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2.04.6 Geology Description <br />Figure 2.5.2 (Section A -A') is a view due North and all data and <br />interpretation on this cross-section are in the plane of section. This view <br />shows the mined width of the graben at the McClane portal, and projected <br />mine development to the eastern permit boundary. After completion of the <br />rock slopes, the mains were developed approximately along this cross- <br />section as referenced in the development map (Figure 2.1-1). <br />Figure 2.5-3 (Section B' -B") is a view looking northeast showing the <br />graben's disruption of the Cameo Coal seam. Hole numbers 7-15-3-3, 7- <br />15-4, and 7-22-2 are in the plane of section. Also noteworthy is the split <br />seam which will allow the possibility of mining both seams where <br />interburden and roof rock integrity allow. <br />Figure 2.5-7 (Section B -B') is a view looking northeast and all data in this <br />cross section are in the plane of the section and shows the thickness of <br />the Cameo seam to be mined. See Figure 2.1-5 for projected seam <br />thickness and location. <br />With the development of the surface facilities, the underground workings, <br />and the lack of alternative access, the McClane Portal has proven to be <br />the most logical access to the coal reserves within the graben. Originally it <br />was estimated between 2.0 million and 2.5 million tons of recoverable coal <br />lie in the Cameo Seam within the McClane Graben. Extensive overburden <br />to the northeast terminated recovery potential. Rock slopes were initiated <br />eastward out of the graben in the summer of 1990. The completion the <br />slopes allowed access to the larger, uninterrupted reserves east of the <br />graben. However, mining conditions within the graben to the northeast <br />have indicated that where overburden exceeds 1,400 feet; coal recovery <br />becomes economically questionable and technically difficult. <br />Geological Conditions <br />As the development of the mine has increased, so has knowledge of roof <br />and floor conditions. Although some top coal was left in various parts of <br />the mine to stabilize roof conditions, an understanding of strata type that is <br />most likely to cause roof support problems has been gained. In general, <br />based upon knowledge from mining, widely scattered drill holes, and <br />PR -02 2.04-10 08/11 <br />