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e <br />ESPEY, HUSTON & ASSOCIATES, INC. <br /> <br />from the older Cretaceous rocks. These deposits are present in the lower elevations <br />of the mine plan area and occur as valley fill. Locally, soil creep and small landslide <br />debris derived from weather weakened Cretaceous age strata aze present along a <br />few moderately steep slopes north of the Northern No. 1 (FF-Seam) Mine. <br />Northern Coal Company reports that, according to company derived <br />drilling information, the Williams Fork Formation is about 2,965 feet thick. <br />Hancock and Ebq (1930) described three coal-beazing groups within the formation <br />and a relatively coal-bazren middle zone about 1,000 feet thick separating the lower <br />two coal groups. In descending stratigraphic order, the coal groups and approximate <br />thicknesses aze: The Lions Canyon Coal group (1,000 feet), the Goff Coal group (700 <br />feet), bazren interval and the Fairfield Coal group (1,300 feet). The Lions Canyon <br />Coal group and its basal Lions Canyon Sandstone Member have been removed by <br />erosion throughout most of the region and is present only outside the mine plan area <br />• in section 19, T2N, R93W, 6th P.M., 134 miles northwest of the Rienau No. Z (G- <br />Seam) Mine. <br />Lithologically, the Williams Fork Formation consists of a thick series of <br />predominately non-mazine interbedded to laminated sandstones, siltstones, mud- <br />stones, shales, cazbonaceous shales and abundant coal seams of vazying thicknesses. <br />All of the beds, except the coals, aze quite vaziable in lithology and laterally <br />discontinuous, being traceable only over short distances. Sandstones aze fine- to <br />medium-grained and thickest in the Fairfield Coal group with individual units of 25 <br />to 50 feet common. In the Goff group, the sandstones and other units aze thin and <br />quite erratic and may contain 15 to 50 percent shale and clay size fragments as <br />matrix. <br />No coal outcrops aze exposed along the south facing exposures of the <br />Williams Fork Formation. However, large areas of "clinkered" or "burned" strata, <br />800 to 1,000 feet thick aze present, especially where the abundantly coal-beazing <br />Fairfield Coal group is exposed. These burned azeas aze the result of in-situ <br /> <br />F-4 <br />