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Whirlwind Mine Groundwater Characterization Report <br /> Water quality of the upgradient water sources is not expected to be impacted as mining <br /> activities occurs downgradient within the Salt Wash unit. EFR has provided ore pad <br /> engineering plans to protect the Brushy Basin aquifer from potential migration of ore <br /> leachate. <br /> • Fate of water that seeps into the mine workings <br /> As mentioned in Section 8.2, EFR intends to seal any leaking vent shafts and drill hole <br /> that intercept workings. Water that seeps into the workings will be used for underground <br /> mining operations as needed and as allowed with the existing water right. Any excess <br /> groundwater that accumulates will be pumped to sumps or pumped to the surface, <br /> treated and discharged under a state discharge permit. No mine water will be allowed to <br /> discharge from the mine without treatment. <br /> • Water balance <br /> True equilibrium conditions may not develop within the relatively short mining life of 10 <br /> years as discussed in Section 8.3. During mining, EFR will treat an existing mine water <br /> as mentioned above. Any groundwater drawdown that may develop is expected to result <br /> in a steep, relatively narrow cone of depression due to the moderate hydraulic <br /> conductivity that may be associated with the Salt Wash. As an aquiclude, the long-term <br /> drawdown will likely not extend more than a few hundred feet from the workings in a 10- <br /> year period. Any drawdown will eventually recover. However, any groundwater that may <br /> exist in the Salt Wash that may be depleted from mining should have a minimal effect on <br /> the hydrologic balance as most of this water likely discharges by evapotranspiration at <br /> the downgradient outcrop. <br /> After bulkhead construction, the Salt Wash will be sealed from leakage of Brushy Basin <br /> groundwater in the Whirlwind Decline. The flooded portion of the decline will be <br /> restricted to the lower Brushy Basin. This groundwater is expected to return to near <br /> natural flow paths; most of the flooded zone will infiltrate into the Brushy Basin <br /> sandstone unit as overall head allows. Some water from the flooded zone may also <br /> infiltrate into the exposed mudstone units. No new surface spring development is <br /> expected as the decline has been flooded for a total of over 30 years, and no new <br /> springs have been discovered. <br /> Western Water& Land, Inc. 63 <br />