Falls City Uranium Disposal Cell, Texas

A demolished uranium mill and associated radioactive tailings were consolidated into this mound, 40 miles south of San Antonio, in 1994. The mill operated from 1961 to 1973, extracting uranium from local sandstone using a sulfuric acid leaching process. An injection well solution mining process continued until 1982. The 127-acre disposal cell contains 7 million dry tons of contaminated material, and is 62 feet tall, and 2,600 feet long. Though the sides of the mound are covered with erosion-preventing riprap rock, the flat top of the mound has a 30-inch deep growing medium with 6 inches of topsoil to allow grass to grow, returning moisture to the atmosphere through evapo-transpiration. The mill site is nearby.