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• /. Quantitative Impacts of Mining <br />includes some seepage flow (results in an apparent increase in fault flow and decrease in azea <br />seepage). The flow from the fault itself may be leveling off to a sustained production from <br />recharge. <br />During the third quarter of 1989, the New Elk Mine was temporarily sealed. Previous mine <br />inflow studies recorded inflows of approximately 123 gpm, of which 109 gpm was being <br />generated from mined out areas totaling approximately 2800 acres. Any mine inflows are <br />currently flooding the abandoned mine workings. <br />An estimation of the extent of flooding within the workings was made. This analysis assumed <br />that all areas of the mine below the elevation of 7025' were equally flooded. A copy of the <br />mine map vas acquired and the extent of workings was measured at 739.78 acres. The coal <br />reportedly averaged 8 feet in height in this area, and the mining resulted in 70 percent recovery <br />of the coal. The length of the flood limit line on the floor of the mine is 13850 feet. <br />(739.78 ac) x (43560 ftZ/ac) x (8 ft) x (70%) = 180,458,974 ft' <br />(if flooded from floor to roof), minus <br />(8 ft) x (13850 ft) x (8 ft) / (4.5%) / 2 = 9,848,889 ft' <br />(perimeter correction), equals <br />170,610,085 ft' x 7.4805 gal/ft3 = 1,276,248,741 gallons <br />Flooding occurred over approximately 4 years, at 365 days per year, 24 hours per day and 60 <br />minutes per hour, or over 2,102,400 minutes. <br />1,276,248,741 gallons / 2,102,400 minutes = 607 gpm <br /> <br />Since mine inflows were never of such magnitude, the assumptions of the analysis were re- <br />examined. Mine working may not be hydraulically connected due to mine configuration and <br />seals. In addition, there may be some upslope workings with trapped air pockets. Portions of <br />the mine may have been left to flood at varying times and rates over the years; mine records are <br />not available to reconstruct events or to establish a flooding history. Basin will commence a <br />monitoring program to estimate current rates of inflow. <br />The 1980 WWL report made a projection that drawdowns of one foot would be seen at distances <br />ranging from 4100 - 7700 feet from the perimeter of the mine based on varying estimates of <br />vertical leakance. The previous mine inflow analysis indicated that Cases IIB and IIIB <br />reasonably fit the results observed at the Golden Eagle Mine. Therefore, new estimates of the <br />21 <br />