Editorial

4 pages, 4780 KiB

Open AccessEditorial

Editorial for Special Issue “Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization, and Repository”

by Yassine Taha and Mostafa Benzaazoua

Minerals 2020, 10(1), 21; https://doi.org/10.3390/min10010021 - 25 Dec 2019

Cited by 7 | Viewed by 2867

Abstract

The mining industry continues to face many challenges due to its potential environmental impacts [...] Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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Research

Jump to: Editorial, Review, Other

15 pages, 3995 KiB

Open AccessArticle

Desulfurization of the Old Tailings at the Au-Ag-Cu Tiouit Mine (Anti-Atlas Morocco)

by Abdelkrim Nadeif, Yassine Taha, Hassan Bouzahzah, Rachid Hakkou and Mostafa Benzaazoua

Minerals 2019, 9(7), 401; https://doi.org/10.3390/min9070401 - 30 Jun 2019

Cited by 28 | Viewed by 4484

Abstract

Tailings from the abandoned Tiouit mine site in Morocco are mainly composed of sulfides, hematite, and quartz. They contain 0.06–1.50 wt % sulfur, mostly in the form of pyrite, pyrrhotite, and chalcopyrite. The tailings also contain gold (3.36–5.00 ppm), silver (24–37 ppm), and [...] Read more.

Tailings from the abandoned Tiouit mine site in Morocco are mainly composed of sulfides, hematite, and quartz. They contain 0.06–1.50 wt % sulfur, mostly in the form of pyrite, pyrrhotite, and chalcopyrite. The tailings also contain gold (3.36–5.00 ppm), silver (24–37 ppm), and copper (0.06–0.08 wt %). Flotation tests were conducted to reprocess the tailings for Au, Ag, and Cu recovery, and at the same time to prevent acid mine drainage (AMD) generation through the oxidation of sulfide minerals, including pyrite, sphalerite, arsenopyrite, chalcopyrite, galena. The flotation results confirmed that environmental desulfurization is effective at reducing the overall sulfide content in the tailings. The recovery of sulfides was between 69% and 75%, while Au recovery weight-yield was between 2.8% and 4.7%. The test that showed the best sulfur recovery rate and weight-yield was carried out with 100 g/t CuSO₄ (sulfide activator) and 50 g/t of amyl xanthate (collector). The goal of this study was also to assess the remaining acid-generating potential (AP) and acid-neutralizing potential (NP) of the desulfurized tailing. The geochemical behavior of the initial tailings sample was compared to that of the desulfurized tailings using kinetic weathering cell tests. The leachates from the desulfurized tailings showed higher pH values than those from the initial tailings, which were clearly acid-generating. The residual acidity produced by the desulfurized tailings was most likely caused by the hydrolysis of Fe-oxyhydroxides. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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31 pages, 3037 KiB

Open AccessArticle

Environmental Impact of Mine Exploitation: An Early Predictive Methodology Based on Ore Mineralogy and Contaminant Speciation

by Aurélie Chopard, Philippe Marion, Raphaël Mermillod-Blondin, Benoît Plante and Mostafa Benzaazoua

Minerals 2019, 9(7), 397; https://doi.org/10.3390/min9070397 - 28 Jun 2019

Cited by 17 | Viewed by 6280

Abstract

Mining wastes containing sulfide minerals can generate contaminated waters as acid mine drainage (AMD) and contaminated neutral drainage (CND). This occurs when such minerals are exposed to oxygen and water. Nowadays, mineralogical work—when it is done—is independently and differentially done according to the [...] Read more.

