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Publications (10 of 19) Show all publications
Nwaila, G. T., Ghorbani, Y., Becker, M., Frimmel, H. E., Petersen, J. & Zhang, S. (2020). Geometallurgical Approach for Implications of Ore Blending on Cyanide Leaching and Adsorption Behavior of Witwatersrand Gold Ores, South Africa. Natural Resources Research, 29(2), 1007-1030
Open this publication in new window or tab >>Geometallurgical Approach for Implications of Ore Blending on Cyanide Leaching and Adsorption Behavior of Witwatersrand Gold Ores, South Africa
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2020 (English)In: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981, Vol. 29, no 2, p. 1007-1030Article in journal (Refereed) Published
Abstract [en]

Gold production in South Africa is projected to continue its decline in future, and prospects for discovery of new high-grade deposits are limited. Many of the mining companies have resorted to mining and processing low-grade and complex gold ores. Such ores are technically challenging to process, which results in low recovery rates, excessive reagent consumption and high operating costs when compared to free-milling gold ores. In the Witwatersrand mines, options of blending low-grade gold ores with high-grade ores exist. Although it is well known that most of the Witwatersrand gold ores are highly amenable to gold cyanidation, not much is known on the leachability of blended ores, especially the effects of mineralogical and metallurgical variability between different gold ores. In this study, we apply a geometallurgical approach to investigate mineralogical and metallurgical factors that influence the leaching of blended ores in a set of bottle shaker and reactor column tests. Three gold-bearing conglomerate units, so-called reefs, i.e., Carbon Leader Reef, Ventersdorp Contact Reef and the Black Reef, all in the Carletonville goldfield, were sampled. The ores were prepared using a terminator jaw crusher followed by vertical spindle pulverizer (20 kg aliquot) and high-pressure grinding rolls (80 kg aliquot). Mineralogical analysis was conducted using a range of complementary tools such as optical microscopy, QEMSCAN and micro–XCT. The results show that Witwatersrand gold ores are amenable to the process of ore blending. Some of the ores, however, contain impervious inert gangue and reactive ore minerals. Leach solution can only access gold locked in impervious gangue minerals through HPGR-induced pores and/or cracks. The optimum ore blending ratio of the bottle shaker experiments (p80 = − 75 μm) comprises 60% Carbon Leader Reef, 20% Ventersdorp Contact Reef and 20% Black Reef and yields 92% recovered Au over a leach period of 40 h. Blended ores with high carbonaceous material (> 1 wt% carbonaceous material, (Black Reef = 36–60%) yield lower recoveries of 60–69% Au). Ore leaching at the mixed-bed reactor column (− 75 μm and − 5.6/+ 4 mm) yields about 70% over a leach period of two weeks. We therefore suggest that the feasibility of ore blending is strongly controlled by the mineralogy of the constituent ores and that a mixed-bed reactor may be a viable alternative method for leaching of the low-grade Witwatersrand gold ores. Material from certain reefs, such as the Black Reef, has synergistic/antagonistic (nonadditive) blending effects. The overall implication of this study is that ore blending ratios, effects of comminution on mineral liberation, an association of gold with other minerals, and gold adsorption behavior will greatly inform future technology choices in the area of geometallurgy.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Gold, Geometallurgy, Cyanide leaching, Ore blending, Process mineralogy, Witwatersrand gold ores
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-75498 (URN)10.1007/s11053-019-09522-4 (DOI)00520600500026 ()2-s2.0-85069463696 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-04-06 (johcin)

Available from: 2019-08-13 Created: 2019-08-13 Last updated: 2020-04-06Bibliographically approved
Bahrami, A., Kazemi, F., Alighardashi, A., Ghorbani, Y., Abdollahi, M. & Parvizian, A. (2020). Isolation and removal of cyanide from tailing dams in gold processing plant using natural bitumen. Journal of Environmental Management, 262, Article ID 110286.
Open this publication in new window or tab >>Isolation and removal of cyanide from tailing dams in gold processing plant using natural bitumen
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2020 (English)In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 262, article id 110286Article in journal (Refereed) Published
Abstract [en]

