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.. ~. <br />2.04.6(2) (a) (i) <br />limited due to depth of burial, limited recharge and low permeability. <br />~lthough additional sandstone units have been noted at a considerable <br />depth below the Rollins Sandstone, the Iles Formation probably consists <br />of only the Rollins unit in this area. The Mancos Shale which lies <br />immediately below the Rollins is very thick in the area and the <br />sandstones contained within it are probably marine in origin and not ~ <br />of transgressive-regressive nature such as Rollins. Other than the <br />Rollins Sandstone the Iles Formation is not of significance to the <br />discussion of the P.ed Canyon Mine development. <br />Bowie Shale: Bowie Shale member Mesaverde Group. The coals which <br />are being mined by Grand Mesa Coal Company and are included in ~ <br />the permit application are contained within the lower shale member <br />of the Williams Fork Formation, Mesaverde Group. The dominant <br />lithology of the entire shale group is generally medium to dark <br />grey, silty to sandy, moderately soft, and usually rich in <br />carbonaceous particles. Zntersprersed with the claystone and <br />shale are numerous, laterally nonextensive sandstone units and <br />•siltstone beds. Sandstones are generally lenticular, very fine ~, <br />grained, well cemented with calcareous cement, characterized by <br />small scale channel type cross bedding, including some claystone <br />and shale clasts and carbonaceous particles. Mons of. these <br />sandstones appear to be extensive enough to provide predictable <br />or usable aquifers and very often (as evidenced in the roof of <br />the present Red Canyon Al Mine workings) are completely dry.' <br />Glacial outwash alluvium: As can be seen on the Geology flap, <br />2.04.5-1, a large percentage of the permit area is overlain by <br />glacial debris consisting primarily of basalt boulders and gravels <br />with some sand and silts derived from glaciation of the top of <br />Grand Mesa to the north. This glacial debris is separated from <br />the coal seams by tens to perhaps hundreds of feet of claystone <br />and shale as described above. This claystone and shale effectively <br />isolates the coal seams from having any influence on this unit <br />except where immediately in contact in eubcrop. <br />r 1 <br />\J <br />RF.VISFD May 8, 1981 <br />52 <br />~:r.`,. ~;.~ <br />,..., <br />