Butte Mine Waste Repository gets formal nod from EPA, DEQ

The Berkeley Pit bit the dust, at least for the foreseeable future, as a place to dump contaminated soils from Superfund sites in the so-called Silver Bow Creek Conservation Area.

The Butte Mine Wastes Repository, after being dismissed early on as being too small, ultimately got the nod after the Atlantic Richfield Co. and Butte-Silver Bow County recognized the repository could expand to receive the large volume of wastes requiring excavation in the years ahead.

The Butte Mine Repository was nominated by a Repository Siting Study Advisory Committee that first met in June 2021. Other sites considered and rejected included Shields Avenue and the Kelley Mine Area, which would have been close to the community of Centerville.

By one estimate, 1.1 million cubic yards of historic mining and smelting-related wastes will be excavated in the Silver Bow Creek Conservation Area, where project areas include Grove Gulch, Buffalo Gulch, Diggings East, Northside Tailings, Butte Reduction Works and the Blacktail Creek Riparian Area.

One cubic yard is roughly equivalent in size to a conventional washing machine.

On February 23, EPA and the Montana Department of Environmental Quality approved the continued use and expansion of the existing Butte Mine Waste Repository.

The repository is in the general vicinity of the Granite Mountain Memorial and northwest of the Berkeley Pit. The site's 33 acres are owned by Butte-Silver Bow and Atlantic Richfield. Siting studies report that surface and groundwater would flow from the Butte Mine Waste Repository into the Berkeley Pit.

The haul route from project sites in the Silver Bow Creek Conservation Area will likely travel George Street, Montana Street, Front Street, Harrison Avenue and Civic Center Road before reaching Montana Resources property for the final haul.

Work at the Diggings East project area is scheduled to begin in August.

A news release from EPA said the selection of the Butte Mine Waste Repository site followed a collaborative effort, but many people in Butte felt the process of choosing a site was insufficiently public.

The Repository Siting Study Advisory Committee included representatives from Atlantic Richfield, Butte-Silver Bow, DEQ, Montana Resources, the Citizen’s Technical Environmental Committee, or CTEC, and others.

On Thursday, CTEC will host two people long-involved in the repository siting quest, Josh Bryson from Atlantic Richfield and Eric Hassler from Butte-Silver Bow. They will discuss the mine waste repository and what is planned for design and construction for 2026.

Atlantic Richfield inherited liability for the environmental sins of the Anaconda Co., the original polluter in Butte and Anaconda and along Silver Bow Creek and the Clark Fork River.

CTEC’s mission includes informing the public about the often esoteric, jargon-filled doings of federal Superfund in Butte.