Hydrogeology of the San Xavier Mining Laboratory and Geophysics Test Site and surrounding area

Abstract

Water level, permeability, and water quality data indicate that the aquifer beneath the San Xavier Mining Laboratory is unconfined, high permeability, and isolated from the adjacent, upgradient aquifer. The aquifer at San Xavier has been dewatered considerably due to past pumping at the mine and at nearby open-pit mines. Water levels have not recovered due to the low permeability of the upgradient aquifer, and the restriction of the flow of ground water across the thrust fault separating the upgradient and San Xavier aquifers. The Mining Laboratory is in full compliance with the Aquifer Protection Permit issued to the facility by the Arizona Department of Environmental Quality. The ground water at the mine meets all state and federal primary drinking water standards. The future use of the aquifer does not appear to be threatened by research being conducted at the mine.