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To the south of the anticline, the axis of the Collom Syncline, a downward fold, passes directly <br />through the permit area, trending north 70 degrees west and plunging from 0 to 20 degrees to the <br />North. In the northeastern corner of the permit area, near Streeter Fill, the Collom Syncline is <br />influenced by the Elkhorn Syncline which results in strata having an eastward dip and north - <br />south strike (see Map 7 and Figure 1 in the PAP). <br />There appears to be no evidence of faulting in the permit area; however, linear features that may <br />be fault -related have been observed from aerial photographs. These lineations trend <br />approximately north 70 degrees west, north 45 degrees west and north 30 degrees east, with near <br />vertical inclinations. No faults have been identified in the Collom Pit area. Faults have been <br />identified in Morgan Gulch, northwest of the Collom Pit near the axis of the Collom syncline. <br />Two nearly vertical joint sets with the primary having a strike ranging between N55° W and N6U <br />W and the secondary having a strike of N19P E have been identified within the proposed Collom <br />permit expansion area. <br />The coal -bearing strata of interest to the Colowyo operation are stratigraphically located in the <br />Mesaverde Group which is of upper Cretaceous age. The Mesaverde Group consists of the Iles <br />and Williams Fork Formations, and overlies the Mancos Shale. The Williams Fork consists of <br />alternating beds of sandstone, sandy shale, carbonaceous shale and coal. The coal to be mined <br />lies within a 392 -foot interval in the Fairfield Member of the Williams Fork Formation. The <br />quality of the coal seams is midway between bituminous and sub -bituminous. 9,000 feet of <br />Mesozoic and 4,500 feet of Paleozoic sediments underlie these coal beds. The Williams Fork <br />Formation is estimated to be 1,700 feet thick in the revised permit area and is underlain by the <br />ridge -forming Trout Creek Sandstone member of the Iles Formation. <br />The Williams Fork Formation consists of a sequence of interbedded sandstones, siltstones, <br />sandy, silty, or carbonaceous mudstones and coal. These sediments are typical of the cyclothems <br />deposited along the western interior of North America during Late Cretaceous time. The site- <br />specific stratigraphy is described in Exhibit 6 and on Map 8 of the PAP. <br />Results of test borings are included in Section 2.04.6 Geology Description, Volume 15, for the <br />Collom expansion. Test borings resulted in information on the presence of subsurface water, <br />characterization of the physical properties of the overburden, and testing and evaluation of the <br />geochemical properties of the overburden. Additional discussion of the results of this testing can <br />be found in Section B. III. E. of this document. <br />Coal seams Y through G will be mined in the proposed Collom Pit. Coal seam thicknesses in the <br />Collom permit expansion area vary from 5 to 11 feet. The coal to be mined is midway between <br />bituminous and sub -bituminous, low ash, low sulfur coal. <br />PR -04, Colowyo Coal Mine C1981-019 19 August 2016 <br />