2009-07-01_REPORT - C1980007 (6)

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West Elk Mine 2008 Annual Hydrology Report 57 maximum of 0.43 mg/l; dissolved magnesium of 10.7 mg/1 compared to the baseline maximum of 8.6 mg/l; total manganese of 0.02 mg/1 compared to the baseline maximum of 0.010 mg/l; dissolved potassium of 3.64 mg/1 compared to the baseline maximum of 2.9 mg/l; total selenium of 0.005 mg/1 compared to the baseline maximum of below lab detection limits (<0.001); dissolved sodium of 28 mg/1 compared to the baseline maximum of 23.3 mg/l; TDS of 222 mg/1 compared to the baseline maximum of 170 mg/l; and TSS of 40 mg/1 compared to the baseline maximum of 28 mg/l. No water quality parameter measurements over baseline values were observed in WY 2008 at the Lick Creek Flume, Horse Gulch, or East Gulch East of Horse Gulch monitoring sites. 5.1.2 Impacts to Area Stream Water Quantity As mentioned previously, stream flows for the Upper North Fork of the Gunnison (USGS), Middle Sylvester Gulch, Lower Minnesota Creek (USGS), Upper Minnesota Creek Flume (USGS), Upper, Lower and Middle Dry Fork Flume, Lick Creek Flume, Deep Creek Ditch, and the Minnesota Reservoir Flume are measured with data loggers that collect data continuously. Stream flows of the other monitored streams (Upper and Lower Sylvester Gulch, Lower Gribble Gulch, Horse is Gulch; East Gulch east of Horse Gulch, Upper and Lower Deep Creek. Box Canyon, Upper and Lower Raven Gulch, Deer Creek, and Poison Gulch) are measured as instantaneous flow three times per year, corresponding with rising limb, peak flow, and low flow periods. No specific flow data are available for the Lower North Fork of the Gunnison, although no stream flow impacts from mining are expected. Potential impacts to stream flows are based on dramatic decreases or total loss of stream flow due to subsidence. Based on the flow monitoring data through WY 2008 (Appendices A and B), mining-induced impacts to the water quantity of these streams has not occurred. It is important to note that in previous years (WY 2001 - WY 2006) the flow data from the Upper and Lower Deep Creek (Appendix A) stations have been designated as suspect, due to channel variations and the lack of flumes. Current monitoring (including WY 2008) protocols specify the collection of instantaneous flow measurements three times per year. 5.1.3 Impacts to the North Fork of the Gunnison River MCC discharges water (Figure 9) to the North Fork of the Gunnison River via sedimentation ponds (MB-1, MB-2R, MB-3, MB-4 and MB-5) and direct discharges to Sylvester Gulch (including Outfalls 017A and 018A). The major cations and anions of the sedimentation pond discharge 0 water are sodium and bicarbonate. Water discharged from MB-1, MB-2R and MB-4 in WY 2008 June 2009 HydroGeo, Inc.