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An unidentified Ca-Fe-Mn-Zn phase was common in the delta sample, occurring as minute
<br /> inclusions within larger ettringile grains. It is assumed that this is an amorphous phase.since it Climax orebody i White t al. 1981),which helps explain its absence from he C scans of the
<br /> was not identified on the XRD scans,although it is unknown whether it is an oxide,hydroxide or samples with a significant tailings component. The presence in calcite n the Canadian mine
<br /> carbonate phase. Although gypsum was indicated to be relatively abundant on the XRD sear,onlysludge samples has been attributed to various factors, including carbonation resulting from
<br /> one area Containing this mineral was located during the microprobe examination. aeration,presence of prosebumt lime to the 19at)or the presence of carbonate resulting from the use
<br /> of soda ash during ore processing(Zinck 1997;Zinck et al. 1997).
<br /> The presence of calcite in Mayflower sludges is attributed to the carbonation of excess calcium
<br /> 5 DISCUSSION OF RESULTS released during the water treatment process. A whitish precipitate identified a Calcite in XRD
<br /> scans often forms during spring runoff near 6-riser in Mayflower pond. Elevated flows of water
<br /> generated during snowmelt require batch treaunent,leading to inefRcient lime usage. We believe
<br /> 5.1 Chemical and mineralogical characteristics
<br /> that the over-liming of the water leads to excess Calcium in the water Column,which is carbonated,
<br /> leading to formation of calcite. Although the presence of Calcite is an indicator of inefficient lime
<br /> The four samples collected in this study fall into two categories,those dominated by wastewater usage, it nevertheless contributes to sludge stability through the addition of supplemental
<br /> treatment sludge and those with a significant tailings component. The average bulk chemistry of neutralizing Capability.
<br /> the two sludge-rich samples compares closely to the chemistry of fresh sludges from four •basic• Static acid generation tests performed on the four samples again illustrate the difference
<br /> mine-related water treatment systems in Canada (Zinck et al. 1997; Table 5), although the between the sludge-rich and tailings-rich samples. Sludge-rich samples,with their low sulfide •
<br /> comparison is not particularly meaningful since the concentrations of the various metal species sulfur,elevated sulfate sulfur(reflecting ettringite)and elevated NP(reflecting the presence of the
<br /> clearly depend on the geological characteristics ofthe particular,orebody that was exploited during calcite and possibly muttered lime)possess considerable ability to neutralize any acid produced
<br /> mining. The concentration of calcium on the other hand,primarily reflects the mass of lime that and buffer pH. The tailings-rich samples possess elevated sulfide sulfur,low sulfate sulfur and low
<br /> has been added to the water to achieve treatment. The type and proportion of calcium-bearing NP, indicating that the" materials have the potential to generate acidity. Mayflower pond
<br /> mineral species can provide some indication of the treatment efficiency(Zinck at al, 1997). mitigates the potential for acid generation from this facility since it Contains high pH water and
<br /> acts a an aquemts cover to minimize oxidation.
<br /> Table 5. Bulk chemistry of water treatment sludges from this study and from-basic'Canadian mine water
<br /> treatment systems. 6 ACKNOWLEDGMENTS
<br /> a sites pH Al(Y.) Ca0%) Fe I%) Mr,(%) Zn I%) This paper Could not have been completed without technical assistance and advice from D.
<br /> Brosnehan, R,Corbett,T.Van Wyngarden and R. Paulsen. This paper is published with the
<br /> This study 1 9.9 4.7 24.5 2.6 1.2 0.5 permission of Cyprus Amex Minerals Company,which is gratefully acknowledged. Critical
<br /> reviews by J.W.Danni,L.A.Darling,W.D.Doepken,C.G.Janes and FJ.Kane improved the
<br /> Average from ffbasicm 4 9.8 2.4 17.0 9.2 1,9A 2.2 paper.
<br /> Canadian systems'
<br /> 'data from(Zinck is al.1997).A�avenge of two analyses.
<br /> REFERENCES
<br /> When compared to the sludge samples from Canadian metal mines, the Mayflower sludge Brosnahan, D.R. 1997-SFM examination of 6-riser and delta samples. Unpublished internal
<br /> samples have unusual mineralogical characteristics. The Canadian samples generally feature Cyprus Chntar Metals Company report,7 p. •
<br /> gypsum,bassanite,calcite and an amorphous,metal-scavenging phase as she major Ca-bearing Corbett,R 1997.X-ray d)f raction analysis of Climax Mayflower wastewater treatment sludges.
<br /> species. Mayflower sludge contains only minor gypsum but has abundant ettringite,which is Unpublished Internal Cypn Climax Metals Company report,8 p.
<br /> perhaps best known in the concrete industry,where formationofsecorrdaryettriagile canadversely Day, R.L. 1992. The effect of secondary ettringite formation on the durability of concrete: a
<br /> affect the durability of concrete(Day 1992). Ettringite is reportedly stable in the pH range 11.5 literature analysis. Portland Cement Association Research and Development Bulletin No.
<br /> to 12.5,with limited dissolution oceurring er pH 10 and complete dissolution by pH 2(D.Hassem RD 108T, 115 p.
<br /> written Communication 1997). Sobek,A.A.,Schuller,W.A.,Freeman,J.R.&Smith,R.M. 1978.Field and laboratory methods
<br /> The occurrence of fluorite(CeF,)in Mayflower sludge is unexpected,although this mineral applicable to overburderss and minesoils. U.S Faviromnemal Protection Agency EPA-6002-
<br /> occurs in the Climax embody as;anhedral grains included by feldspar and within the groundmass 78-054,403 p.
<br /> of the host porphyry(While et of 1991). Fluorite generally accounts for less than one percent of White, W.H., Bookstrom, A.A., Kamilli, RJ., Canter, M.W., Smith, R.P., Rants, D,E. &
<br /> the orebody,although the Lower intrusive series locally hosts ten to fifteen percent,and Climax- Steininger, R.C. 1981.Character and origin of Climax-type molybdenum deposits. In B.J.
<br /> type magma are considered to be relatively F-rich. Fluorite was identified by XRD and Skinner(ed),Economic Geology Seventh--ftfth.4miwrsary Volume:270-316.
<br /> microprobe in sludge-rich samples,but was not detected in XRD scans of tailings-rich samples, Voynick.S.M.1996.Climax:the history ofColorofo i Climax Molybdeman Afire.Missoula,MT:
<br /> suggesting that fluorite precipitated from the water treatment effluent along with the other sludge Mountain Press Publishing Company.
<br /> constituents. Fluoride in the mine water was presumably scavenged by excess Calcium resulting Zinck, J.M. 1997. Acid mine drainage treatment sludges in the Canadian mineral industry:
<br /> from lime neutralization. physical, chemical, mineralogical and leaching characteristics. Proceedings of the Fourth
<br /> Calcite is relatively abundant in Mayflower sludge,but is only a minor component of the Jntemasional Conference on Acid Rock Drainage, Vancouver,B.C.: 1693-1708.
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