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Hydrogeological Evaluation of Van 4 Mine <br />Geologic and Hydrogeologic Conditions <br />¦ Groundwater from the Dakota aquifer has high concentrations of TDS, chloride and <br />sulfate with neutral pH; <br />¦ Groundwater from the Salt Wash aquifer has moderate concentrations of TDS, <br />chloride and sulfate with neutral pH; <br />¦ Groundwater from the Navajo Aquifer varies with depth and hydrogeological unit. <br />Groundwater from depths of less than 500 ft. has moderate to high concentrations <br />of TDS, chloride and sulfate, with moderate to slightly alkaline pH. Groundwater <br />from depths greater than 500 ft. has very high concentrations of TDS, sulfate and <br />chloride, and slightly alkaline pH. <br />As described previously, the underground mine workings are not currently accessible <br />and groundwater quality data from the direct vicinity of the Van 4 mine are not <br />available. <br />2.3.6 Existing and Potential Future Uses of Groundwater <br />Existing or potential future uses of groundwater in the vicinity of the Van 4 Mine are <br />limited because most of the surrounding land is public land administered by the U.S. <br />Department of the Interior, Bureau of Land Management (BLM). Groundwater use in <br />the direct vicinity of the Van 4 Mine area is not occurring, and the primary future use <br />of groundwater in the area is likely for industrial uses to support underground <br />mining operations. In the area of Fawn Springs, located approximately 1.5 miles <br />downgradient of the mine, groundwater uses may also include occasional livestock or <br />wildlife uses. <br />Exhibit 2-4 shows existing wells in the area of the Van 4 mine. These wells are all <br />related to other uranium mining activities in the area and include one well permitted <br />for industrial use and five monitoring wells. Most of these wells are located in an area <br />of extensive previous uranium mining located approximately 2 miles north of the Van <br />4 Mine. This mining area is located on the slope break between Monogram Mesa and <br />Paradox Valley to the north. It is unlikely that these wells would be affected by <br />Denison activities, because of the distance from the Van 4 Mine site. One of the <br />existing monitoring wells is located on Monogram Mesa approximately 1.3 miles west <br />of the Van 4 Mine. This well is permitted by Cotter Corporation, another uranium <br />mining company. This well is unlikely to be affected by the Denison activities because <br />it is located west of a tributary to Bull Canyon. Groundwater flow on both sides of the <br />tributary is likely towards the south into Bull Canyon based on the orientation of the <br />hydrogeologic units and topography. Therefore, groundwater would not be expected <br />to flow from the Van 4 Mine towards the northwest. <br />0 cm <br />2-13 <br />draft final van 4 hydnogeology report.doc