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r ~ TWBNTYM166 IIIIII'lllll"IIIII sss Twentymile Coal Corporation 7~ COAI. COMPANY 29515 Routf County Road # 27 A Cyprus Ama: Company Oak Creek, Colorado 80467 970-879-3800 April 11, 1997 Janet Binns RECEIVED Environmental Protection Specialist Division of Minerals and Geology 1313 Sherman Street, Room 215 AF'H 1 ~ 1997 Denver, Colorado 80203 Division of Minerals g Geology RE: TR 26, Midterm Review Adequacy Response Permit No. C-82-056 Dear Ms. Binns: This will serve to provide the Division direction as to the handling of the material that TCC's consultant, TuttleApplegate, Inc., will be hand delivering today. The materials the Division will be receiving are as follows: • Revised Map 31, Postmining Topography, • Revised Map 25, Surface Area Cross-Sections • SedCad Documentation for permanent diversions and lower PG 2-1 drainage • Cut and fill discussion The revised maps, both postmining topography and surface area cross sections, have utilized the latest mapping that was completed last fall. The final topography has been modified to address the drainage concerns raised by the Division. The location of the permanent diversions are shown on Map 31. It was determined that constructing permanent diversions is more visually appealing than riprapping segments of the drainage coming over the face of the slope. Also, the construction of the diversions and final grading of the portal azea assures all this disturbed drainage is routed to Pond D. The SedCad demonstration is provided as backup for the design of the diversions and the lower segment of PG 2-1. Both the maps and SedCad demonstrations are certified by a registered professional engineer. Finally, text is provided by the consultant to address the Division's bonding concerns. The end result is that the proposed postmining topography can be achieved with the material in the adjacent spoil and pad areas for the shop and ofTice facilities. It appears the bond is sufficient to cover these activities. Janet, I will hold off forwazding this information to the other agencies until I have received the Division's comments on the submittal. I'm optimistic that this should address all of the outstanding issues. Thanks for working through this with us. I believe the final product justified the wait on the updated mapping.