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• <br />1 <br />West Elk Mine 2009 Annual Hydrology Report <br />1.0 INTRODUCTION <br />This Mountain Coal Company, LLC (MCC) West Elk Mine 2009 Annual <br />Hydrology Report (AHR) describes details of the hydrologic monitoring activities and <br />summarizes pertinent data with respect to mining operations as required by MCC's Permit <br />C-1980-007 with the Colorado Division of Reclamation, Mining and Safety (CDRMS) for <br />the Water Year 2009 (WY 2009), October 1, 2008 through September 30, 2009. <br />1.1 Overview of Mining Operations <br />The West Elk Mine is an underground coal mining operation that produces bituminous coal <br />and conducts other mining activities including surface crushing, conveying and load out. MCC <br />utilizes two chemicals in their treatment process: aluminum sulfate for flocculation in <br />sedimentation ponds and sodium hypochlorite for drinking water treatment. <br />During WY 2009, mining was conducted in the E-seam in longwall panel E1, as well as <br />development mining of the E. South Mains, Chute 1, and headgates for longwall panels E2 and E3. <br />(Map 1B). There was no mining in the B-seam in WY 2009 (Map 1A). <br />2.0 HYDROLOGIC SUMMARY OF WATER YEAR 2009 <br />During WY 2009, October 1, 2008 through September 30, 2009, the total annual <br />precipitation in the vicinity of the West Elk Mine was below average at the Paonia 1 SW (56306), <br />McClure Pass (59743/0007K09S), and Overland Reservoir (59853/0007K14S) meteorological <br />and Snotel stations compared to historical (30 year) total annual precipitation data (CCC, 2010; <br />NRCS, 2010a; NRCS 2010b; WRCC, 2010). During WY 2009, the snow water equivalent (SWE) <br />data were above the historical annual averages at Overland Reservoir and McClure Pass stations <br />(NRCS SNOTEL, 2010c), resulting in above average to near average stream flows in the permit <br />and surrounding areas (Figures 1-5). <br />2.1 Climatological Data <br />Precipitation and snow water equivalent (SWE) data for the permit and surrounding area <br />for WY 2009 were derived from the Paonia I SW (56306), Overland Reservoir <br />(59853/0007K14S), and McClure Pass (59743/0007K09S) meteorological and Snotel stations <br />(CCC, 2010; NRCS, 2010a; NRCS 2010b; WRCC, 2010). Figures 1, 2, and 3 depict the WY 2009 <br />total monthly precipitation data compared to the 30-year historical average (1971-2000). The total <br />annual precipitation in WY 2009 was 11.37 inches at Paonia 1SW, 27.90 inches at Overland <br />Reservoir and 32.60 inches at McClure Pass (CCC, 2010; WRCC, 2010). The total annual <br />precipitation in WY 2009 corresponds to about 75%, 91%, and 92%, respectively, of the historical <br />June 2010 <br />HydroGeo, Inc.