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• have been kept. A procedure for collecting this <br />information is being established. Since mining <br />began, no water has been allowed to accumulate in <br />the mine. She total volume of water pumped from the <br />mine by December 31, 1980 was 2,429,000 gallons <br />(Table F is the raw data of pumping volumes). <br />Conservatively, assuming that all water pumped out <br />of the mine by December 31, 1980 was from mine <br />inflow since mining began in August, 1979( about <br />518 days), the average rate of mine inflow was <br />4,690 gal/day. A rough estimate of the area of the <br />walls of the mine by December 31, 1980 is 214,400 <br />ft2 (mine progress map provided by Northern Coal). <br />Dividing this area by 2 to obtain an average wall <br />area during the period of mining gives 107,200 ft2 <br />through which 2,429,000 gallons passed in 518 days. <br />• This translates into a representative hydraulic <br />conductivity of 0.044 gal/day/ft2 for the FF coal <br />seam in the area mined by December 31, 1980. This <br />is much lower than the average hydraulic conduct- <br />ivities of almost 10 gal/day/ft2 seen in the 1979 <br />aquifer tests on observation wells (Appendix B, <br />Section G-5.0). Continued physical observation of <br />inflows in the other mine, Rienau #2, indicate, <br />however, that inflow occurs primarily through the <br />area near the working face of the mine within about <br />200 feet of the face. Assuming this is a more <br />accurate area through which the mine inflow occurs, <br />a second calculation of the average hydraulic <br />conductivity would be 0.366 gal/day/ft2. This <br />number is much closer to the hydraulic . <br />conductivities of the observation wells (Appendix <br />B, Section G-5.0). <br /> <br />f (1 Leonard Rice CortsuRing Water Engineers krc. <br />