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r" <br /> t <br /> -------------------------- ------------------------------------------------------------- .... ._______... ... ... ... . ... ... . .___________________ <br /> Map 1: The ]],156 69 acre Trapper Mine permit boundary and the area's <br /> typical pre-mine dendritic drainage pattern <br /> Physiographic Setting <br /> Trapper Mine extends across the northern slope of the Williams Fork Mountains between <br /> elevations of 6,500 ft. and 7,800 ft. The crest of the Williams Fork Mountains forms a long <br /> ridge extending east/west at elevations between 7,400 and 7,800 ft. The Yampa River flows <br /> generally from east to west a short distance north of the permit area. The Williams Fork River <br /> skirts the south side of the mine site and flows into the Yampa River one mile west of the <br /> mine. <br /> Geologic Setting <br /> The bedrock at the ground surface in the Trapper permit area is an interbedded sequence of <br /> sandstones, siltstones, shale, and coals comprised of the Cretaceous-age Williams Fork <br /> Formation. The Williams Fork Formation forms part of the regionally extensive Mesa Verde <br /> Group. Younger unconsolidated alluvial deposits of Quaternary age form a thin mantle over the <br /> Williams Fork Formation in stream drainages. Structurally, the mine is situated on the south <br /> limb of the northwest-plunging Big Bottom syncline. Major faults extend across the region, <br /> but none have been found in the permit area. <br /> Coal Seam Stratigraphy <br /> The Williams Fork Formation is stratigraphically subdivided into three units or members. These, <br /> in ascending order are: <br /> 6 <br />