2014-08-13_PERMIT FILE - C1981018A (2)

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• The B Horizon Sandstone is the uppermost continuous sandstone in the Iles Formation equivalent. The top of B Horizon Sandstone shown on the accompanying stratigraphic column (see Figure II.B-1) is considered the contact between the Iles Formation and the Lower Williams Fork Formation. Immediately above the B Horizon Sandstone, the lithology of the Mesaverde becomes notably finer grained. Siltstones, mudstones, carbonaceous shales and coal predominate, with coarser grained sediments filling a secondary role as sporadically occurring, laterally discontinuous sandstones. On the basis of this lithologic change, Mesaverde Group sediments lying above the top of the B Horizon are considered Lower Williams Fork Formation equivalents. The entire coal bearing portion of the Lower Williams Fork is well exposed in the northeast wall of Scullion Gulch. The coal bearing interval has been measured and described at numerous locations along this outcrop. Data gathered during exploration drilling indicates that the Upper Williams Fork Formation equivalent can be separated from the Lower Williams Fork Formation on the basis of lithology and depositional origin. The contact between the finer grained lagoonal-paludal, carbonaceous deposits of the Lower Williams Fork and the coarser grained terrestrial deposits of the Upper Williams Fork is marked by the thick cliff-forming lenticular sandstones that support the northeast rim of Scullion Gulch. North and east of this rim, the surface of the mine plan area is developed upon dip slopes of the thick, lenticular • sandstone layers of the Upper Williams Fork Formation. The face up areas for both the east and west mine portals are located on the steeply sloping northeast wall of Scullion Gulch. As mentioned, the strata exposed on this slope are of the siltstone, carbonaceous shale predominated Lower Williams Fork Formation. The thickness, attitude and lithology of these outcrops are described in detail in a report entitled "Preliminary Geologic Field Mapping, Scullion Gulch area, Rio Blanco County, Colorado", by Cameron Engineers, dated June 1978. The results of surface mapping correlate very well with the lithologic and geophysical logs of bore holes drilled in the Scullion Gulch area. Refer to the log of hole #21013-16 and its comparison with the nearby measured section begun at Station 3. 11.6.2 Geologic Structure The Deserado Mine Permit area lies on the southwest flank of the Red Wash syncline, an asymmetrical flexure on the northeast flank of the Rangely anticline. The axis of the syncline trends northwest/southeastgnd plunges to the southeast into the much larger synclinal structure of the Piceance basin. The proposed refuse disposal area lies astride the apparent synclinal axis. Map 4 (in the Maps and Illustration Volumes is a geologic map of the area. Dips within the mine permit application area vary from 7 degrees to the northeast in leases D-047201, C-023703, C-0126669, C-8424, C-8425, 04693 and COC-51551 (hereinafter referred to as the lease area), to flat beneath most of the refuse disposal area, to as much as 70 degrees to the • south/southwest along the northern edge of the disposal area, clearly illustrating the asymmetrical nature of the Red Wash syncline. The entire coal bearing sequence and much of the overlying (Permit Renewal #3 1/99) II.B-3