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joints more readily than highly oxidized and weathered coal beds <br />do; however, both have undergone similar stresses and have <br />developed similar readjustment features that are apparent in the <br />subsurface. <br />The site specific stratigraphy is described in Exhibit 6, <br />Geological Information, and is graphically shown on the Geologic <br />Cross Section A-A' (Map 8) and the Geologic Cross Section B-B' (Map <br />9). Three additional geologic cross sections (C-C', D-D', and <br />E-E') that show the coal seam geometry and pit limits are provided <br />in Map 9A. The topographic locations of the geological cross <br />sections are found on the Geology Map (Map 7). <br />The coal seams to be mined at the Colowyo operation are the "Y3", <br />"Y2", "X", "A2", "A3", "B1", "C", "D", "E", and "F" coal seams. <br />These coal seams are found in the Williams Fork Formation and lie <br />within a sequence of sedimentary rocks characterized by sandstones, <br />claystones, siltstones, shales and carbonous and silty shales. <br />This sedimentary sequence is typical of cyclothems deposited along <br />the linear clastic shoreline located at the western edge of an <br />epicontinental seaway which was located in interior western North <br />America during most of Late Cretaceous time. <br />The analyses of the various coal seams to be mined are shown in <br />Table 1, Typical Coal Seam Analyses. <br />Exploration test borings have been conducted within the permit area <br />and have been utilized for the following purposes: <br />Location of Subsurface Water - Since the holes were generally dry, <br />the primary circulation medium for most exploration bore holes <br />drilled within the mine plan area was either compressed air or <br />drilling mud when fractures were encountered. Several drill holes <br />throughout the area encountered minor amounts of ground water; <br />however, all of the data obtained to date by Colowyo and the USGS <br />have indicated that groundwater occurrences in the area are not <br />continuous but rather are a series of perched systems. Information <br />on groundwater occurrence is set forth under Section 2.04.7. <br /> <br />2.04.6-6 <br />