 West Park St.
Butte MT 59701
(406) 496-4281

Top of Page

Community Resources

The following links exit the site Exit

Pit Watch is a website that monitors the water levels in the Berkeley Pit and provides information about the history and cleanup of the site to the public.

Citizens Technical Environmental Committee (CTEC) is a group of volunteer citizens who work with EPA, the State of Montana, responsible parties, and others to make the Superfund process and cleanup decisions in the Butte and Clark Fork Basin area of Montana understandable to everyone. CTEC manages a website that provides a listing of updates and recent news.

Atlantic Richfield’s Butte Cleanup Data Site is a website where the public can find information and data about the remediation of the Butte Priority Soils Superfund site.

The City and County of Butte-Silver Bow maintains a Superfund Division Web page that includes information and resources about the Superfund designation in Butte and the Residential Metals Abatement Program.

Top of Page