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Mayo and Associates, LC <br />3. COMPARATIVE ANALYSIS OF GROUNDWATER INFLOWS <br />• <br />I Groundwater inflows into Utah and Colorado Coa] mines provide valuable insight into <br />conditions that maybe encountered during E Seam mining at West Elk Mine. These <br />regions have a common geologic history, and similaz climate and groundwater <br />conditions. <br />The common geologic and hydrogeologic conditions shazed by the Somerset Coal Field, <br />Colorado•and coal fields in the Wasatch Plateau and Book Cliffs, Utah aze described <br />below. <br />' 2.1 Geologic Conditions <br />I • West Elk ~fline is located in the Rocky Mountain Coal Province, which includes portions <br />of Colorado, Montana, New Mexico, Utah, and Wyoming. Many of the coal reserves <br />were deposited neaz the western shoreline of the Cretaceous Interior Seaway. The marine <br />seaway had a maximum width of more than 1,000 miles and extended from the present <br />day Gulf of Mexico to the Artic Ocean (Figure 1). <br />i The coal-bearing units aze primarily composed of fluvial and beach sandstone and <br />' mudstone and shale. Coal formed from thick accumulations of organic material <br />deposited in landward swamps adjacent to the shoreline (Figure 2). The swamps <br />received fresh water from neazby eroding mountains and were subject to periodic <br />' inundation from both fluvial and marine sand and mud in response to sea level <br />• fluctuations as stream channels carrying detridal sediments, migated laterally at low to <br />Evaluation of Potential Groundwater Inflows 12 February 24, 2004 <br />Associated with E Seam Mining, <br />I West Elk Mine, Somerset, Colorado <br />