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Geology - Rules 2.04.5 and 2.04.6 <br /> The applicant describes the geology of the permit and adjacent area in Section 2.04.5 of the <br /> permit application. Additional information is detailed on Map 9, which details the geology <br /> of the lease area, as well as the coal outcrop line and the strike and dip for the F and B <br /> Seams. Stratigraphic information is shown on Maps 10 through 23. <br /> The permit area lies on the southeast margin of the Piceance Basin and just south of Grand <br /> Mesa. The general geology of this area consists of gently (three to five degrees) <br /> north-northeast dipping beds of sandstone, shale, and coal of upper Cretaceous and early <br /> Tertiary age. <br /> The geologic formations exposed in the North Fork Drainage Basin consist of Late <br /> Cretaceous to Early Tertiary Age sedimentary strata, Tertiary Age igneous intrusives, and <br /> Quaternary Age alluvial and colluvial deposits. The units are described below in ascending <br /> order. <br /> The Mancos Shale is the oldest strata exposed in the region, and is of Late Cretaceous Age. <br /> This unit is composed of over 4,000 feet of gray marine shales and minor interbedded buff <br /> sandstones. This unit is highly erodible and unstable. Erosion and oversteepening of slopes <br /> in this formation produce the numerous rock falls and landslides observed in the lower North <br /> Fork Drainage Basin (Junge, 1978). <br /> The Mesaverde Formation is of Late Cretaceous Age and conformably overlies the Mancos <br /> Shale. This formation consists of approximately 2,300 feet of marine and terrestrial <br /> sedimentary rocks. The Mesaverde Formation is the coal-beating formation in the region <br /> and is divided into four main members; the Rollins Sandstone, the Lower Coal Bearing <br /> (Bowie) member, the Upper Coal Bearing (Paonia) member, and the Barren <br /> (Undifferentiated) member (Johnson, 1948). <br /> The Rollins Sandstone is a white to buff-colored, well sorted, medium- to fine-grained <br /> sandstone, ranging from 150 feet to 300 feet thick. This sandstone is regionally extensive <br /> and resistant in outcrop and forms prominent cliffs. <br /> The Lower Coal Bearing (Bowie) member consists of 260 to 350 feet of interbedded gray <br /> shales, thin to thick lenticular beds of buff-colored, fine- to medium-grained sandstones, and <br /> coals. Three coal horizons exist in this member, the A (Old King) horizon, the B (Somerset) <br /> horizon, and the C (Bear) horizon. The A horizon is immediately above the Rollins <br /> Sandstone and is not currently mined at any operation in the vicinity. The B horizon <br /> contains two coal seams and xcurs about 20 to 120 feet above the Rollins Sandstone and <br /> will be mined by MCC during this permit term. This horizon has been mined and is <br /> currently being mined at the Somerset Mine. The C horizon contains one coal seam that <br /> occurs 50 to 100 feet above the B horizon. This horizon has been mined at U.S. Steel's Elk <br /> Creek Mine and the Bear No.. 1 and 2 Mines, and is currently mined at the Bear No. 3 <br /> Mine. The top of the member is usually capped by a massive buff-colored sandstone up to <br /> 90 feet in thickness. This sandstone, however, appears not to be a single persistent bed, but <br /> is actually several thick lenticular sandstones occurring at progressively lower stratigraphic <br /> horizons from east to-west. <br /> 8 <br />