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• <br /> <br />federal effluent limitations also applies to discharges from the VLF. The Carlton <br />Tunnel discharge area was evaluated; a series of settling ponds have been <br />installed to collect carbonate precipitates from the discharged water, and <br />refinements to this system are in planning.-The Carlton Tunnel discharge has <br />been evaluated by a licensed hydrogeologist and determined to be from multiple <br />infiltration sources, only one of which is related to the CC&V operation. <br />As the VLF is operated as azero-discharge facility, in all except the most <br />extraordinary precipitation events, water will not be discharged into Arequa <br />Gulch, and there will be no mixing zone. However, if such a situation were to <br />occur, the current CDPES permits would permit a discharge of 0.020 mg/1 WAD <br />cyanide. The hydrogen peroxide destruct system would be operated at the <br />external storage pond as necessary in such an event to achieve these values prior <br />to discharge. It should also be noted that the cyanide monitoring requirement <br />has been removed from the Carlton Tunnel discharge permit on the basis of a <br />long history of nondetects and "reasonable potential analysis." A cyanide <br />monitoring requirement still remains in the Fourmile Creek spring permit <br />(located downstream from the settling ponds below the Carlton Tunnel <br />discharge; monitoring data also indicate a long history of nondetects for cyanide <br />at this sampling point, however, it is understood that CC&V has prepared the <br />data and has submitted documentation to substantiate a similar "reasonable <br />potential analysis" exemption for the Fourmile Creek permit: <br />4.6 Implement measures designed to manage seepage from cyanide <br />facilities to protect the beneficial uses of ground water. <br />The operation is: ^ in full compliance <br />^ in substantial compliance <br />^ not incompliance ...with Standard of Practice 4.6. <br />Discuss the basis for the Finding/Deficiencies Identified: <br />• <br />'The CC&V operation has installed a double synthetic liner design component at <br />the PSSAs (i.e., the in-heap solution pond system) over a layer of compacted <br />clayey soil. The liner design also includes a LVSCS between the synthetic liners, <br />Cyanide solution seepage is collected in this system, which drains to a central <br />sump/collection point prior to being continuously pumped back to the heap. <br />The LVSCS is monitored on a daily basis. A pumpback arrangement is located <br />Cresson Project <br />Name of Mine <br />-~'~~~ ~ <br />~--'' <br />Signature of Lead Auditor <br />10 September 2007 <br />Date <br />Page 18 of 41 <br />