2009-07-01_REPORT - C1980007 (6)

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West Elk Mine 2008 Annual Hydrology Report 69 likely due to poor well construction, so no water level monitoring data are available subsequent to WY 2006 at this site. The water level in the Upper Dry Fork Alluvial well in WY 2008, ranged from a maximum of 16.37 feet to a minimum of 12.80 feet and averaged 15.15 feet, compared to 16.90, 13.30, and 15.13 feet, respectively, in WY 2007. The water level in the Lower Dry Fork Alluvial well in WY 2008 and ranged from a maximum of 6.28 feet to a minimum of 2.3 feet and averaged 5.07 feet, compared to 6.99, 2.67 and 5.32 feet, respectively, in WY 2007. The water level changes in the Lower and Upper Dry Fork Alluvial wells are likely due seasonal changes to the alluvial groundwater associated with the Dry Fork stream flows. Water levels at the Upper and Lower Dry Fork Alluvial wells are expected to be variable in WY 2009. Water levels dropped from an average depth of 162 feet in WY 2007 to an average depth of 167 feet in WY 2008 at monitoring Well 3-11-01, a difference of about 5 feet. The water level in well 3-11-01 in WY 2008 ranged from 165.3 feet (May 2008) to 169.3 feet (August 2008). The water level changes may be the result of mining activities. The water levels in Well SOM-23-H-4 and SOM-80 were relatively steady in WY 2008 and ranged from 138.9 to 137.4 feet and from 92.8 to 90.8 feet, respectively. The water level at Well 96-2-2 varied about 1.1 feet in WY 2008. No other monitoring wells showed significant water level changes during WY 2008. 6.0 ADEQUACY OF THE MONITORING PROGRAM MCC's hydrologic monitoring program has been operated in accordance with Permit No. C-1980- 007, as revised by Technical Revision No. TR-88 and Permit Revision No. PR-10. PR-10 includes a revised comprehensive hydrologic monitoring plan for the entire permit area including the South of the Divide (SOD) mine plan area. A more detailed description of the hydrologic monitoring plan is presented in Exhibit 71 in the permit document (CDRMS, 2006). 6.1 Mining Related Hydrologic Impacts Since 1999, there have been no significant long-term adverse mining related hydrologic impacts reported in surface water or spring resources in the western permit area, specifically the Gribble Gulch area (WWE, 2001; HydroGeo, 2002; HydroGeo 2003; HydroGeo, 2004; HydroGeo, 2005; HydroGeo, 2006; and HydroGeo, 2007). Gribble Gulch was undermined from years 1995 to 1997; therefore, future mining related hydrologic impacts in this area are not anticipated. June 2009 HydroGeo, Inc.