Gilsonite as a natural occurrence of bitumen and due to the presence of carbon in its structure is a suitable adsorbent for a wide variety of pollutants. In this research, the adsorption of cyanide from the wastewater of gold processing plants using gilsonite were investigated. In this way, the effect of particle size of gilsonite, the weight and mixing time with solution, on the amount of cyanide adsorption have been studied. In addition, in one experiment, the effect of processed gilsonite on its adsorption ability was investigated. Based on the obtained results, the maximum adsorption of 61.64% was obtained in the size range of −1+0.5 and −2+1 mm of gilsonite. With increasing adsorbent weight and mixing time, the cyanide adsorption rate were increased. On the other hand, with the processing of the gilsonite sample, the amounts of adsorption were increased considerably. This study indicated that gilsonite can be used as an isolation and absorbent in the structure and floor of the tailing dumps of mineral processing plants.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Gold processing wastewater, Cyanide removal, Gilsonite, Adsorption, Kinetic
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-77859 (URN)10.1016/j.jenvman.2020.110286 (DOI)000527016200018 ()32090887 (PubMedID)2-s2.0-85079618691 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-02-25 (alebob)

Available from: 2020-02-25 Created: 2020-02-25 Last updated: 2020-05-14Bibliographically approved
How Kuan, S., Ghorbani, Y. & Chieng, S. (2020). Narrowing the gap between local standards and global best practices inbauxite mining: A case study in Malaysia. Resources policy, 66, Article ID 101636.
Open this publication in new window or tab >>Narrowing the gap between local standards and global best practices inbauxite mining: A case study in Malaysia
2020 (English)In: Resources policy, ISSN 0301-4207, E-ISSN 1873-7641, Vol. 66, article id 101636Article in journal (Refereed) Published
Abstract [en]

In mining the concept of sustainable development often encounters a paradoxical meaning as numerous mines in the past have closed due to exhausted amounts of ores. Despite the paradox, sustainable development and mining can be made compatible, if mining activities are carried out responsibly and sustainably. This holds true especially in the developing world where illegal and unregulated mining is still being practiced. In Malaysia, annual production of bauxite ore increased drastically from 208,770 tonnes in 2013, to 962,799 tonnes in 2014. The increase stemmed primarily from Indonesia banning exports of bauxite in 2014 to boost its own aluminium smelting industry. This led China to suffer low bauxite supply to meet its national aluminium production demand. Subsequently, mining companies flocked to the hills around Kuantan, Malaysia which host large amounts of low-grade bauxite where the ore is procured and exported to China via seaway. The immediate spike in bauxite production came with environmental and health consequences for residents due to unregulated rampant mining. Consequently, the authorities imposed a temporary moratorium on bauxite mining from Jan 15, 2016 with exceptions for exports of stockpiled bauxite. As a result, production in 2016 dropped to 342,924 tonnes from a peak of 7,164,956 tonnes in 2015. After extending the moratorium nine times, the government announced recently that there would be no further extension and mining could resume in April 2019 with new standard operating procedures (SOP). This work analyses the gap between local standards and global best practices and discovers a disconnect between the two, largely centred around the area of environmental management and performance. The work also elucidates the weaknesses in the current SOP and strategies are proposed to resolve these shortcomings. Recommendations are made to bring Malaysian bauxite mining practices to international standards by stressing on improved sustainability indicators, policy provisions and data transparency.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Sustainable mining, Bauxite, Malaysia, Economic, Environmental and social impacts, Bauxite mining SOP
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-77896 (URN)10.1016/j.resourpol.2020.101636 (DOI)2-s2.0-85080101719 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-02-27 (svasva)

Available from: 2020-02-27 Created: 2020-02-27 Last updated: 2020-04-22Bibliographically approved
Guntoro, P. I., Ghorbani, Y., Butcher, A. R., Kuva, J. & Rosenkranz, J. (2020). Textural Quantification and Classification of Drill Coresfor Geometallurgy: Moving Toward 3D with X-rayMicrocomputed Tomography (μCT). Natural Resources Research
Open this publication in new window or tab >>Textural Quantification and Classification of Drill Coresfor Geometallurgy: Moving Toward 3D with X-rayMicrocomputed Tomography (μCT)
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2020 (English)In: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981Article in journal (Refereed) Epub ahead of print
Abstract [en]

