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<br />III Iilllllllllll III <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman $t.. Room ? 15 <br />Denver, CO 80203 <br />Phone: 13031 866-3562 <br />FAX: (3031 832-8106 <br />September 28, 1992 <br />Gary W. Wendt <br />Peabody Coal Company <br />Western Coal Division <br />1300 South Yale <br />Flagstaff, Arizona 86001 <br />RE: Seneca II-W Mine (C-82-057) <br />Technical Revision 19 <br />Pond 005 Construction Certification <br />Dear Mr. Wendt: <br />pF COO <br />Nom.;; ~ <br />.~~. <br />~~b <br />r876 ~ <br />toy Romer <br />Governor <br />Michael B. long <br />Division Director <br />The Division has reviewed your application for Technical Revision 19. Based on a review of <br />the materials submitted and several field inspections, the Division has the following adequacy <br />issues: <br />1. Please modify exhibit 13-SA to include rip rap placed on the west side of <br />Diversion 7, at the outlet of drainage from the west. <br />2. Since the as-built configuration of the pond decreased the projected sediment <br />storage substantially, there should be a method of determining the current level <br />of sediment in relation to the required cleanout level. Please submit a plan for <br />periodic monitoring of sediment levels in the pond. <br />3. Reduction of the pond capacity resulted in the top of the dewatering pipe sitting <br />below the sediment cleanout level. If sediment would accumulate at or near that <br />level, the pipe would not be functional. Peabody should either extend the top <br />of the pipe, or commit to a lower sediment cleanout level. <br />4. Relocation of the pond embankment resulted in an acute angle at the junction <br />of the secondary spillway and Diversion No. 7. The west side slope of Diversion <br />No. 7 should be adequately armored to prevent erosion of the side slopes and <br />channel bottom. <br />5. Page 4 of the "Supplemental Geotechnical Investigation for Haul Road G", <br />contained in Attachment 13-3, discusses properties of soils in and around the <br />Haul Road G construction area. Paragraph 4 reads: <br />