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Grants Mining District

San Mateo Creek Basin

The San Mateo Creek Basin comprises approximately 321 square miles within the Rio San Jose drainage basin in McKinley and Cibola counties, New Mexico. This basin is located within the Grants Mining District (GMD).

The 85 legacy uranium mines with recorded production and 4 legacy uranium mill sites comprising the GMD may have contributed to degradation of ground water quality within the San Mateo Creek Basin. Some background ground water contaminant concentrations associated with remediation of the Homestake Mining Company (HMC) Superfund Site exceed federal and state drinking water standards as well as state ground water standards.

The table below is sortable by document title, geographical subarea, county, year, and tribal or non-tribal status.

Document Title Geographical
County Year Tribal or
San Mateo Creek Basin Preliminary Assessment Ambrosia Lake Cibola
2008 Non-Tribal
San Mateo Creek Basin Phase I Site Investigation Ambrosia Lake Cibola
2010 Non-Tribal
San Mateo Creek Basin Phase II Site Investigation Ambrosia Lake Cibola
2012 Non-Tribal
San Mateo Creek Basin Administrative Settlement Agreement and Order on Consent for Remedial Investigation / Feasibility Study Central Study Area Cibola McKinley 2019 Non-Tribal