Consultants recommend Butte Mine Waste Repository as preferred site for priority soils; council hears plans for multi‑year hauling
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Summary
Consultants recommended using the existing Butte Mine Waste Repository to hold about 1.1 million cubic yards of priority soils removed from the Butte Hill, and outlined haul-route options, mitigation measures and a draft schedule that could begin excavation in August.
Atlantic Richfield Company consultant Josh Bryson told the Butte‑Silver Bow Council of Commissioners’ Committee of the Whole that his team’s EPA‑guided siting study recommends the Butte Mine Waste Repository as the preferred location for roughly 1,100,000 cubic yards of mine waste excavated from remediation projects on the Butte Hill.
Bryson said the study evaluated multiple sites — including Westside Soils, Whiskey Gulch, Opportunity Ponds, Interstate Pit, Alice Pit and the Pittsmont Dump — and concluded the Butte Mine Waste Repository is already approved for this use under the 2006 Record of Decision and the 2020 consent decree. “It allows us to begin hauling waste and placing it today as we revise the O&M plan to make it current,” Bryson said.
Why it matters: using an approved repository promises to accelerate cleanup work on corridor projects, but it brings traffic, staging and reclamation tradeoffs that residents and commissioners raised during a lengthy question‑and‑answer period.
Key details in the presentation and Q&A:
- Project size and schedule: Bryson said the program would move about 1,100,000 cubic yards of material over an estimated 5–7 years, with a mobilization goal of Aug. 1 and excavation beginning about Aug. 15. He said the program’s timing and staging differ from commercial earthmoving because the work is subject to regulatory oversight and water management.
- Haul volumes and traffic: The team estimated about 1,500 cubic yards moved per day (20 cubic yards per truck), which could require as many as 300 truck trips on heavy work days. Bryson framed that as a modest local increase compared with overall traffic through the Civic Center intersection: “There are 17,000 vehicles that pass by the Civic Center intersection with Harrison Avenue every day,” he said, adding the project would aim to avoid peak commute windows.
- Route options and mitigations: Two haul alternatives are under evaluation — crossing the BNSF corridor and routing across Shields Avenue versus accessing the mine property through a secured gate. Proposed mitigations include a coordinated traffic‑control plan approved with Butte‑Silver Bow and Montana Department of Transportation, haul‑time restrictions (avoid peak commute periods and community events), road cleaning and on‑site measures (rumble strips, sweepers, water trucks), operator training and in‑cab driver behavior monitoring systems.
- Repository capacity and reclamation approach: Bryson said a 2015 operations and maintenance plan showed roughly 700,000 cubic yards of capacity in the county repository. New geotechnical work gives “pretty high confidence” the repository can be raised vertically (but remain below the Granite Mountain Memorial elevation) to house about 1,400,000 cubic yards. Bryson said the project will generally postpone final slope reclamation until larger fills are completed to avoid re‑covering soil lifts with new waste.
- Alternatives considered: The consultant said rail spurs, conveyors and slurry pipelines were evaluated but posed economic, spatial or permitting complications; slurry options were contingent on using the Berkeley Pit, which the team eliminated during step‑5 site analyses.
Public comment and process notes: Residents and advocates urged continued review of alternatives (Evan Barrett noted Opportunity Ponds and rail options), and commissioners pressed for clarity on haul routes, road‑repair guarantees and how stockpiles on mine property would be managed. Bryson said Atlantic Richfield carries financial assurance for remedy work and that the project team would look to memorialize commitments (for example, via memoranda of understanding) about road repairs and tracking damages. He said the final evaluation and recommendations report would be submitted in one to two weeks for EPA review and concurrence.
What’s next: Bryson said EPA and the Montana DEQ will consider stakeholder and public input and then notify Atlantic Richfield and Butte‑Silver Bow whether they concur with recommending the existing Butte Mine Waste Repository. The council did not vote on the recommendation at the meeting; the presentation concluded and commissioners placed Communication 2621 on file for the record.
