2009-02-10_PERMIT FILE - C1981022 (5)

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Sauer - 2.04.6 Drillhole locations are shown on the Mine Area Geology Maps, (Maps 2.04-143)?nd drillhole logs • and other relevant geologic information is included in Exhibit 2.04-E3,`6eologic Information. Tooograohv The topography of the mine permit area includes a portion of the valley of the North Fork of the Gunnison River along the southern permit boundary, elevated river terraces along the northern margin of the valley, relatively steep mountain sideslopes and exposed rocky cliffs rising up from the terraces; numerous steep-sided drainages along the mountain slopes with intervening ridgelines; and relatively flatter mountain park areas along and north of the northern permit boundary. Elevations range from approximately 6,000 feet amsl along the North Fork Valley to over 8,500 feet amsl on the highest mountain peaks to the north. Stratigraohv Within the mine permit and adjacent areas, surface rock exposures and mine development will occur within the sequence of sedimentary rock units described in the following sections in descending order from the ground surface and shown on Figure 2.04.6-F1, Typical Geologic Cross-Section. In addition to the primary sedimentary units, isolated igneous intrusives maybe encountered as noted. Wasatch Formation (Tertiary) - The Wasatch (also designated as the Ruby) Formation overlies the Mesa Verde Formation along a regional low-angle unconfommiry. It consists of red and buff shales and red sandstones in the upper part of the formation, and red to gray conglomerates in the lower portion. The indicated source for these units would be weathered volcanic rocks, with some remnant weathered volcanic rocks evident in the lower 100 to 200 feet of arkosic and conglomerate beds of this formation. The Ohio Creek Conglomerate, which is the basal conglomerate unit, is a regional • marker and commonly referenced geologic mapping datum Mesa Verde Formation (Cretaceous) - The Mesa Verde Formation is the primary coal-bearing formation in this region and conformably overlies the Mancos Shale Formation. It consists of approximately 2,300 feet of inter-bedded coal searns, sandstones, shales, and siltstones that are sub- divided into the following members: Barren Member - The upper portion of the Mesa Verde Formation, which is approximately 1,600 feet in thickness, contains no coal seams. It consists primarily of buff, lenticular sandstones with minor interbedded gray shale units. Paonia Member - The Paonia Member, which ranges from 300 to 500 feet thick in this area, is composed of roughly equal proportions of shales and interbedded buff, lenticular sandstones with some coal seams. The top of the Paonia Member is a massive cliff-forming buff sandstone approximately 100 feet thick, or more. Due to its lenticular nature, the unit is not continuous and there may be some variation in its location and elevation within the stratigraphic sequence. The Paonia Member contains the locally significant D and E coal seams. Bowie Member - The Bowie Member, which ranges from 270 to 350 feet thick in this area, consists primarily of gray shales with inter-bedded lenticular buff sandstones and coal seartu. The top of the Bowie Member is marked by a massive buff sandstone and several locally significant coal seams occur in the upper portion of this member. Similar to the Paonia Member, the capping sandstone unit is discontinuous and may occur at slightly different horizons in the sequence. The Bowie Member contains the A, B, and C coal seams. • Rollins Sandstone Member - The Rollins Sandstone, which ranges from 120 to 200 feet in thickness, is a massive, cross-bedded, medium to coarse-grained, buff to white sandstone unit. In other areas, it's massive nature results in prominent cliff exposures, although in this area, it occurs near the base of or below the exposed stratigraphic sequence. The Rollins Sandstone lies conformably on the PR04 2.04-9 Revised August 2000