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Mayo and Associates, LC <br />~. 4.0 WEST ELK MINE E SEAM HYDROLOGIC CONDITIONS <br />4.1 Geologic Setting <br />The E Seam, located in the middle of the Upper Coal Member about 200 feet above the B <br />Seam (Figure 12), crops out along the cliffs on the eastern side of Minnesota Creek. <br />From the Minnesota Creek outcrop the E Seam dips northeast about 3° degrees (i.e., <br />gradient = 0.054) and is buried beneath overlying Mesaverde Group rocks at Raven <br />Gulch and Raven Mesa azeas (Figure 17). <br />The contour lines in the figure are the anticipated elevation, in feet, of the base of the E <br />Seam. The stratigraphic interval between the E Seam and the underlying B Seams largely <br />' consists of about 150 to 200 feet of foreshore (beach) and shoreface (offshore) sandstone <br />'~ of the Bowie Sandstone (West Elk Mine, 2004 Personal Communication). The Bowie <br />Sandstone has a similaz depositional history and mineralogical composition as the Rollins <br />Sandstone (Koontz, 2004 Personal Communication). <br />Using drill core data West Elk Mine has mapped an extensive network of river scoured <br />channels locate above the E Seam (Figure 17). Channels are typically 2,000 to 3,000 feet <br />wide and 10 to 15 feet thick. ]n places the sandstone channels aze in direct contact with E <br />Seam coat and elsewhere as much as 15 feet offiner-grained sediments separates the <br />channel sand from the E Seam. <br />West Elk Mine has also mapped a series ofsub-parallel tectonic faults that will be <br />intercepted by E Seam mine workings (Figure 17). These faults aze the same faults <br />Evaluation of Potential Groundwater Inflows 57 February 24, 2004 <br />Associated with E Seam Mining, <br />p West Elk Mine, Somerset, Colorado <br />