1995-08-11_REVISION - M1977493 (9)

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. migratory birds. Instant Nokes Reagent and Phosphorous Pentasulfide (P2S5) Phosphorous pentasulfide is a principal ingredient in Nokes Reagent. Nokes Reagent is a mixture of caustic soda beads (NaOH) and phosphorous pentasulfide in solution with water. The addition of NaOH to the solution maintains a pH>11 which prevents the release of H2S. The reagent is incorporated into the mill circuit as a lead and copper depressant. Presently, Climax uses only Instant Nokes Reagent; liquid Nokes premixed with NaOH prior to delivery. During past operations, Climax mixed Nokes Reagent at the mill site in a Nokes mixing tank inside the Nokes building. As per Table 1, some solid P2S5 still remains in the Nokes building. Phosphorous pentasulfide is a reactive and ignitable greenish-yellow solid with a "rotten egg" smell which can affect the human body through inhalation, ingestion, and dermal contact. While solid phosphorous pentasulfide can cause dermal irritation, the primary health hazard associated with this material is the release of hydrogen sulfide gas upon contact with water. Hydrogen sulfide can be a primary health hazard which acts as an irritant to mucus membranes and can produce severe breathing difficulties. High concentrations can stop breathing immediately. • Phosphorous pentasulfide, if released to the environment where it contacts water, will react by producing hydrogen sulfide gas and phosphoric acid. Both of these by-products can be injurious to aquatic and terrestrial biota. Phosphorous pentasulfide can be neutralized with an alkaline substance such as lime,NaOH, soda ash, etc. Conoco Light Oil Conoco Light Oil (similar to#2 diesel) is a combustible petroleum distillate commonly used as a heating fuel. At Climax, it is used as a collector/cleaner (regrind) reagent in the milling process. Aside from being combustible, Conoco Light Oil is an aspiration hazard and a skin irritant. In the environment, Conoco Light Oil reacts similar to other petroleum fuels and can cause short- term damage to terrestrial and aquatic ecosystems. Spills should be contained with inert absorbents, and contaminated soils removed. Dow Toth 250 Dowfroth 250 is utilized in the mill circuit as a flotation frother. Its component is • polypropylene glycol methyl ethers. It is a non-hazardous polymer. Primary exposure pathways are dermal contact and eye contact where it may cause localized irritation. If ingested, 8