Texture is one of the critical parameters that affect the process behavior of ore minerals. Traditionally, texture has been described qualitatively, but recent works have shown the possibility to quantify mineral textures with the help of computer vision and digital image analysis. Most of these studies utilized 2D computer vision to evaluate mineral textures, which is limited by stereological error. On the other hand, the rapid development of X-ray microcomputed tomography (µCT) has opened up new possibilities for 3D texture analysis of ore samples. This study extends some of the 2D texture analysis methods, such as association indicator matrix (AIM) and local binary pattern (LBP) into 3D to get quantitative textural descriptors of drill core samples. The sensitivity of the methods to textural differences between drill cores is evaluated by classifying the drill cores into three textural classes using methods of machine learning classification, such as support vector machines and random forest. The study suggested that both AIM and LBP textural descriptors could be used for drill core classification with overall classification accuracy of 84–88%.

Keywords
X-ray computed micro-tomography (μCT), Machine learning, Texture quantification, Local binary pattern, Co-occurrence matrices
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-78871 (URN)10.1007/s11053-020-09685-5 (DOI)
Available from: 2020-05-13 Created: 2020-05-13 Last updated: 2020-05-13
Lishchuk, V., Koch, P.-H., Ghorbani, Y. & Butcher, A. R. (2020). Towards integrated geometallurgical approach: Critical review of current practices and future trends. Minerals Engineering, 145, Article ID 106072.
Open this publication in new window or tab >>Towards integrated geometallurgical approach: Critical review of current practices and future trends
2020 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 145, article id 106072Article, review/survey (Refereed) Published
Abstract [en]

Geometallurgy has become an important tool for mitigating production risks and improving economic performance in the modern mining industry. Multiple definitions and visions of geometallurgy have been proposed during the last decades. Most of them define geometallurgy as a bridge between geology and mineral processing. Such a definition is rather confusing since process mineralogy claims to be such “bridge” too. Therefore, the main objective of the present paper is to provide a broad image of geometallurgy covering planning, executing and evaluation of geometallurgical programs. Such a vision of geometallurgy was developed within a research project PREP, which was aimed at “resource effective mineral processing”. PREP is a holistic geometallurgical approach independent of deposit type. The approach differentiates geometallurgical programs based on the complexity of the problem and the desirable outcome. Particular attention was paid to the planning of the geometallurgical programs, data management, and new tools development. The practical usage of the approach was tested with three case studies: iron-apatite ore, VMS, and Cu porphyry deposits. Some examples of applying geometallurgy for the iron-apatite ore are shown in this paper. The result, the guidelines on planning, executing and evaluating a geometallurgical program, are given in this paper.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Resource efficient, Mineral processing, Primary resources, Geometallurgy, Modelling and simulation, Mine’s production chain
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-76530 (URN)10.1016/j.mineng.2019.106072 (DOI)000498752100002 ()2-s2.0-85073942458 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-28 (svasva)

Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-12-20Bibliographically approved
Chelgani, S. C., Parian, M., Semsari, P., Ghorbani, Y. & Rosenkranz, J. (2019). A comparative study on the effects of dry and wet grinding on mineral flotation separation: a review. Journal of Materials Research and Technology, 8(5), 5004-5011
Open this publication in new window or tab >>A comparative study on the effects of dry and wet grinding on mineral flotation separation: a review
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2019 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 8, no 5, p. 5004-5011Article, review/survey (Refereed) Published
Abstract [en]

