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West Elk Mine 2008 Annual Hydrology Report 58 <br />ranged from near neutral to moderately alkaline with pH values ranging from 7.01 to 8.67 s.u. and <br />with average TDS concentrations ranging from 338.5 to 6,976 mg/1(Table 12). <br />The major cations and anions of the Sylvester Gulch discharge water are also sodium and <br />bicarbonate. The mine water (017A) discharged to Sylvester Gulch in WY 2008 was slightly to <br />moderately alkaline with pH values ranging from 8.2 to 8.99 s.u. and with average TDS <br />concentrations ranging from 2,134 to 2,580 mg/I (Table 12). There was no discharge from pond <br />SG-1 (018A) in WY 2008. <br />A salinity (TDS) loading analysis of the MCC's WY 2008 discharges was completed relative to the <br />current North Fork Cumulative Hydrologic Impact Assessment (CHIA) (CDMG, 2003). The <br />CHIA was conducted to assess the potential cumulative hydrologic impacts of mining and other <br />activities in the North Fork Valley on the North Fork's water quality and flow. The CHIA <br />determined that no significant hydrologic impacts were expected as a result of mining activities at <br />the West Elk Mine. The CHIA assumed that MCC's contribution to the North Fork of the <br />Gunnison River would be a maximum of 5,520 gpm with a TDS concentration of 2,500 mg/l. <br />The total WY 2008 discharge rate from the mine, as accounted from the CDPS reports, was <br />approximately 1,427 gpm (Table 12). Based on this value, the flow-weighted maximum annual <br />salinity (TDS) load from MCC's mining operations was 8,758.1 tons. This represents about 5.3 <br />percent of the value used in the CHIA. A comparison of the salinity loading from MCC's mining <br />operations to the CHIA study is shown on Table 14. <br />No mining induced impacts to water quality or flows in the North Fork are anticipated in WY <br />2009, because mine discharges are not expected to increase and the discharge water quality is <br />expected to remain the same. <br />Table 14. Summary of Salinity Lnndina in the Nnrth Fw r of tho (_,inn;enn <br /> Average Maximum Flow Calculated <br />Scenario Continuous Weighted TDS Annual Salinity Percent of <br /> Discharge Rate Concentration Loading CHIA Loading <br /> ( m) (m /1) (tons/ ear) <br />WY 2008 1,427 6,523 8758 5.3 <br />2003 CHIA (2) 5,520 2,500 30,159 - - <br />(i) Using WY 2008 CDPS DMR volumes <br />(2) Based on maximum permitted discharge rate <br />• <br />June 2009 HydroGeo, Inc.