2017-02-03_PERMIT FILE - C1980004 (2)

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2.04.6 Geology Description (1) General Requirements STRATIGRAPHY The surface geology of the permit area is made up of the Mesa Verde Group of upper Cretaceous Age, the Wasatch Formation of lower Tertiary Age, and alluvium and colluvium of Quaternary Age. All local coal seams lie in the Mount Garfield Formation of the Mesa Verde Group. There are four distinct coal beds which may or may not be present within the permit area. The upper two zones are inconsistent stringers which occasionally converge to form a minable reserve. Both lower seams are more predictable, and in the case of the Cameo seam, much thicker. Each coal zone is addressed separately below. The Mount Garfield Formation lies conformably upon the Sego Sandstone, the lowest member of the Mesa Verde Group in the permit area, which in turn overlies the Mancos Shale. The Mount Garfield Formation consists of buff to gray, fine and medium grained sandstones, light to dark gray shales, and includes all four of the coal bearing zones. The Cameo Seam will vary in thickness from under five feet to over twenty five feet; often separating into two or more distinct seams as identified on the interburden map, Figure 2.1-7. The formation identifies the classic delta paleoenvironment in which most coals are formed. The multiple coal seams and thinly laminated interbeds of sandstones and shales are evidence of the many transgressive and regressive events which characterize the formation. The sandstones are often lenticular and cross bedding is quite common. The Hunter Canyon Formation, which is locally the uppermost unit of the Mesa Verde Group conformably overlies the Mount Garfield Formation. The exact contact is difficult to precisely delineate throughout the permit area. Visually and lithologically the two formations are very similar, but the Hunter Canyon Formation includes no coal bearing zones. This formation is assumed to represent the sequence of beds which would form upland from the coal forming delta paleoenvironment of the Mount Garfield Formation. PR -02 2.04-8 08/11