_GENERAL DOCUMENTS - C1981017 (283)

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Tile Morrison Formation is of Ada Formation. This formation c fitly colored, variegated shales, a units Q within this formation are h V The Cretaceous Age, Dakota nation. DYOle� This unit consists of 100 T ored sandstone, which is locall is very resistant to erosion and i Sedimentary rock strata e: a mines are the Cretaceous Age Mancos and the Tertiary Age Wasatch Fore 3,000 to 4,000 feet of dark gray a Mancos shale consists of two sh, ember. This formation is highly erosive, wm,.,, _ of broad valleys along the strike of this formation anu n„ in total suspended solids in areas east of the mines. The saline nature of this marine shale formation results in an increase in total dissolved solids downstream and east of the mines. Conformably overlying the Mancos shale is the Mesaverde Group. This group is divided into two formations; the Iles Formation and the William Fork Formation. The Iles consists of the basal Cozzette sandstone member; the middle member consisting of shales, siltstones and fine-grained sandstones; and the upper Rollins sandstones consist of medium to very fine-grained resistant sandstones. The two sandstones are ridge and cliff formers The Williams Fork Formation consists of over 5,000 feet of sandstones, siltstones, shales and coals. This formation conformably overlies the Iles Formation and consists of marine and terrestrial deltaic deposits. The Williams Fork Formation is divided into three members; the lower coal-bearing Bowie member, the upper coal-bearing Paonia member, and the non-coal-bearing Barren member. The Bowie member is between 675 and 850 feet thick in the area of the mines, and is composed of four general submembers. In ascending order, these submembers are: 1) 420 to 480 foot thick coal-bearing lower Bowie shale; 2) 30 to 130 foot thick diddle sandstone; 3) 150 to 200 foot thick Upper Bowie shale submember; and 4) 50 to 100 foot thick Upper sandstone suomember. The lower Bowie coal -bearing shale submember contains several coal seams. These coal seams vary in thickness and lateral extent along the Grand Hoyback. In the area around the Sunlight Mine, there are three minable coal seams; the "h-d" seam, the "C" seam, and the "0" seam. The "A-B" seam and the "C" seams have been previously mined, and the "C" and "0" seams are currently being mined in the Sunlight '-line. Three commercially minaole coals of the Lower Bowie shale suomemoer ( "A" -V' aria "C" seams) are located in the area of the North Thompson Creek Mines. The North Thompson Creek No. 1 Mine i5 currently mining the "A" seam. The inactive 4o. 2 '•line was within the "B" seam. in the area of the Coal Basin mines, there are two minaole seams, the "A" and 118" seams. The "d" seam is being mined at the Coal Basin ,lo. 1 , 3, 4 and 'lines. The two seams are separated by 0 to 39 feet of interburaen.