Sherwood Mine- Spokane Indian Reservation, 1978-1984

The Sherwood Mine, a uranium mine on the Spokane Indian Reservation, produced 2,100 tons of uranium ore per day between 1978 and 1984. Decommissioning of the mill began in 1992 and cleanup activities concluded in 1996. The radioactive tailings, along with mill site soils, building equipment, and contaminated debris, were encapsulated in an engineered disposal cell constructed on site. This disposal cell contained about 2.9 million tons of uranium mill tailings and an additional 350,000 cubic yards of contaminated mill site materials. The estimated radium-226 activity in the impoundment is 470 curies.