2020-08-07_REVISION - M1980244 (11)

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- ICMC RECERTIFICATION SUMMARY AUDIT REPORT Standard of Practice 4.5: Implement measures to protect fish and wildlife from direct or indirect discharges of cyanide process solutions to surface water. ® in full compliance with CC&V is: ❑in substantial compliance with Standard of Practice 4.5 ❑not in compliance with Summarize the basis for this finding: The operation is in FULL COMPLIANCE with Standard of Practice 4.5; implement a comprehensive water management program to protect against unintentional releases. CC&V operates with zero discharge of process solutions and no discharge of cyanide solutions to surface waters have occurred during the recertification period. Under the Discharge Permit Number CO0043648, CC&V is authorized to discharge from two outfalls: 1)Outfall 001 A:discharge to the Arequa Gulch from the sedimentation pond (i.e.,water from the VLF1 underdrain system), and 2)Outfall 00513:discharge of treated process water from the ESP to the Arequa Gulch if extraordinary storm events cause the ESP capacity to be exceeded.The auditors reviewed DMR reports for the certification period to confirm no discharge of cyanide solutions to surface waters. CC&V does not have any indirect discharge of cyanide solutions to surface waters. CC&V operates with zero discharge of process solutions. CC&V monitors for cyanide in compliance points downstream from the cyanide process facilities at Stations AG 2.0,GV 02, GV 03,T 02, and WCSW 01.Analytical data from 2014 to 2016 from these stations showed that free cyanide concentrations are<0.010 mg/L(i.e., below laboratory detection limit).Therefore, no impact to beneficial uses has occurred. Standard of Practice 4.6: Implement measures designed to manage seepage from cyanide facilities to protect the beneficial uses of groundwater. ®in full compliance with CC&V is: ❑in substantial compliance with Standard of Practice 4.6 ❑not in compliance with Summarize the basis for this finding: The operation is in FULL COMPLIANCE with Standard of Practice 4.6; implement measures designed to manage seepage from cyanide facilities to protect the beneficial uses of groundwater. CC&V has implemented measures to protect groundwater below and downgradient of the operation. Measures include: ■ VLF facilities with zero discharge.The ore storage liner system of the VI-Fs consist of soil liner placed on a prepared subgrade and overlain by geomembrane, which is then overlain by a pipe drain system embedded in drainage cover fill material.The liner system within the PSSAs consists of soil liner, overlain by geomembrane, overlain by solution collection fill material, overlain by geomembrane, which is then overlain by drainage cover fill material.Additionally, the VLFs are equipped with leak detection and collection systems. ■ All cyanide tanks and pipes have been designed with secondary containments such as concrete or lined containments. In addition,the entire perimeter of the cyanide facilities is lined with a geomembrane. ■ CC&V conducts weekly inspections of the leak collection systems and VLF underdrains to ensure that the facility is functioning as designed and protective of the environment.Additionally, CC&V has installed several monitoring well immediately downgradient of the cyanide process facilities to monitor groundwater. CC&V Mine July 28,2017 Name of Facility Signature of Lead Auditor Date July 2017 Golder Report No.1663584-003-R-RevO 13 Associates