Mining wastes containing sulfide minerals can generate contaminated waters as acid mine drainage (AMD) and contaminated neutral drainage (CND). This occurs when such minerals are exposed to oxygen and water. Nowadays, mineralogical work—when it is done—is independently and differentially done according to the needs of the exploration, geotechnics, metallurgy or environment department, at different stages in the mine development process. Moreover, environmental impact assessments (EIA) are realized late in the process and rarely contain pertinent mineralogical characterization on ores and wastes, depending on countries’ regulations. Contaminant-bearing minerals are often not detected at an early stage of the mine life cycle and environmental problems could occur during production or once the mine has come to the end of its productive life. This work puts forward a more reliable methodology, based on mineralogical characterization of the ore at the exploration stages, which, in turn, will be useful for each stage of the mining project and limit the unforeseen environmental or metallurgical issues. Three polymetallic sulfide ores and seven gold deposits from various origins around the world were studied. Crushed ore samples representing feed ore of advanced projects and of production mines were used to validate the methodology with realistic cases. The mineralogical methodology consisted in chemical assays and XRD, optical microscopy, SEM and EPMA were done. Five of the ores were also submitted to geochemical tests to compare mineralogical prediction results with their experimental leaching behavior. Major, minor, and trace minerals were identified, quantified, and the bearing minerals were examined for the polluting elements (and valuables). The main conclusion is that detailed mineralogical work can avert redundant work, save time and money, and allow detection of the problems at the beginning of the mine development phase, improving waste management and closure planning. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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20 pages, 3259 KiB

Open AccessArticle

In Situ Effectiveness of Alkaline and Cementitious Amendments to Stabilize Oxidized Acid-Generating Tailings

by Abdellatif Elghali, Mostafa Benzaazoua, Bruno Bussière and Thomas Genty

Minerals 2019, 9(5), 314; https://doi.org/10.3390/min9050314 - 22 May 2019

Cited by 32 | Viewed by 3662

Abstract

This study investigates the effectiveness of alkaline and cementitious additives in the in situ stabilization of localized acid-generating tailings from a closed gold mine in Abitibi–Témiscamingue, Québec (Eagle/Telbel mine site). Five field cells (including one control) were constructed and equipped with mechanisms for [...] Read more.

This study investigates the effectiveness of alkaline and cementitious additives in the in situ stabilization of localized acid-generating tailings from a closed gold mine in Abitibi–Témiscamingue, Québec (Eagle/Telbel mine site). Five field cells (including one control) were constructed and equipped with mechanisms for collecting vertical water infiltration and surface runoff. The five cells included: (C1) Control cell; (C2) 5 wt % limestone amendment; (C3) 10 wt % limestone amendment; (C4) 5 wt % half ordinary Portland cement and half fly ash amendment; and (C5) 5 wt % ordinary Portland cement amendment. The control cell showed an acidic behavior (pH < 4.5) with variable concentrations of Fe, Al, Zn, and Cu. The amendments were used to neutralize the acidic leachates and decrease dissolved metal concentrations. Leachates from surface runoff samples of amended cells were less loaded with metals compared to samples of vertical infiltration. All amendment formulations increased the pH of the leachates from approximately 4 to circumneutral values. Furthermore, metal and metalloid concentrations were greatly limited, except for Cr and As for the carbonate-based amendments. Metal(-oid) stabilization was successfully achieved using the different amendment formulations, with the exception of C2, which still released As. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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25 pages, 13387 KiB

Open AccessArticle

Characterization and Economic Potential of Historic Tailings from Gravity Separation: Implications from a Mine Waste Dump (Pb-Ag) in the Harz Mountains Mining District, Germany

by Kerstin Kuhn and Jeannet A. Meima

Minerals 2019, 9(5), 303; https://doi.org/10.3390/min9050303 - 16 May 2019

Cited by 26 | Viewed by 4608

Abstract

In contrast to modern tailings from froth flotation, little is known about historic tailings from gravity separation. However, they may be of economic interest due to their higher metal grades compared to modern tailings. As an example for these types of historic tailings, [...] Read more.

