2009-08-13_PERMIT FILE - C1981019A (4)

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RULE 2 PERMITS enerally consists of interbedded sandstones, mudstones and sited in predominantly anear-shore terrestraa Mesavei'de Group -The Mesaverde Group g the presence of both sea-level changes, indicated by siltstones of varying thicknesses. These beds were depo Williams Fork Formations and environment, with the sedimentation i ouencon b is of the Iles and fo orations; however, in the area of marine and non-marine rocks. The g P overlies the ManCO thick coal beds are found onl an the W ilhms Fork Formation. Y the Colowyo Mine, Iles F-~~at~°n -The Iles Formation conformably overlies thi Marcos Shale. It is exposed on the a ge south and west of the permit area and acdto a mands deposited along a reg ssional of the Axial Basin and 5ed of a thickness of approximately 1,500 feet. It is compo ocean mazgin. fine- to medium-grained, poorly sorted The Iles is generally comprised of light brown- to white, calcareous sandstone inteorbedded with red and dazk maroo onafoy and silty carbonaceous shale. nd in the formation. A thick sandstone at the cop of the Iles Formation, the r drill holes in the Danforth Hills and lenticular coal beds are is a reliable marker horiz Trout Creek Sandstone Member, surrounding areas. well-sorted, massive sandstone that was The Trout Creek Sandstone is light-colored, fine-grained, t is enerally 60 to 80 feet. The deposition of the Trout Creek Sandstone marked deposited in a marginau-marine or littoral environment. ThonthTh resulting clean blanket sand formed varies across the area b g lex is an aquifer of regional extent in northwestern a major regression of the Late Cretaceous seaway in this reg e forming unit in the Danforth Hills, has by this migrating beach and barrier island comp sures. Colorado. The Trout Creek Sbedcan e of its ~haraot mm whiteg andstone expo . been called the "White Rock mined at South Taylor The Trout Creekbsaadsroximately1590tfeetowest surface recoverable seam to be (the Gsv seams) y PP The W illiams Fork Formation is the predominant coal-bearing unit in a are Williams Fork Formation - sandstones, of the active mine and the Permit revision area. The fuTmcelof interb ddedytan toltiight gray Formatwn. The Williams Fork consists of a typical Iagoonal seq a mudstones and coals. This sedi eeof an light gray to gray siltstones, sandy, silty, or carbonaceous gr Y le of cyclothems deposited along a lineaz clrad'mshnto lowermosa delt is sediments sequence ~s an examp es from beach sands g g r deltaic deposits deposited in a epicontinentai seaway. The formation rang to middle and uppe deposited by sluggish brackish water at the base, bayou setting in the upper pnrttons of the formation. This sequence was formed as the shore transgresse seaward, resulting in the gradation from mazine sediments below the formation to terrestrial sediments above the formation. C_ J South TaylodLower Wilson -Rule 2, Page 29 Revision Date: 11!30/06 Revision No.: PR-02