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iiiiiiiiiiiniiim <br />~?~AT'F nF ~'C~i ~R A,L1Q <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1113 Sherman $t-, Room 21 S <br />Denver, CO 80203 <br />Phone: 13031 866-3567 <br />FAX: (3071 832-8106 <br />DATE; November 16, 1992 <br />T0. Susan Morrison _ <br />~~~~ <br />FROM: Jim Pendleton ~~ ~-~ <br />RE: Peabody C onse to Adequacy Comments on Certification of <br />Haul Road G and Pond 005 at Seneca II-W Mine (>•R-19) <br />(Permit Nor C-82-051) <br />OF' COQ <br />~'~` ~I <br />•;'~~ . <br />~ Ig)6 <br />Rov Romer <br />Governor <br />Michael B. Lnny+ <br />Divi>ion Director <br />I have reviewed Pebody's supplemental submittal in response to our earlier <br />adequacy comments. Northwest Colorado. Consultants, Inc., who performed the <br />original density testing for Haul Road G and Pond 005, responded to my <br />questions regarding their notes. I had cited four instances in which they had <br />identified an inadequacy in compaction or preformance of the soils. In each <br />instance their supplemental comments resolved my concern, indicating that the <br />original deficiency had been remedied. <br />I also noted that Peabody provided a revised stability analysis for the <br />oversteepened cut slope within Pond 005, in response to your concern. Their <br />analysis appears to have been performed properly. 58-Slope is the analytical <br />program resident upon the Technical Information Processing System (TIPS). <br />While Peabody Coal's staff used literature references for shear strength of <br />the sandy-clay slope material, the values chosen are relatively conservative. <br />In light of their commitment to perform quarterly slope stability monument <br />monitoring of the subject cut slope, I recommend that the Division accept the <br />amended stability analysis and approve the steepened cut slope design. <br />cc: Larry Routten <br />Doc. No: 5387E <br />JP/jP <br />