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AAL <br /> DOWL H KM <br /> August 19, 2014 <br /> Mr. Michael Cunningham <br /> Environmental Protection Specialist <br /> Division of Reclamation, Mining and Safety <br /> Department of Natural Resources <br /> 1313 Sherman Street, Room 215 <br /> Denver, CO 80203 <br /> michael.cunningham(i)_state.co.us <br /> RE: Section 6.3.12 Exhibit L: Permanent Man-Made Structures, Leadville Mill, Tailings <br /> Storage Facility <br /> Mr. Cunningham, <br /> I am a Professional Civil Engineer, registered in the State of Colorado, and have been asked by <br /> Union Milling Company (UMC) to respond to Section 6.3.12 (b) of Permit M1990-057 for the <br /> Leadville Mill located near Stringtown, Colorado in Lake County. <br /> The regulation requires: <br /> "where such an agreement cannot be reached, the applicant shall provide an <br /> appropriate engineering evaluation that demonstrates that such structure shall <br /> not be damaged by activities occurring at the mining operation" <br /> Work Scope <br /> The "structure" as defined in 6.3.12 is the access driveway (the Drive) to an adjacent residence <br /> owned by Dale Wibbenmeyer. The mailing address for Mr. Wibbenmeyer is PO Box 1005, <br /> Leadville, Colorado, 80461. 1 have confirmed that the Drive is located within 200 feet of the <br /> operation and is therefore subject to the conditions of this regulation. Mr. Wibbenmeyer's <br /> residence is not located in the potential drainage way from the Union Milling Company TSF and <br /> is not subject to this evaluation. <br /> Engineering Evaluation <br /> The engineering evaluation included a site visit on June 9 2014 to inspect the embankment, as <br /> constructed and to review engineering design criteria, drawings, and engineering reports, <br /> including a slope stability evaluation and permeability study. This information was provided to <br /> the Colorado Department of Reclamation, Mining and Safety (CDRMS) in UMC's permit <br /> application dated April 2013, and is therefore not included in this letter. <br /> As reported in Section 4.3 of the permit document, the following comments/observations of the <br /> design parameters are made: <br /> • The new TSF was constructed over the existing TSF. Confirmed by reviewing <br /> historic photographs. <br /> 303-674-1256 ■ 303.845-9502(e-fax) ■ P.O.Box 17780 ■ Golden,Colorado 80402 ■ 32045 Castle Court,Unit 101 ■ Evergreen,Colorado 80439 . dowlhkm.com <br /> Alaska-Anchorage,Fairbanks,Juneau,Ketchikan,Palmer ■ Arizona-Tempe,Tucson ■ Montana-Billings,Bozeman,Butte,Great Falls,Helena,Miles City <br /> Colorado—Golden,Montrose ■ Oregon-Bend ■ North Dakota-Dickinson ■ Washington-Redmond ■ Wyoming-Gillette,Lander,Laramie,Sheridan <br />