Laserfiche WebLink
177'DID <br /> 0\1 <br /> OURAY SILVER MINES <br /> 111N1M AND,vA::E y <br /> December 27, 2016 <br /> VIA U.S. Mail and Email <br /> Travis Marshall, Environmental Protection Specialist <br /> Colorado Division of Reclamation, Mining, and Safety <br /> 1313 Sherman Street, Room 215 <br /> Denver, CO 80203 <br /> Ouray Silver Mines Inc. (OSM)owns and operates the Revenue Mine located—5 miles southeast of Ouray, <br /> Colorado on County Road 26 under Colorado Division of Reclamation, Mining, and Safety(DRMS) permit number <br /> M2012032 (Permit). The recent Permit required fourth quarter 2016 groundwater sampling produced chloride <br /> results above the Permit groundwater standard (2 mg/L) in well GW-2A at 2.1 mg/L, results attached. DRMS <br /> was notified of the results on December 6,via a telephone call to Travis Marshall. During the call, DRMS <br /> indicated a lack of concern with the low chloride concentration. <br /> Because the GW-2A chloride result was within error for the method,OSM asked that the lab rerun the sample <br /> under a different method (M300.0- Ion Chromatography).This second analysis produced similar results with <br /> chloride detected at 2.27 mg/L, attached. <br /> Simultaneously,OSM began researching the origin of the very low chloride standard.A review of the standards <br /> proposed in the March 11, 2015 letter to DRMS indicated that an in-stream standard of 0.011 mg/L had been <br /> applied in the derivation of the Permit standards.A subsequent review of in-stream standards for Sneffels Creek <br /> revealed that the 0.011 mg/L standard is for residual chlorine that was incorrectly applied to the chloride Permit <br /> limit.Thus, OSM will be submitting new Permit limits for chloride in the upcoming technical revision.The <br /> drinking water chloride standard is 250 mg/L for water supply uses.There is no agricultural groundwater <br /> standard for chloride, and there is no chloride standard for Sneffels Creek. <br /> Given the lack of regulatory concern regarding the chloride result,the incorrect application of a chlorine in- <br /> stream standard to the chloride Permit limit, and the challenges of sampling in the winter, OSM requests to <br /> forgo additional sampling. <br /> Sincerely, <br /> CaA CZ <br /> Clinton L. Fletcher <br /> President, Ouray Silver Mines Inc. <br /> Attachment(s): <br /> A—Q4 2016 Groundwater Sampling Results <br /> B—GW-2A Chloride Analyses by Ion Chromatography <br /> PO Box 564, 1900 Main Street,Unit 1, Ouray, Colorado,USA 81427 <br /> Tel. 970-325-9830—Fax. 970-325-9824 <br />