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West Elk Mine 2004 Annual Hydrology Report 33 Creek data logger was taken out of the protective box, the battery drained, and the monitoring data is missing from June 11, 2004 through November 11, 2004. HydroGeo technicians replaced the Upper Deep Creek battery on November 11, 2004 and it appeazed to be in good working order. 5.1.2 Impacts to the North Fork of the Gunnison River MCC discharges water (Figure 3) to the North Fork via sediment ponds (MB-2R and MB-4) and direct discharges to Sylvester Gulch (discharge points 017A and 018a). The major cations and anions of the sediment pond dischazge water are sodium and bicazbona[e. The sediment pond dischazge water is slightly alkaline with an average pH ranging from 6.60 to 7.92, with average TDS concentration ranging from 250 mgA to 1,600 mg/1. The major cations and anions of the Sylvester Gulch discharge water are sodium and bicarbonate. The Sylvester Gulch dischazge water is slightly alkaline with pH values ranging from 8.00 to 8.33 and average TDS concentrations ranging from 2,233 mgA to 2,833 mgA (Appendix C). A salinity (TDS) loading analysis of the MCC's WY 2004 discharges was completed relative to the current North Fork Cumulative Hydrologic Impacts Analysis (CHIS) (CDMG, 2003). The CHIS analysis was conducted to assess the potential cumulative hydrologic impacts of mining and other • activities in the North Fork Valley on the North Fork's water quality and flow. The CHIS analysis determined that no significant hydrologic impacts were expected as a result of mining activities. The CHIS assumed that MCC's contribution to the North Fork would be a maximum of 5,520 gpm with a TDS concentration of 2,500 mgA. The total WY 2004 dischazge from the Project as reported from the CDPS reports was approximately 231 gpm (Table 9). Based on this value the flow-weighted maximum annual salinity (TDS) load from the Project was 1,163 tons. This represents about 4 percent of the value used in the CHIS. The overall all general water balance for the Project as presented in Figure 3 was estimated to be about 248 gpm which is only 7 percent greater than that presented in the CDPS reports. Based on this value the flow-weighted maximum annual salinity (TDS) load from the Project was 1,176 tons, This also represents about 4 percent of the value used in the CHIS. A summary of the salinity loading from the Project compared to the CHIS study is shown on Table 11. August zoos HydroGeo, Inc.