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CMCR was concerned that material cast into the drainage could <br />potentially be unstable. PCC engineers ran slope stability analysis <br />using oatq~uter programs to predict the actual factor of safety against <br />slope failure after reclamation. Actual site and spoil characteristics <br />were used in the analysis as well. In older to insure that the slope <br />would not beoan? 100$ saturated over time, an underc~ain was designed to <br />allow passage of ground water thrax~i the fill so as not to oo~romise <br />the integrity of the fill. <br />'ihe other aspect of the plan was the *~+~ i relnent to address the excess <br />spoil regulations. PCC, in the revision, positively demonstrated that <br />approximate original contour (AOC) was to be achieved even with the <br />atmimt of spoil beitg cast into the drainage. <br />Zhe above engineering aspects led directly to the other major sections <br />addressed in the application; topsoil (removal and replacement), <br />posttnine wntour (including stream channels), and the reclamation plan. <br />Please refer to this revision for detailed plans. <br />Additional drilling in the area after the application was sutmitted <br />showed that the wolf Creek coal seam was actually deeper than originally <br />anticipated. Assessing the situation, PCC decided that due to dragline <br />limitations, the operations plan would have to be revised again. 79Zis <br />included not moving the dragline as far down the hill in order for the <br />dragline to operate closer to its capacity in the somewhat shallower <br />overburr]en. Zhis plan was addressed in Technical Revision No. 8. <br />Additional items in Revision No. 8 included recalculated slope <br />stability analysis, stream charutel erosional stability plans, new <br />postmine contours for the Wolf Creek revision area, revised Operations <br />and Surface Water Control Plans, and a development drilling program for <br />the Seneca Mine. <br />Minor Revisions <br />Throughout this permit term, numerous minor ~xJes or revisions had to <br />• be made to the operations aryl reclamation plans or facilities within the <br />permit boundary. 'These are listed below with a short explanation of <br />each revision. <br />-11- Revised 11/11/94 <br />