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• coming from an adjacent hydrologic unit. One possible source is the <br />Middle Sandstone. Based upon water level observations, the Middle <br />Sandstone is experiencing a head decline. Assuming that all the flow is <br />from the Middle Sandstone, the Jacob-Lohman Method was used to estimate <br />the inflows to the mine from the sandstone. The fault zone was assumed <br />to be a large diameter well tapping the overlying Middle Sandstone. <br />Because the fault zone and possible surrounding formation are fractured, <br />the apparent permeability of the unit would be higher than that normally <br />measured in the Middle Sandstone. <br />Based upon this analysis, the transmissivity was estimated to be 200 to <br />250 ftz/day (1500 to 1900 gpd/ft), and the storativity was estimated to <br />be 0.0001 to 0.001. As expected, the transmissivity is significantly <br />higher than that normally measured in the Middle Sandstone. The <br />predicted inflows are presented on Table 4, Predicted Flows to the 2 <br />West Mains Fault - No. 5 Mine. As would be expected, the inflow will <br />decrease in time. <br />• <br />Channel Sand <br />In portions of the Empire tract (including the Utah Tract) there is a <br />channel sand immediately overlying the F seam. It overlies <br />approximately 110 acres of the mine and averages approximately 30 feet <br />thick. The average head on this sand unit is 200 feet. The storativity <br />is estimated to be 0.0001. Based upon permeability analysis of core <br />samples from this unit, the permeability is estimated to be 1 gpd/ftz. <br />The permeability and porosity of the channel sand is presented in Table <br />5, Permeability and Porosity of Channel Sand. <br />The Jacob-Lohman method was used to estimate the additional inflow to <br />the mine from this unit. Based upon a maximum of 36,000 ft2 of roof <br />being exposed in one day, the inflow would be approximately 45 gpm for <br />the first day. The long term inflow from the total channel sand would <br />. be approximately 10 to 20 gpm, therefore, the total additional inflow <br />from the channel sand would be approximately SO gpm. <br />-11- <br />