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West Elk Mine 2006 Annual Hydrology Report 40 5.1.1 Impacts to Area Stream Water Quantity and Quality The West Elk mining activity has approached only two perennial streams in the Project area, Minnesota Creek and Deep Creek. Long wall mining operations in the Minnesota Creek drainage area took place from July 1998 to February 2001. Longwall mining in the Deep Creek drainage began in March 2001. Based on the water quality and flow monitoring data from WY 2006 (see Appendices A, B, and C), there have been no apparent mining-induced impacts to the water quality or quantity of these streams with the exception of Sylvester Gulch. The water sampled at the Middle and Lower Sylvester Gulch monitoring stations in WY 2006 consisted almost entirely of the permitted mine water releases. Therefore the analyses at these locations show considerable mining related increases in constituent levels and flows when compared with baseline data. It is important to note that in WY 2006 as well as in previous years (WY 2001 - 2005), the flow data from the Upper and Lower Deep Creek (Appendix A) stations are suspect, due to the lack of flumes and channel variations. Current monitoring requires instantaneous flow measurements three times per year (CDRMS, 2006). On November 12, 2005, there was an accidental surface release of Sily-Ex fire fighting foam to the lower Dry Fork of Minnesota Creek and the main stem of Minnesota Creek. It was estimated that about one gallon of the foam reached the streams (MCC, 2007). The spill was immediately reported to the Colorado Division of Public Health and Environment (CDPHE), U.S. Forest Service, and CDRMS (Incident Report #2005-746, MCC 2005) and downstream water users. Subsequent studies and reports by HydroGeo (2005a) and WMC (2005) showed that the release was non toxic and the only impact to the Dry Fork and Minnesota Creek was a temporary build up of foam. 5.1.2 Impacts to the North Fork of the Gunnison River MCC discharges water (Figure 8) to the North Fork via sedimentation ponds (MB-2R and MB-4) and direct discharges to Sylvester Gulch (discharge points 017A and 018a). The major cations and anions of the sedimentation pond discharge water are sodium and bicarbonate. The sediment pond discharge waters are slightly alkaline with pH values ranging from 6.83 to 8.83 and with average TDS concentration ranging from 460 mg/1 to 1,315 mg/1. The major cations and anions of the Sylvester Gulch discharge water are also sodium and bicarbonate. The Sylvester Gulch discharge water is slightly alkaline with pH values ranging from 7.48 to 8.95 and average TDS concentrations ranging from about 2,488 to 3,600 mg/1. u December 2007 HydrOGeO, Inc.