In contrast to modern tailings from froth flotation, little is known about historic tailings from gravity separation. However, they may be of economic interest due to their higher metal grades compared to modern tailings. As an example for these types of historic tailings, the inner structure, as well as the economic potential (Pb, Zn, Cu, Ag, Sb), of the old Bergwerkswohlfahrt mine waste dump in Germany were studied. The investigations focused on textural, geochemical, and mineralogical properties. For this purpose, an extensive drilling program was undertaken. The drill cores were subsequently analyzed with a laser-induced breakdown spectroscopy (LIBS) core scanner to obtain the detailed spatial distribution of potentially valuable elements. The fine-sized residues could be differentiated into different layers, all of them including valuable metals in varying proportions. The strong variations in stratification and in metal distribution over short distances are caused by the batch-wise deposition of the tailings. This heterogeneity within short distances has to be taken into account for future exploration of these types of deposits. The application of a core scanner using LIBS is very convenient for detailed spatial analysis of drill cores, however, the calibration effort, particularly for heterogeneous sample material, is proportionally large. The valuable metal content for Bergwerkswohlfahrt was estimated to be 8000 metric tons of Pb and 610,000 ounces of Ag. Although of limited economic value, recycling might finance future remediation costs. Furthermore, the occurrence of historic tailings in nearby clusters may present further recycling opportunities. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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15 pages, 3514 KiB

Open AccessArticle

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

by Bingxin Zhou, Shaotao Cao, Fangfang Chen, Fangfang Zhang and Yi Zhang

Minerals 2019, 9(5), 269; https://doi.org/10.3390/min9050269 - 30 Apr 2019

Cited by 6 | Viewed by 3847

Abstract

Recovering alkali from Bayer red mud is crucial for storage security, resource utilization and environmental protection. In this study, the addition of MgO and/or CaO was conducted to recover alkali from red mud with a hydrothermal method for the first time. A synergistic [...] Read more.

Recovering alkali from Bayer red mud is crucial for storage security, resource utilization and environmental protection. In this study, the addition of MgO and/or CaO was conducted to recover alkali from red mud with a hydrothermal method for the first time. A synergistic result with a residual Na₂O/SiO₂ weight ratio of 0.03 was obtained by adding the blend of CaO and MgO at an appropriate temperature. MgO was found to be more temperature-dependent than CaO when substituting Na₂O from red mud due to their different hydration processes. The alkali recovery was controlled by a reaction at a temperature of <200 °C and by internal diffusion at a higher temperature for MgO, but controlled by internal diffusion for CaO in the whole temperature range studied. The formation of hydrotalcite-like compounds with a loose structure was verified with the help of XRD, FTIR, and SEM-EDS. It was proved that both the reaction kinetics and the characteristics of solid products have a significant influence on the recovery of alkali. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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14 pages, 3185 KiB

Open AccessArticle

Effect of High Mixing Intensity on Rheological Properties of Cemented Paste Backfill

by Liuhua Yang, Hongjiang Wang, Hong Li and Xu Zhou

Minerals 2019, 9(4), 240; https://doi.org/10.3390/min9040240 - 18 Apr 2019

Cited by 26 | Viewed by 4420

Abstract

Cemented paste backfill (CPB) consists of a mixture of fine particles, mainly consisting of tailings and cement dispersed in water. Therefore, it is necessary to introduce an intensive shearing force into the paste during mixing in order to maintain an equilibrium between agglomeration [...] Read more.

Cemented paste backfill (CPB) consists of a mixture of fine particles, mainly consisting of tailings and cement dispersed in water. Therefore, it is necessary to introduce an intensive shearing force into the paste during mixing in order to maintain an equilibrium between agglomeration and dispersion. It is influential for the macroscopical fluidity and rheological properties when changes occur in the microstructure of CPB under shear. However, the research on how mixing affects the properties of CPB is still in its infancy. This paper puts an insight into the relation between the mixing intensity and the rheological behavior of the CPB. It can be demonstrated that two threshold mixing intensities exist in this process. After passing the first or lower threshold, the rheological parameters (yield stress and viscosity) of the paste decrease. After passing the second threshold, a continued increase is observed. The changes in rheological properties are connected with physical and chemical changes in the microstructure of the CPB. The results are discussed in light of the three concepts “structural breakdown”, “thixotropic breakdown”, and “thixotropic behavior” of rheological properties of CPB. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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23 pages, 4084 KiB

