Showing papers on "Tailings published in 2015"
TL;DR: In this article, the acid mine drainage is the most prevalent and damaging environmental concern associated with mining activities, and the potential for the generation of saline, basic and neutral drainage containing elevated concentrations of dissolved metals, non-metals, and metalloids has recently been recognized as a potential environmental concern.
362 citations
TL;DR: In this article, the authors investigated the effect of acid acid neutralization on the mobility of sulfide-oxidation products within sulfide mine tailings and found that the extent of acid neutralisation is a principal control on the pore-water pH.
261 citations
TL;DR: In this article, the authors proposed an improved framework for mine tailings management that considers key sustainable development pillars: technological, economic, environmental, policy, and social aspects, which can guide the mining sector to choose its management strategy based on sustainable development concepts.
212 citations
TL;DR: The field continues to be challenged by the lack of a cost-effective, accurate analytical technique for NAs or an understanding of all the organic constituents in process-affected water that may be contributing to observed toxicity and thus requiring treatment.
156 citations
TL;DR: In this article, a case study of arsenic-bearing gold mine tailings from Nova Scotia is presented to demonstrate the application of mineralogical techniques to improve human health risk assessment and the long-term management of historical mine wastes.
144 citations
TL;DR: Interestingly, evenness of the microbial communities, but not its richness, increased with contamination level, and taxa with high metabolic plasticity like Ktedonobacteria and Chloroflexi were found with higher relative abundance in more contaminated samples.
128 citations
TL;DR: In this article, the authors measured variations in the Cd and Pb isotope ratios in polluted topsoils surrounding the Jinding Pb-Zn mine in China, so that the sources of the metals could be traced.
113 citations
TL;DR: The GEMTEC conceptual model/guide is developed to provide the new scientific approach and knowledge for remediation of mining wastes and acid mine drainage for sustainable rehabilitation of mining waste.
113 citations
TL;DR: In this article, a comparison between polyacrylamide (PAM) flocculants and two promising alternative polymers: inorganic-organic hybrid and temperature-sensitive polymers is presented.
Abstract: Efficient dewatering of oil sands tailings is imperative to reduce the environmental footprint of oil sands operators. Currently there is no mature technology capable of effectively treating oil sands tailings and completely eliminating the use of tailings ponds. Consolidated tailings and paste technology are the most extensively used dewatering methods. However, the high concentrations of divalent ions in the water recovered using the consolidated tailings process impedes the re-utilization of this water in the bitumen extraction process. Accumulation of ions does not occur in the case of paste technology; however, this technology, similarly to the consolidated tailings process, recovers only part of the water from tailings and produces high-water content sediments (25–30 wt. % solids) that sill requires special storage. This happens because the sediments produced by polyacrylamide (PAM) flocculants are not closely packed and require the application of other consolidation technologies (e.g., freeze-thaw, filtration, centrifugation) to obtain dry and self-supportive tailings. This review focuses on examining alternative flocculants that could potentially replace PAM polymers in mature and new dewatering technologies. Flocculants are a key element of many tailing treatments including paste technology and filtration. The “ideal” flocculant would increase the ability of these technologies to dewater tailings, resulting in higher water recovery and sediment consolidation without affecting water chemistry or increasing operational costs. This review presents a comparison between PAM flocculants and two promising alternative flocculants: inorganic-organic hybrid and temperature-sensitive polymers. Each flocculant type is evaluated in terms of its flocculation mechanisms and its dewatering efficacy.
108 citations
TL;DR: In this paper, the authors present current knowledge on factors and parameters influencing emission estimates, and challenges pertaining to the development of current emissions factors, and provide a more accurate and representative understanding of emissions from oil sands tailings ponds.
105 citations
TL;DR: In this article, the functional properties of biochar, and microbial cycling of nutrients in soil, especially phytoremediation of mine tailings, industrial waste, sewage sludge, and contaminated soil using biochar are discussed.
TL;DR: In this article, the feasibility of using two natural and renewable biopolymers, xanthan gum and guar gum, to stabilize mill tailings for dust control was investigated.
Abstract: Mine tailings, or mill tailings (MTs), are highly susceptible to wind erosion (dust) and have brought about different environmental and safety concerns. Many efforts have been attempted to stabilize MTs for dust control, but all have drawbacks. The current study investigates the feasibility of using two natural and renewable biopolymers, xanthan gum and guar gum, to stabilize MTs for dust control. Moisture retention and wind tunnel tests were performed to evaluate, respectively, the enhancement of water retention capacity and the improvement of resistance to wind dispersal after MTs were treated with biopolymer solutions of different concentrations. Because the resistance to the formation of dust is closely related to how easy the particles can be detached from the surface, a flat-ended cylindrical penetrometer was manufactured and used to evaluate the surface strength (maximum penetration force) of dry MT specimens treated with biopolymer solutions of different concentrations. Scanning electron ...
