The Doe Run Company’s former Block P mill and mine sites are located in Montana’s Barker-Hughesville mining district within the Lewis and Clark National Forest. Concerns about environmental impacts associated with historical mining activities at the sites prompted the company to evaluate the impacts of metals leaching and acid rock drainage at six inactive mine sites in the upper Galena Creek watershed, the inactive lead-zinc mill site, and associated tailings basins. Doe Run’s primary concerns were mobilization of lead, zinc, and other metals to groundwater; direct human and environmental contact with low-pH materials; the impact of acidic drainage on surface water bodies; and ongoing discharges of contaminated water from mine adits (horizontal passages to the surface).
Barr assessed groundwater in the bedrock and alluvium, and then evaluated potential sources of inflow to the mine workings. We conducted a geotechnical evaluation of waste-rock piles at the site and assessed potential waste-rock repository locations to conclude that consolidating waste rock in a central location and capping it with an engineered cover will minimize the potential for precipitation infiltration, reducing the likelihood that infiltrating water will become acidic drainage. Barr designed the repository and stream channel, planned and implemented revegetation and long-term monitoring and maintenance programs, including a post-excavation sampling program comparing geochemistry of existing soil quality with project objectives, and provided construction observation.
Senior Environmental Engineer
Senior Environmental Scientist
Vice President Senior Geological Engineer