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DEPARTMENT OF NATURAL RESOURCES David H. Getches, Executive Director MINED LAND RECLAMATION DIVISION DAVID C. SHEITON, Director Richartl D. Lamm Governor DATE: February 7, 1984 T0: .Sandy Emrich FROM: P.C. Saletta ~]~, RE: Adequacy Review - CYCC Energy No. 3 Mtne Pursuant to your request I have reviewed the CYCC Energy No. 3 Mine Permit application. The following comments are made on each of the sections of the permit which I reviewed. Grading and Backfilling Portal Pit Area The application states the applicant's intent to backfill the abandoned Middle Creek Mtne portal pit according to cross sections submitted on Map No. 13. Some previous concern was expressed as to whether the materials density tests were adequate. It is apparent that the tests performed which Indicate a swell factor of 26X can be verified by the applicant's and the Division's experience in the Twenty Mile Park Basin. I believe the 26X swell factor 1s adequate. More importantly, however, I am concerned with the volume of material in the stockpile that will be used as the spoils backfill. The applicant states that approximately 1,128,000 bank cubic yards will be needed to backfill the ,portal pit, only 986,000 cubic yards are available with a deficit of 142,000 cubic yards. The 986,000 cubic yards is presumably loose material from the overburden stockpiles to the north and west of the portal pit. F15t of all there are no calculations to verify how much material is stockpiled. Secondly there is no mention of grading technique with regard to compaction effort or lift height. This concern is primarily to address the problem of saturation due to ground water inflow. Minimizing permeability and porosity will substantially decrease the volume of water saturating the backfilled pit. The applicant intends to scrape overburden material surrounding the pit area to make up for the deficit 142,000 BCY. This presents no major environmental or engineering concern provided that grading and backfilling conform to the design as presented in the permit cross sections on Map 13 of the permit application. The applicant also states that a survey will be performed to ensure approximation of contouring as designed. 423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. (303) 866-3567 ~~~ I~~I~~I~~II~~ I~~