Stibnite/Yellow Pine Mining Area

Overview

The Stibnite/Yellow Pine Mining Area covers about 3,000 acres in the Payette National Forest near Yellow Pine, Idaho. Mining ran from the early 1900s through the late 1990s, producing antimony and gold. During World War II, the site was the nation's largest source of strategic metals, including antimony and tungsten. EPA proposed adding it to the National Priorities List (NPL) in September 2001, but the State of Idaho did not concur, so it remains a proposed NPL site. No final remedy has been selected yet.

Heavy metals such as arsenic and antimony, along with cyanide, contaminate soil, groundwater, surface water, and sediment across the site. Major contamination sources include tailings piles, smelter waste, heap-leach pads, and mine tunnel adits along the East Fork of the South Fork of the Salmon River and Meadow Creek. People face risks from ingesting or touching these contaminants. Hazardous substances that build up in fish also threaten the human food chain. Wildlife living in or feeding from contaminated surface water are at risk too. Human exposure status cannot be determined due to insufficient data, and contaminated groundwater continues to migrate.

EPA and the U.S. Forest Service have worked on the site since 1982. Early efforts included encapsulating tailings, diverting streams, removing contaminated sediments from "poison ponds," and excavating arsenic-laden waste rock. In January 2021, EPA and the Forest Service entered a cleanup agreement with Midas Gold Corporation, now known as Perpetua Resources. That agreement covers three stream diversion projects, removal of up to 25,000 tons of sediment and waste from Lower Meadow Creek, removal of 200,000 tons from the Bradley Man Camp Dumps with an on-site repository, removal of about 100,000 tons from the Northwest Bradley Dump, and characterization of mine adits. The most recent removal action started in June 2021. One source states completion is expected in 2025, while another estimates the work will finish between May and July 2026, with an additional removal action starting between January and March 2027. Physical construction of cleanup has not been completed, and the site is not yet ready for its anticipated use.

The area currently supports recreation and ecological conservation within the Boise and Payette National Forests. Midas Gold submitted a plan in 2016 to reopen the mine, and the Forest Service is reviewing that proposal along with an Environmental Impact Statement.

Community members can get involved through EPA's Community Involvement Plan, which was built with input from residents, local governments, and community organizations. EPA released a Responsiveness Summary covering 11 public comments received in mid-2021. The administrative record is available for public review. Residents can contact EPA's community involvement or remedial project team at any time using the information below.