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2. Length in water (feet) is the same as the total length of the cuts for each year. <br /> 3. Time in water is the result of dividing the length in water for a given year by the <br /> pit advancement per day for the same year. This value represents the number of days <br /> the pit will be open and subject to pit inflow each year. <br /> 4. Pit advancement is the constant length in feet per day that the pit will advance for <br /> the year. It is calculated by dividing the total area to be mined in a given year by <br /> a constant pit width. The constant pit width use for years 1 and .2 is 150 feet. For <br /> years 3, 4, and 5 a constant pit width of 105 feet was used. <br /> 5. The geometric mean values for transmissivity, hydraulic conductivity, and storage <br /> coefficient were collected from aquifer tests and determined by using the following <br /> equation: <br /> Xg = (X1*X2*X3...Xn)1/n <br /> 6. The saturated thickness for each aquifer was based on water level monitoring values <br /> that were representative of the area to be mined in a given year. <br /> 7. QNATURAL is the amount of aquifer through flow which will be intercepted by each <br /> years pit advancement in gallons. <br /> 8. QDRAINACE is the linear portion of inflow from aquifer storage in gallons. <br /> 9. QTOTAL is the sum of QNATURAL and QDRAINACE for a given year in gallons. <br /> Mining in Nucla East is projected to intercept both the overburden and Dakota coal <br /> aquifers for all five year. <br /> MODFLOW Analysis for Calculating Pit Inflows and Drawdowns. <br /> Introduction. MODFLOW was used to model changes in the ground water system in the <br /> vicinity of the Nucla mining complex caused by pit dewatering. Simulations for both the <br /> overburden and coal aquifer were performed. No modifications to the MODFLOW code were <br /> necessary. <br /> 17-9 Revised 04/11/88 <br />