1995-08-11_REVISION - M1977493 (9)

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• Caustic Soda Beads (NaOH) Caustic soda beads are granules of sodium hydroxide (NaOH). Caustic soda is used in the mill circuit to raise the pH of process water and to adjust the pH of cyanide solution and Nokes Reagent. It also can be used as a neutralizing agent in the event of an acid spill. It is a strong corrosive alkali which can affect the human body through inhalation, ingestion, and dermal contact. It is corrosive to any tissue with which it contacts. Effects can vary from mild irritations to destructive burns (internally or externally) depending upon the type, degree, and length of exposure. Severe exposures, particularly those resulting from ingestion, may lead to death. In the presence of acidic conditions such,as acid rock drainage or acid mine drainage,NaOH will neutralize acid. It is used to raise the pH of acidic waters and soils. Should NaOH be delivered directly into a non-process water or a non-acidic water environment, it would cause short-term impacts to aquatic communities by raising the system pH to potentially intolerably high levels. Long-term impacts would be negligible to non-existent since NaOH does not bioaccumulate. Sulfuric Acid(H2SO4) • Sulfuric acid is used in the primary treatment system to adjust the pH of treated water to within the permit stipulated range of pH 6.5 - 9.0 prior to discharge to Ten Mile Creek. Sulfuric acid is a corrosive which can affect the human body through inhalation, ingestion, and dermal contact. Effects can vary from mild irritations to severe burns (internally or externally) depending upon the type, degree, and length of exposure. Repeated chronic exposure to dilute solutions may cause dermal irritations, whereas similar exposure to vapors or mists may cause erosion of teeth and inflammation of the eyes and mucus membranes of the nose, throat, and lungs. In the environment, sulfuric acid can be directly toxic through its corrosive nature or by lowering pH levels to the point of toxicity. In addition, even in very dilute forms which may not be injurious to human health, chronic releases of sulfuric acid can dissolve metals from rocks which, in turn, can damage aquatic and, in some instances, terrestrial ecosystems. Acid rock drainage, either natural or man-induced, exemplifies the latter situation. Sulfuric acid is readily neutralized by the addition of alkaline substances such as NaOH, CaO, or limestone. Calcium Oxide(CaO) CaO, also known as lime or quicklime, is used in the water treatment circuit at Climax to raise the pH and lower metal levels through precipitation. Lime also is used in the mill to adjust the pH of process water. Presently, lime is stored at three locations; the tailing delivery house, the Lime 10