2009-07-01_REPORT - C1980007 (6)

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West Elk Mine 2008 Annual Hydrology Report 54 • Creek Ditch monitoring station in WY 2008. One sample was collected from Deep Creek Ditch in WY 2008. Water quality measurements above baseline values in Deep Creek Ditch included: dissolved aluminum of 0.359 mg/l compared to the baseline maximum of 0.15 mg/l; total arsenic of 0.004 mg/I compared to the baseline maximum of 0.0006 mg/l; dissolved boron of 0.51 mg/l compared to the baseline maximum of below lab detection limits (<0.01 mg/1); dissolved copper of 0.023 mg/l compared to the baseline maximum of below lab detection limits (<0.01 mg/1); dissolved iron of 0.19 mg/l compared to the baseline maximum of 0.14 mg/1; pH of 6.4 s.u. compared to the baseline minimum of 7.8 s.u., total selenium of 0.002 mg/l compared to the baseline maximum of below lab detection limits (<0.001 mg/1); and sulfate of 19.55 mg/l compared to the baseline maximum of below lab detection limits (<10 mg/1). Stream water quality measurements above baseline values were observed at the following monitoring stations in WY 2008, but they are not mining related since mining has not and is not occurring in these areas. The elevated measurements are likely due to the high stream flows that occurred in WY 2008. The water quality measurements above baseline values observed at the Upper Dry Fork Flume are not mining related, but included dissolved aluminum concentrations of 0.544 mg/l compared to the is baseline maximum of 0.16 mg/I; total arsenic levels of 0.015 mg/I compared to the baseline maximum of 0.002 mg/l; dissolved calcium of 16.7 mg/I compared to the baseline maximum of 8.8 mg/l; dissolved magnesium of 3.58 mg/1 compared to the baseline maximum of 1.7 mg/l; and dissolved sodium of 16.61 mg/I compared to the baseline maximum of 6.5 mg/l. One sample plus a duplicate (two samples total), were collected at the Middle Dry Fork Flume in WY 2008. The water quality measurements above baseline values at the Middle Dry Fork Flume are not mining related but included conductivity of 255.53 and 250.61 µmhos/cm compared to the baseline maximum of 76 µmhos/cm; dissolved iron of 0.38 and 0.39 mg/1 compared to the baseline maximum of 0.11 mg/l; and pH of 7.5 and 7.43 s.u. compared to the baseline maximum of 6.7 s.u. With the exception of dissolved iron, there were no measurements over baseline values at the Lower Dry Fork Flume in WY 2008. Dissolved iron levels were slightly elevated, 0.2 mg/l, compared to the baseline maximum of 0.178 mg/l. One sample was collected at the Minnesota Reservoir Flume in WY 2008. The water quality measurements above baseline values observed at the Minnesota Reservoir Flume are not mining related, but included dissolved aluminum of 0.352 mg/l compared to the baseline maximum of 0.08 . mg/l; total arsenic of 0.077 mg/l compared to the baseline maximum of 0.001 mg/1; dissolved boron of 1.01 mg/1 compared to the baseline maximum of 0.02 mg/I; dissolved copper of 0.04 mg/1 June 2009 HydroGeo, Inc.