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this formation produce the numerous rock falls and landslides observed in the lower North Fork <br />Drainage Basin (Junge, 1978). <br />The Mesaverde Formation is of Late Cretaceous Age and conformably overlies the Mancos <br />Shale. This formation consists of approximately 2,300 feet of marine and terrestrial sedimentary <br />rocks. The Mesaverde Formation is the coal-bearing formation in the region and is divided into <br />four main members; the Rollins Sandstone, the Lower Coal Bearing (Bowie) Member, the Upper <br />Coal Bearing (Paonia) Member, and the Barten (Undifferentiated) Member (Johnson, 1948). <br />The Rollins Sandstone is a white to buff-colored, well sorted, medium- to fine-grained sandstone, <br />ranging from 150 feet to 300 feet thick. This sandstone is regionally extensive and resistant in <br />outcrop and forms prominent cliffs. <br />The Lower Coal Bearing (Bowie) Member consists of 260 to 350 feet of interbedded gray shales, <br />thin to thick lenticulaz beds ofbuff-colored, fine- to medium-grained sandstones, and coals. <br />Three coal horizons exist in this member, the A (Old King) horizon, the B (Somerset) horizon, <br />and the C (Beaz) horizon. The A horizon is immediately above the Rollins Sandstone and is not <br />currently mined at any operation in the vicinity. The B horizon contains two coal seams and <br />occurs about 20 to 120 feet above the Rollins Sandstone and will be mined by MCC during this <br />permit term. This horizon has been mined and is currently being mined at the Elk Creek Mine. <br />The C horizon contains one coal seam that occurs 50 to 100 feet above the B horizon. This <br />horizon has been mined at Oxbow Mining's Elk Creek Mine and was mined at the Beaz No. 1 <br />and 2 Mines. The top of the member is usually capped by a massive buff-colored sandstone up to <br />90 feet in thickness. This sandstone, however, appeazs not to be a single persistent bed, but is <br />actually several thick lenticulaz sandstones occurring at progressively lower stratigraphic <br />horizons from east to west. <br />The Upper Coal Bearing (Paonia) Member consists of 200 to 500 feet of gray shales, <br />interbedded, buff-colored, lenticulaz sandstones, and coals. The top of this member is generally <br />considered to be capped by a massive, cliff-forming sandstone. Three coal horizons have been <br />identified in the Upper Coal Member, the D (Oliver) horizon, the E (Hawk's Nest) horizon, and <br />the F horizon. The D horizon occurs directly above the massive sandstone of the Lower Coal <br />Bearing Member and contains three seams. This horizon is currently mined in the Bowie #1 <br />Mine. The E horizon occurs about 130 feet above the D horizon and contains two coal seams. <br />This horizon has been mined at the Hawk's Nest Mine and was mined at the Blue Ribbon Mine. <br />The West Elk Mine is mining the E Seam, but has not mined the E seam on Jumbo Mountain <br />because this seam is split and comprised of several thin (< 5 ft.) coal benches which are sepazated <br />by rock partings. The F horizon contains two coal seams and has been mined at the West Elk <br />Mine. At the mine site, the coal is immediately overlain and underlain by shale. Coal seams of <br />the F horizon do not exist to the north of the North Fork of the Gunnison River in thicknesses <br />sufficient for mining. In the Jumbo Mountain azea, the F Seam thins to less than five feet in <br />thickness and is of limited aerial extent. Therefore, MCC does not plan to mine this seam in <br />Jumbo Mountain. <br />Overlying the Upper Coal Member is the Barren Member of the Mesaverde Formation. This unit <br />consists of interbedded sandstones, siltstones, shales, and coals. The unit is not thought to be of <br />marine origin and, as a result, the sandstones and the coals are highly lenticular, discontinuous, <br />27 <br />