2020-08-03_REVISION - M1980244 (11)

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ICMC RECERTIFICATION SUMMARY AUDIT REPORT CC&V has performed metallurgical tests on the various ore types and sources to determine the optimal cyanide addition rates to the HGM. The HGM design criteria document indicates that the cyanide targets (pounds per ton [lb/t] free cyanide) are: 2 lb/t at the first leach tank and 1 lb/t at the last leach tank. No changes in ore characteristics have occurred since 2014 and therefore these targets are still current. CC&V has evaluated control strategies for cyanide additions and currently implements a manual sampling strategy at the HGM. The manual strategy consists of conducting titration tests at four locations every four hours at the mill. The auditors reviewed examples of completed mill daily leach round reports as well as interview metallurgical personnel to confirm that the strategy was being used during the recertification period. Standard of Practice 4.3: Implement a comprehensive water management program to protect against unintentional releases. CC&V is: in full compliance with Standard of Practice 4.3 in substantial compliance with not in compliance with Summarize the basis for this finding: The operation is in FULL COMPLIANCE with Standard of Practice 4.3; implement a comprehensive water management program to protect against unintentional releases. CC&V has updated the water balance model evaluated during the 2014 recertification audit to incorporate the new cyanide facilities (i.e., the HGM, ADR2, and VLF2) into the model. The current water balance is a probabilistic model, updated by Ecological Resource Consultants, Inc. in November 2015 using GoldSim. In addition, CC&V has developed an operational water balance in Excel to track the day-to-day operations. The auditors observed that the operational model and reviewed a technical memorandum summarizing the approach used for the development of the GoldSim model and the model results to verify compliance. The water balance models are comprehensive in that they include: solution application rates and leach cycles; tonnage loaded, make up water; precipitation and evaporation; undiverted run on; maximum pumping rates and pond capacities; ore moisture contents; a 100 year 24 hour storm of 3.5 inches and a drain down volume resulting from 12 hours of power loss for the PSSAs. The model does not include power outage for the HGM because the effects would be negligible given that the HGM would simply shutdown in case of a power failure. The model conservatively considers no other solution losses than evaporation and ore moisture uptake. Freezing and thawing are of short duration in the mine area and therefore they effect is negligible and not considered. No solutions are treated for discharge. Groundwater is prevented from interacting with leach solutions by the liner systems. The GoldSim model is probabilistic since it was developed based on a stochastic analysis in GoldSim that represents input variables with distributions. Operating procedures incorporate inspection and monitoring activities to implement water balance and prevent overtopping of the PSSAs and the ESP. CC&V has pond level indicators installed at all ponds and monitor pond levels every shift. Pond levels are automatically downloaded and integrated into the operational water balance model. Pond levels are also documented in the ADR solution reports. As indicated in the Permit M 1980 244, Cresson Project Mine Life Extension 2 and evaluated during the GoldSim model update in 2015, the PSSAs have adequate storage to hold the summation of the mine’s operating volume, along with the greater value of either the solution accumulation due to seasonal climatic variation at a 95% confidence level or the 100 year, 24 hour storm volume plus a drain down volume resulting from the 12 hours of power loss. As a criterion for evaluating adequacy of storage in each facility, five feet of freeboard is required to be maintained in each PSSA based on the model results. CC&V has developed an operating criterion for the PSSAs to maintain operating solution levels in each PSSA at 80 percent capacity or less, providing this way more than the recommended freeboard of 5 feet in each PSSA. The auditors reviewed examples of completed ADR solution reports and graphs of pond levels for the entire recertification period to confirm that the pond level monitoring and inspections were conducted and evaluated as required, and that that the maximum operating volume level was not exceeded throughout the recertification period. Only one exceedance of the total pond occurred in May 2015 at the VLF1 PSSA Phase 1 due to an expected rainfall CC&V Mine Name of Facility __________________________________ Signature of Lead Auditor July 28, 2017 Date July 2017 Report No. 1663584-003-R-Rev0 11