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'• 3.3 Coal Geology <br />' The carbonaceous zone containing the coal beds of interest occupies the basal 200 to 300 feet of <br />the Lower Williams Fork Formation of the Mesaverde Group. Within this interval, seven (7) <br />' apparently distinct coal seams have been identified. In ascending order, these seams are: <br />• B Seam <br />' • D Seam <br />• E Seam <br />' • F Seam <br />• G Seam <br />• H Seam <br />' • J Seam <br />In addition to the seven (7) seams listed above, a Thin somewhat continuous coal located <br />' immediately below the B Horizon in the Iles Formation has also been identified. This coal, referred <br />to as Iles Seam, has been included in the reserve estimates. Plate 3 is an Index map showing the <br />location of cross sections. Plates 4, 5 and 6 show seven typical stratigraphic cross sections, (struc- <br />ture is shown below each section) and illustrates the stratigraphic relationship of the seven seams <br />in the Lower Williams Fork plus the Iles Seam. Four (4) typical geophysical logs are included as <br />M Plate 13 for illustration. Only the B and D Seams are of sufficient thickness and areal extent to be <br />considered economically recoverable. The other five seams which overlie the B and D Seams are <br />' thinner and less continuous and are not mineable. These upper five seams are difficult to correlate <br />over large areas within the Deserado Mine area. The seven seams located in the Lower wlliams <br />Fork are briefly described in the following: <br />' 3.3.1 13 Seem The B Seam is the thickest and most laterally persistent coal seam in the <br />Deserado Mine area. This seam varies from less than four feet thick to over twenty feet thick. <br />' Although this is the thickest seam in the area and underlies the entire Deserado Mine area it is also <br />the most geologically complex of the seven seams. Seam complexity is the result of partings and <br />' major seam splits which tend to divide the seam into two major parts which are identified as: lower <br />and upper B seam. Previously, (MLR Permit Section II.B), the lower, upper B Seam, and upper B <br />Seam split were referred to as the A Seam, B Seam and C Seam respectively; where the B Seam <br />' is not split, the Seam was previously referred to as the A/B/C Complex. Plates 4, 5 and 6 show the <br />stratigraphic relationship of the B Seam and splits to the underlying B Horizon sandstone, the Iles <br />Seam, and the other six seams located stratigraphically above the B Seam. Exploration drilling has <br />defined major splits in the B Seam. These splits render coal in the B Seam unrecoverable in <br />portions of the Deserado Mine logical mining unit. Plate 10 is the isopach map of the mineable B <br />' Seam and shows the location of major partings. <br />• 11 <br /> <br />