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5.1.1.2. Sodium Cyanide (Liquid) <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 <br /> cyanide is a 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 <br /> water found at two locations in the mill: (1) 3300-gallon tank in the cyanide storage and mixing <br /> room in the northwest corner of the Regrind Tunnel, and (2) 240-gallon tank in the Regrind <br /> Circuit in the west end of 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 <br /> which flows to the tailing delivery system. The bermed capacity is capable of containing the <br /> total maximum volume spilled. Spill prevention and control at the 240-gallon tank above the #6 <br /> float cell consists of making sure the feeder valves are shut and lines are intact, but the only <br /> physical containment existing is the abandoned float cells below the grated floor underneath the <br /> tank. <br /> Countermeasures: (1) Avoid mixing any liquid cyanide with acids, prevent body contact, and <br /> avoid inhaling vapors. (2) Contain the liquid spill with sorbent booms or pillows if possible. <br /> Mop up with floor dry if a small quantity is spilled. (3) Diking may be required if the 3300- <br /> gallon tank ruptures, although existing bermed containment will keep the liquid cyanide within <br /> the storage building. (4) Spills from the 240-gallon tank above #6 float-cell should.be directed <br /> with plastic sheeting or equivalent into the abandoned float cell beneath the floor grating. <br /> Nearest Clean-up Equipment: A spill control kit is located in the west end of the mill, adjacent <br /> to the Regrind Area and pebble lime storage. See Figure 1. Floor dry and clean shovels are <br /> located in the cyanide storage room. A barrel of caustic soda beads is kept onhand in the cyanide <br /> storage and mixing room, and hypochlorite is available in the Domestic Water Treatment <br /> Building. <br /> Monitoring: The cyanide storage and mixing room is checked at least daily. The 240-gallon <br /> tank in the Regrind Circuit in the west end of the mill is checked on each shift the mill operates <br /> or at least daily. <br /> Reporting: All liquid cyanide spills should be reported to the Environmental Coordinator, <br /> immediately, using the attached "Spill Incident Form" (See Appendix 1). In the unlikely event <br /> that containment by existing berms in the cyanide storage and mixing room, or containment in <br /> the abandoned number 6 float cell is unsuccessful, and if waters of the State are threatened, then <br /> the reporting procedures in Sections 4.2, 4.3, and 4.4 should be followed. <br /> 11 <br />