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ID:71~93254 <br />~/-~• Cripple Creek & Victor Go <br />\\ _~ AJonl Vonturo-VWw PWc MInMq OonVnY.AW~WUr <br />u[r/il~ 7./ OpnrNloro Ollle~ <br />`A.77iv P.O. Box 191, 2755 State Highway 87 <br />Victor, Colorado 00660 <br />(719) 669-2977 • FAX (719) 886.9254 <br />July 12, 1994 <br />JUL 13'9 8:57 No .008 P.02 <br />IIIIIIIIIIIIIIII~ <br />Id Mining Company 999 <br />Englewood OHIu <br />5251 DTC Parkway, Suite 700, Englewood <br />Colorado 80111 <br />(303) 089-0700 • FAX (303) 669-0707 <br />SENT BY FACSIMILL• -COPY FOLLOWS BY MAIL <br />Mr. Berhan Keffelew <br />Environmental Protection Specialist <br />Colorado Department of Natural Resources <br />Division of Mines and Geology <br />Office of Mined Land Reclamation <br />1313 Sherman Street, Roont 215 <br />Denver, Colorado 80203 <br />Reference: Cresson Projcrt• Permit Nunlller M-80-244: Valley j.cach Underdraitt <br />Confi,P_uration. <br />Dear Mr. Keffelew: <br />In accordance with our discussion of ]arc this afternoon, we are submitting to you the <br />proposed change itt a segment of the underdrain wnfiguration. This change will maintain the <br />flow capacity of the underdrnin and improve the construction technique. The revised cross <br />section is submitted as Attachment 1 to this request. <br />This change in configuration will only occur uoeradient of the area where the total width of <br />]he underdrain is to be 20 feet or less. In the remainder of rite area where the (oral width <br />increases from 20 up to 100 feel, the original configuration will remain. <br />Tltc original configuration is one of the entire underdrain excavated to a single grade wills t11e <br />pipes located in the middle of the excavation and the pipe bedding material piled around and <br />over the pipes. Tlten the larger underdrain material will be placed on top of the bedding <br />material as well as beside rite bedding material and across the entire design width of rite drain <br />area (up to 100 feet}. In the areas narrower than 20 feet, with the proposal change, it will <br />be much more efficient to excavate a trench for the pipes, lay the pipes in bedding material, <br />and then fill that trench with bedding tnatcrial. Tlten the bench area above the trench will be <br />filled to the design cross-section with rite larger underdrain rock -which covers the: beddng <br />rock in the lower trench. <br />