The 71-acre radioactive tailings disposal mound built by the DOE for the interment of 3.5 million cubic yards of material from two former Union Carbide uranium mill operations in the nearby town of Rifle. The Rifle Disposal Site is on 205 acres of Estes Gulch, former BLM land, transferred to the DOE in 1991. The cell sits on an alluvial fan surface, and the structure reflects this form.
