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Madge Coal Drawdowns <br />Sege Creek Slde <br />T = 0.0084 ft2/day <br />t = 190 days in (2006) <br />0 = 227,043 pals/19D days = 1,195 gel/day = .83 gpm = 16D ft3/day <br />S is calculated to match a t of 190 days and a drawdown of 52 feet <br />Pit area in water = 32.27 acres/5 pits = 281,136 ft2 <br />s = total potential head = 52 feet <br />1. Aree of equivalent uelll<r2 = 281,136 ft2, r = 299 feet <br />2. Calculate u for 52 ft of draudown <br />Y(u) = 4 x iT x .0084 x 52 = .034306 u = 2.26 <br />160 <br />• <br />3. Calculate S that will give 52 ft of drewdown in 315 days et a radius of 299 ft. <br />S= 4 x .0084 x 190 z 2.26 = .00016 <br />299 x 299 <br />4. Calculate u for 1 ft. drawdown <br />W(u) = 4 xTT'x .0084 x 1 = .00066 u 5.48 <br />160 <br />5. Calculate distance to 1 ft. drawdown us inp S = .00016 <br />r1 = (4 x .0084 x 190 x 5.48)1/2 = 46B ft to the 1 ft. drawdown contour <br />.00016 <br />b. Calculate u for 5 ft. drawdown <br />Y(u) = 4 xZT x .0084 x 5 = .003299 u = 4.11 <br />160 <br />7. Calculate distance to 5 ft. drawdown using S = .00016 <br />r5 (4 x .008E x 190 x 4.11)1/2 = 405 ft. to the 5 ft. dreudown contour • <br />.00016 <br />Revised 03/01/95 <br />