2007-08-17_PERMIT FILE - C1981035A (9)

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that comprises a transitional sequence above the Mancos shale; and an upper massive sandstone member consisting of thick, massive beds of even-textured, medium-grained sandstone that form conspicuous cliffs in the northern portion of the project area. The Point Lookout sandstone is reported to maintain a rather uniform thickness of about 400 feet across the Hesperus area, but the sandstone beds at any given horizon become progressively .finer grained eastward and the lower member thickens at the expense of the massive sandstone member. In the project area, the massive sandstone member of marine origin is about 100 feet thick and the lower transitional member is about 300 feet thick. MENEFEE FORMATION The Menefee formation is the middle member of the Mesa Verde Group and consists of a complex assemblage of lenticular cross-bedded sandstone beds, gray, brown, and black shales, and coal beds. The formation is characterized by irregular bedding and rapid lateral changes of lithology. The contact of the Menefee with the underlying Point Lookout sandstone is conformable. In most places the contact is marked by a sharp break between the carbonaceous shales and coals of the Menefee and the clean sandstone of the massive member of the Point Lookout. Locally, through the eastern half of T35N, and R12W, the basal Menefee is reported to consist of massive sandstones and the separation is not readily made. The Menefee formation thins in an eastward direction from approximately 350 feet in the Cherry Creek Valley, about four miles west of the Hesperus project area, to about 123 feet in the Florida River valley about 15 miles east of the project area. Most of the variations of thickness of the Menefee formation are reported to be thinner where the more compressible shale and coal dominate the section. Locally, thickness variations of the Menefee can be attributed to scouring action of the water source responsible for the disposition of the overlying Cliff House Sandstone. From an area near the head of Hay Gulch in Section 27, T35N, R 11 W, east to the La Plata River, the upper coal bearing horizon is significantly thinned and apparently replaced by the overlying Cliff House Sandstone. This upper coal bearing horizon is scoured to where the upper coal seam, so prevalent in the Hay Gulch area, is completely absent. The Menefee formation is of non-marine origin throughout the Hesperus area. The petrographic impression of the formation varies with its lithologic character, but over most of the area it is slightly less resistant than the overlying and underlying formation. CLIFF HOUSE SANDSTONE The Cliff House Sandstone is the upper formation of the Mesa Verde Group in the Hesperus area and is of marine origin. It generally consists of irregular to lenticular ledges of hard fine to medium-grained calcareous sandstone enclosed in softer argillaceous fine sandstone, mudstone, and silty shale. Like the Point Lookout sandstone, the Cliff House sandstone is reported to decrease in grain size in an eastward direction. Ten to fifteen miles east of the project area, the formation is composed of soft dark-gray mudstone and fine sandy silt-shale with an occasional very thin lentil of fine sandstone in the lower part. The Cliff House sandstone has an average thickness of 350 feet throughout National King Coal, LLC King I Mine Section 2.04.6 Page 2 February, 2007