Hardrock tailings remediation at the Amalgamated Mill Site, Willamette National Forest, Oregon

Situated in Oregon’s Willamette National Forest, the Amalgamated Mill operated in the 1930s to process metal-sulfide minerals. When the mine was abandoned, approximately 5,930 cubic meters (7,800 cubic yards) of uncontrolled tailings containing elevated lead concentrations was left perched over Battle Ax Creek. In 1990, the United States Forest Service directed an emergency removal to move the tailings from within and immediately adjacent to the creek to an area up-slope. In 1996, the Forest Service, Persis Corporation, and Oregon Department of Environmental Quality cooperatively followed the CERCLA process to select a permanent remedy. The proposed remedy would have mixed the tailings with dry cement and encapsulated the mixture within a lined and capped engineered monoflll. The public was not convinced the proposed remedy was safe and protective. Ultimately, federal funds were appropriated to compliment private funds and implement a remedy acceptable to the public, disposal in an off-site landfill.