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Chemical Fixation: In the initial screening process, kiln dust <br />and three proprietary materials were selected for detailed <br />evaluation. waste rock /tailings from Gregory and Argo were <br />treated with each of the four selected fixation agents. The <br />resultant fixed materials were then subjected to a series of <br />leaching tests to document the effectiveness of the treatment. <br />In all cases, the fixation agents tested were effective in <br />reducing leachate concentrations. In some cases, leachate <br />concentrations were below AwQC for Zinc. However, in one case, <br />the leachate contained extremely high values for aluminum <br />(27,700 ug /L ;. Because of this result, this fixation agent was <br />eliminated from evaluation. Kiln dust and two proprietary agents <br />were all considered further. Based on cost and leachate quality, <br />kiln dust is the most cost - effective. Kiln dust would be applied <br />at an application rate of approximately o.58 tons per cubic yard <br />of available tailings and Waste rock material. Approximately 9 <br />inches of kiln dust would be mixed in with the top 9 inches Of <br />tailings and waste rock material and then compacted. <br />Fixation of the tailings and waste rock piles is a permanent <br />solution that removes exposure to human health and the <br />environment. <br />Reprocessing Alternative: The reprocessing alternative considers <br />the tailings and waste rock piles as an economic resource and <br />recovers the inherent monetary value while generating a waste <br />which may not be detrimental to the environment. In order to <br />evaluate this option, a three -phase characterization task was <br />undertaken: <br />o Evaluating the parameters necessary to process the waste <br />rock /tailings; <br />o Determining if the resultant waste is a hazardous waste; and <br />o Performing a cost analysis of all Options. <br />The reprocessing studies were conducted on a bench scale <br />level by International Process Research Corporation of Golden, <br />Colorado. Two options were evaluated, namely: <br />o Reprocessing of all materials; and <br />o Reprocessing of all materials less than tWO inches with <br />disposal of coarse fraction as a waste rock. <br />22 <br />