Superfund Site Profile

Removal actions have been conducted to address the most immediate threats to human health and the environment. A remedial program has been implemented and will assist in determining the nature and extent of contamination and selecting cleanup alternatives. The site consists of two areas referred to by EPA as operable units (OUs).

In 2016, a site-wide Remedial Investigation (RI) report was completed that describes the nature and extent of contamination at the site and includes the human health and baseline ecological risk assessments.

Final Remedial Investigation Report, Barker Hughesville Mining District Superfund Site (PDF) (4,402 pp, 651.9 MB, About PDF)

Several actions are being taken at the site in 2017/2018:

  • A final feasibility report for OU 1 for the site is expected to be issued 2018. The feasibility study evaluates various cleanup alternatives.
  • Doe Run Resources (Doe Run), a mining company under an EPA enforcement order, plans to conduct the following work:
    • Grout/or foam closed seeps adjacent to Galena Creek.,
    • Relocate Galena Creek adjacent to the historic Block P Mine to allow more room to strengthen and stabilize the toe of the hillside adjacent to the Block P Mine.
    • Continue monitoring of the reclamation previously completed at the Block P Mill and Mine Complex and conduct any necessary maintenance.
    • Prepare plans for closing the Grey Eagle and Block P Mine adits.
  • Benchscale testing of the Danny T Mine adit discharge is expected to continue building upon work completed in 2014 and 2015.

Final Report: Danny T Adit Treatability Study – Year 1 Technical Memorandum (PDF) (590 pp, 6.6 MB, About PDF)


The 6,000-acre Barker Hughesville Mining District site is located south of Great Falls and about 12 miles east of Monarch in Judith Basin and Cascade Counties. Rich silver and lead ores were discovered in the Barker Hughesville area in 1879. Mining activity occurred there until 1893 and again at the beginning of the 20th century through the 1940s.

The site contains about 46 known abandoned mines strewn with waste rock dumps, tailings and seeping mine openings. The abandoned mines have contaminated soil, sediment, groundwater and surface water with arsenic and metals such as copper, zinc, cadmium, and lead.