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• STATION 18+00 <br />The analysis of this area was complicated by the fact that the original slope was <br />not extremely stable, a common condition in the mine area. The analysis of the <br />assumed original slope indicates a factor of safety of only 1.154. The existing <br />configuration with the road has a factor of safety of 1.081. Since the slope has shown <br />no tendency of failing in the nearly twenty years, it is assumed that the soil parameters <br />or underground stratigraphy is not accurately defined within the data set. Although a <br />"true" factor of safety will not be generated, the relative stability of the various <br />configurations can be attained. <br />The next configuration that was tested for this line was for the reclaimed <br />configuration. The analysis yielded a factor of safety of 1.166. The reclaimed <br />configuration includes backfilling the cut with material that will be compacted to achieve <br />a density of 135 pounds per cubic foot, while it was assumed that the original ground <br />has a density of 120 pounds per cubic foot. The backfill was also assumed to have a <br />higher cohesion, 300 vs. 200 psf, since it will be a blend of the existing gravelly material <br />• and the highly cohesive soils found in the upper portions of the road. It was noted that <br />none of the failure circles generated by REAME intersected the reclamation backfill. <br />Therefore, the failure would occur in the host material not in the backfill. <br />Since this analysis did not yield a factor of safety of 1.3 or higher, and none of <br />failure circles involved the backfill, analysis of just the backfill was performed. The <br />analysis of the backfill itself indicates a factor of safety of 2.115. Since the backfill is <br />shown to be stable, the stability of the original configuration is the weak point. No effort <br />to enhance the overall stability of the slope would be capable of creating a 1.3 factor of <br />safety without a major reduction in the steepness of the original slope. This option is not <br />feasible. <br />• Permit Renewal 3-10 08/03 <br />