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Mark Loye Crystal Hill Mining Company <br />Dept. of Natural Resources 13100 County Road 42 -K <br />Mined Land Reclamation Division Del Norte, Colorado 81132 <br />423 Centennial Building RECEIVED <br />1313 Sherman St. V !► <br />Denver, Colo. 80203 AUG 1 fi 1s85 August 14, 1985 <br />Re: Mine Permit #81 -282 <br />MINED LANE) <br />Dear Mark: RECLAMATION DIVISION <br />Pursuant to regulations applying to mine permit #81 -282, we <br />hereby request a technical revision to our permit so that we can steepen <br />our ultimate pit highwall. <br />In April, 1985 Crystal Hill Mining Company began to re- evaluate <br />it's 53' open pit highwall an §le. The developing pit gave us exact <br />stability information by exposing the various rock zones and contacts. <br />Our first step was to contact John F. Abel Jr. who is an aquatance <br />of our joint venture partner,;Draco Hines Inc.. John came to the mine <br />for a tour in mid -April and wrote the attached letter of recommendations <br />to our partners. The letter includes references to Richard D. Call who <br />wrote the original "Crystal Hill Pit Wall and Waste Dump Stability" <br />report that was submitted with the original permit application. <br />Crystal Hill Mine has yet to make a decision on laying the existing <br />highwall back this winter. The enclosed report that Abel completed in <br />July lends itself to highwall steepening in certain pit areas. Page <br />6 of the Abel report divides the pit into 6 sectors of stability. <br />Table 23 summarizes the safe highwall angles. <br />Crystal Hill Mine has grouped these sectors into 3 mineable <br />sectors as shown on the attached sheet. Mining sector #1 would be mined <br />at a 60.1° overall slope angle or a 75° bench face angle if the <br />overall slope height is :� 60 ft.. Mining sector #2 would be mined at <br />a 53.7° 6verall -sl6pe angle whjch is equal to the existing pit highwall. <br />Mining sector #3 would be mined at a 64.5° overall slope. <br />We hope you will approve this technical revision and present it <br />to the board in the September meeting. <br />If you have any questions, please contact me. <br />5 cerel <br />Daniel D. Ki <br />Mining Engineer <br />