TL;DR: In this article, the authors investigated the effect of bacterial strains on bioleaching and fractionation of heavy metals in mine tailings from a Cu-Ag mine in the Philippines.
TL;DR: A review of the hydrometallurgical processes by which U is extracted from ore, the biogeochemical processes that can affect the fate and transport of U and associated elements in the environment, and possible remediation strategies for site closure and aquifer restoration can be found in this paper.
TL;DR: A brief history of the development of the geopolymerization technology was reviewed with particular emphasis on the differences between conventional geopolymers, alkali-activated metallurgical slags, and zeolites as discussed by the authors.
Abstract: A new class of construction materials has been in development in the past several decades through geopolymerization reactions of aluminosilicate minerals, which can potentially replace ordinary Portland cement (OPC). In this paper, the brief history of the development of the geopolymerization technology was reviewed with particular emphasis on the differences between “conventional” geopolymers, alkali-activated metallurgical slags, and zeolites. Studies on both the raw materials and the alkali activators in the geopolymerization processes were also reviewed. As oil sands tailings and many mine tailings contain aluminosilicate minerals as their main constituents, geopolymerization reactions have been explored as a potential technological route to treat these tailings for tailings consolidation and heavy metal fixation.
TL;DR: In this paper, the influence of the gradation of tailings on the qualities of coarse tailings used for cemented paste backfill (CPB) was assessed and the relationship among tailings fineness, packing density and unconfined compressive strength (UCS) was discussed.
TL;DR: It is shown here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings and can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD.
Abstract: Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53–57%) and cobalt (55–60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach ...
TL;DR: In this paper, the authors summarize the published research on flocculation performance within the context of complex fine tailings systems and describe the compositional complexity of mature fine-tailings to help the design of more representative model tailings system.
Abstract: It is hard to treat fine tailings resulting from oil sands extraction processes. No current fine tailings treatment technology can completely eliminate tailings ponds, despite considerable efforts to address the slow settling of fines and to facilitate the consolidation of sediments. Some treatments use coagulants and coarse solids to form composite or consolidated tailings; others use polymer flocculants. The performance of polymer flocculants is evaluated empirically, with fine tailings often being considered as a black box. Some fundamental studies use single clay systems, such as kaolinite suspended in water, as models to evaluate the performance of polymer flocculants. While it is easier to relate polymer performance to specific conditions in these simpler systems, it is difficult to translate these results to the treatment of the much more complex tailings environment. For the rational design of polymer flocculants, one must understand the interactions between polymers and the several components in tailings. With this information in hand, one can optimize the molecular structure of polymer flocculants to treat oil sands tailings efficiently. In this review, we summarize the published research on flocculation performance within the context of complex fine tailings systems. Furthermore, we describe the compositional complexity of mature fine tailings to help the design of more representative model tailings systems.
TL;DR: Data suggest the bioaccessibility and lability of metal(loid)s are altered by mineral weathering, which results in both the downward migration ofMetal(loids)s to the redox boundary, as well as the precipitation of metal salts at the surface.
TL;DR: In this article, the authors investigated the influence of dolomite tailings on hydration, properties of Portland cement and volume stability due to possible dedolomitization.
TL;DR: Several organic compounds typical of combustion emissions and bitumen are enriched relative to forest soils for fugitive dust sources near oil sands operations, consistent with deposition uptake by biomonitors.
Abstract: Geological samples were collected from 27 representative locations in the Athabasca Oil Sands Region (AOSR) in Alberta, Canada. These samples were resuspended onto filter substrates for PM2.5 and PM10 size fractions. Samples were analyzed for 229 chemical species, consisting of elements, ions, carbon, and organic compounds. These chemical species are normalized to gravimetric mass to derive individual source profiles. Individual profiles were grouped into six categories typical of those used in emission inventories: paved road dust, unpaved road dust close to and distant from oil sand operations, overburden soil, tailings sands, and forest soils. Consistent with their geological origin, the major components are minerals, organic and elemental carbon, and ions. The sum of five major elements (i.e., Al, Si, K, Ca, and Fe) and their oxidized forms account for 25–40% and 45–82% of particulate matter (PM) mass, respectively. Si is the most abundant element, averaging 17–18% in the Facility (oil sand operations...
TL;DR: It is demonstrated that operations releasing large amounts of suspended crushed rock such as exploration drilling and submarine tailings disposal near sponge beds should be carefully planned to avoid long-term losses of benthic ecosystem functions, such as organic matter re-mineralization.
TL;DR: In this article, the geochemical behavior and immobilization performances of two low sulfide tailings-based mortars, commonly used in the upper-Moulouya region (eastern Morocco) as surface finishing mortars were evaluated.
TL;DR: The long-term influence of a shallow water cover limiting sulfidemineral oxidation was examined in tailings deposited near the end of operation in 1951 of the former Sherritt-Gordon Zn-Cu mine (Sherridon, Manitoba, Canada) as discussed by the authors.
