Prediction of Acid Mine Drainage from Duluth Complex Mining Wastes in Northeastern Minnesota

Lapakko, Kim A.

doi:10.21000/jasmr88010180

Cited by 18 publications

(14 citation statements)

References 10 publications

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“…Our (Fig. 2), consistent with numerous Duluth Complex weathering experiments that have shown similar correlations with sulfide mineral content of the rock (34,43,44). From the available data, we were not able to discern whether the observed trends in microbial community structure and diversity were related to pH itself, to sulfide mineral content, or to a combination of these and other factors.…”

Section: Discussionsupporting

confidence: 83%

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA

Jones

Lapakko

Wenz

et al. 2017

Appl Environ Microbiol

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The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfidebearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula, as well as from diverse clades of uncultivated Chloroflexi, Acidobacteria, and Betaproteobacteria. Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste.IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest undeveloped source of copper and nickel on Earth. Microorganisms are important catalysts for sulfide mineral oxidation, and research on extreme acidophiles has improved our ability to manage and remediate mine wastes. We found that the microbial assemblages associated with weathered rock from the Duluth Complex are dominated by organisms not widely associated with mine waste or mining-impacted environments, and we describe geochemical and experimental influences on community composition. This report will be a useful foundation for understanding the microbial biogeochemistry of moderately acidic mine waste from these and similar deposits.

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Section: Discussionsupporting

confidence: 83%

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA

Jones

Lapakko

Wenz

et al. 2017

Appl Environ Microbiol

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“…Of particular importance is the oxidation of sulphide minerals and consequent generation of sulphuric acid, a process broadly termed ‘acid mine drainage’. Lapakko (1991) provides a comprehensive literature review on this subject including classic studies.…”

Section: Introductionmentioning

confidence: 99%

Seasonal stratification and mixing in a recently flooded mining void in tropical Australia

Boland¹,

Padovan²

2002

Lakes & Reservoirs

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Enterprise Pit Lake is a water‐filled mining void located in Australia’s wet/dry tropics south of Darwin in the Northern Territory (13°49.6′S, 131°49.8′E). In the mid‐1990s, the void was rapidly filled by the artificial diversion of the nearby Pine Creek watercourse. Profile data and surface water quality data were collected in the lake on a monthly basis from November 1998 to October 1999. Analysis of this data showed that Enterprise Pit Lake was strongly stratified for most of the year with deep mixing occurring once during the middle of the cool, dry season (August, 1999). The relatively small volume of its epilimnion and its low productivity allowed significant oxygen concentrations to remain in the hypolimnion of the lake when it was strongly stratified. Low pH values in a layer of water with a depth of approximately 35 m and located in the lake’s hypolimnion might be associated with several factors, including enhanced sulphide oxidation on the walls of the pit in this region.

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“…Whereas dissolution of these minerals can neutralize the acid produced by low-sulfur mine wastes (Lapakko 1988, Lapakko and Antonson 1993, Morin 1993, laboratory experiments and field data indicate that their dissolution may not be capable of maintaining a drainage pH above 6.0 for mine wastes of moderate sulfur content Antonson 1991, Lapakko 1994). It should be noted, however, that dissolution of these minerals, and the attendant acid neutralization, will generally increase as particle size decreases.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Neutralization Potential Determinations for Metal Mine Waste and a Proposed Alternative

Lapakko¹

1994

ASMR

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Standard acid-base accounting (standard ABA), modified ABA, and B.C. Research initial static tests tended to overestimate the neutralization potential (NP) present as calcium carbonate and magnesium carbonate, with the extent of overestimation depending on the minerals present in the 10 metal-mine wastes examined. For 6 of the 10 samples the static test NP values were within about 10 kg/mt CaC0 3 of the calculated mineralogic NP. These samples were composed largely of qua1tz and sheet silicates (mica, chlorite, kaolinite, montrnorillonite). The excess acid neutralization measured for these samples was apparently due to the presence of some (less than 10 % ) calcium feldspar in the samples. For the standard ABA and modified ABA methods, the NP overestimation was higher (13 to 47 kg/mt CaC0 3 ) for samples containing larger amounts of calcium feldspar, pyroxene, olivine, or iron carbonate minerals. The extent of overestimation for the B.C. Research initial NP was typically slightly higher than the standard ABA and modified ABA and was greatest for samples containing iron carbonate. The maximum overestimations by the standard ABA, modified ABA, and B.C. Research initial test NP values were 33, 31, and 49 kg/mt CaC0 3 , respectively. A newly proposed method of NP determination, NP available above pH 6, was more accurate than these three methods. Six of the 10 NP values determined by this method were approximately equal to the mineralogic NP values. For the remaining 4 samples, this NP was within 3 kg/mt CaC0 3 of the mineralogic NP. Additional

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Prediction of Acid Mine Drainage from Duluth Complex Mining Wastes in Northeastern Minnesota

Cited by 18 publications

References 10 publications

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA

Seasonal stratification and mixing in a recently flooded mining void in tropical Australia

Evaluation of Neutralization Potential Determinations for Metal Mine Waste and a Proposed Alternative

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