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as a primary drinking water source because of its great <br />depth outside stream valleys and the ready availability <br />of better quality surface water near the stream valleys. <br />MCC has mapped the B seam overburden thickness with <br />potential areas of ground water inflow highlighted. <br />These areas of potential inflows, similar to the <br />F seam, are associated with fracture zones beneath <br />drainages and near outcrops and areas of low over- <br />burden. Based on experience in the F seam in these <br />areas, the inflows are predicted to be minor in nature. <br />MCC has made inflow estimates for the B seam mine plan <br />for the five-year permit area. The "probable maximum" <br />estimate of mine inflow shows a peak or initial inflow <br />rate of about 15 gallons per minute (gpm) and a long <br />term steady rate of about 10 gpm. This estimate is <br />based on a rate of mining of 1.4 million tons per year <br />and no ventilation portals extended to the northern <br />outcrop. <br />A "worst case maximum" estimate of mine inflow was also <br />performed. This case showed an initial inflow rate of <br />about 45 gpm and a long term steady inflow rate of <br />about 30 gpm. This case was based on a mining rate of <br />2.8 million tons per year, installation of a <br />ventilation portal along the outcrop, and an increased <br />inflow constant for unknown conditions. <br />The B seam mine will not cause significant hydrologic <br />impacts to groundwater systems in the five-year permit <br />area based on the data provided. <br />The majority of springs (shown on Map 55> are located <br />at or above the F seam outcrop. A few springs have <br />been identified between the E and F seam outcrops. No <br />springs have been identified below the E seam outcrop. <br />Monitoring of springs for baseline data and to assess <br />impacts of mining in the F seam has been carried out <br />for the past ten years by MCC. Evidence to date <br />indicates that mining has very little, if any, impact <br />on spring flows. <br />The depth of overburden where the B seam will be mined <br />in the area of the springs ranges from 400 to in excess <br />of 1,000 feet. Based on experience in the F seam and <br />geotechnical work, the springs will not be affected <br />significantly by mining in the B seam under these <br />overburden depths. <br />Some inflows to the mine are expected as mining <br />proceeds under Lone Pine and Gribble Gulches as the <br />valley features are fracture controlled. Inflows in <br />-39- <br />