2008-01-08_REPORT - C1980007 - Laserfiche WebLink

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West Elk Mine 2006 Annual Hydrology Report 46 • seasonal variation or possibly the result of down gradient dewatering of the B-Seam during mining operations. Water levels are expect to remain steady or rise in WY2007 Monitoring Well 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 WY2006 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 not representative of impacts related to the B- Seam ground water zone. The casing in this well collapsed in August 2006 and future water monitoring will not be possible. No other monitoring wells showed significant water level changes during WY 2006. 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. Amore 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 (Si1vEx was short 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, and HydroGeo, 2006). Gribble Gulch was undermined from years 1995 to 1997, therefore, future mining related hydrologic impacts in this area are not anticipated. In WY 2006 the West Elk Mine hydrologic monitoring program was conducted in accordance with all permit and contractual stipulations. The data collected were adequate to assess potential Project-induced impacts to the area's hydrologic system, with the exception of data collected at two surface water stream stations (Upper and Lower Deep Creek) and seven monitoring wells with casing damage (SOM-45-H-1, SOM-2-H, SOM-16-H, 96-27-1, SO.W-1, SOM-23-H-4, and SOM- 23-H-1). The data collected from the Upper Deep Creek and Lower Deep Creek surface water monitoring • stations in WY 2006 and previous years are not reliable, due to naturally occurring erosion and sediment deposition resulting in continuously changing stream bed characteristics and the lack of a December 2007 HydroGeo, Inc.