2009-07-01_REPORT - C1980007 (6)

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West Elk Mine 2008 Annual Hydrology Report 53 • elevated dissolved iron of 0.02 mg/1 compared to the baseline maximum of 0.01 mg/l, and slightly elevated conductivity of 467.08 µmhos/cm compared to the baseline conductivity of 462 µmhos/cm. The Upper Sylvester Gulch monitoring station is upstream from the mine water discharge points. Data from three sampling rounds plus one duplicate sample (four samples total; extended parameter suite) were collected at Middle Sylvester Gulch in WY 2008. Several parameters in Middle Sylvester Gulch exceeded the maximum baseline values in WY 2008 for one or more of the samples collected: chloride 87.21 and 10.9 mg/1 compared to the baseline maximum of 10 mg/l; conductivity of 1,232.64 and 948.15 µmhos/cm compared to the baseline maximum conductivity of 800 µmhos/cm; and hardness of about 312 and 228 mg/1 compared to baseline maximum of 234 mg/l; pH of 8.84 and 8.81 s.u. compared to the baseline maximum of 8.70 s.u. Sulfate and TDS concentrations were above baseline levels for all samples. Sulfate levels ranged from 89.73 to 107.02 mg/1 compared to the baseline maximum of 80 mg/l. TDS levels ranged from 608 mg/I to 818 mg/l compared to the baseline maximum of 584 mg/l. Data from one sample and a duplicate were collected in Lower Sylvester Gulch in WY 2008. The samples had elevated conductivities of 730.5 and 730.34 µmhos/cm compared to the baseline maximum of 597 µmhos/cm; elevated total • iron concentrations of 1.78 and 1.75 mg/1 compared to the baseline maximum of 0.17 mg/I; elevated TDS of 469 and 472 mg/I compared to the baseline maximum of 430 mg/l; and elevated TSS of 171 and 173 mg/1 compared to the baseline maximum of 120 mg/1. It should be noted that water quality in Middle and Lower Sylvester Gulch is affected by mine water discharge that is regulated by MCC's CPDS permit. MCC's mining activity has approached only two perennial streams in the permit area, Minnesota Creek and Deep Creek. Longwall mining operations in the Minnesota Creek drainage area took place from July 1998 to February 2001. There are no baseline data for Upper Minnesota Creek (WWE, 2001). None of the tested parameters for Lower Minnesota Creek exceeded permit or baseline limits in WY 2008. Longwall mining in the Deep Creek drainage began in March 2001. With the exception of dissolved iron, none of the tested parameters for Upper and Lower Deep Creek exceeded the baseline limits in WY 2008. Upper Deep Creek had elevated dissolved iron of 0.13 mg/l compared to the baseline value of 0.04 mg/l. The elevated dissolved iron value is not due to mining impacts, but is likely the result of the above normal flows in WY 2008. The water sample from Deep Creek Ditch is collected from a trans-basin diversion ditch that routes • water from the Little Gunnison Creek to Upper Dry Fork and has not been impacted by mining operations. Several water quality measurements above baseline values were observed at the Deep June 2009 HydroGeo, Inc.