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available recharge areas in the northern bench region appears to be the most likely <br />explanation to why the Salt Wash sandstones are saturated in the JD -9 Mine. <br />8.4 Groundwater Monitoring <br />In response to DMO requirements imposed by the DRMS, Cotter installed a lysimeter <br />and a groundwater monitoring well downgradient of the mine and waste rock pile to <br />quantify the water quality in the soils and the Salt Wash sandstone. During years of <br />monitoring, no water was recovered from the lysimeter indicating insufficient <br />precipitation capable of maintaining adequate soil moisture at depth. <br />A monitoring well was placed down - gradient of the mine workings and is located in a <br />good position to detect possible impacts from the subsurface mining or the waste rock <br />pile. If groundwater is impacted by mining operations and flows toward the Fawn <br />Springs discharge area, the well will provide an earlier warning system. The monitoring <br />well was drilled to a depth 240 ft and completed in saturated sandstones of the Salt Wash <br />member. Recent water levels at the site indicate a depth to water of 188.5 ft BCL (below <br />casing level). It is clear from the groundwater analysis presented in Table 4 (Section 9) <br />that water quality in the Salt Wash is poor. High concentrations of total dissolved solids <br />such as carbonate and sulfate plus ore related constituents such as uranium and radium <br />226, result in groundwater that is not a potable water source. <br />A strong argument can be made that the existing monitoring well is representative of <br />background water quality conditions for the Salt Wash sandstone. High levels of <br />uranium and radium are not surprising considering that the groundwater occurs in a <br />natural mineralized zone. High levels of total dissolved solids (represented by <br />conductivity) and sulfate are indicative of older groundwater that tends to evolve toward <br />the composition of sea water the longer water moves along subsurface flow paths. Using <br />the major ion evolution sequence first proposed by Chebotarev (1955), groundwater in <br />the Salt Wash would be classified in the intermediate zone — with less active groundwater <br />circulation and high total dissolved solids where sulfate is the dominant ion in this zone. <br />The intermediate zone is an indication of old groundwater found either in deep geologic <br />basins or in low permeability environment that have been isolated from the surface <br />environment for substantial periods of time. <br />Calculated groundwater flow rates of less than a foot per year support the conclusions of <br />the water quality data indicating the Salt Wash sandstone is not a source of domestic or <br />industrial water. Dewatering operations during active mining reversed groundwater flow <br />directions, further limiting the spread of mining related constituents in the groundwater. <br />While the location of the existing monitoring well establishes a compliance point to <br />detect possible impacts to the groundwater system and provides adequate warning of <br />potential environmental impacts, it also provides data on existing groundwater quality <br />conditions. A traditional up- gradient or background monitoring well would have to be <br />drilled on Monogram Mesa and would provide similar information on water quality data <br />that already exists with the down - gradient monitoring well. Cotter is willing to comply <br />with the Division's future request to install an up- gradient well but the costs do not <br />O'Connor Design Group Inc. U - 17 <br />