Open AccessArticle

Spatial Mapping of Acidity and Geochemical Properties of Oxidized Tailings within the Former Eagle/Telbel Mine Site

by Abdellatif Elghali, Mostafa Benzaazoua, Bruno Bussière and Thomas Genty

Minerals 2019, 9(3), 180; https://doi.org/10.3390/min9030180 - 14 Mar 2019

Cited by 17 | Viewed by 4195

Abstract

At some orphaned and abandoned mine sites, acid mine drainage can represent a complex challenge due to the advanced tailings’ oxidation state as well as the combination of other factors. At the field scale, several parameters control sulfides’ oxidation rates and, therefore, the [...] Read more.

At some orphaned and abandoned mine sites, acid mine drainage can represent a complex challenge due to the advanced tailings’ oxidation state as well as the combination of other factors. At the field scale, several parameters control sulfides’ oxidation rates and, therefore, the acidity generation. The objective of this paper is to map the acidity and geochemical properties of oxidized tailings within a closed tailings storage facility. Based on systematic sampling, various geochemical parameters were measured within the oxidized Joutel tailings, including the: Neutralization potential, acid-generating potential, net neutralization potential, neutralization potential ratio, paste pH, thickness of oxidized, hardpan, and transition zones. The different parameters were integrated in geographical information system (GISs) databases to quantify the spatial variability of the acidity and geochemical properties of oxidized tailings. The oxidized tailings were characterized by low sulfide (mainly as pyrite) and carbonate (mainly as siderite/ankerite) contents compared to unweathered tailings. Acidic zones, identified based on paste pH, were located in the eastern portion of the southern zone and at the northern tip of the northern zone. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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16 pages, 5254 KiB

Open AccessArticle

Towards Greener Lixiviants in Value Recovery from Mine Wastes: Efficacy of Organic Acids for the Dissolution of Copper and Arsenic from Legacy Mine Tailings

by Richard A. Crane and Devin J. Sapsford

Minerals 2018, 8(9), 383; https://doi.org/10.3390/min8090383 - 03 Sep 2018

Cited by 16 | Viewed by 5000

Abstract

In many cases, it may be possible to recover value (e.g., metals, land) from legacy mine wastes and tailings when applying leaching-based remediation such as dump/heap leaching or in-vessel soil washing. However, if the lixiviant used has the potential to cause environmental damage [...] Read more.

In many cases, it may be possible to recover value (e.g., metals, land) from legacy mine wastes and tailings when applying leaching-based remediation such as dump/heap leaching or in-vessel soil washing. However, if the lixiviant used has the potential to cause environmental damage upon leakage, then this approach will have limited practicability due to actual or perceived risk. This study focused on comparing the efficacy of organic acids, namely methanesulfonic (CH₃SO₃H) and citric (C₆H₈O₇) acid, with mineral acids, namely sulfuric (H₂SO₄) and hydrochloric (HCl) acid, for the dissolution of Cu and As from mine tailings. The advantage of the former acid type is the fact that its conjungate base is readily biodegradable which should thereby limit the environmental impact of accidental spill/leakage (particularly in non-carbonate terrain) and might also be directly useful in capture/recovery systems coupled with percolation leaching (e.g., as an electron donor in sulphate-reducing bioreactors). The operational factors acid concentration, leaching time, mixing intensity and solid–liquid ratio, were tested in order to determine the optimum conditions for metal dissolution. HCl, H₂SO₄, and CH₃SO₃H typically exhibited a relatively similar leaching ability for As despite their different pKa values, with dissolutions of 58%, 56%, 55%, and 44% recorded for H₂SO₄, HCl, CH₃SO₃H, and C₆H₈O₇, respectively, after 48 h when using 1 M concentrations and a 10:1 L:S ratio. For the same conditions, H₂SO₄ was generally the most effective acid type for Cu removal with 38% compared to 32%, 29% and 22% for HCl, CH₃SO₃H and C₆H₈O₇. As such, CH₃SO₃H and C₆H₈O₇ demonstrated similar performances to strong mineral acids and, as such, hold great promise as environmentally compatible alternatives to conventional mineral acids for metal recovery from ores and waste. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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17 pages, 7573 KiB

