Monument Valley Uranium Mill Site, Arizona

A uranium mill operated at this location from 1955 to 1968 to concentrate uranium ore mined nearby. For the last few years the mill used sulfuric acid leaching process. The milling left a radioactive mill tailing pile, as well as other hazards. Clean up of the site was initiated as part of the federal governments Uranium Mill Tailings Remediation Act Project. Most of the contaminated material was interred in the large disposal cell near Mexican Hat, Utah, 15 mile north. Though the buildings have been removed, the mill site here continues to be monitored, due to concerns about groundwater contamination and other lingering residue. The site covers approximately 90 acres, on Navajo Nation land.