2008-06-27_REPORT - C1980007 (4)

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West Elk Mine 2007 Annual Hydrology Report 48 • Monitoring Well 01-11-1, completed in the B-Seam, showed a rise in water level from November 2001 to April 2002, but has steadily dropped about 125 feet over the ensuing period through September 2007. This is likely due to mining and dewatering of the B-Seam. The water level in this well may continue to fall in WY 2008. Monitoring Well SOM-3B, installed in the B-Seam, is located up-gradient of current mining operations. The water level in this well has steadily dropped about 15 feet in 3 years. However, during WY 2006 the water level increased several feet. During WY 2007, thick mud lining the inside of the well casing prevented reliable deployment of the water level sounder; therefore, water level measurements are not available for WY 2007. Water level recordings at Well SOM-313 will be attempted again in WY 2008. Monitoring Well SOM 23-H-1 completed in the B-Seam, showed water level fluctuations of 40 feet during the baseline data collection period in WY 2005. In WY 2006 the water level rose over 30 feet. The casing of this well is believed to be compromised or broken and water levels may be influenced by shallow ground water inflows and are, therefore, not representative of potential impacts related to the B-Seam ground water zone. The casing in this well collapsed in August 2006 and future water level monitoring at this site is not feasible. • No other monitoring wells showed significant water level changes during WY 2007. 6.0 ADEQUACY OF THE MONITORING PROGRAM Since June 2006 the West Elk Mine hydrologic monitoring program has operated in accordance with Permit Revision 10 (PR-10), for Permit C1980007, Technical Revision No. 88 (approved in August 1999). PR-10 was approved in the middle of WY 2006 (CDRMS, 2006). PR-10 includes a revised comprehensive hydrologic monitoring plan for the entire Project area including the South of the Divide (SOD) area. A more detailed description of the hydrologic monitoring plan is presented in Exhibit 71 in the PR-10 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 Project 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 2008 HydroGeo, Inc.