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5.1.1.2. Sodium Cyanide (Liquid) <br />Not currently (May 2004) onsite due to standby status ojthe mine. <br />Description: Sodium cyanide is a mill reagent, used for pyrite, chalcopyrite, lead and copper <br />depression. It is used in the grinding and flotation phases of the milling process. Sodium cyanide is a <br />highly toxic chemical and special precautions are required when cleaning a spill. <br />Locations: Liquid sodium cyanide is a mixture of caustic soda beads (sodium hydroxide) and water <br />found at two locations in the mill: (1) 3300-gallon tank in the cyanide storage and mixing room in the <br />northwest corner of the Regrind Tunnel, and (2) 240-gallon tank in the Regrind Circuit in the west end of <br />the mill. <br />Spill Potential: Low at both locations. <br />Potential Volume Spilled: 3300 gallons in storage room or 240 gallons above #6 float cell. <br />Prevention and Control: The cyanide storage room is a bermed facility with a floor drain which flows <br />to the tailing delivery system. The bermed capacity is capable of containing the total maximum volume <br />spilled, Spill prevention and control at the 240-gallon tank above the #6 float cell consists of making <br />swe the feeder valves are shut and lines are intact, but the only physical containment existing is the <br />abandoned float cells below the grated floor underneath the tank. <br />Countermeasures: (1) Avoid mixing any liquid cyanide with acids, prevent body contact, and avoid <br />inhaling vapors. (2) Contain the liquid spill with sorbent booms or pillows if possible. Mop up with <br />• floor dry if a small quantity is spilled. (3) Diking may be required if the 3300-gallon tank ruptures, <br />although existing benned containment will keep the liquid cyanide within the storage building. (4) Spills <br />from the 240-gallon tank above #6 float cell should be directed with plastic sheeting or equivalent into <br />the abandoned float cell beneath the floor gating. <br />Nearest Clean-up Equipment: A spill control kit is located in the west end of the mill, adjacent to the <br />Regrind Area and pebble lime storage. See Figwe 1. Floor dry and clean shovels are located in the <br />cyanide storage room. A barrel of caustic soda beads is kept on hand in the cyanide storage and mixing <br />room, and hypochlorite is available in the Domestic Water Treatment Building. <br />Visual Inspections and Integrity Testing: The cyanide storage and mixing room is checked at least <br />daily during operations. The 240-gallon tank in the Regind Circuit in the west end of the mill is checked <br />on each shift the mill operates or at least daily. <br />Reporting: All liquid cyanide spills should be reported to the Environmental Department, immediately, <br />using the attached "Spill Incident Form" (See Appendix I). In the unlikely event that containment by <br />existing berms in the cyanide storage and mixing room, or containment in the abandoned number 6 float <br />cell is unsuccessful, and if waters of the State aze threatened, then the reporting procedures in Sections <br />4.2, 4.3, and 4.4 should be followed. <br />Conformance with Applicable Requirements: Since no cyanide is in use [at the time of this writing <br />(May 2004)] the facility is in conformance with applicable regulatory requirements. <br />15 <br />