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1 ~I • • III III III III IIII III <br />I ~_. ..\ .999 <br />TR9PPER DINING INC. <br />April 27, 1987 <br />CERTIFIED P577401644 <br />Mr. Gregg Squire <br />Colorado Mined Land Reclamation Division <br />423 Centennial Building <br />1313 Sherman Street <br />Denver, CO 80203 <br />Dear Gregg: <br />Re: Technical Revision No. 34: Construction of Sediment <br />Control Ponds in 1987. <br />Trapper Mine has planned an extensive sediment pond construction program for <br />1987. Five existing ponds will have embankments reconstructed and new spill- <br />ways installed. Additionally, five new ponds will be constructed. Tables <br />34-1 and 34-2 list the ponds and appropriate maps showing detailed designs. <br />This technical revision incorporates [he new spillway design proposed for the <br />1987 ponds, removal of Johnson Pond 7A and removal of Johnson Gulch Diversion <br />No. 1 and 2. <br />All ponds to be built or modified will incorporate the general spillway <br />design approved in Technical Revision No. 25 (Pyeatt and Johnson Gulch Redi- <br />ment Control Plan). However, slight modifications have been made in the <br />design of the principal spillway. Instead of a semi-circular metal flume, a <br />concrete lined, "V" bottom ditch will be used. On ponds East Buzzard No. 1 <br />and West~Buzzard No. 1, coconut fiber or landglas will be used to compare its <br />effectiveness to the concrete lined ditch. See Maps TR34-1 thru TR34-10 for <br />detailed designs of the structures. <br />The five ponds to have the embankments reconstructed will be closely monitored <br />by the certifying engineer. At present, the embankments to be rebuilt will be <br />rebuilt only above the stage of the existing principal spillway (culvert). <br />Any necessary field modifications will be made by the engineer and noted in <br />the embanlwent certification. <br />Gregg, these changes have caused Trapper to revise information previously sub- <br />mitted in Permit Revision 2 (PR-2). Attached are corrected tables 4.8-6, <br />4.8-7 and 4.8-7a. Revised page 4-192 is attached as well; it clarifys the <br />principal spillway design and updates the background information submitted in <br />Appendix Q. Corrected pages are to be inserted in Appendix 0, Sections I, II, <br />IV, VI, X, XI, and XIV. In addition, a new page (V-Ditch Spillways) is to be <br />added to Section XIV, after the "Open Channel Flow" calculation page. <br />~~~~' ~~ <br />APR 2 j 19g~ D <br />f ~EC~~A ~~N d~V/S~0 <br />N <br />cont. <br />P.O. Box 187 <br />Craig. Colorado 81626 <br />(303) 824-4401 <br />