Uranium ore has been mined in the U.S. for over 40 years. Raw uranium ore was milled to concentrate the uranium, leaving tailings behind.
Tailings are leftover rock and soil containing residual uranium and radium.
In the 1950s and 1960s, before the potential hazard of these materials was understood, uranium mill tailings were used as fill dirt in some construction activities. See Appendix A for a list of the site names and locations. Some dots may represent more than one site. Uranium was milled at Riverton, Wyoming, from 1958 to 1963. This site is located within the Wind River Indian Reservation.