_GENERAL DOCUMENTS - C1981017 (283)

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-13- The Iles Fornation consists of two sandstone-, •nembers ,divided by i 1 ,000 foot "tongue" of shale. The lower member, the Cozze"tte, is a 6 f,)ot layer of very fine grained silty sandstone, which overlies a 40 foot thick layer of silty to sandy shale. The upper sandstone member of the Iles Formation, known as the Rollins, is 120 feet to 140 feet thick. A shale tongue of 5 feet to 30 feet thickness, and identical to the underlying shale, occurs 4ithin th,. Rollins member 25 feet to 75 feet above the base. The Rollins sand,to!i•: varies in grain from very fine to coarse, but medium texture predominates. Within the overlying Williams Fork Formation, two sandstone members, known as the Middle and Upper sandstone members, separate thick shale formations. Above the sandstone members lie coal sea,ns. Above the Rollins formation and the "B" bed or Coal Basin seam is a thick layer of mudstones, sandstones and shales of 370 feet to 425 feet in thickness, known as the Lower Bowie Shale Submember. Bowie shale occurs in the Williams Fork Formation. The Middle sandstone submember ov?rli :; '::>> Lower Bowie shale and is similar in many respects to the Rollins sandstone. It ranges in thickness from 30 feet to 130 feet and is fine-to-medium grained, quartzitic to feldspathic, poorly to moderately sorter}, with a clay matrix at the ti)p. Directly above the Niiddle sandstone is a coaly, black to gray, sandy siltstone which merges into the overlying coal seam, known as "N" Creek or Middle Bed Seam. The coal seam r.an+3+2s from 5 feet to 20 feet thick, and is mined from the No. 2 mine entry. The overlying sequence is the Upper Bowie shale submember. It consists of mudstones, sandstones, and shales and is around 200 feet thick. The upper sandstone submember, which overlies the Upper Bowie shale, is up to 100 feet thick. It is similar to the Rollins and Middle sandstone, except that grain size is somewhat more coarse. Above the Upper sandstone, is the Paonia shale member of the '4illiams Fork Formation. It consists of and includes the Placita and Sunshine Coal Intervals. The coal seams mined at Coal Basin ar,a the "3" "•niddle" bed. The two other seams in Coal 3asin are considered uneconomic to mine using current mining methods. F,jrther inf ornation on the geology of the permit area can 5e found in Volume 4, Chapter III-0 of the application. The analyses of roof rock and coal (z7e floor material is coal ) in Section I1I-0, 'lolume 4, indicate that the materials are ?enerally tii;h in iron and 'nave a sigh soaium adsorption ratio (SAR) . a sample of