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<br /> <br />Dennis Conn <br />March 31, 1989 <br />Page Two <br />Distribution of Lithologies <br />In order to examine the probable impact of the B seam mining, we <br />utilized available stratigraphic cross sections and logs to examine <br />the relative amount of durable versus nondurable rock types in the <br />critical areas. During the mining of the B seam, the predominant <br />materials which will effect the strength of the waste rock will be the <br />coal and the rocks of the immediate roof. The rock mechanics testing <br />of the B seam coal versus the F seam coal indicate the B seam coals <br />have a higher mean compressive strength than the F seam coals (which <br />should exert a small positive effect on the strength of the waste). <br />of more significance, however, is the strength and character of the <br />non-coal waste rock. In order to make comparisons between the F and <br />H seam, we utilized the 10 feet immediately above the seam (i.e., the <br />immediate roof) as an indicator of the change in character of the waste <br />rock going into the pile. This was done along a north-south cross <br />section (section A-A') running the full length of the life of mine <br />permit area (hole #SOM-13 through MG-10). Results may be seen on <br />histograms plotted in Figure #1. As may be seen, the immediate roof <br />• of the B seam contains a higher percentage of sandstone than the <br />immediate roof of the F seam. On that basis, we would anticipate the <br />waste rock from B seam mining to have equal or greater strength <br />characteristics than the current waste material being produced from F <br />seam mining. <br />In order to develop the B seam mine, a slope will be required from the <br />F seam to the B seam through the interburden materials. In order to <br />examine the impact of the waste rock produced by slope construction, <br />we again looked at the distribution of lithologies in the F to B seam <br />interburden. This was done at three different locations near the <br />present mine workings and the proposed location of the slope. (i.e., <br />at hole location #SOM-13, SOM-36 and DH-3). Results can be seen again <br />on Figure 1. The relative percentage of sandstone present in these <br />materials increases even further above the levels present in the F <br />seam. This is largely due to the presence of a thick marine sand <br />immediately below the D seam level which will be encountered by the <br />slope. Therefore, we would again anticipate the waste materials <br />produced by slope construction to equal or exceed the strength of the <br />waste materials currently being produced. <br />West Elk Coal Company personnel have estimated the volume of waste <br />materials produced by slope construction to be on the order of 54,000 <br />tons. This material would be placed along with present production <br />waste within Phase III of the existing waste pile. Given the limited <br />volume of material and its blending with current production wastes, <br />impacts should be minimal, but if anything, favorable. It is our <br />understanding that the waste rock associated with slope construction <br />will be crushed underground, prior to it's transport by conveyor to <br />the surface (primarily in order to reduce wear and maintenance on <br />