2008-06-27_REPORT - C1980007 (4)

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West Elk Mine 2007 Annual Hydrology Report 49 • In WY 2007 the West Elk Mine hydrologic monitoring program was conducted in accordance with all permit and contractual stipulations. The data collected in WY 2007 were adequate to assess potential Project-induced impacts to the area's hydrologic system, with the exception of seven damaged monitoring wells (SOM-45-H1 (Sept. 2002), SOM-2-H (Jul. 1999), SOM-16-H (Sep. 2000), 96-27-1 (Apr. 2002), SOW-1 (Jun. 2002), SOM-23-H-1 (Aug. 2006), and SOM 13 (Jun. 2007). As a result of damage to these wells, no water quality and water level data were collected from these wells in WY 2007. As noted in previous annual hydrology reports, the flow 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 flume. Pressure transducers and data loggers were installed in the open stream channels at the Deep Creek stations. Control channel sections were established at each site in 1996; however, flumes were not installed at these locations in order to limit impacts based on U.S. Forest Service concerns. The Deep Creek stream channel is very dynamic and has changed considerably since the sites were established. As a result of erosion and sediment deposition, the control channels used to calibrate the pressure transducers and gauge the is stream flows are constantly changing and the flow data collected for Deep Creek in WY 2002 (HydroGeo, 2003), WY 2003 (HydroGeo, 2004), WY 2004 (HydroGeo, 2005), WY 2005 (HydroGeo, 2006), and WY 2006 (HydroGeo, 2007) are not considered reliable. The Upper and Lower Deep Creek stream station flows are currently being monitored on a three times per year basis during regular rising limb, peak flow, and low flow monitoring visits. 7.0 SUMMARY During WY 2007, all aspects of hydrologic related mining operations at the Project were conducted in accordance with all permit and regulatory compliance stipulations. Based on the surface water, ground water, spring and seep, underdrain, and mine inflow monitoring data collected to date, Project mining operations did not cause any significant impacts to local surface or ground water resources in WY 2007. As MCC's mining operations shift from the west side of the Project area to the south and east side, the Project's hydrologic monitoring program will need to be revised accordingly. A new comprehensive hydrologic monitoring plan was proposed as part of the South of the Divide Permit Revision Application. This plan was approved by the CDRMS in June 2006 and was implemented in WY 2007. r L? June 2008 HydroGeo, Inc.