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W. W. WHEELER <br />& ASSOCIATES, INC. <br />W,V r ROSOLWCOS Fllpir)OCVS, <br />January 24, 2014 <br />Mr. Miguel Hamarat <br />Climax Molybdenum Company, Henderson Mine <br />1746 County Road 202 <br />Empire, CO 80438 <br />Re: #1333.0 - Henderson Mill <br />Tailing Pond Flood Storage <br />Dear Miguel: <br />WWW.WWWHEELER.COM <br />As requested, we have evaluated the availability of flood storage capacity in the Henderson <br />tailing impoundment using information from the spring and fall 2013 pond surveys. The <br />spring survey of the beach and pool area was performed in May and the fall survey was <br />performed in October. Figure 1 is the pond contour map that was generated by Wheeler <br />from the fall survey point data. A similar map was prepared for the spring survey. The <br />survey shows that the average dam crest elevation of 1 Dam at the end of the spigot <br />deposition season is about 8868.1 feet, which is a 3.7 -foot increase from last year. The <br />minimum elevation surveyed along the dam crest was 8864.9 feet, which actually occurred <br />on 3 Dam. This information, as well as other characteristics of the pond, is summarized in <br />the table in the upper right -hand corner of the pond map drawing. Table 1 and Figure 2 is <br />the elevation- capacity data for the impoundment that was generated from the fall 2013 <br />contour map. Note that this data is representative of the pond at the time of the pool survey <br />and changes continuously as additional tailing is deposited. <br />One of the primary uses of the survey data is to evaluate the flood storage capacity <br />conditions in the water system. As summarized on Figure 1, at the approximate time of the <br />fall survey there was a total system surcharge storage capacity of about 8,507 acre -feet in <br />the system. This capacity includes both the TSF and East Branch Reservoir and is based <br />on 0.5 feet of residual freeboard below the minimum dam crest elevation of 8,864.9' and a <br />water level of 8,854.1'. The current flood storage requirement for the system is 3,582 <br />feet. This requirement is based on hydrologic modeling of the probable max <br />3700 S. INCA STREET I ENGLEWOOD, CO 801 1 0-3405 <br />303-761-41 30 1 FAX 303-76 1 -2B02 <br />