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Whirlwind Mine Groundwater Characterization Report <br /> from this strict water type. The Brushy Basin water chemistry is distinctly different from <br /> Burro Canyon source water chemistry. <br /> 6.2.3 Salt Wash <br /> The occurrence of groundwater in the Salt Wash is limited to data collected from the uppermost <br /> Top Rim sandstone unit. The Top Rim sandstone is the primary ore zone for the uranium and <br /> vanadium mining in the region. <br /> The hydrogeologic investigation by Umetco at borehole BM00-1 was conducted to investigate <br /> groundwater occurrence and chemistry in the hydrostratigraphy of the Whirlwind Mine and <br /> vicinity. The investigation at BM00-1 showed that, after several hours of allowed recharge time, <br /> no groundwater could be pumped from the packer test interval that spanned 50 ft of the Top <br /> Rim of the Salt Wash. Similarly, exploration holes drilled by Cotter in 1996 and by EFR in 2007 <br /> did not show that the Salt Wash was a viable aquifer. As pointed out in Appendix D of the mine <br /> permit, borehole BM00-1 was drilled to within about 200 ft of the Whirlwind Decline and mine <br /> workings that had been flooded for almost 20 years, yet no groundwater was indicated in the <br /> Salt Wash interval. <br /> If the Top Rim sandstone was a saturated aquifer, it is likely that it would show confined <br /> conditions due to the general confining conditions of the overlying Brushy Basin. But the <br /> occurrence of groundwater in the Top Rim sandstone is not obvious. Key evidence of <br /> unsaturated conditions is the lack of mines discharging water in the area. Since the geologic dip <br /> is to the northeast, most mines tunneled into the Top Rim unit should drain freely if sufficient <br /> groundwater is produced. Some mines that collar in the Top Rim may have shown small <br /> amounts of discharge in the past but are not showing discharge presently (EFR, 2008a). Mine <br /> water discharge would be expected to be substantial if the Top Rim sandstone were a saturated <br /> aquifer. Even with the low permeability indicated by hydraulic tests of the Top Rim, the <br /> thousands of linear feet of exposed surface of the unit would yield notable inflow. A simple <br /> conservative Darcy equation calculation shows that an 8-foot high by 100-foot long exposure of <br /> saturated Top Rim sandstone would only produce 0.02 gpm using the hydraulic conductivity <br /> value of 4.82 X 10-3 ft/day (Section 4.3). Workings of the older mines easily exceed 10,000 <br /> linear feet which would produce a flow rate of 20 gpm. From anecdotal evidence, these types of <br /> flows were not observed in the mines (EFR, 2008a). A large part of the source of pooled water <br /> Western Water& Land, Inc. 41 <br />