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,~~o <br />{{,~~~~ , <br />~p~ oi~~~25 e~`I <br />2 <br />January 26, 2007 <br />Mr. Raymond Nalepa <br />Colorado Department of Public Health and Environment <br />Water Quality Control Division -Permits and Enforcement <br />4300 Cherry Creek Drive South <br />Denver, CO 80222-1530 <br />Phone: (303)692-3603 <br />RE: PERMIT CO-0036684: 4"' QUARTER 2006 DMR SUBMITTAL <br />Dear Mr. Nalepa: <br /> <br />Twentymile Coal Company <br />29515 Routt County Road # 27 <br />Oak Creek, Colorado 80467 <br />(970) 879-3800 <br />Please find enclosed the above referenced discharge monitodng reports for the period from October 1, 2006 through <br />December 31, 2006. Outfall 001A (62 FCT) flowetl each week of the period. No permit limitation exceedences were noted <br />(with exception of the quarterly W ET test, see paragraph below) during the pedod. <br />A Quarterly Whole Effluent Toxicity (WET) test was conducted for Ouffall OOtW on October 24, 2006. Test results indicated <br />ihat the effluent was not acutely toxic to fathead minnow survival, but was acutely toxic to Cerlodaphnia dubla survival. This <br />resulted in TCC subsequently conducting four axelerated W ET tests. Three of the four subsequent tests passed for C. Dubia <br />survival, putting TCC back in compliance. Copies of the WET Test Report Forms are included with this submittal. Results on <br />DMR reflects the final passing percentages. <br />Please contact me directly at (970) 870-2750 for any further questions or additional information. <br />r6~~~ <br />Brian A. Watterson, P.G. <br />Geologist, Environmental Group <br />Twentymile Coal Company, <br />Enclosures <br />cc: DMG <br />CWPS Permit No. CO-0036684 file <br />