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The lowermost seam planned for development is the G(ab). Figure 2.04.6 of the PAP shows the <br /> geologic cross-sections and dip of all the coal seams to be mined. Cross section locations are <br /> shown on Figures 2.04.6-4A - 2.04.6-4F of the PAP. <br /> 3.2.4 Topography <br /> The East Pit, West Pit and Section 16 Pit mining sites lie just west of the northward flowing Good <br /> Spring Creek, which is paralleled by Colorado Highway 13. The area is gently sloping and upland <br /> ranging from about 7,640 feet near the southwest corner to 6,560 feet near the northeast corner of <br /> the permit area. Valleys that cut into the upland surface are generally narrow (V- shaped) and <br /> approximately 250 feet to 500 feet deep. The topographic surface north of the East Pit, West Pit <br /> and Section 16 Pit mining sites is dominated by two ridges approximately two miles long, trending <br /> north northeast and bounded by Good Spring Creek, Taylor Creek and Wilson Creek. <br /> The South Taylor mining area lies north and west of the northward flowing Good Spring Creek and <br /> south-southwest of the other pits. The area is also just south of the northeastward flowing Taylor <br /> Creek,which runs adjacent to the Section 16 Pit and West Pit. Much of the area was gently sloping <br /> upland rangeland, but the valleys were steeply sloping, with slopes in excess of 20 percent in some <br /> areas. <br /> The Collom area occupies the south-central headwaters of the synclinal axial basin along the <br /> Danforth Hills and drains to the northeast, eventually into the Yampa River. Elevations range from <br /> just below 6,400 feet to approximately 8,550 feet. Upland side slopes range from moderately steep <br /> to steep (>35 percent) whereas the areas between drainages generally exhibit flatter slopes with a <br /> northeasterly aspect between 1 and 5 percent. <br /> 3.2.5 Geology <br /> Geologic information is found in Sections 2.04.6, Maps 7 through 9A, and Exhibit 6 of the PAP. <br /> The permit area lies approximately six miles south of the axis of the Axial Basin Anticline, a large <br /> northwest trending fold found in the southern Uinta region of the Piceance Basin. The anticline <br /> structure and corresponding Collom Syncline to the south consist of thousands of feet of marine- <br /> deposited sediments of Cretaceous age. <br /> To the south of the anticline, the axis of the Collom Syncline, a downward fold, passes directly <br /> through the permit area, trending north 70 degrees west and plunging from 0 to 20 degrees to the <br /> north. In the southeastern corner of the permit area near the Streeter Fill, the Collom Syncline is <br /> influenced by the Elkhorn Syncline which results in strata having an eastward dip and north south <br /> strike (see Map 7A in the PAP). <br /> There appears to be no evidence of faulting in the permit area; however, linear features that may be <br /> fault related have been observed from aerial photographs. These linear features trend <br /> approximately north 70 degrees west, north 45 degrees west and north 30 degrees east, with near <br /> vertical inclinations. <br /> The coal-bearing strata of interest to the Colowyo operation are stratigraphically located in the <br /> Mesa Verde Group within the Williams Fork Formation of the upper Cretaceous age. The <br /> 15 <br /> Permit Revision No.5(PR-05),G 1981-019 <br />