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STATE OF COLORADO <br />~~~DIVISION Of MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 C O L D RAD O <br />Denver, Colorado 80203 / DIVISION o E <br />Phone: (303) 866-3567 J/ MINERAL S <br />FAX: (303) 832$106 G E O L O G Y <br />//////,~,~r' 0.EC LANATION•MINING <br />January 29, 2004 V IlC SAFETY•SCIENCE <br />ly` Bill Owens <br />Mr. John W. Rozelle Governor <br />T~' Lafazee West Ina ~ Greg E. Walther <br />1400 West 64 Avenue Executive Director <br />Denver, CO 80221 Ronald W. Cattany <br />Division Director <br />¢~ / Q S t 6r / Natural Resource Trustee <br />RE: Desi n In ormation or East Pit Inlet and Outlet Str ur s Bunn Ranch Pit, Lafarge <br />Reference No. 805-430, Technical Revisio R-00 Permit No. M-1980-131 ~/ <br />Dear Mr. Rozelle: <br />The Division of Minerals and Geology (DMG) has completed a review of the technical revision TR-001 <br />application for the Bunn Ranch Pit. The TR-001 application requests approval to install inlet and outlet <br />structures at the perimeter of the eastern most of the Bunn Ranch gravel pits. These structures are <br />intended to non-erosively pass over bank flood flows from the Yampa River, up to the 100-yeaz flood <br />flows, through the pit. The inlet structure is to be installed into an eroded notch in the eastern berm <br />where flood flows overtopped the berm in the spring of 2003; the outlet structure will be located <br />directly across the pit to the west. <br />The DMG has no problems or issues with the design drawings submitted with the TR-001 application. <br />However, we are unable to review the adequacy of the structures to safely pass the design 100-year <br />flood flows without the hydrology and hydraulic information that form the basis of the design. In <br />particulaz, what aze the anticipated flow rates and velocities through the structures during a 100-yeaz <br />flood, and what were the analyses conducted to determine these design parameters? <br />The decision date established by DMG for TR-001 is Febnlary 9, 2004. Please provide the additional <br />information prior to that date or, alternatively, provide a letter extending the review period. If you have <br />any questions, please contact me at 303-866-4063. <br />Sincerely, <br />Allen C. Sorenson <br />Reclamation Specialist <br />cc: Cazl Mount, DMG (via email) <br />Steve Miller, Johnson, Kunkel, and Associates, Inc. (via fax) <br />c:lacsUAANER MACHINEVvfy DocumenislBunn Ranch trl adequacy.doc <br />Office of Office of Colorado <br />Mined Land Reclamation Active and Inactive Mines Geological Survey <br />