2010-02-24_REVISION - C1996083 (2)

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• z.oa.s A shown on Map 7 there are numerous faults in the permit and adjacent area. The faults in the central portion of the permit area trend N40 °W and dip 70 to 80 degrees to the northeast. These high angle normal faults have an apparent strike slip component. The throw of the fault ranges from 7 to 30 feet. The down side is the south side of the fault. The faults that have been mined through a slip faults. Although present drill hole spacing is adequate for detection of large scale faults (approximately 50 ft. displacement), uncertainty exists in predicting faulting with less displacement, and the probability of encountering "blind ", unexpected faults within the mine workings is moderate. The geologic structure of the permit area may be modified by the nearby location of igneous intrusive bodies. Coal seams in this area have been coked and devolitized by suspected sills, undoubtedly related to the Miocene Iron Point Pluton (Junge, 1976). The combined effect of extension type structural features, nearby igneous activity, and frequency of inferred structures may indicate the presence of an igneous complex at depth beneath the area. Regional geophysical studies or deep drilling would be required to confirm this idea. The D -2 coal seam overburden ranges in thickness from less than 100 feet to greater than 2,000 ft., and is characterized by alternating claystone, siltstone, sandstone, and minor carbonaceous horizons. The lithologies comprising the barren member of the Mesaverde formation are typically laterally discontinuous and undergo abrupt facies changes within short distances. The stratigraphic interval between recognizable horizons may also change drastically, making correlation difficult. The base of the barren member is approximately 700 ft. above the top of the Rollins sandstone and the total thickness varies greatly as a result of topographic elevation and erosional geomorphology. 0 PR -12 2.04-17- 02110