TL;DR: Radionuclides distribution in the uranium mill tailing showed a profound influence on soil properties and microbial diversity, which might provide valuable data for further research towards a better understanding of the radioactive contamination in uranium mill Tailings in southeastern China.
TL;DR: In this article, a catastrophic breach of the Mount Polley mine tailings impoundment released ~25 Mm3 of tailings and water and scoured an unknown quantity of overburden into the West Basin of Quesnel Lake.
Abstract: On 4 August 2014, a catastrophic breach of the Mount Polley mine tailings impoundment released ~25 M m3 of tailings and water and scoured an unknown quantity of overburden into the West Basin of Quesnel Lake. We document Quesnel Lake and Quesnel River observations for 2 months postspill. Breach inflows raised Quesnel Lake by 7.7 cm, equivalent to ~21 M m3. The West Basin hypolimnion was modified immediately, exhibiting increased temperature (~5°C to 6–7.5°C), conductivity (110 to 160 μS/cm), and turbidity (<1 to 200–1000 nephelometric turbidity units (NTU)). Cooscillating seiches moved West Basin hypolimnetic water both westward and eastward contaminating the Main Basin. Postspill, high-turbidity water propagated eastward (~1 cm/s), introducing a persistent ~20 m thick layer below the thermocline and an ~30 m thick layer at the bottom. The contaminant introduction, mobilization, and bioaccumulation may pose risks to resident and anadromous fish stocks, which support recreational, commercial, and First Nations fisheries.
TL;DR: In this article, a concrete mix of grade 40MPa was prepared in the laboratory with water-cement ratio of 0.5 and the concrete were cured for 1, 2, 3, 7, 14 and 28 days.
Abstract: Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did ...
TL;DR: The sequencing of 16S rRNA and internal transcribed spacer (ITS) fungal RNA gene amplicons from chlor-alkali residue and from an adjacent undisturbed soil to define the composition and assembly of the rhizosphere microbial communities indicates that environmental filtering is more likely to occur through the activity of tree roots rather than as a result of specific soil characteristics and could be an important force in the assembly of at least some microbial communities.
Abstract: Revegetation of the tailings dumps produced by various industrial activities is necessary to prevent dust storms and erosion and represents a great challenge for ecological restoration. Little is known about the microbial colonisation and community structure of revegetated tailings following site exploitation. Here, we report the sequencing of 16S rRNA and internal transcribed spacer (ITS) fungal RNA gene amplicons from chlor-alkali residue and from an adjacent undisturbed soil to define the composition and assembly of the rhizosphere microbial communities. After quality filtering, a total of 72,373 and 89,929 bacterial sequences and 122,618 and 111,209 fungal sequences remained for community analysis from undisturbed soil and tailings dump samples, respectively. These reads were affiliated with 45 bacterial and 9 fungal phyla and 113 bacterial and 35 fungal classes. We observed a clear dominance of Gammaproteobacteria at our study site (24% of total sequences), especially of the Pseudomonas genera (72% of Gammaproteobacteria sequences), together with the dominance of a few fungal taxa, such as Hebeloma and Geopora. However, we also noticed that the core microbiome comprised 64.4% and 62.4% of the bacterial and fungal genera, respectively, despite marked differences in soil physico-chemical properties. A heatmap of correlations between soil parameters and taxa confirmed that approximately 50% of the 33 dominant taxa colonised both types of soil. We further demonstrated that the global bacterial-fungal network topology of the dump approximated that of the undisturbed soil. Our approach illuminates the importance of studying more than just a single component of the microbial community and represents a step forward in uncovering the microbial ecology of disturbed environments beyond what is generally found in conventional studies. Our study also provides novel global community proxies that have led us to conclude that environmental filtering is more likely to occur through the activity of tree roots rather than as a result of specific soil characteristics and could be an important force in the assembly of at least some microbial communities.
TL;DR: In this paper, a long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland, and the results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development.
Abstract: Engineering microbial diversity to enhance soil functions may improve the success of direct revegetation in sulphidic mine tailings. Therefore, it is essential to explore how remediation and initial plant establishment can alter microbial communities, and, which edaphic factors control these changes under field conditions. A long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland. The control and amended and/or revegetated treatments were sampled from the 3-year-old trial. In total, 24 samples were examined using pyrosequencing of 16S rRNA genes and various chemical properties. The results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development in the tailings. All treatments were dominated by typical extremophiles and lithotrophs, typically Truepera, Thiobacillus, Rubrobacter; significant increases in microbial diversity, biomass and frequency of organotrophic genera (typically Nocardioides and Altererythrobacter) were detected in the revegetated and amended treatment. We concluded that appropriate phytostabilization options have the potential to drive the microbial diversity and community structure in the tailings toward those of natural soils, however, inherent environmental stressors may limit such changes.
TL;DR: The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during theBioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailing by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency.