Preoperational assessment of solute release from waste rock at proposed mining operations

Lapakko, Kim A.

doi:10.1016/j.apgeochem.2015.01.010

Cited by 21 publications

(18 citation statements)

References 37 publications

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“…Some of these suggestions parallel those of Parbhakar-Fox and Lottermoser (2015) and of Parbhakar-Fox et al (2013), who emphasized the need for better mineralogical determinations before running kinetic tests. We endorse Lapakko's (2015) recommendations to use transparent models for environmental predictions, to compile a database of waste rock drainage concentrations, and to create a repository for environmental information collected by agencies and others throughout the life of a mine. We go further to suggest evaluating concentration-controlling phases, compiling and making publicly available information on environmental characterization, remediation successes and failures, and producing five-year reviews of the effectiveness of remedial technologies.…”

Section: Suggestions For Improvementmentioning

confidence: 99%

“…The factors that affect leachate concentrations and dissolution rates in laboratory tests compared to field conditions include the (1) test length, (2) time interval chosen from HCT results for use in predictions, (3) quantity and distribution of rock or waste samples and the degree to which they are representative of field compositions, (4) method of solid sample preparation, (5) particle size and available surface area, (6) length of storage of solid samples before testing starts, (7) time necessary for microbial oxidizers to grow, (8) geochemical reactions that may add or remove constituents, such as the formation of soluble salts and the precipitation of insoluble hydrous ferric oxides, (9) temperature, (10) humidity, (11) method of leachate application in the laboratory test, (12) method by which predictions are calculated from HCT results, (13) liquid:solid ratio in the test vs. the field, (14) preferential flow through mine wastes, (15) field climatic conditions compared to humidity cells, and (16) availability of oxygen in the field piles. Many of these issues were discussed in the review by Lapakko (2015). This paper recognizes that all the factors are important, and most of them will be mentioned, but the primary emphasis is on factors 2, 8, and 11.…”

Section: Introductionmentioning

confidence: 99%

“…This paper, in contrast to those cited above, applies geochemical modeling to the entire set of HCT data to determine how this approach might improve mine water quality prediction. To the best of our knowledge, this approach has not been taken before in publicly available literature except in two conference proceedings (Lapakko andBerndt, 2003, andSeal et al, 2015). Important questions to be addressed are whether pyrite (or other sulfide) oxidation rates can be distinguished from rates of other processes, such as secondary mineral dissolution and precipitation, and how HCT data could be used for prediction once the geochemical processes are better identified.…”

Section: Introductionmentioning

confidence: 99%

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A geochemical examination of humidity cell tests

Maest¹,

Nordstrom

2017

Applied Geochemistry

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Humidity cell tests (HCTs) are long-term (20 to >300 weeks) leach tests that are considered by some to be the among the most reliable geochemical characterization methods for estimating the leachate quality of mined materials. A number of modifications have been added to the original HCT method, but the interpretation of test results varies widely. We suggest that the HCTs represent an underutilized source of geochemical data, with a year-long test generating approximately 2,500 individual chemical data points. The HCT concentration peaks and valleys can be thought of as a "chromatogram" of reactions that may occur in the field, whereby peaks in concentrations are associated with different geochemical processes, including sulfate salt dissolution, sulfide oxidation, and dissolution of rock-forming minerals, some of which can neutralize acid. Some of these reactions occur simultaneously, some do not, and geochemical modeling can be used to help distinguish the dominant processes. Our detailed examination, including speciation and inverse modeling, of HCTs from three projects with different geology and mineralization shows that rapid sulfide oxidation dominates over a limited period of time that starts between 40 and 200 weeks of testing. The applicability of laboratory tests results to predicting field leachate concentrations, loads, or rates of reaction has not been adequately demonstrated, although early flush releases and rapid sulfide oxidation rates in HCTs should have some relevance to field conditions. Knowledge of possible maximum solute

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Section: Suggestions For Improvementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A geochemical examination of humidity cell tests

Maest¹,

Nordstrom

2017

Applied Geochemistry

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“…Implications for kinetic testing of mine waste. Field and laboratory rock weathering experiments are widely used to assess acid generation and metal release from mine waste (http://www.gardguide.com [33,50]), but few humidity cell studies have included microbial analysis (e.g., see references 9, 41, and 51). Microbial community analysis could be useful because microorganisms are a sensitive indicator of geochemical conditions.…”

Section: Discussionmentioning

confidence: 99%

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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“…Solid-phase characterization and kinetic tests were used to predict solute release from mine wastes projected to be generated by proposed mining and associated operations (Lapakko, 2015). The quantities of various metals and characteristics that influence their dissolution were investigated using mineralogical, petrographic, and geochemical analyses.…”

Section: Careful Characterization Of White Aluminummentioning

confidence: 99%

Mine Drainage Generation and Control Options

Wei

Rodak

Zhang

et al. 2016

Water Environment Research

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This review provides a snapshot of papers published in 2015 relevant to the topic of mine drainage generation and control options. The review is broken into 3 sections: Generation, Prediction and Prevention, and Treatment Options. The first section, mine drainage generation, focuses on the characterization of mine drainage and the environmental impacts. As such, it is broken into three subsections focused on microbiological characterization, physiochemical characterization, and environmental impacts. The second section of the review is divided into two subsections focused on either the prediction or prevention of acid mine drainage. The final section focuses on treatment options for mine drainage and waste sludge. The third section contains subsections on passive treatment, biological treatment, physiochemical treatment, and a new subsection on beneficial uses for mine drainage and treatment wastes.

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Preoperational assessment of solute release from waste rock at proposed mining operations

Cited by 21 publications

References 37 publications

A geochemical examination of humidity cell tests

A geochemical examination of humidity cell tests

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

Mine Drainage Generation and Control Options

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