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March 13, 2013 <br />Page 3 of 4 <br />Mr. Wally Erickson <br />and Quarterly Sampling Reports after receipt from the laboratory and are included in Appendix <br />A of this report. <br />Underdrain flows were monitored monthly at the base of the embankment. The underdrain flows <br />for 2012 ranged from a low of 26 gpm to a high of 37 gpm. The mean underdrain flow for 2012 <br />was 32.42 gpm. The monthly underdrain flows were submitted previously to the Division in the <br />Monthly Reports and are included in Appendix A of this report. <br />The piezometers at the tailing embankment were monitored monthly. The tailing impoundment <br />piezometers measurements for 2012 were either dry or contained less than 12 inches of water. <br />Therefore the piezometers were not sampled. The monthly tailing impoundment measurements <br />were submitted previously to the Division in the Monthly Reports and are included in Appendix <br />A of this report. <br />Water treatment plant sludge was transferred from the drying pad to the tailings impoundment in <br />August 2012. Approximately 87.5 tons of sludge was transferred during the 2012 calendar year. <br />The monthly sludge management information was submitted previously to the Division in the <br />Monthly Reports and is included in Appendix A of this report. <br />Technical Revisions/Permit Amendments <br />BMRI continues to follow and comply with the current approved technical revision TR -26 (May <br />23, 2000). The alluvial hydrologic system for the Rito Seco and West Pit continued to be <br />managed for 2012 in compliance with TR -26. For 2012, the water management systems have <br />maintained the West Pit hydrologic gradient groundwater elevation at 8582 feet (ft) above mean <br />sea level (amsl) or lower, which is below the Rito Seco stream channel elevation. This elevation <br />has been continually maintained at or below 8582 ft amsl since February 8, 2000. Maintaining <br />this elevation removes the potential for the West Pit groundwater to percolate to the surface or <br />flow to Rito Seco Creek. <br />Additionally, the two groundwater recovery wells (M -32 and M -33), were operated during the <br />2012 calendar year. Groundwater pumped from these wells was either treated at the West Pit <br />Water Treatment Plant and discharged to the Rito Seco per the Colorado Department of Health <br />and Environments discharge permit, or pumped to the Tailings Disposal Facility for <br />management. In 2012, the West Pit water treatment plan treated and discharged a total of <br />64,367,423 gallons of water to the Rito Seco Creek. Additionally, a total of 35,611,800 gallons <br />or water was transferred from the West Pit back to the Tailing Disposal Facility. Historic <br />seepage locations along Rito Seco Creek were monitored monthly and remained dry for the 2012 <br />calendar year. <br />Technical revision(s) and/or permit amendment(s) were not submitted for the 2012 calendar <br />year. <br />