Water scarcity dictates to limit the use of water in ore processing plants particularly in arid regions. Since wet grinding is the most common method for particle size reduction and mineral liberation, there is a lack of understanding about the effects of dry grinding on downstream separation processes such as flotation. This manuscript compiles various effects of dry grinding on flotation and compares them with wet grinding. Dry grinding consumes higher energy and produces wider particle size distributions compared with wet grinding. It significantly decreases the rate of media consumption and liner wear; thus, the contamination of pulp for flotation separation is lower after dry grinding. Surface roughness, particle agglomeration, and surface oxidation are higher in dry grinding than wet grinding, which all these effects on the flotation process. Moreover, dry ground samples in the pulp phase correlate with higher Eh and dissolved oxygen concentration. Therefore, dry grinding can alter the floatability of minerals. This review thoroughly assesses various approaches for flotation separation of different minerals, which have been drily ground, and provides perspectives for further future investigations.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Flotation, Energy consumption, Grinding media type, HPGR, Dry grinding, Wet grinding
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-75591 (URN)10.1016/j.jmrt.2019.07.053 (DOI)000486630400124 ()
Note

Validerad;2019;Nivå 2;2019-10-28 (johcin)

Available from: 2019-08-20 Created: 2019-08-20 Last updated: 2019-10-28Bibliographically approved
Bahrami, A., Ghorbani, Y., Sharif, J. A., Kazemi, F., Abdollahi, M., Salahshur, A. & Danesh, A. (2019). A geometallurgical study of flotation performance in supergene and hypogene zones of Sungun copper deposit. Mineral Processing and Extractive Metallurgy
Open this publication in new window or tab >>A geometallurgical study of flotation performance in supergene and hypogene zones of Sungun copper deposit
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2019 (English)In: Mineral Processing and Extractive Metallurgy, ISSN 2572-6641Article in journal (Refereed) Epub ahead of print
Abstract [en]

The feed of mineral processing plants, usually consist of different minerals from various geological zones, which show different behavior in separation processes. In this research, samples from supergene and hypogene zones were provided to investigate the flotation behavior of copper minerals. Flotation experiments were carried out in three phases of supergene sample, hypogene sample and mixed samples. Based on the results, the recovery rate of the mixed sample was 83.61%, which is 7.63% and 1.79% higher than the recovery of the samples of hypogene and supergene zones, respectively. The concentrate grade values obtained for blended, hypogene zone and supergene zone are 10.32%, 2.81% and 12.37%, respectively. The maximum values of flotation constant and infinite recovery are 0.956 (s−1) and 88.833% for the mixed sample. It was also concluded that the highest amount of k and infinitive recovery were related to supergene zone sulfide flotation which are 0.831 (s−1) and 84.33% respectively.

Place, publisher, year, edition, pages
Taylor & Francis, 2019
Keywords
Sulfide minerals, oxide minerals, supergene, hypogene, recovery, flotation rate
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-73223 (URN)10.1080/25726641.2019.1591794 (DOI)
Available from: 2019-03-18 Created: 2019-03-18 Last updated: 2019-03-18
Guntoro, P. I., Tiu, G., Ghorbani, Y., Lund, C. & Rosenkranz, J. (2019). Application of machine learning techniques in mineral phase segmentation for X-ray microcomputed tomography (µCT) data. Minerals Engineering, 142, Article ID 105882.
Open this publication in new window or tab >>Application of machine learning techniques in mineral phase segmentation for X-ray microcomputed tomography (µCT) data
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2019 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 142, article id 105882Article in journal (Refereed) Published
Abstract [en]

X-ray microcomputed tomography (µCT) offers a non-destructive three-dimensional analysis of ores but its application in mineralogical analysis and mineral segmentation is relatively limited. In this study, the application of machine learning techniques for segmenting mineral phases in a µCT dataset is presented. Various techniques were implemented, including unsupervised classification as well as grayscale-based and feature-based supervised classification. A feature matching method was used to register the back-scattered electron (BSE) mineral map to its corresponding µCT slice, allowing automatic annotation of minerals in the µCT slice to create training data for the classifiers. Unsupervised classification produced satisfactory results in terms of segmenting between amphibole, plagioclase, and sulfide phases. However, the technique was not able to differentiate between sulfide phases in the case of chalcopyrite and pyrite. Using supervised classification, around 50–60% of the chalcopyrite and 97–99% of pyrite were correctly identified. Feature based classification was found to have a poorer sensitivity to chalcopyrite, but produced a better result in segmenting between the mineral grains, as it operates based on voxel regions instead of individual voxels. The mineralogical results from the 3D µCT data showed considerable difference compared to the BSE mineral map, indicating stereological error exhibited in the latter analysis. The main limitation of this approach lies in the dataset itself, in which there was a significant overlap in grayscale values between chalcopyrite and pyrite, therefore highly limiting the classifier accuracy.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
X-ray micro-tomography (µCT), Machine learning, Mineral segmentation, Feature-based classification, Feature matching
National Category
Metallurgy and Metallic Materials Geology
Research subject
Mineral Processing; Ore Geology
Identifiers
urn:nbn:se:ltu:diva-75703 (URN)10.1016/j.mineng.2019.105882 (DOI)000488141400014 ()2-s2.0-85070948239 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-27 (svasva)

