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with embedded claystone and sandstone fragments in sizes ranging <br />from gravel to boulder-sized pieces. The slope-wash was underlain by <br />hard sedimentary bedrock consisting of sandstone and shales. <br />3. At Portal P3 the typical spoil consisted of a clayey gravel (GC). The <br />typical spoil at Portal R1 classifies as a clay, borderline clayey sand <br />(CL-SC). The finer nature of the R1 typical spoil is attributed to the 10- <br />footthick clay slope-wash layer present in the test pit at this location. <br />Overall, the typically spoil from R1 showed slightly lower strengths <br />than the typical spoil from P3 which is to be expected considering the <br />higher clay content. The friction angles for the two types of typical <br />spoil were generally consistent at different degrees of compaction, the <br />cohesion varied depending on the degree of compaction. The lowest <br />strength value measured was a friction angle of 28 degrees with a <br />cohesion of 400. <br />4. The stability of seven sections through the proposed portal areas were <br />analyzed. The results of the stability analysis indicate factors of safety <br />which significantly exceed the 1.3 minimum required by regulation. We <br />believe the post-mining topography results in a stable configuration. <br />Significant water build up within the reclaimed areas is not anticipated. <br />• Provision of a drain across the portal areas to prevent excessive water <br />build up in the area is recommended. <br />5. There is a potential for some seepage out of the portal areas. For this <br />reason we recommend that a drain system be installed across the front <br />of the portals. Our calculations indicate that a gravel section of 12 <br />square feet is capable of conveying flows in excess of 25 gallon per <br />minute. The drain should be sloped at a minimum 1 percent slope to <br />daylight. <br />6. We recommend the portal areas be reclaimed by placing and <br />compacting the excavated material using conventional earthmoving <br />operations. We recommend compaction to at least 90 percent of <br />standard Proctor maximum dry density. The moisture content of the <br />material is not considered critical, sufficient moisture should be <br />available to achieve compaction. It would be preferable to place the <br />backfill material at or below optimum moisture content to reduce <br />settlement and increase the strength of the compacted material. We <br />believe compaction should be applied to layers on the order of 8 to 12 <br />inches in thickness. <br /> <br />LORENCI70 COAL COMPANY, LLO <br />CTLR 25,861 2 <br />