Laserfiche WebLink
West Elk Mine <br />-10 Protection of Hydrological Balance - 2.05.6 (3)(a -i) <br />The purpose of this section is to assess the probable hydrologic consequences from mining of the <br />E Seam within the South of Divide and Dry Fork permit revision areas. This includes <br />impacts to the surface water as well as the groundwater systems within the active mining area. <br />The existing surface water and groundwater resources that may be impacted are described in <br />Section 2.04.7. Key findings in Section 2.04.7 include: (1) Many of the streams in the permit area <br />are ephemeral with flows occurring only in response tosnowmelt and significant rainfall <br />events. Dry Fork of Minnesota Creek is apparently a perennial stream, flowing only in response <br />to snowmelt runoff and rainfall events. However, because the currently available data does not <br />specifically indicate whether the majority of Dry Fork is ephemeral, intermittent, or perennial, MCC <br />will continue to monitor the flows through the Dry Fork flumes, the interbasin diversion operational <br />data, and visually check the flows in the fall after water is no longer being diverted to Dry Fork to <br />determine if the stream is ephemeral, intermittent, or perennial. Due to the importation of water <br />via the transbasin Deep Creek Ditch, the Dry Fork stream channel carries water later into the <br />surmner than would naturally occur. The presence of a couple of springs downstream of <br />Minnesota Reservoir and below the outcrop of the E Seam, may be able to sustain flow in part of <br />the lower Dry Fork reach (the exception is a small portion of the Deep Creek channel in <br />Section 35); (2) The vast majority of springs in the South of Divide permit area are located at least <br />400 feet above the E Seam; and (3) With the exception of certain fault systems, groundwater is very <br />limited in the active coal lease area and there are no groundwater supply wells at the mine or in the <br />immediate vicinity that could be affected by mining. There are no "aquifers" in the permit area that <br />will be undermined. <br />Hydrologic consequences that are evaluated herein include: <br />• Disruption, loss, or relocation of ephemeral stream or spring flows <br />• Changes in ephemeral stream or spring water quality <br />• Disruption or loss of reservoir or stock pond capacities <br />• Disruption, loss or storage of groundwater in certain formations, which could, in turn, affect <br />the limited water resources in the area including springs and stock ponds <br />• Changes in groundwater quality as a consequence of groundwater movement from one <br />formation to another or as a result of interception and/or storage of groundwater witlL tl�e <br />none <br />• Wetland impacts <br />Information contained in the following sections demonstrates that only in limited circumstances can <br />these probable hydrologic consequences occur within the West Elk Mine permit area. A discussion <br />of these circumstances. their consequences, and protection, mitigation, and monitoring measures is <br />provided. <br />2.05-174 Revised June 2005 PRIG, January 2006, March 2006; Rev. May 2006 PRIQ, Nov. 2006 TR107; Sep. 2007 PR12; Feb 2008 PRI2 <br />