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Description of the Environment The proposed Foidel Creek Mine is located approximately fifteen miles southwest of Steamboat Springs, in Routt County, Colorado. The permit area varies in elevation from 6,600' to 7,500' with the portal opening at 6,885'. Generally, the topography consists of gently rolling hills. Flatter topography is evident in the valleys of the major streams draining the area, Fish Creek and Foidel Creek. Prominent cliffs have formed where massive sandstone units outcrop. The mine is located in the upper reaches of the Yampa River Basin. The proposed permit area and adjacent areas are drained by Foidel Creek, an intermittent stream dominated by effluent discharges, and Fish Creek, a perennial steam. Fish Creek drains east into Trout Creek whereas Foidel Creek runs northeast to Middle Creek before joining Trout Creek. The Fish Creek and Foidel Creek drainages have been impacted previously by surface mining upstream and downstream of the underground mine's existing and planned surface facilities. Operation plans call for undermining both streams at a single location. Alluvial valley floors have been identified within and downstream of the proposed permit area on Fish Creek, downstream from the proposed permit area on Foidel Creek, at the confluence of Foidel and Middle Creek, and on Trout Creek from its confluence with Middle Creek downstream to the Yampa River. The proposed permit area lies on the south end of the regionally significant Sand Wash structural basin. Locally significant are the rock units of Twentymile Park Basin which dip 5° - 30° toward the central portion of the basin. Normal faulting has been identified throughout the permit area, trending northwest to southeast, with displacement of zero to 85 feet. A reverse fault running in an arcuate line northward through the west central part of the basin shows displacement of 0-80°. The near-surface bedrock units are composed of sedimentary rocks of marine and non-marine origin. These sedimentary rocks were formed through the transgression and regression of an epicontinental sea and are comprised of sequences of sandstones, siltstones, shales and coal. Four geologic formations exist in the vicinity of the proposed Foidel Creek underground mine. They are, in ascending order, the Mancos Shale, the I1 es and Williams Fork of the Mesaverde Group, and the Lewis Shale (see Figures 3 and 4 of this document). These strata were all deposited during the late Cretaceous Period. Generally, the strata dip to the center of the basin at about 7°. Three economically important coal seams, the Lennox, Wadge, and Wolf Creek coals, are located within the locally important, Middle Coal Group of the Williams Fork Formation. The Wadge coal seam will be mined in the -5-