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410'0000;'00�00 <br />I0` <br />OXBOW MINING, LLC <br />3737 Hwy 133 P.O. Box 535 Somerset, Colorado 81434 USA Tel (970)929 -5122 Fax <br />(970)929 -5177 <br />August 8, 2013 <br />Ms. Tania Watson <br />Colorado Department of Health, WQCD <br />Permits and Enforcement Section <br />WQCD -PE -B2 <br />4300 Cherry Creek Drive South <br />Denver, CO 80246 -1530 <br />RECEIVED <br />AUG 14 2013 <br />DMSION OF RECLAMATION <br />MINING AND SAFETY <br />Re: CDPS Permit No. COG850064, Outfall 01513, July 23 -27, 2013 WET Study Results <br />Report, Oxbow Mining, LLC., Elk Creek Mine. <br />Dear Ms. Watson: <br />Enclosed is the August 1, 2013 WET Study Report for testing conducted on July 23 -27, 2013. <br />The study was for a chronic WET test conducted using fathead minnows and Ceriodaphnia <br />dubia. The study was conducted during the first month of the 3rd Quarter to insure that a sample <br />was obtained from the dewatering of the mine during the mine recovery operation. There is <br />some possibility that the mine dewater pumps will be shutdown and removed later in the quarter <br />and water samples will no longer be available. <br />As expected, due to high levels of alkalinity, the Chronic WET test of the test species <br />Ceriodaphnia dubia failed at the 100% effluent level. The % survival of the C. dubia at the 50% <br />dilution level was 100 %. The Chronic WET test of the test species Fathead Minnows (P. <br />promelas) passed. Please see the attached August 1, 2013 report from Enviro -Chem Analytical, <br />Inc. for the details of the test. All other non -wet analysis results were in accordance with the <br />Permit conditions. <br />The Division should recall that on May 3, 2013, Oxbow sent an email requesting a change of <br />Chronic WET test species from Ceriodaphnas dubia to Daphnia magna due to anticipated <br />alkalinity. The testing Laboratory had given Oxbow an advance advisory that the WET test <br />would likely fail with C. dubia because of the elevated alkalinity expected in the mine water. The <br />Division indicated to Oxbow it was unable to grant a change in species for Chronic WET testing, <br />only acute WET testing. <br />The alkalinity in the discharge waters are not an isolated contaminant, rather it is a natural <br />occurrence in all of the underground coal mines located in the North Fork Valley. Because of the <br />occurrence of high alkalinity, Enviro -Chem Analytical, Inc. indicated we could expect the same <br />results if accelerated testing were to commence. Therefore, Oxbow is specifically requesting <br />relief from accelerated testing. <br />• Page 1 <br />