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Nalco 7873: Nalco 7873 is a flocculant used in the mill thickener feed <br /> circuit. Ten(10) drums are stored in the regrind area of the mill building. <br /> Caustic Soda Beads: Dry sodium hydroxide is used to adjust the pH of <br /> NaCN and Nokes Reagent. It also is kept available to neutralize sump <br /> drainage as needed. Drums of sodium hydroxide are stored in the cyanide <br /> storage and mixing room, at the Nokes building, and in the moly dryer <br /> building. Containment in the cyanide storage and mixing room is discussed <br /> relative to cyanide. Only small amounts are stored at the Nokes building <br /> and at the moly dryer building(several drums). <br /> ETDL: Process water leaving the mill System is used to gravity transport tailing material as a <br /> slurry to the tailing impoundments through the tailing delivery line located along the east side of <br /> the impoundments. This line is constructed of 42" concrete pipe which completely isolates the <br /> tailing slurry from the environment until it is deposited in one of the impoundments. The line is <br /> constructed on a nominal grade of 1.2%. Where grades are in excess of 1.2%, concrete drop <br /> structures have been installed. Although the tailing slurry can be delivered to each of the <br /> impoundments, in the near future, only the Ten Mile impoundment will be used for deposition. <br /> In addition to conveying tailing slurry, the ETDL collects drainages from the McNulty waste <br /> rock dump and the camp area. The tailing delivery system is shown in Figure 1. <br /> Robinson Tailing Impoundment and No I Dam: As discussed in Section 5.2.1, the Robinson <br /> tailing impoundment encompasses approximately 667 acres. No. 1 Dam and a small portion of <br /> the southern part of this impoundment impacts the upper Eagle River watershed and is discussed <br /> in Section 5.2. The remainder, and majority portion, of the impoundment lies at the top of the <br /> Ten Mile Creek watershed. <br /> The Robinson impoundment contains mill tailing material. As discussed in Section 5.2.1, tailing <br /> material from the Climax mill circuit is recognized as containing significant sulfur and is therefore <br /> potentially acid producing. <br /> The Robinson impoundment is near capacity and, although it could be re-engineered and <br /> reconstructed for additional tailing storage, present and near-future plans are to reclaim the <br /> Robinson impoundment. However, even when reclaimed, the Robinson tailing impoundment <br /> remains both a potential source of contamination and an important EPF. As an EPF, it is the <br /> first line control and containment for potential contaminants originating from the E-Dump, OP <br /> dumps, and breaks in the up-gradient ETDL. The impoundment also acts as the first down-line <br /> containment facility for any potential release of designated chemicals used in the mill/concentrate <br /> production process. <br /> 25 <br />