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• It was anticipated that springs would again flow in the vicinity <br />of SP4, because this is the area where the mineable seams outcropped and <br />mining was initiated. From this point mining proceeded in a southerly <br />direction up-dip. It is expected that any major flows will continue to <br />surface in this vicinity or down-dip of the mining disturbance. <br />There is a possibility that other seeps might surface within the <br />upper reaches of the reclaimed area. This might occur if subsurface water <br />were to contact a buried road and fallow it downgrade to a point where the <br />flows would come to the surface. It is expected that the volume of water <br />within these areas would be very minor, occurring after the spring runoff <br />and would dry up during the summer months. <br />Water balance <br />Available hydrogeologic data to evaluate the hydrologic <br />characteristics of the backfill material is limited. Some preliminary work <br />has been completed at the CYCC Mine and The Seneca II Mine to characterize <br />spoil aquifers. <br />Preliminary data indicates that recharge rate of the spoils <br />aquifer is 15-25 percent of the annual precipitation. Assuming that the <br />annual precipitation for the mine is 16 inches, a figure of 3 inches of <br />recharge per year for the backfilled areas that are fully consolidated and <br />vegetated has been accepted as reasonable. <br />• The total recharge calculation is as follows: <br />Area of Reclaimed backfill = 330 acres or 14,374,800 ft2 <br />Estimated Annual Recharge Rate = 0.25 ft./yr. <br />Total Recharge = 14,374,800 ft2 X 0.25 ft./yr. = 3,593,700 ft3/yr. <br />= 82.5 Acre Foot/yr. <br />or 51 gpm <br />o, f r9- c~ <br />The total recharge is approximately 82.5 acre feet, equivalent to <br />an average rate of 51 gpm. <br />Additional groundwater into the spoil from surrounding areas is <br />considered minimal due to the location of the mine in the upper edge of the <br />syncline. This was confirmed by the lack of groundwater observed entering <br />the pit during the mining operation. <br />Discharge <br />Limited discharge rate data for the HG Mine is available to date. <br />It is anticipated that there will be a significant increase in discharge <br />rate during the snowmelt period. During this time ,water levels in the <br />backfill area reach their maximum levels. This results in a maximum <br />hydraulic gradient towards the discharge areas. <br />i <br />Acre -See+ `1"~ ~`°`'m =r` ,~ c~~°`7 F =~~ ~"'~ ,; Revised November, 1986 <br />. ' ,n~,i 7~hnr; wr <br />Yca/ 3es cl ~*+7~ <br />ricrr ~Et X ~f~s-. t~,~ XZ'Z~~)P~'~ _ b~ <br />