Design And Construction Of Uranium Disposal Facilities For The Panna Maria Project, Texas

INTRODUCTION The Panna Maria Uranium Project is located in South Texas, between San Antonio and Corpus Cristi, approximately 10 kilometers (6 miles) north of Karnes City, Texas. The tailings disposal facilities are located immediately south of the mill area and the central portion of the west pit. The mine and mill drainage pond is located north of the tailings pond. Location of the facilities is shown in Figure 1. The tailings pond is a disposal area for mill process wastes and has a capacity for storage of approximately 9 million metric tons (10 million tons) of tailings. This capacity is adequate for approximately 10 years of milling at a maximum rate of 2,700 metric tons (3,000 tons) per day. The tailings disposal facilities were designed to essentially eliminate discharge of contaminated waters to preclude degradation of surface streams or ground water. Water levels in the ponds will be maintained. through reuse in the mill and by evaporation. WASTE CHARACTERISTICS The sources of waste that is stored in the tailings pond include runoff from the mill area and tailings from the mill processing. The tailings consist of a sand slime slurry; the percentage passing the No. 200 sieve varies depending on the ore material, and it is generally in the range of 10 to 25 percent. The tailings have a density of approximately 1.2 metric tons per cu m (75 lb per cu ft) and an average specific gravity of 2.55. The liquid effluent from the mill consists of waste solutions from the grinding, leaching, extraction, and washing circuits of the mill. These solutions have an initial pH of 1.5 to 2.0 and contain the remnants of the leaching agents used in the mill process, sulfates, some silica as the primary dissolved solid, and trace quantities of soluble metals. This liquid is discharged with the solids into the tailings pond and is diluted by rainfall and runoff from the tailings dam. Runoff from the mill area, drainage from the mine area, and de-oiled water from truck washing facilities is discharged into the mine and mill drainage pond. Runoff from the mill area drains approximately 28 hectares (70 acres) from offices, shops, the mill site, the ore pad, haul roads, and adjacent areas. Mine drainage is collected in the mine area and pumped to the mine and mill drainage pond.