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V V V V CENGINEERING <br />611 Skyline Road - Laramie, WY 82070 - (307) 742-0031 <br />FAX (307) 721-2913 - E-mail: infolar@wwcengineering.com <br />May 17, 2010 <br />CDPS Permit CO-0032638 <br />DEWIED <br />MAY 2 0 2010 <br />Qiv>•rl?y,? v. ,. <br />Mining Ond 5a <br />Joe Campbell <br />Colorado Department of Public Health and Environment <br />Water Quality Control Division <br />4300 Cherry Creek Drive South <br />= Denyer,_Colorado , 80246-1530 <br />RE: Edna Mine, January 2010, Reported Violation <br />Dear Mr. Campbell: <br />This letter presents a response to the Water Quality Control Division (WQCD), Colorado <br />Department of Public Health and Environment (CDPHE), Reported Violation letter dated <br />May 4, 2010 by Kelly Morgan and received by Chevron Mining on May 11, 2010. In <br />January 2010 Chevron Mining reported a violation of potentially dissolved manganese <br />(30 day avg) at Outfall 004A at the Edna Mine, with a result of 2080 ug/L and a permit <br />limitation of 1550 ug/L. This exceedance is the first to date in regard to the manganese. <br />The Edna Mine is a reclaimed surface coal mine. Underground mining began in the early <br />1930's and surface mining began in the late 1940's. Mining disturbance ceased in <br />December 1994 and coal production ceased September 1995. All reclamation activities <br />were completed by December 1996. Currently, all activities at the site involve <br />monitoring and maintenance of reclaimed lands and retained buildings. The site is <br />currently in the last stages of final bond release. <br />All known springs and seeps and all stormwater originating from and/or contacting <br />reclaimed areas resulting from previous mining activities passes through approved <br />permanent sedimentation ponds. Discharge at Outfall 004A is a combination of surface <br />runoff and spoils spring water released from Moffat Pond to an unnamed tributary to <br />Trout Creek. Discharge that reaches Trout Creek, downstream of the sample location, is <br />diluted by the perennial flows of Trout Creek. <br />The Colorado Discharge Permit System (CDPS) Permit No CO-0032638 was renewed <br />May 14, 2007 with an effective date of July 1, 2007. Prior to this renewal, manganese <br />was not reported. The manganese concentration exceedance in January 2010 is an <br />anomaly, since it is the only one of 34 reported monthly average concentrations that has <br />exceeded the permit limit. However, while this is the only time that the monthly average <br />concentration has exceeded the permit limit, a review of historical samples results reveals