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non-commercially mined in the Yoast mine. Above the Middle Coal Group is the Twentymile <br />Sandstone, a 100-200 foot thick fine-grained, massive sandstone. The upper unit of the Williams <br />Fork Formation, which contains the Upper Coal Group of the Mesaverde group, consists of layers of <br />sandstone, sandy shale, shale, and coal. The thickness of this unit varies from approximately 200 to <br />850 feet throughout the region. The Williams Fork comprises the upper 200 to 850 feet of the <br />Cretaceous Mesaverde Group. <br />Underlying the Williams Fork Formation is the Iles Formation, which is the lower member of the <br />Mesaverde and the oldest unit to out crop in the permit area. The Iles Formation is approximately <br />1500 feet thick. The basal unit of the Iles Formation is the Tow Creek Sandstone, a 35-125 foot thick <br />massive, fine-grained, well-sorted sandstone. Overlying the Tow Creek Sandstone is a 1200-foot <br />thick interval of interbedded shales, sandstones and coals known as the lower coal group. The Iles <br />Formation is crowned by the Trout Creek Sandstone, which is a massive fine-grained sandstone with <br />a thickness of approximately 100 feet. <br />The Late Cretaceous Mancos Shale underlies the Iles Formation and outcrops southwest of the <br />permit boundary along Sage Creek and the Sage Creek Anticline. The Mancos Shale is a dark grey <br />marine shale with interbedded sandstones neaz the top and interbedded sandstone and limestone neaz <br />the bottom. <br />Overlying the Mesaverde Group is the Lewis Shale, a homogeneous marine shale with a thickness of <br />between 1000 and 1500 feet. The Lewis Shale is overlain by the Cretaceous Lance Formation and <br />the Tertiary Fort Union Formation. The Wasatch Formation of Eocene age unconformably overlies <br />the Fort Union Formation. It is comprised primarily of fresh water stream-laid sandstone and shale <br />deposits. Unconsolidated alluvial, terrace, and surficial deposits of Quaternary age overlie the <br />exposed geologic formations in some areas, particularly along larger streams. <br />The proposed permit area lies structurally between the parallel, south-southeast trending Sage Creek <br />and Fish Creek anticlines. The axis of the Sage Creek Anticline is situated about one to two miles <br />west of the western edge of the Yoast permit azea. The axis of the Fish Creek Anticline originates <br />near Scotchman's Draw and extends south-southeasterly dividing the northern first five-yeaz mine <br />block from the neck portion of the permit area. <br />The rock units in the proposed permit azea dip predominantly I S to 20 percent to the north in the <br />north mine block, to the northwest in the neck azea, and to the west in the south mine block. More <br />extreme dips of 25 to 35 percent occur locally in the northwest and northeast parts of the north mine <br />block. The rock units are apparently unaffected by any significant faulting within the permit azea. <br />Surface Water <br />The Yoast Mine drains to Sage Creek on the west side, and to Grassy Creek on the east side. Sage <br />Creek and Grassy Creek are perennial tributaries to the Yampa River. Armand Draw and Scotchmans <br />Gulch aze intermittent drainages which drain from the northern side of the proposed permit azea into <br />Grassy Creek. The Yampa River then flows to the Green River and eventually the Colorado River. <br />Refer to Figure 3 for more detail. <br />Yoast Mine 10 August 3, 2005 <br />