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Piping and pumping systems are inspected regularly and a preventative maintenance system is in <br />place to assure proper repair and proper function. <br />Ruptures or leaks in barren solution piping on the VLF can occur. Piping has been changed out <br />over the years in that steel headers are now used. Additionally, the ADR pumping system is <br />equipped with a pressure loss or flow increase alarm system that automatically shuts down the <br />pumping system should a rapid change in pressure or flow occur. Procedures are in place for <br />restarting the pumping system once an alarm has been triggered and the pumps have been <br />automatically shut down. These systems are disabled when necessary to make piping changes on <br />the VLF. It is recognized that additional risk is incurred during the time periods when the system <br />is disabled or overridden for operational reasons. <br />7. Overtopping of the internal solution reservoirs in the VLF <br />The VLF Pregnant Solution Storage Areas (PSSA) are managed and monitored daily to assure <br />appropriate solution levels. The PSSA capacity is designed using a probabilistic water balance <br />model to contain normal operating solution levels, 12 hour VLF drain down, precipitation <br />resulting from a 100 year 24 hour storm, and additional precipitation based upon seasonal <br />variability. <br />Solution volumes and fresh water addition are managed through a computer model to predict <br />future operating levels of the PSSAs given time of year and probability of precipitation, fresh <br />water addition to the system, and ore stacking plans. An external storage pond of approximately <br />20 million gallon capacity is in place to accept excess solution should a scenario occur that <br />requires additional storage volume beyond that provided in the PSSAs internal to the VLF. <br />Excess pumping capacity exists to ensure the ability to move solution from the PSSA to the top <br />of the VLF. Backup generator power is in place to power the pumps in the event of failure of <br />commercial power. <br />8. Power outages including failure of backup generator power <br />Commercial power loss can occur. In the event of loss of commercial power, CC &V has in place <br />sufficient diesel generator capacity to power the primary systems to assure solution can be <br />moved from the PSSAs to the ADR and to the VLF, thus preventing overtopping of the internal <br />PSSAs. In the event of mechanical failure of one of the generators, use of available power <br />would be prioritized to the appropriate PSSA pumps. Diesel fuel is stored on site. In the event of <br />an extended power outage, additional diesel fuel would be delivered to the site via tanker truck. <br />if truck delivery of additional diesel were a problem due to road closures or transportation issues, <br />mine production could be curtailed to provide available diesel for emergency power generation. <br />9. Pump failures <br />Each PSSA is fitted with multiple pumps and excess pumping capacity to facilitate proper <br />solution movement during a pump failure. <br />Cyanide Emergency Response Plan <br />EMS: AGANA /CCV Printed Copies are Uncontrolled <br />G: \EMS \Plans \Emergency Response Plans \Cyanide Emergency Response Plan \CERP.doc <br />-5- <br />August 17, 2010 <br />Doc.# E -012 <br />Rev 07 <br />