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water. These procedures have been established at our refineries in Nevada and have been <br /> improved over the years to the point where spills are extremely rare. <br /> CC&V will epoxy the concrete floor in the area around the retort and the long term mercury flask <br /> storage area as shown in the attached drawing(attachment 2). <br /> F. Third page, third paragraph —If elemental Hg is exposed to the room in the AGADR where the <br /> retort is to operate, how will the room be: 1) monitored for Hg and, 2)ventilated to maintain <br /> indoor air quality standards while preventing uncontrolled release of Hg vapor to the <br /> environment? <br /> CC&V Response: <br /> 1) The retort is an air tight vessel and no mercury vapors should escape the control <br /> system. Currently CC&V monitors for vaporized mercury inside of the Arequa gulch <br /> Absorption, Desorption, and Recovery Facility (AGADR) using a hand held Jerome <br /> 631-X meter. Due to security concerns the access to the refinery is strictly controlled, <br /> employees can only enter the refinery when CC&V's security guards are present. <br /> Furthermore only a select number of employees can enter the refinery even when <br /> security is present. CC&V will commit to monitoring the refinery for vaporized <br /> mercury only when the refinery security is present. <br /> 2) Currently there is an emission control system over the blast furnace which draws <br /> approximately 5,000 cubic feet a minute through the refinery. The emission control <br /> system for the furnace contains two carbon bed scrubbers that are capable of <br /> removing vaporized Mercury. In addition to the emission control system over the <br /> blast furnace, the retort also has an air handling system. The retort has a ventilation <br /> system around the heated vessel and vent hood above the door. The system has a fan <br /> which is capable of moving 3,000 cubic feet a minute. The fan pulls air around the <br /> retort to help regulate the temperature of the retort and the temperature of the <br /> refinery, if a leak were to occur this system would likely prevent vaporized mercury <br /> from entering the refinery. <br /> G. Fourth page, last paragraph-How much water is expected to be collected in the condenser and <br /> therefore transferred to the one ton flask? Does this include the water used for the after cooler <br /> backflush discussed on p. 19 of Attachment 5 (Installation, Operation. & Maintenance Manual <br /> for 6 ft3 Electric Mercury Retort). If so, is this volume of water factored into the life of mine <br /> anticipated volume of Hg? (Note: both experience and the MSHA document identified in <br /> Comment B indicate water is NOT an effective blanket shield for elemental Hg). <br /> CC&V Response: The amount of water produced is a direct function of how much water content <br /> is present in the electrowinning concentrate. During the Retort operating cycle the water <br /> contained in the electrowinning concentrate will vaporize first and condense out in the collector, <br /> along with the mercury. When the cycle is complete the refinery operator will open the valve on <br /> the collector and the contents of mercury and water will exit the collector into a bucket. This also <br /> includes the water that is collected from back flushing the after cooler. The operator will decant <br /> the water into another bucket and pour the mercury into the storage flask; the decanted water will <br /> be introduced back into the process solution at AGADR. Decanting the water is relatively simple <br /> since the mercury is denser than the water and sinks to the bottom of the bucket quickly. There <br /> will be approximately less than 1 inch of water contained in the mercury flask at all times,the rest <br /> of the water is introduced back into the process solution. <br /> 3 <br />