Open AccessArticle

Recovery of Residual Silver-Bearing Minerals from Low-Grade Tailings by Froth Flotation: The Case of Zgounder Mine, Morocco

by Boujemaa Drif, Yassine Taha, Rachid Hakkou and Mostafa Benzaazoua

Minerals 2018, 8(7), 273; https://doi.org/10.3390/min8070273 - 27 Jun 2018

Cited by 12 | Viewed by 6020

Abstract

The need to explore more complex and low-grade silver ores and to develop novel and cost-effective processes to recover silver from waste is becoming an important challenge. This paper aims to characterize old, low-grade, silver tailings generated by the former Zgounder silver mine, [...] Read more.

The need to explore more complex and low-grade silver ores and to develop novel and cost-effective processes to recover silver from waste is becoming an important challenge. This paper aims to characterize old, low-grade, silver tailings generated by the former Zgounder silver mine, located in Morocco. Understanding the mineralogical composition, particularly the silver deportment, was critical to allow the recovery of silver from these tailings. More than 88 samples of low grade tailings were sampled and characterized using chemical and mineralogical techniques. Froth flotation was used to recover silver bearing minerals using a combination of different collectors (dithiophosphate, dialkyl dithiophosphinates, Aero 7518, Aero 7640, alkyl dithiophosphates and potassium butyl-xanthate). The main goal was to optimize the flotation process at a laboratory scale through the testing of different parameters, such as collectors and frother types and dosage, activators and sulphidizing agents, and pH conditions. The characterization results showed that silver content varied between 30 and 440 ppm with an overall average content of 148 ppm. Silver occurs mainly in the form of native silver as well as in association with sulphides, such as acanthite and pyrite. Minor amounts of sphalerite, chalcopyrite, arsenopyrite, and hematite were identified. The flotation results showed the following optimum conditions: particle size of 63 µm, conditioning pH of 8.5, a combination of butyl-xanthate and dithiophosphate as collectors at a dosage of 80 g/t each, a concentration of 200 g/t of the activating agent (CuSO₄), 30 g/t of methyl isobutyl carbonyl (MIBC) frother and a duration time of 8 min with slow kinetics. With these optimal conditions, it was possible to achieve a maximum silver recovery yield of 84% with 1745 ppm Ag grade to be cyanided. Moreover, the environmental behavior of the final clean tailings was demonstrated to be inert using Toxicity characteristic leaching procedure (TCLP) leaching tests. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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18 pages, 2272 KiB

Open AccessArticle

Mobility and Attenuation Dynamics of Potentially Toxic Chemical Species at an Abandoned Copper Mine Tailings Dump

by Wilson Mugera Gitari, Rendani Thobakgale and Segun Ajayi Akinyemi

Minerals 2018, 8(2), 64; https://doi.org/10.3390/min8020064 - 12 Feb 2018

Cited by 9 | Viewed by 3887

Abstract

Large volumes of disposed mine tailings abound in several regions of South Africa, as a consequence of unregulated, unsustainable long years of mining activities. Tailings dumps occupy a large volume of valuable land, and present a potential risk for aquatic systems, through leaching [...] Read more.

