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May 30, 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 @state.co.us <br />The Union Milling Company <br />P.O. Box 620490 <br />Littleton, CO 80162 -0490 <br />+1.303.947.3499 <br />RECEIVED <br />MAY 3 0 2014 <br />Division of Reclamation, <br />Mining & Safoty <br />v' <br />RE: Leadville Mill; M1990 -057, Response to Amendment Review No. 4 Third Adequacy <br />for Stormwater /)�- M Q It <br />Dear Mr. Cunningham, <br />Following are Union Milling Company's (UMC) responses to Adequacy Review No. 4 Third <br />Adequacy for Stormwater queries from Tim Cazier in a memorandum dated 23 May 2014. <br />1. Pape 5, last paragraph. A CN of 79 is proposed for the outslope of the TSF, (assumed fair <br />grass cover). It is the Division's experience that tailings dams are seldom vegetated during <br />operations. Please revise the CN to a non - vegetated conditions (such as pervious, "newly <br />graded area" HSG Q CN = 91) or describe an aggressive revegetation plan for the TSF <br />outslope. <br />Response: <br />Please see response in Question 9. <br />UMC's responses to questions 2 -8 in the Second Adequacy letter dated 22 April 2014 are <br />considered adequate by the Division and are not repeated here. <br />Drawing DR -1. <br />9. The Division believes there is insufficient capacity for sediment retention at the southwest <br />corner of the TSF. Please include an additional sediment basin near the southwest corner of <br />the TSF. The Division believes there is insufficient capacity for sediment retention... The <br />response to this comment is partially adequate. The proposed silt fence will suffice as a <br />temporary BMP. However, given the challenge in establishing vegetation at the site's high <br />elevation and on 2H.1 V slopes, the Division believes a more permanent solution may <br />