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?Climax Molybdenum t,? <br />Henderson Operations <br />19302 County Rd. 3 <br />Parshall, CO 80468 <br />303.569.3221 Tel <br />970.725.3267 Fax <br />April 23, 2008 tvd <br />Allen Sorenson <br />State of Colorado <br />Division of Reclamation, Mining and Safety <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />('e ?bs <br />RE: Upset Condition involving the release of process water from tailing. <br />impoundment, Permit No. M-1977-342 <br />Mr. Sorenson: <br />Henderson Mill is providing this follow-up notice pursuant to Rule 8.2.3 of the DRMS <br />Rules and Regulations. <br />This notice is regarding the release of tailings from the crest of the Number 1 Tailing <br />Dam, which occurred on April 22, 2008 at 8:55am due to upset conditions at the <br />Henderson Mill facility. Approximately 2000 gallons of water (100gpm for 20 minutes) <br />from the crest traveled down the groin of the dam to the toe. At this point, the flow path <br />split and 50-60% flowed back into the existing seepwater channel, while 40-50% flowed <br />into an interceptor canal through an 8-inch pipe that was originally installed for storm <br />water management from a separate area. The interceptor canal eventually intersects with <br />the Williams Fork River approximately 1.1 miles away. <br />(a) The breach in the dam crest was repaired within the hour and the flow path <br />of the release was completely routed into the seepwater channel at the toe <br />of the Number 1 Dam, where it is intended to flow. The material affected <br />by the upset was consolidated and managed back in the tailings system. <br />The 8-inch culvert which conveyed the material from an old storm water <br />ditch to the canal has been permanently closed. BMPs have been placed <br />in the canal to intercept any suspended solids. <br />(b) Henderson does not anticipate that the released water will adversely <br />impact human health, property or the environment. This is based on the <br />fact that the released water flowed at a rate of 40-50 gpm for <br />approximately 20 minutes into a freshwater canal flowing at 1,370 gpm <br />and eventually into a river flowing at 20,645 gpm. Given run-off <br />conditions heavily diluting the upset the overall benign composition of the <br />tailing material, we do not anticipate any adverse impact. <br />RECEIVED / <br />APR 2 9 2008 <br />Division of Reclamation, <br />Mining and Safety