Large volumes of disposed mine tailings abound in several regions of South Africa, as a consequence of unregulated, unsustainable long years of mining activities. Tailings dumps occupy a large volume of valuable land, and present a potential risk for aquatic systems, through leaching of potentially toxic chemical species. This paper reports on the evaluation of the geochemical processes controlling the mobility of potentially toxic chemical species within the tailings profile, and their potential risk with regard to surface and groundwater systems. Combination of X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) techniques, show that the tailing profiles are uniform, weakly altered, and vary slightly with depth in both physical and geochemical properties, as well as mineralogical composition. Mineralogical analysis showed the following order of abundance: quartz > epidote > chlorite > muscovite > calcite > hematite within the tailings profiles. The neutralization of the dominant alumino-silicate minerals and the absence of sulfidic minerals, have produced medium alkaline pH conditions (7.97–8.37) at all depths and low concentrations of dissolved Cu (20.21–47.9 µg/L), Zn (0.88–1.80 µg/L), Pb (0.27–0.34 µg/L), and SO₄²⁻ (15.71–55.94 mg/L) in the tailings profile leachates. The relative percentage leach for the potentially toxic chemical species was low in the aqueous phase (Ni 0.081%, Cu 0.006%, and Zn 0.05%). This indicates that the transport load of potentially toxic chemical species from tailings to the aqueous phase is very low. The precipitation of secondary hematite has an important known ability to trap and attenuate the mobility of potentially toxic chemical species (Cu, Zn, and Pb) by adsorption on the surface area. Geochemical modelling MINTEQA2 showed that the tailings leachates were below saturation regarding oxyhydroxide minerals, but oversaturated with Cu bearing mineral (i.e., cuprite). Most of the potentially toxic chemical species occur as free ions in the tailings leachates. The precipitation of secondary hematite and cuprite, and geochemical condition such as pH of the tailings were the main solubility and mobility controls for the potentially toxic chemical species, and their potential transfer from tailings to the aqueous phase. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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Review

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13 pages, 409 KiB

Open AccessFeature PaperReview

Re-Thinking Mining Waste through an Integrative Approach Led by Circular Economy Aspirations

by Maedeh Tayebi-Khorami, Mansour Edraki, Glen Corder and Artem Golev

Minerals 2019, 9(5), 286; https://doi.org/10.3390/min9050286 - 10 May 2019

Cited by 172 | Viewed by 29083

Abstract

Mining wastes, particularly in the form of waste rocks and tailings, can have major social and environmental impacts. There is a need for comprehensive long-term strategies for transforming the mining industry to move toward zero environmental footprint. “How can the mining industry create [...] Read more.

Mining wastes, particularly in the form of waste rocks and tailings, can have major social and environmental impacts. There is a need for comprehensive long-term strategies for transforming the mining industry to move toward zero environmental footprint. “How can the mining industry create new economic value, minimise its social and environmental impacts and diminish liability from mining waste?” This would require cross-disciplinary skills, across the social, environmental, technical, legal, regulatory, and economic domains, to produce innovative solutions. The aim of this paper is to review the current knowledge across these domains and integrate them in a new approach for exploiting or “re-thinking” mining wastes. This approach includes five key areas of social dimensions, geoenvironmental aspects, geometallurgy specifications, economic drivers and legal implications for improved environmental outcomes, and circular economy aspirations, which are aligned with the 10 principles of the International Council on Mining and Metals (ICMM). Applying circular economy thinking to mining waste presents a major opportunity to reduce the liability and increase the value of waste materials arising from mining and processing operations. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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27 pages, 2208 KiB

Open AccessReview

Mining Waste and Its Sustainable Management: Advances in Worldwide Research

by José A. Aznar-Sánchez, José J. García-Gómez, Juan F. Velasco-Muñoz and Anselmo Carretero-Gómez

Minerals 2018, 8(7), 284; https://doi.org/10.3390/min8070284 - 02 Jul 2018

Cited by 89 | Viewed by 10686

Abstract

Growing social awareness of the need to adequately treat mining waste in order to protect the environment has led to an increase in the research in this field. The aim of this study was to analyze the dynamics of the research focused on [...] Read more.

