Agreement for Investigating Impact of Mine Water Discharge at San Mateo Creek Basin Site in New Mexico

In November 2019, the U.S. Environmental Protection Agency (EPA) reached an agreement with Homestake Mining Company of California, Rio Algom Mining, LLC, and United Nuclear Corporation regarding the San Mateo Creek Basin Legacy Uranium Mines Superfund site in New Mexico. Under the agreement, the companies will conduct a remedial investigation/feasibility study (RI/FS), valued at $15 million, and pay the Agency for future cleanup costs. The agreement fulfills a goal of the EPA’s Superfund Task Force, which placed the site on the Administrator’s Emphasis List of sites targeted for immediate and intense action.

Moving remedial investigation work forward at the site is an important step in understanding and more thoroughly characterizing the extent of the contamination to address.

On this page:

• Information about the Companies
• Information about the San Mateo Creek Basin Superfund Site
• Overview of the Administrative Settlement Agreement and Order on Consent for RI/FS
• Contact Information

Information about the Companies

The following companies listed below conducted operations at one or more underground uranium mines and/or mills within the site are parties to the settlement agreement:

• Homestake Mining Company, founded in 1877, was one of the largest gold mining businesses in the United States. The company was acquired by Barrick Gold in 2001.
• Rio Algom Mining, LLC, headquartered in New Mexico, is a mining and milling company.
• United Nuclear Corporation was acquired by General Electric in 1996. Its function is to oversee remaining decommissioning at its former sites.

Information about the San Mateo Creek Basin Superfund Site

The San Mateo Creek Basin Legacy Uranium Mines Superfund site is located within Cibola and McKinley counties and is comprised of private, state, Navajo Nation, and federal lands managed by the U.S. Forest Service and the Bureau of Land Management. It is part of the larger Rio San Jose drainage basin and represents an area of extensive uranium mining and milling activity that occurred primarily from the late 1950s through the 1980s.

The extensive exploration and extraction program conducted by the uranium mining industry since the 1950s included the drilling of thousands of exploratory boreholes and the development of over one hundred uranium mines and several large uranium mills. The legacy of these mining and milling operations resulted in the discharge of significant quantities of liquid and solid wastes and the widespread contamination of soils, surface sediments, streams and groundwater with radionuclides and heavy metals.

The RI/FS work requirements outlined in the agreement will more thoroughly characterize contamination in the Central Study Area that was outlined in a 2018 two-phase groundwater investigation to document the impacts from historic mine water discharges throughout the site. The responsible parties will collect data about site conditions, study the nature and extent of contamination, assess risk to human health and the environment, and evaluate potential options for cleaning up the site.

More information about the site is available from the Agency’s San Mateo Creek Basin webpage.

Overview of the Administrative Settlement Agreement and Order on Consent RI/FS

Under the settlement, the responsible parties will: (1) undertake remedial investigation work at the Central Study Area of the site; (2) pay future costs associated with EPA’s oversight of the work; and, (3) secure financial assurance for the $15 million estimated cost of the cleanup work.

The agreement also requires the parties to pay the EPA’s costs for their future cleanup work at the site, including an initial payment of $700,000. The responsible parties will also provide  $50,000 for a qualified community group to hire a technical advisor and develop a technical assistance plan.

Contact Information

For more information contact:

Pamela Travis
Assistant Regional Counsel
U.S. Environmental Protection Agency
Region 6
1201 Elm Street
Dallas, TX 75270
(214) 665-8056
[email protected]

Nicholas Sciretta
Attorney-Advisor
U.S. Environmental Protection Agency
(202) 564-7416
[email protected]

Brian Motto
Attorney-Advisor
U.S. Environmental Protection Agency
(202) 564-6009

[email protected]
1200 Pennsylvania Avenue, NW
Washington, D.C. 20460