2013-04-10_PERMIT FILE - C1981019A (10)

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RULE 2 PERMITS A distinctive bed in the formation is a smectite layer, with an average thickness of two to three feet. Formed from the deposition of a volcanic ash, Colowyo has identified this bed as the `Km' (this bed may be equivalent to the Yampa Bed in the Williams Fork to the north). The bed has been identified as an aquiclude. It is approximately 165 feet above the top of the Trout Creek. Sandstone, and underlies the lowest seam proposed to be mined by at least 330 feet. Thus, there should be no impact from the mining operations to the underlying Trout Creek Sandstone. The upper Williams Fork Formation is composed of upper and middle deltaic sediments in the vicinity of the Colowyo Mine. This is evidenced by an increase in mudstone and less continuous sandstone layers than is found at other locations in the region (Kiteley, 1983; Geocid, 1998). Coarse - grained sediments in the proposed Collom mining area are typified by channel and bay -fill sandstones. These are of limited extent and laterally discontinuous. Structure The regional geologic structure of the Danforth Hills is a complex of folds dominated by the Axial Basin Uplift to the north of the Colowyo revised permit area and the Piceance Basin on the south. The Axial Basin Uplift, an anticline, or arch, is a southeastward extension of the larger Uinta Mountain Arch to the west, which trends west by northwest. Between the Axial Basin anticline and the basin is a series of synclines, anticlines, and monoclines. The Collom permit expansion area is located between the Axial Basin anticline on the north and the Danforth Hills anticline to the south. Starting on the north end of the Collom permit expansion area, the Axial Basin anticline is an asymmetrical fold, the axis of which trends north 60 degrees ( °) west, with strata dipping (inclining) steeper on the south side of the axis than on the north. The rocks of the broad anticline have not been stressed sufficiently to cause them to break severely, but a few discontinuous normal faults trending primarily parallel to the anticlinal axis are found in the area. The south flank of the anticline has several secondary folds trending subparallel and at approximate right angles to the main anticlinal axis. The southern limb of the Axial Basin anticline is shared with the Collom syncline. The Little Collom X pit will be transected by the axial trough of the Collom syncline. The Collom Lite pit will be located on the 3.5° to 8.5° northeastward dipping strata on the southern limb of the Collom syncline and northern limb of the Danforth Hills anticline. The northeast trending Morgan syncline is located on the western boundary of the Collom permit expansion area (Map 7A). The axis of the Collom syncline is approximately parallel with the Axial Basin anticline and as previously mentioned passes through the northern portion of the Collom permit expansion area. Bedding orientation, as measured on surface outcrops, has a strike of around North (N) 70° West (W). Dips on the shared limb with the Axial Basin anticline can exceed 45 °, but are normally between 25° and 35° and dip to the south. The south flank of the syncline has dips between 5° and 20° to the north (Map 7A). South and east of the Collom permit expansion area is the Wilson Creek Dome, part of the Danforth Hills anticline. A producing petroleum reserve, the dome is capped by the Iles Formation. This uplift has caused the Lower Wilson area to be uplifted and only the bottom 700 feet of the Williams Fork is present. The beds in this area have a strike to the northwest with dips to the northeast of approximately 7 °. No faults have been identified in the Collom mine area. Faults have been identified in Morgan Gulch, west of the Little Collom X pit near the axis of the Collom syncline. Two nearly vertical joint sets with the primary having a strike ranging between N55 °W and N60 °W and the secondary having a strike of N 19 °East (E) have been observed in the Collom permit expansion area. Collom — Rule 2, Page 29 Revision Date: 9/28/11 Revision No.: PR -03