GENERAL30475 - Laserfiche WebLink

Home Browse Search

3.2.3 Coal Resources to be Mined Eight major coal seams aze mined in the East Pit, West Pit and Section 16 Pit at the Colowyo Mine. These aze the "Y", "X," "A", "B", "C", "D", "E" and "F" seams (PAP, page 5). The seams vary in thickness from 2.5 to 15 feet, and overburden thickness varies as a function of structural geology and topography. In the South Taylor Mining azea, 17 seam and sub-seam complexes will be mined. The seams are the "A", "B", "C", "D", "E", F" and "G" seams and their seam complexes (for example, the G-Seam is sepazated into G7, G8 and G9 in the South Taylor Area). The seams vary in thickness from 1.5 feet to 17 feet and the overburden and interburden thickness vanes, on average, from 2 feet to 65 feet. Figure 2.04.6-3B in the PAP contains a generalized diagram of the seams to be mined as well as the overburden and interburden. 3.2.4 Topography The East Pit, West Pit and Section 16 Pit mining sites lie just west of the northwazd flowing Goodspring (also refereed to as Good Spring) Creek, which is paralleled by Colorado Highway 13. The area is a gently sloping upland ranging from about 7,640 feet near the southwest corner to 6,560 feet near the northeast corner of the permit area. Valleys that cut into the upland surface are generally narrow, V-shaped, and about 250 to 500 feet deep. The topographic surface north of the proposed East Pit, West Pit and Section 16 Pit mining sites is dominated by two ridges about two miles long, trending north-northeast, bounded by Goodspring, Taylor and Wilson Creeks. The South Taylor Mining area lies north and west of the northward flowing Goodspring Creek, which is paralleled by Colorado Highway 13. The azea is also just south of the northward flowing Taylor Creek, which runs adjacent to the current Section 16 and West Pits. Much of the azea is gently sloping upland rangeland from approximately 8,400 feet to 7,900 feet. Much of the azea on the perimeter of the South Taylor mining area is steeply sloping, with slopes in excess of 20%. 3.2.5 Geology Geologic information is found in Sections 2.04.6, Maps 7 through 9A, and Exhibit 6 of the PAP. The permit area lies about six miles south of the axis of the Axial Basin Anticline, a large northwest-trending fold found in the southern Uinta region of the Piceance Basin. The anticline structure and corresponding syncline (Collom Syncline) to the south consist of thousands of feet of marine deposited sediments of Cretaceous age. To the south of the anticline, the axis of the Collom Syncline, a downward fold, passes directly through the permit area, trending north 70 degrees west and plunging from 0 to 20 degrees to the North. In the southeastern corner of the permit area, neaz Streeter Fill, the Collom Syncline is influenced by the Elkhorn Syncline which results in strata having an eastward dip and north-south strike (see Map 7 and Figure 1 in the PAP). Proposed Decision and Findings of Compliance 4 May 2007 Permi[ Revision 02 Page 17