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JD-9 Mine Report <br />Geoscience Services <br />For the simulations, a conservative approach was adopted that assumed aworst-case <br />scenario. Because there is a limited amount of technical data available for the hydraulic <br />and transport parameters of the geologic strata under the site, these parameters were <br />estimated using the best available geotechnical data available from the literature. Since <br />there is commonly a range of values associated with these hydraulic and geochemical <br />parameters, values that result in the highest transport rates were selected. <br />2.0 Site Description <br />The JD-9 mine is located southwest of Paradox Valley on the flanks of <br />Monogram Mesa. According to the geologic map for the area (Cater, 1954), the waste <br />pile for this mine will be located on the Brush Basin member of the Morrison Formation <br />(Figure 1}. The rock units in this azea dip to the southwest at approximately one degree. <br />The JD-9 mines the upper sandstone unit of the Salt Wash member of the Morrison <br />Formation that contains some groundwater as evident by dewatering operations at the <br />~~ mine. There is a small spring located to the south of the mine named Fawn Spring. <br /> Visual inspection of the spring indicates small seepage faces that discharge only a few <br /> gallons of water per day. Consequently, it is expected that the spring has only a minimal <br /> <br /> effect on groundwater flow in the area and any movement of groundwater in the upper <br />• sandstone member of the Salt Wash Member or the underlying Entrada Formation will be <br />~ controlled by the regional geologic structure. Consequently, any potential discharge of <br />~ groundwater from the mine site will occur in Bull Canyon located to the southwest. <br /> <br /> The potential transport of constituents of concern from the JD-9 site will occurs as <br /> <br /> horizontal transport following the regional dip of the rocks through the Upper Salt Wash <br />• sandstone with leakage downward eventually reaching the Entrada Sandstone. <br /> Comparisons with modeling conducted at the SM-18 mine will consider the differences <br /> in the hydrogeology when evaluating the environmental impacts at the JD-9 mine site. <br /> <br /> <br /> <br /> <br /> <br />~ 2 <br /> <br /> <br />