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Slope Evaluation and Remediation <br />West Elk Mine <br />Somerset, Colorado <br />Published maps including the 1 degree x 2 degree preliminary geologic map by Tweto, <br />et al. (see map below, 1976 and the Colorado Geologic map by Tweto (1979 depict <br />the site as underlain by Upper Cretaceous Mesaverde Formation (Kmv). <br />ILA <br />ID <br />II 110 "S <br />rdl <br />Project - . <br />v <br />p " *•, 1 f <br />, <br />The Mesaverde Formation typically consists of sandstone bedrock interbedded with <br />shale and coal, ranging in color from light brown to tan to gray and black (coal). <br />Although numerous publications are available regarding coal viability, production, and <br />other economic studies, there is little or no published information regarding the existing <br />landslide complex that is known to underlie the West Elk Mine. Adjacent geologic maps, <br />e.g., Cabondale 30 minute by 60 minute Geologic Quadrangle, reference surficial <br />colluvium deposits that consist of boulder to clay -sized materials derived from talus <br />slope, landslide, debris flow, eathflow, mudflow, slump, soil creep and solifluction <br />features. We understand that the mine retained consultants to evaluate the older <br />landslide complex at the West Elk Mine property which resulted in the design and <br />3 Tweto, Ogden, Steven, T.A., Hail, W.J. and Moench, R.H., 1976, Preliminary geologic map of the Montrose <br />1 degree x 2 degrees quadrangle, northwestern Colorado: U.S. Geological Survey, Miscellaneous Field <br />Studies Map MF -761, scale 1:250000. <br />4 Tweto, Ogden, 1979, Geo logic Map of Colorado: U.S. Geological Survey, Special Geologic Map, scale <br />1:500000. <br />Job No. 11 -6014 GROUND Engineering Consultants, Inc. Page 4 <br />