2008-06-27_REPORT - C1980007 (4)

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West Elk Mine 2007 Annual Hydrology Report 47 is The water level drop in these wells may be due to the up-gradient diversion of surface water runoff in the area. Well SOM-45-11-1 and Well SOM-45-11-2 have been affected by the underlying longwall mining in Panel 13. These wells are completed in the barren member of the Mesaverde Formation above the F Seam respectively. The interburden between this horizon and the mined interval is about 800 feet thick. The well casing in SOM-45-11-1 collapsed between June and September 2002 and the well is no longer functional. The dropping water level in SOM-45-H-2 stabilized in WY 2005, recovered slightly in WY 2006, and continued to recover in WY 2007. Ground water levels appear to have stabilized and are recovering since mining operations ceased in this area in 2000-2001. Water levels are expected to continue to rise in WY 2008, due to natural recharge. The casing in Well 96-27-1 collapsed between September 2001 and April 2002 and the casing in Well SOW.-1 collapsed between April and June 2002. The casing in well SOM 23-H-1 was obstructed in August 2006. As a result, these wells are no longer functional and no water level or water quality data are available for these sites for WY 2007. The water level in monitoring Well SOM-76, installed in the F-Seam, has dropped over 60 feet • since WY 2003, including a 15 foot drop observed in WY 2007. This is most likely the result of seasonal variation or possibly mining operations in the Northeast Panel area. Water levels will likely rise in Well SOM-76 after mining operations cease in this area. The water level in monitoring well SOM-3-E showed a continuing decline in water level from installation in 2003 to May 2006, with the exception of a suspect measurement in 2005. Since May 2006, the water level has stabilized in WY 2007. The previous decline in water level was most likely a function of drought conditions in recent years and is not believed to be the result of mining activities. The water level in Well SOM 3-E is expected to remain stable in WY 2008. Monitoring Well SOM 129-H showed a rise of about 50 feet in water levels early in WY 2002, and remained high in WY 2005, WY 2006, and WY 2007. Monitoring Well RAV-4b, completed in the B-Seam, had a sharp drop in water level of about 36 feet in WY 2003, remained steady in WY 2004, and dropped again in WY 2005 (20 feet). The lowering of the ground water level in this well is likely due to mining of the Northeast Panel area and dewatering of the B-Seam. The water level rose slightly in WY 2006, most likely due to mining and dewatering and subsequent recharge of the B-Seam. The water level in this well remained stable in WY 2007 and is expected to remain stable in WY 2008. June 2008 HydroGeo, Inc.