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Grants Mining District

San Mateo Creek Basin Phase I Site Investigation

The New Mexico Environment Department Superfund Oversight Section has conducted a Site Investigation (SI) of the San Mateo Creek basin legacy uranium mine and millsites, which is located in Cibola and McKinley counties, New Mexico.

The objective of the SI is to evaluate the Site using the Hazard Ranking System and the Superfund Chemical Data Matrix to determine if a threat to human health and the environment exists such that further action under CERCLA is warranted. This phase of the SI focuses is on evaluating ground water quality in comparison to federal and state drinking water standards as well as state ground water standards in existing private wells, and identifying receptors to ground water contamination. Subsequent phases may specifically target alluvial and bedrock aquifers through installation of monitor wells in order to identify areas, and possibly specific legacy uranium sites within the San Mateo Creek basin from which ground water contamination most likely originates. Additional SI phases may target characterization of sediments throughout the basin for the same objectives. Results from these SI phases are expected to provide Information necessary to prioritize Individual legacy uranium sites within the San Mateo Creek basin for further detailed investigation.

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