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rmftogsandWe Waste 980?Mlla0emr Rotterdam,ISBN9D5410922X <br /> Zinck, 1.M., Wilson, L.1., Chen, T.T., Griffith, W., Mikhail, S. & Turcotte, A.M. 1997. Stability of Water treatment sludge,Climax Mine,Colorado <br /> Characteriulion and stability of acid mine drainage treatment sludges.MEND Interim Report <br /> 3.42.2:61 p.+appendices. Part H: Leaching characteristics <br /> R.Craig Ford <br /> Cyprus Climas Metals Company Tempe.Ariz.,USA <br /> John L.Clapper&Bryce R.Romig <br /> Climax Molybdenum Company Climru Mine,Colo.,USA <br /> ABSTRACT: Ponds have been used as reactors for lime neutralization water treatment at the • <br /> Climax Molybdenum Mine since 1977. with sludge disposed of in two of the three tailings <br /> impoundments at the site. Proposed changes to the water treatment process resulted in a program <br /> to detemtine the long-term geochemical stability of sludge in the Mayflower impoundment. <br /> Sludge samples were collected from four locations in the Mayflower impoundment to evaluate the <br /> spatial variability of water 11matment products throughout the water pool;two samples are sludge- <br /> rich,two other samples have a significant tailings component. All samples were subjected to a <br /> sequential batch extraction(SITE)procedure at pH 7 and 9,allowing their behavior to be evaluated <br /> under conditions of increasing fluid-sludge ratios. The results of the SBE indicate that there is <br /> little potential for dissolution of metal-bearing phases under neutral to alkaline conditions. <br /> IINTRODUCTION <br /> The chemical and mineralogical characteristics of water treatment sludge samples from the <br /> Mayflower impoundment at the Climax Mine were described in a companion paper(Ford at al. <br /> 1997;this volume). On the basis of these properties,the four samples were subdivided into those <br /> dominated by water treatment products and those with a significant tailings component,derived <br /> from the underlying impoundment. This paper describes the leaching characteristics of the four • <br /> samples. <br /> 2 SLUDGE SAMPLING AND ANALYTICAL METHODS <br /> Details pertaining to collection of the four sludge samples is described in the companion paper <br /> j (Ford et al. 1997,this volume). Solids were subjected to a sequential batch extraction(SBE) <br /> procedure which models the leaching behavior of geological materials as they are subjected to <br /> inceasing fluid-sludge ratios. A schematic diagram showing the layout of the SBE used for this <br /> study is portrayed in Figure I. Fresh Iixivianl and solids madded at the different steps to achieve <br /> the desired nuid-sludge ratios. The charges were agitated in an end-over-end fashion for IS hours. <br /> Solids carried over to the following step were pressure filtered before proceeding. Each SBE <br /> consisted of five extractions at fluid-sludge ratios of 0.5, 4, 6, 12 and 24. Two SBEs were <br /> performed for each sample,at pH 7 and 9. The lixivisnl used in the SBE was seepage from 3-dam, <br /> located at the upgradient(south)and of Mayflower.The pH of 3-dam seep water was modified to <br /> pH 7 and 9 with Na(OH). The chemical composition of modified 3-dam seep water is presented <br /> in Table 1. Leachate samples derived from pressure filtration were analyzed by ICP(EPA <br /> M200.7)for Al,CC Fe and Mn. Acidity,total alkalinity,bicarbonate,carbonate,hydroxide end <br /> 656 657 <br />