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I1 <br />U <br />Wes[ Elk Mine 2002 Annual Hydrology Report <br />• Water in produced coal and GOB (145 ac-ft) <br />• Mine sump discharge and drilling water (415 ac-ft) <br />• Mine ventilation moisture (37 ac-ft) <br />• Miscellaneous mine seepage and evaporation (15 ac-ft) <br />• Pond evaporation (22 ac-ft) <br />• WTP (8 ac-ft) <br />• Runoff from surface operations\pond discharge (41.6 ac-ft) <br />• Total Outflow = 683.6 ac-ft <br />The total volume of water entering the mine during WY2002 was 642 ac-ft versus a total outflow <br />of 683.6 ac-ft, a net difference of+41.6 ac-ft (surface operations discharge). <br />5.0 ASSESSMENT OF MINE INDUCED HYDROLOGIC IMPACTS <br />5.1 Surface Water <br /> <br />MCC maintains a network of 17 stream flow gaging stations throughout the permit and lease areas, <br />listed in Table 4. The locations of the stations are shown on Map 2. Daily mean flow tables aze <br />shown in Appendix A. Stream hydrographs are presented in Appendix B and water quality is in <br />Appendix C. <br />5.1.1 Area Stream Water Quantity and Quality <br />Mining activity has approached only two major drainages, Minnesota Creek and Deep Creek. <br />Long wall mining approached the area of the Minnesota Creek drainage in July of 1998 and Deep <br />Creek in March of 2001. There have been no mining induced impacts to the stream flow or water <br />quality data of these streams. <br />5.1.2 North Fork of the Gunnison <br />~J <br />MCC discharges to the North Fork via sediment ponds (MB-2R and MB-4) and direct discharges to <br />Sylvester Gulch from the mine water pumping facility (MWPF). The major cations and anions of <br />the pond discharge water are sodium and bicarbonate. The sediment pond discharge water is <br />slightly alkaline with a pH ranging from 6.93 to 8.17, with TDS concentration ranging from 200 <br />mg/1 to 930 mg/1. The major cations and anions of the MWPF discharge water are sodium and <br />bicarbonate. The MWPF discharge water is slightly alkaline with a pH ranging from 7.94 to 8.32, <br />with TDS concentration ranging from 2,542 mg/1 to 3,500 mg/l. <br />A salinity (TDS) loading analysis of the MCC's WY2002 discharges was completed relative to the <br />current North Fork Cumulative Hydrologic Impacts Analysis (CHIA) (CDMG, 1997). The CHIA <br />analysis was conducted to assess the potential cumulative hydrologic impacts of mining and other <br />24 <br />Project # 00301 HydroGeo, Inc. <br />