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contribute an average of 0.09 cfs to Fish Creek in the downstream discharge <br />area. TABLE 12 shows that the maximum mine water discharge could increase the <br />7 day, 10-year flow 64%, but that the average mine water discharge would <br />increase the average low flow 6%. Two periods must be addressed for long-term <br />impacts to surface water flows. For the three-hundred and fifty years <br />following mining, ground water discharge to Fish Creek will be non-existent <br />and surface flows will decrease 0.09 cfs. Once the original potentiometric <br />head is established in Twentymile Park, discharge from the flooded workings <br />into the Wadge overburden aquifer will average 54 gpm (0.12 cfs). The Trout <br />Creek sandstone will again resume discharging 30 gpm (0.07 cfs) for a total <br />ground water discharge of 84 gpm (0.19 cfs). This will increase base flows <br />6.6-30%. <br />TABLE 13: Summary of Influences of Foidel Creek Underground Mine on Fish <br />Creek Flow. <br />Site 1001 <br />7 day, 10-year <br />Discharge <br />Average Base Flow <br />Life of Mine Impacts <br />from Mine Inflow <br />Discharge <br />Maximum Discharges <br />Average Discharges <br />Post-Operation Impacts <br />First 350 years <br />Discharge of Flooded <br />Workings <br />Discharge Percent Change Percent Change <br />(cfs) to 7 day, 10-year Q To Average Low Flow <br />0.64 NA NA <br />3.00 NA NA <br />+0.41 +64% +14% <br />+0.17 +27% +16% <br />-0.09 -14% +6.6% <br />+0.19 +309U +6.6% <br />Cumulative Hydrologic Impact Study <br />A. Ground Water <br />The Foidel Creek underground mine will be one of nine mines rimming the <br />Twentymile Park Synclinal Basin. The other mines in the ground basin are: <br />Apex No. 2 Mine, Edna Mine, Seneca No. II Mine, the CYCC Mine No. 1 No. 2, <br />Eckman Park Mine, and the affiliated Little Middle Creek Tract, and Energy No. <br />3 Mine and the adjacent Middle Creek Mine. The CYCC Mines, Eckman Park and <br />the Middle Creek Mine are owned by Cyprus Western Coal Equipment Company and <br />permitted under two CMLRD permits (TABLE 4). Impacts from the Middle Creek <br />mine will be addressed separately from the other Cyprus mines, due to the fact <br />that it was an underground mine. <br />-49- <br />