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However, neither are of mineable thickness over sufficient area to be of any economic interest. <br />Correlation of these seams is difficult due to the sporadic occurrence of numerous thin coal lenses in <br />the interval containing F and G. <br />H Seam The sequence of rocks overlying the G Seam is characterized by numerous thin, <br />discontinuous lenses of coal and carbonaceous shale interbedded with siltstone and thin, occasionally <br />calcareous sandstones. The interval ranges from about 15 to 50 feet in thickness. The top of this <br />zone is marked by the H Seam. However, the mineable thickness of coal occurs in isolated pockets <br />not amendable to subsurface mining. <br />J Seam Above the H Seam, the stratigraphy is typified by an increasing abundance of coarser <br />grained non-coal bearing sediments. Thick lenticular sandstones are prevalent with only occasional <br />occurrences of thin coal lenses. The J coal seam is particularly conspicuous as a thin but continuous <br />seam sandwiched between thick lenticular sandstone units. It essentially marks the contact between <br />the Upper and Lower Williams Fork Formations. The J Seam has no mining potential. Isolated <br />occurrences of mineable coal thickness of limited areal extent are found in the Deserado Mine area. <br />II.B.4 Physical and Chemical Properties of Strata Section II.B.1, entitled General stratigraphy, <br />describes the lithologic characteristics of the strata found in the lease area. These strata are grouped <br />into three stratigraphic units, the Iles, the Lower Williams Fork and the Upper Williams Fork. The rock <br />• tunnels and all activity associated with mining the B and D Seams will be confined to the Lower <br />Williams Fork Formation. As required in the Colorado Mined Land Reclamation Board letter of 29 <br />August 1980, and as required by 30 CFR 817.42, the Code of Colorado Regulations <br />2.04.6(2)(a)(iv)(D) and 4.09.1(12)(b), and other applicable state and federal laws and regulations, <br />chemical analyses of the strata to be affected have been performed to identify any potential <br />acid-forming, toxic-forming or alkalinity producing materials. The samples analyzed were the Lower <br />Williams Fork Formation, B and D roof and floor, and the expected mine waste material (that is the <br />D parting greater than 1.6 specific gravity). These analyses are included in Appendices 8 and 9 of this <br />section (II.B). <br />Samples of strata for overburden analysis were taken from three exploration drill holes. The <br />characteristics of the overburden encountered in these holes is representative of overburden <br />characteristics throughout the lease area. Samples of roof and floor rock were taken from the same <br />three holes and from one additional hole. The roof and floor samples were subjected to separate <br />analysis. The characteristics of the roof and floor rock in these four locations are representative of roof <br />and floor characteristics throughout the lease area. <br />Overburden samples were composited from drill cuttings collected during the exploration drilling <br />programs, As a matter of record, drill cuttings were routinely collected at five-foot intervals from <br />surface to total depth at each exploration drill hole. The cuttings were subsequently described, <br />catalogued, and stored. To composite the cutting samples for overburden analysis, the geophysical <br />(Permit Renewal #3 1/99) II.B-6 <br />