Gold and silver mining near Minturn, Colorado starting in the 1880s left behind roughly 70 miles of underground tunnels, waste rock piles, tailings piles, and the abandoned town of Gilman spread across 235 acres at about 8,000 feet elevation. The site, known as Eagle Mine, was placed on the National Priorities List under the federal Superfund program. Heavy metals including arsenic, cadmium, chromium, copper, lead, manganese, and zinc have contaminated soils, groundwater, and surface water across the property. Mining waste reduced fish populations and aquatic life in the Eagle River downstream from the site and threatened two drinking water wells serving roughly 1,500 Minturn residents.
Cleanup began in the late 1980s under a consent decree. Key actions included plugging mine openings to reduce acid generation, opening a water treatment plant in 1990 that still operates today, consolidating and capping nearly one million tons of tailings under an engineered multi-layer cover, and relocating Minturn's town wells upstream to a safer location. The Maloit Park Wetlands were reclaimed after visible contamination. EPA declared construction of required cleanup elements complete in September 2001. A 2017 Record of Decision Amendment expanded groundwater collection and adjusted cleanup levels for several metals. Human exposure is currently under control, but groundwater contamination has not yet stabilized and the site is not ready for all anticipated future uses.
Cleanup is organized into four operable units covering different geographic areas. The main sitewide unit has been under ongoing remedial action since 2018. A soils unit was partially deleted from the National Priorities List in September 2021 after its remedial action finished. The north property redevelopment area was partially deleted in August 2023, with remedial design work scheduled to finish in February 2025 and remedial action estimated to wrap up between September and November 2026. A 5.31-acre trestle subarea has already been removed from cleanup requirements, and remediation of the Maloit Park subarea was approved in 2025 with work anticipated to begin in Spring 2026. EPA is currently conducting a seventh Five Year Review, due by December 2026.
Community members can stay involved through quarterly public stakeholder meetings held at Minturn Town Hall. In-person community interviews for the five-year review process were held on June 16, 2026. The Eagle River Watershed Council holds a Technical Assistance Grant that allows the group to hire independent technical advisors to review cleanup work. To join the mailing list, schedule an interview, or ask questions, contact the EPA Community Involvement Coordinator.
