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West Elk Mine <br />2.04 -52 Rev. 06/05- PR10, 03/06- PR10, 04/06- PR10, 09/07- PR12; 05/22- MR462 <br /> <br /> <br />about 150 gpm but intersects with this fault system in adjacent entries produced an inflow of <br />approximately 8,000 gpm. <br /> <br />As a result of the BEM and 14HG Fault intersects and large respective inflows, Mayo and <br />Associates conducted an investigation to characterize these fault-related groundwater inflows <br />and the potential for encountering additional water-filled fault systems. A report was issued on <br />this subject in August 1998 (Mayo and Associates, 1998). A more thorough discussion of these <br />inflows and the results of the Mayo and Associates investigation can be found later in this <br />section. <br /> <br />Mayo and Associates also conducted a hydrogeologic characterization of the permit and adjacent <br />area in 1999. A complete copy of this report is included as Exhibit 18. That characterization was <br />based on 1) A synthesis of existing hydrogeologic information, 2) Isotopic data collected in 1998, <br />and 3) The results of Dr. Mayo’s in-mine, fault-related, groundwater inflow investigation (Mayo <br />and Associates, 1998). <br /> <br />A 2004 Mayo and Associates study, considered the information obtained from previous <br />investigations both in the North Fork Valley and in eastern Utah coal mines in similar geologic <br />formations and hydrogeologic conditions as they pertained to mining of the E Seam in West Elk <br />Mine. A discussion of the potential projected effects on groundwater from E Seam mining from <br />that study can be found later in this section and in Section 2.05.7 (Probable Hydrologic <br />Consequences). A complete version of this report is included as Appendix 18B in this permit <br />revision text. <br /> <br />As a result of these investigations (Mayo and Associates, 1999, Mayo and Koontz, 2000 and <br />Mayo and Associates, 2004), it was concluded that groundwater inflows to West Elk Mine issue <br />from groundwater systems that are part of the inactive groundwater regime as it relates to the <br />genesis, composition and storage of the water. As discussed in Section 2.04.6 (Other Geologic <br />Factors That May Affect Mining Conditions), the inactive zone includes ancient stored water <br />residing in sand channel bodies, porous sections of fluvial or marine sand lenses or the damaged <br />zones of fault and fracture systems. Conversely, the active zone includes water derived from <br />rain and snowmelt stored in the near surface colluvium, alluvium or shallow bedrock formations <br />(generally less than 500 feet in depth). Demonstration of the ancient characteristics of the water <br />contained in strata surrounding West Elk Mine are indicated by the 10,500 year age date <br />assigned to groundwater encountered in the BEM and 14HG Fault systems based on isotopic <br />studies (Mayo and Associates, 1998).