Available from: 2019-08-27 Created: 2019-08-27 Last updated: 2020-02-03Bibliographically approved
Bahrami, A., Ghorbani, Y., Hosseini, M. R., Kazemi, F., Abdollahi, M. & Danesh, A. (2019). Combined Effect of Operating Parameters on Separation Efficiency and Kinetics of Copper Flotation. Mining, metallurgy & exploration, 36(2), 409-421
Open this publication in new window or tab >>Combined Effect of Operating Parameters on Separation Efficiency and Kinetics of Copper Flotation
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2019 (English)In: Mining, metallurgy & exploration, ISSN 2524-3462, Vol. 36, no 2, p. 409-421Article in journal (Refereed) Published
Abstract [en]

This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s−1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Taguchi, Flotation, Collector, Kinetics, Copper, Sungun copper complex
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-71161 (URN)10.1007/s42461-018-0005-y (DOI)000474227100016 ()2-s2.0-85077821361 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-16 (johcin)

Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2020-04-16Bibliographically approved
Torres, C. M., Ghorbani, Y., Hernández, P. C., Justel, F. J., Aravena, M. I. & Herreros, O. O. (2019). Cupric and Chloride Ions: Leaching of Chalcopyrite Concentrate with Low Chloride Concentration Media. Minerals, 9(10), Article ID 639.
Open this publication in new window or tab >>Cupric and Chloride Ions: Leaching of Chalcopyrite Concentrate with Low Chloride Concentration Media
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2019 (English)In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 10, article id 639Article in journal (Refereed) Published
Abstract [en]

In this paper, the effect of the cupric and chloride ions concentrations on copper dissolution from chalcopyrite concentrate was studied in acidified media. Variables included three different concentrations of Cu2+ (0.5, 1.5, and 2.5 g L−1), four different concentrations of Cl (0, 5, 7, and 10 g L−1), two different pH values of 1 and 2, and a constant temperature of 60 °C. Results indicated that addition of Cl to the system improves copper extractions, especially at higher concentrations of Cu2+. Initial copper concentrations in the leaching solution did not significantly affect the copper extraction when Cl was not present. Better copper extractions were obtained at pH 1 as compared with pH 2. As the Cu2+ and Cl concentrations were increased, higher values of redox potential were obtained. According to the formation constants of the chloro-complexes, the predominant species in the Cu2+/Cl system in the studied interval were CuCl+ and Cu2+. Using a model of copper speciation in the experimental range predicted for a single copper concentration with increasing Cl concentration, the Cu2+ concentration decreased significantly while the concentration of the chloro-complex species CuCl+ increased. In the leached residue, evidence of sulfur formation was found using SEM and corroborated by XRD analysis. When chloride is present in the medium, the amounts of copper and iron in the residue decrease, confirming a positive effect of chloride on the extraction of copper from concentrate for the studied conditions.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
copper sulfide, chloro-complex, cupric ion, chalcopyrite, chloride
National Category
Metallurgy and Metallic Materials
Research subject
Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-76440 (URN)10.3390/min9100639 (DOI)000498225200072 ()2-s2.0-85074233412 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-18 (svasva)

Available from: 2019-10-18 Created: 2019-10-18 Last updated: 2019-12-18Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-5228-3888

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