2008-03-21_PERMIT FILE - C1980007 (5)

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.7 • Chapter 3 feet above mean sea level. Groundwater that surfaces in these springs and seeps in the LBA tract area is associated with shallow alluvial/colluvial deposits and does not appear to be hydrologically connected with deeper bedrock aquifers. Static water levels in bedrock aquifers in the West Elk Mine area are many hundreds of feet below ground surface and show no connection to surface water sources. Based on the estimated overburden in the LBA tract in the Deep Creek drainage (1,100 to 1,500 feet) and the maximum estimated fracture zone thickness above longwall panels (380 feet), it does not appear that the perennial springs will be affected by fracture zone-induced drainage. In addition, there is low risk of alluvial/colluvial springs being intercepted by subsidence-induced tension fractures. The lowering of the land surface may cause springs to migrate a few feet, but no discernable loss of water is anticipated. Surface-tension cracks in areas of bedrock cover may intercept precipitation. It is expected that the cracks would temporarily divert precipitation away from the drainage, but that given the expected limited depth of tension cracks (less than 200 feet), the flow would remain in the drainage (USDA Forest Service 2003a). In addition, surface and groundwater resources may be temporarily interrupted. due to drainage into fractures that develop; however, these fractures tend to be short- lived, terminate at a shallow depth, and quickly fill with sediment. Given the ephemeral and seasonal nature of the surface drainages as well as their steep gradient, and influences of the natural geologic instability of the area (landslide potential and high erosion rate/sediment load), subsidence would have minimal long-term impact on channel morphology. Surface and groundwater impacts would diminish rapidly as cracks associated with the longwall face will tend to close after the face passes. Surface cracks that remain open are normally not significant conduits to surface water since they tend to die out a depth (maximum 200 feet) due to the location of the neutral surface and crack intersection with soft material (Agapito 2005, see Appendix B). Appendix C identifies potential lease stipulations to protect or mitigate effects on water, including monitoring needs to assess possible water loss. Affected Environment and Environmental Consequences Alternative C Under this alternative, the stipulation in Appendix C for protecting Deep Creek would be included in the lease. Effects on water resources would also be the same as for Alternative 13 except that the life of the mine would be slightly shorter, and there would be no potential for subsidence to impact Deep Creek, as mining would not be permitted underneath it. Surface water flow or changes in channel morphology resulting in alteration of surface gradient, increases in soil erosion, or landslide potential would not occur under Deep Creek. Potential post-lease surface use (exploration drilling, methane drainage, ventilation shaft construction, etc.) has the potential to affect surface water through surface disturbance related to drill pad and road construction. Depending on the location of these activities, construction could have impacts on sedimentation. in stream channels; however these effects can be mitigated through use of best management practices. These activities have not been noted to cause impacts to groundwater. Any proposed post-lease activities would be analyzed under a separate NEPA analysis if/when those activities are proposed. 3.3.4.2 Cumulative Effects Alternative A The No Action alternative would have no cumulative effects on the :Dry Fork LBA tract, as mine development would not occur. There would be no surface water or groundwater impacts from the LBA. Any past or existing conditions as a result of longwall mining in the West Elk Mine would continue. Specifically, dewatering operations for the West Elk Mine would continue as needed. The CDI-Il'E would continue to regulate treated water discharge through the existing NPDES permits. Natural variability due to climatic variations, flow regimes, and geologic variations would continue to occur. Alternative B Leasing the coal in the Dry Fork LBA would extend the life of the West Elk Mine, thereby increasing the potential for indirect :impacts to surface water Dry Fork Lease-By-Application FEIS 3-23