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Mr. James Pendleton August 30, 1983 Page 3 • The fourth and final attachment (See Figure 4) is cross section B-B'. This cross section parallels the sand- stone channel as closely as our drilling information permits. The top of the F seam is shown at its correct elevation: however, the seam thickness is not accurately represented. This section closely parallels the F seam dip direction, and shows a maximum thickness of sand- stone which approaches 90 feet. The section shows the locations of known fractures which were encountered during mining. It is assumed that the portion of the section between SOME-94 and SOM-13 deviates away from the channel. Discussion: The required hypothetical development presented here is a probable model with three readily acceptable assumptions: 1) Rapid deposition of a thick sequence of sandstone, 2) The configuration of the sandstone must be such that bottom of the unit is convex, and 3) The sandstone must be at least partly lithified before the completion of diagenetic compaction. • A number of features are expected in conjunction with the fractures. These features include: 1) Slips or slickensides: The slickensided surfaces are diagenetic and are found to occur in the roof, the coal, partings in the coal, and in the underclay. These are not considered to be of any unusual significance since they are seen throughout the Mt. Gunnison No. 1 Mine area, in core holes through- out the property and neighboring properties as well as in association with virtually every coal seam where the author has ever worked. 2) Scour areas: These areas are the result of an active channel removing the upper portion of the F seam, resulting in an area where the coal was unusually thin even before the completion of com- paction. 3) F to F rider interburden: The interval between the mine and the F seam rider is found to in- crease dramatically as the amount of sandstone in the interval increases. This indicates that the fine grained sediments on the flanks of the sandstone were only partially compacted as the • sandstone was deposited. Therefore, it is evi- dent that the sandstone was deposited rapidly.