The Richardson Flat Tailings site is located near Park City, Utah. The area includes a 160-acre tailings pond that holds about seven million tons of tailings. Between 1953 and 1982, United Park City Mines (UPCM) leased the site and their mines to various mining firms. These firms operated the mines, used the site for tailings disposal and left 450,000 tons of tailings on site. These activities contaminated soil, air, surface water and groundwater with heavy metals. EPA proposed the site for listing on the Superfund program�s National Priorities List (NPL) in 1988, but ultimately decided not to pursue final listing on the NPL. Remedy construction is underway.