Dawn Mining Company
1.0 General Site Information
2.0 Site Description
The Dawn Ming Uranium Recovery Facility is a former conventional mill site located in Ford County, Washington, located approximately 26 miles northeast of Spokane, Washington (Figure 1). The nearest major surface water body is Chamokane Creek, which abuts the western and northern site perimeter of the now-closed facility tailings impoundment (Figure 2).
Figure 1. Dawn Mining Uranium Recovery Facility Location Map (from Google Maps)
Figure 2. Closed Tailings Impoundment Location Map (modified from Google Earth 2019 Aerieal Photography)
3.0 Site History
The mill actively produced yellowcake from ore between 1956 and 1982 at a maximum production capacity of 600 tons of ore per day (ADAMS Accession Number ML20085J302). During its operations, NRC staff estimates 3.1 million tons of ore were processed using sulfuric acid leach and ionic exchange extraction techniques and disposed in the tailings impoundments. The mill also processed water treatment sludge from the Midnight Mine (source of the ore that was processed) to recover uranium between 1992 and 2001, after which the mill was permanently shut down (ADAMS Accession Number ML053210085). Surface reclamation was performed since 2003 with completion of the final multi-layer cover for the tailings impoundment in 2017.
The closed impoundment has been characterized as four distinct impounds designated as TDA-1 through TDA-4. The closed tailings impoundments cover an area of approximately 133 acres with a maximum height of 40 feet (Figure 2). Tailings impoundments TDA-1 through TDA-3 are contiguous and situated above ground with its perimeter is surrounded by an earthen dike. Tailings impoundment TDA-4 is located below grade. An estimate of total activity has not been provided; however, the 1991 EIS reports for the dose analysis, average activities for the tailings of 240, 240, 17 and 17 picocuries per gram of tailings for Radium-226, Thorium-230, Uranium-234 and Uranium-238, respectively.
The site is and has been owned since operations by Dawn Mining Company, LLC. The State of Washington, as an Agreement State, had the authority to oversee the Dawn Mining Company license for possession, use and storage of radioactive materials. The agency with the State of Washington government responsible for overseeing the licensing is the Department of Health.
Dawn Mining Company submitted an Alternate Concentration Limit (ACL) application (primarily for Uranium) in 2019 for the State of Washington to review. Two uranium groundwater plumes have been characterized at the site, one plume emanating from the three contiguous, unlined, above-ground tailings impoundments TP-1 through TP-3, and another plume from the area in which ore was historically stockpiled at the site. The plumes extend to Chamokane Creek, which is on lands owned by the Spokane Tribe of Indians.
4.0 Current NRC actions/status
NRC currently has no actions for Dawn Mining Company until the CRR is submitted by the State of Washington.
5.0 Expected Transition to DOE for LTS&M
2028 (See DOE LM Site Management Guide, June 2022)
Page Last Reviewed/Updated Friday, October 28, 2022