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Whetstone <br /> Associates• Technical Memorandum <br /> The water level elevations in exploration drill holes were contoured to show the approximate <br /> groundwater potentiometric surface (Figure 4). Note that the contoured surface may be more <br /> representative of the perched water at the contact between the Morrison and Summerville <br /> Formations than of the actual potentiometric surface of the continuously saturated aquifer. Based on <br /> the contoured data, groundwater generally flows to the southwest, along the dip of the bedding <br /> plane, under a hydraulic gradient of 0.04 to 0.10 ft/ft. Cross sections through the ore zone also <br /> demonstrate that groundwater typically occurs near or below the contact(Figure 5 through Figure 9). <br /> S. PROPOSED DOWNGRADIENT MONITORING WELL <br /> Cotter proposes to install a downgradient monitoring well in the Entrada Formation at least six <br /> months prior to the advancement of workings. The proposed monitoring well would be located <br /> within 500 feet of exploration drill hole 79-299E,at the approximate coordinates 1,056,850 East and <br /> 585,600 North(State Plane Colorado Central,NAD 27, feet)as shown in Figure 4. <br /> Based on information from exploration drill hole 79-299E, the expected depth to water is 530 feet <br /> and the proposed total depth of the well is 570 feet. The monitoring well would be constructed using <br /> 4-inch casing and 20 feet of screen. The monitoring well would be permitted through the Colorado <br /> Division of Water Resources and would be drilled, completed, and developed in accordance with <br /> standard environmental protocols for monitoring well construction. Drilling would commence after <br /> the DOE stay on all mining activities in the lease tract is lifted, after the location and well <br /> 41. construction are approved by DRMS, and at least six months prior to the advancement of the <br /> existing underground workings. Seasonal changes in water quality are not expected, due to the <br /> depth of the monitoring well. Accelerated monitoring would be conducted, if necessary, to ensure <br /> that five samples have been conducted for valid statistical analysis of baseline conditions <br /> ‘97. OAEG<, A <br /> c504 A. j ••.`` <br /> ("?302;i= <br /> • <br /> S/ONAL <br /> 4122A.120413 '. <br />