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Section 7 <br />Groundwater Information <br />linear groundwater velocity, this estimated porosity is assumed to be equivalent to <br />the estimated effective porosity of the Salt Wash member sandstones. <br />Groundwater observed in the West Sunday and Topaz Mines occurs within the Salt <br />Wash member of the Morrison Formation. A hydraulic conductivity of 1.1 x 10-4 <br />centimeters per second (cm/ sec.) is estimated for this unit based on intrinsic <br />permeability values provided by Jobim (1962). <br />Exhibit 7-3 presents a range of estimated linear groundwater velocity for the Salt <br />Wash Member of the Morrison Formation in the vicinity of the mines based on the <br />hydraulic conductivity, effective porosity and hydraulic gradient information <br />described above. <br />Exhibit 7-3. Estimated Linear Groundwater Velocity <br />Mine Estimated Estimated Estimated Estimated <br /> Hydraulic Porosity Hydraulic Average Linear <br /> Gradient Conductivity Groundwater <br /> (cm/sec) Velocity <br /> feet/ ear <br />Topaz 0.004 0.11 1.1 x 10-4 4.1 <br />Topaz 0.004 0.14 1.1 x 10-4 3.3 <br />West Sunda 0.006 0.11 1.1 x 10-4 6.2 <br />West Sunda 0.006 0.14 1.1 x 10-4 4.9 <br />Based on the evaluation presented above, the rate of groundwater flow is estimated <br />to range from approximately 3.3 to 6.2 feet per year. This suggests that, if pathways <br />are present for groundwater to travel towards the Dolores River, the travel time for <br />groundwater in the vicinity of the mine affected areas to reach the Dolores River may <br />be on the order of 2600 to 3300 years. However, the complex structural displacement <br />of the Salt Wash aquifer and other hydrogeologic units likely increases the complexity <br />of groundwater pathways, which may affect the travel time towards the Dolores <br />River. <br />r <br />7-9 <br />T:t84988-Denison MinesUask Order 4 - EPP Sunday Mines GmuprFINAL EPPtFINAL - Environmental Protection Plan Sunday Mines.doc