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• Sco e <br />On March 2, 1982, Cyprus Coal Company was asked to provide technical <br />assistance to determine fault displacement and project mining concerns <br />resulting from fault interception, the source of water associated with the <br />first fault, and the possibility of encountering additional faults as <br />mining continues. J&L Drilling, Inc., of Montrose, Colorado, was <br />contracted to conduct an underground drilling program to retrieve core <br />samples of the roof and floor lithologies to assist in the determination. <br />Underground mapping was conducted with special emphasis toward noting <br />changes in water inflow through time, noting changes in cleat orientation, <br />and locating sandstone intrusions that might be predictive of faulting. <br />~• Setting <br />The Eagle No. 5 Mine operates in the F seam within the lower portion <br />of the Cretaceous Williams Fork Formation. However, the 2 West area of <br />the Eagle No. 5 Mine is both depositionally and structurally different <br />than the majority of the property. In the 2 West area the F seam is <br />underlain by shale and sandy shale (siltstone) approximately 31 feet <br />thick, and sandstone which ranges in thickness from 5 to 30 feet. The <br />E seam underlies these units. The F seam is overlain by 18 to 28 feet of <br />shale, sandy shale, and thin coals capped by a locally thick seam herein <br />named the "G" seam. The G to F interburden decreases to the east and <br />north of the 2 West area and the G seam merges with the F, most notably in <br />the area near the 5 A portals. The G seam is then overlain by 0 to 6 feet <br />~~ <br />of shale and 11 to 33 feet of sandstone. <br />