Growing social awareness of the need to adequately treat mining waste in order to protect the environment has led to an increase in the research in this field. The aim of this study was to analyze the dynamics of the research focused on mining waste and its sustainable management on a worldwide scale from 1988 to 2017. A systematic review and a bibliometric analysis of 3577 articles were completed. The results show that research into mining waste has increased, with studies focusing on waste management accounting for almost 40% of the total. The most productive journals in this field were Applied Geochemistry and Science of the Total Environment. The five most productive countries were the United States, Canada, Spain, Australia, and China. Works on the sustainable management of mining waste were in the minority, but it is an area of research that has considerable potential given the growing social awareness of the environmental repercussions of mining activities and the demands for increasingly sustainable practices. The findings of this study could prove useful for studies into mine waste, as they depict a global view of this line of research. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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Other

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17 pages, 1324 KiB

Open AccessCase Report

Environmental and Business Challenges Presented by Mining and Mineral Processing Waste in the Russian Federation

by Marina A. Nevskaya, Sergey G. Seleznev, Vladimir A. Masloboev, Elena M. Klyuchnikova and Dmitriy V. Makarov

Minerals 2019, 9(7), 445; https://doi.org/10.3390/min9070445 - 19 Jul 2019

Cited by 42 | Viewed by 5605

Abstract

Using Murmansk Region, one of Russia’s largest mining regions, as a case study, this paper examines the environmental safety challenges arising in the storage of mining and mineral processing waste (MMPW). It was found that MMPW causes environmental damage even after the deposit’s [...] Read more.

Using Murmansk Region, one of Russia’s largest mining regions, as a case study, this paper examines the environmental safety challenges arising in the storage of mining and mineral processing waste (MMPW). It was found that MMPW causes environmental damage even after the deposit’s exhaustion. While being stored, the MMPW composition experiences a major change in the process properties of the recoverable minerals. As a consequence, the potential value of the MMPW as a mineral resource falls. Imperfections of the regulatory framework, leading to a higher unit cost of recovery and a reduced profitability of MMPW processing, are demonstrated. Potential amendments to the Russian laws are proposed in order to make MMPW processing commercially more viable. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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14 pages, 4280 KiB

Open AccessTechnical Note

Recovering Iron from Iron Ore Tailings and Preparing Concrete Composite Admixtures

by Chang Tang, Keqing Li, Wen Ni and Duncheng Fan

Minerals 2019, 9(4), 232; https://doi.org/10.3390/min9040232 - 15 Apr 2019

Cited by 55 | Viewed by 14486

Abstract

Iron ore tailings (IOTs) are a form of solid waste produced during the beneficiation process of iron ore concentrate. In this paper, iron recovery from IOTs was studied at different points during a process involving pre-concentration followed by direct reduction and magnetic separation. [...] Read more.

Iron ore tailings (IOTs) are a form of solid waste produced during the beneficiation process of iron ore concentrate. In this paper, iron recovery from IOTs was studied at different points during a process involving pre-concentration followed by direct reduction and magnetic separation. Then, slag-tailing concrete composite admixtures were prepared from high-silica residues. Based on the analyses of the chemical composition and crystalline phases, a pre-concentration test was developed, and a pre-concentrated concentrate (PC) with an iron grade of 36.58 wt % and a total iron recovery of 83.86 wt % was obtained from a feed iron grade of 12.61 wt %. Furthermore, the influences of various parameters on iron recovery from PC through direct reduction and magnetic separation were investigated. The optimal parameters were found to be as follows: A roasting temperature of 1250 °C, a roasting time of 50 min, and a 17.5:7.5:12.5:100 ratio of bitumite/sodium carbonate/lime/PC. Under these conditions, the iron grade of the reduced iron powder was 92.30 wt %, and the iron recovery rate was 93.96 wt %. With respect to the original IOTs, the iron recovery was 78.79 wt %. Then, highly active slag-tailing concrete composite admixtures were prepared using the high-silica residues and S75 blast furnace slag powder. When the amount of high-silica residues replacing slag was 20%, the strength of cement mortar blocks at 7 days and 28 days was 33.11 MPa and 50 MPa, respectively, whereas the activity indices were 89 and 108, respectively. Meanwhile, the fluidity rate was appropriately 109. When the content of high-silica residues replacing slag was not more than 30%, the quality of mineral admixtures was not reduced. Last but not least, reusing the high-silica residues during iron recovery enabled the complete utilization of the IOTs. Full article

(This article belongs to the Special Issue Towards a Sustainable Management of Mine Wastes: Reprocessing, Reuse, Revalorization and Repository)

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