2011-09-26_PERMIT FILE - C1981012 (24)

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r. ¢, rya. ~reti,~8 areal extent of the mine (Table ~ to determine mine inflow from the face and roof respet:tively. Three scenarios were exa++~+ned: the existing co~guradon of the Golden Eagle Mine, the configuration for the current permit tens, and the life-of--mine configuration. Case II inflow predictions utilizing the maximum coal trancm~ivity of.1.98 ftZ/day appeared to best neptrstet the situation currently observed at the mine (T'abte ~. Currently the mine is producing an average of 0.14 gpm/acre of mine. Over the last five year, inflow has ranged fiom 0.09 gpm/acre to 0.125 gpm/acre. Figure 6 is a diagram of seepage rates by acres of mined coal over time. This curve corresponds well with the seepage rates anticipated in the 1980 study, ate, due to the homogeneity of saadgraphy, structural geology, topography, and climate, may represent a good way to project future inflows based on total acres mined. Figure 6 also shows a graph of inflows from shafts and holes by acres of mined coal. The slight decline in gpm/acre might represent an offset from dewatering of perched water tables at old sites to additional inflow from newer sites. There will continue to be a constant inflow of 80 to 100 gpm associated with the SE-1 TG fault. The mine is currently using the dischazge for underground dust suppression activities. Should the mine encounter another fault of comparable magnitude, inflows will increase beyond the • current projection. The station for measuring the flow from the fault was relocated, and now includes some seepage flow (results in an apparent increase in fault flow and decrease in area seepage). The flow from the fault itself may be leveling off to a sustained production t'rom recharge. During the third quarter of 1989, the New Elk Mine was temporarily sealed. Previous mine inflow studies recorded inflows of approximately 123 gpm, of which 109 gpm was being generated from mined out areas totaling approximately 2800 acres. Any mine inflows are currently flooding the abandoned mine workings. An estimation of the extent of flooding within the workings was made. This analysis assumed that all azeas of the mine below the elevation of 7062' were equally flooded. A copy of the mine map was acquired and the extent of mains was measured at 286 acres. The coal reportedly averaged 8 feet in height in this area, and the mining resulted in 70 percent recovery of the coal. The length of the flood limit line on the floor of the mine is 13850 feet. (286 ac) x (43560 ft2/ac) x (8 ft) x (60%) = 59,799,168 ft' (if flooded from floor to roof), minus (8 ft) x (13850 ft) x (8 ft) / (4.5%) / 2 = 9,848,889 ft (perimeter correction), equals • 18