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Regarding the 12 April 2012 incident, the DRMS Inspection Report dated 18 April 2012 <br />includes the following: <br />INSPECTION TOPIC: Hydrologic Balance <br />PROBLEM /POSSIBLE VIOLATION: Problem: Process solution spilling onto an area off the VLF <br />liner. Concentration of WAD Cyanide above 10 Ibs /ton or ore is reportable. <br />CORRECTIVE ACTIONS: 2b. CC &V in collaboration with the engineer of record, shall <br />investigate the cause of the spill and formulate a mitigation plan designed to prevent <br />reoccurrence of the problem. The mitigation plan shall be submitted to the Division for review <br />within 90 days of this inspection, and in accordance with the Technical Revision process pursuant <br />to Rule 1.8 of the Mineral Rules and Regulations of the Colorado Mined Land Reclamation Board <br />for Hard Rock, Metal, and Designated Mining Operations. <br />CORRECTIVE ACTION DUE DATE: 7/16/12 <br />In response to this item CC &V herein provides a report addressing corrective actions taken. <br />In collaboration with AMEC, CC &V has identified the primary root cause of the incident as a <br />manganese scale or sludge that, under a series of atypical circumstances, can form within the ore <br />pore space from the utilization of enrichment solution in the leaching process in a specific <br />location of the VLF. It was discovered that this manganese sludge formed and impeded the flow <br />of solution through a specific solution collection pipe within Phase 5 of the VLF. This <br />impedance of that solution flow resulted in a small amount of solution breaching containment in <br />that portion of the VLF, as previously communicated. <br />It is noteworthy that the planned Process Solution Enhancement System ( "PSES ") will ultimately <br />be instrumental in addressing this issue. A technical revision is forthcoming on the process <br />components of this system. Previously submitted TR -64 addressed the liner system associated <br />with the PSES. That liner system has since been constructed with a Construction Quality <br />Assurance ( "CQA ") report for the liner system also forthcoming. <br />The mitigation plan conceptually includes construction of an enhanced, geosynthetically lined <br />containment berm along a portion of the Phase 5 liner perimeter in order to increase the capacity <br />of the area to withstand any future, unforeseen upset process solution conditions in that area of <br />the VLF. <br />The existing liner will be exposed by the removal of the existing Drain Cover Fill ( "DCF ") in the <br />area. A new containment berm approximately 640' in length and a height ranging from 3 feet to <br />approximately 18 feet with a 1 foot flat top will be constructed directly over the existing certified <br />anchor trench. Select structural fill will be utilized for the berm material and it will be placed at <br />a maximum slope of 1.5 horizontal to 1 vertical. <br />The berm will be overlain with double sided textured 80 mil Linear Low Density Polyethylene <br />( "LLDPE "), installed by a qualified liner contractor under the same specifications used on Phase <br />5 of the VLF. <br />The liner will be extrusion welded to the existing exposed liner at varying distances from the toe <br />of the newly constructed berm. The liner will also be anchored along the perimeter of the <br />existing liner footprint without impacting the existing certified anchor trench. <br />