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• face. Springs and seeps further updip have usually <br />dried up within a few days. Changing the inflow <br />area would change the calculation of hydraulic <br />conductivity to 0.08 gal~day/ft2 which is closer to <br />the encountered values. <br />Stream Depletion <br />Stream depletion is assumed to occur by two <br />mechanisms which are: 1) mining will intercept <br />ground water flow from the coals to Curtis Creek; <br />and 2) water in Curtis Creek will infiltrate into <br />the dewatered coal seams (page G-85). The total <br />stream depletion will be the sum of these two <br />effects. The other assumptions relating to stream <br />depletion are restated from pages G-85 and G-86. <br />• 1) Hydraulic conductivities and the transmissiv- <br />ities of the combined coal and fractured overburden <br />sandstone will control the inflow and outflow of <br />water from the coal subcrop under Curtis Creek. <br />2) The average width of the coal subcrops under the <br />saturated unconsolidated material of Curtis Creek <br />is 200 feet. <br />3) The unit flow in the combined coal and fractured <br />sandstone overburden is representative of the <br />pre-mining outflow rate. <br />4) Darcy equation is applicable to calculations of , <br />seepage of water from Curtis Creek into the coal <br />seams. <br /> <br />Leonard Rice CaGwlling Water Engineers. krc. <br />