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  • 1.
    Ahmed, Hesham
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Central Metallurgical Research and Development Institute (CMRDI), Cairo, Egypt.
    New Trends in The Application of Carbon-Bearing Materials in Blast Furnace Iron-Making2018Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, nr 12, artikkel-id 561Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The iron and steel industry is still dependent on fossil coking coal. About 70% of the total steel production relies directly on fossil coal and coke inputs. Therefore, steel production contributes by ~7% of the global CO2 emission. The reduction of CO2 emission has been given highest priority by the iron- and steel-making sector due to the commitment of governments to mitigate CO2 emission according to Kyoto protocol. Utilization of auxiliary carbonaceous materials in the blast furnace and other iron-making technologies is one of the most efficient options to reduce the coke consumption and, consequently, the CO2 emission. The present review gives an insight of the trends in the applications of auxiliary carbon-bearing material in iron-making processes. Partial substitution of top charged coke by nut coke, lump charcoal, or carbon composite agglomerates were found to not only decrease the dependency on virgin fossil carbon, but also improve the blast furnace performance and increase the productivity. Partial or complete substitution of pulverized coal by waste plastics or renewable carbon-bearing materials like waste plastics or biomass help in mitigating the CO2 emission due to its high H2 content compared to fossil carbon. Injecting such reactive materials results in improved combustion and reduced coke consumption. Moreover, utilization of integrated steel plant fines and gases becomes necessary to achieve profitability to steel mill operation from both economic and environmental aspects. Recycling of such results in recovering the valuable components and thereby decrease the energy consumption and the need of landfills at the steel plants as well as reduce the consumption of virgin materials and reduce CO2 emission. On the other hand, developed technologies for iron-making rather than blast furnace opens a window and provide a good opportunity to utilize auxiliary carbon-bearing materials that are difficult to utilize in conventional blast furnace iron-making.

  • 2.
    Aiglsperger, Thomas
    et al.
    Department of Crystallography, Mineralogy, and Ore Deposits, University of Barcelona.
    Proenza, Joaquín A.
    Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona.
    Longo, Francisco
    Falcondo Glencore, Santo Domingo .
    Font-Bardia, Mercé
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Galí, Salvador
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Roqué, Josep
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona.
    Baurier-Aymat, Sandra
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona .
    Fibrous Platinum-Group Minerals in “Floating Chromitites” from the Loma Larga Ni-Laterite Deposit, Dominican Republic2016Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 6, nr 4, artikkel-id 126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This contribution reports on the observation of enigmatic fibrous platinum-group minerals (PGM) found within a chromitite body included in limonite (“floating chromitite”) from Ni-laterites in the Dominican Republic. Fibrous PGM have a Ru-Os-Ir-Fe dominated composition and are characterized by fibrous textures explained by grain-forming fibers which are significantly longer (1–5 _m) than they are wide (~100 nm). Back-scattered electron (BSE) images suggest that these nanofibers are platinum-group elements (PGE)-bearing and form <5 _m thick layers of bundles which are oriented orthogonal to grains’ surfaces. Trace amounts of Si are most likely associated with PGE-bearing nanofibers. One characteristic fibrous PGM was studied in detail: XRD analyses point to ruthenian hexaferrum. However, the unpolished fibrous PGM shows numerous complex textures on its surface which are suggestive for neoformation processes: (i) features suggesting growth of PGE-bearing nanofibers; (ii) occurrence of PGM nanoparticles within film material (biofilm?) associated with PGE-bearing nanofibers; (iii) a Si-rich and crater-like texture hosting PGM nanoparticles and an Ir-rich accumulation of irregular shape; (iv) complex PGM nanoparticles with ragged morphologies, resembling sponge spicules and (v) oval forms (<1 _m in diameter) with included PGM nanoparticles, similar to those observed in experiments with PGE-reducing bacteria. Fibrous PGM found in the limonite may have formed due to supergene (bio-)weathering of fibrous Mg-silicates which were incorporated into desulphurized laurite during stages of serpentinization.

  • 3.
    Dold, Bernhard
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Pooler, Robert
    SGS Minerals Chile, Geometallurgy Area, Puerto Madero 130, Pudahuel, Santiago.
    Optimization and quality control of automated quantitative mineralogy analysis for acid rock drainage prediction2017Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 7, nr 1, artikkel-id 12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low ore-grade waste samples from the Codelco Andina mine that were analyzed in an environmental and mineralogical test program for acid rock drainage prediction, revealed inconsistencies between the quantitative mineralogical data (QEMSCAN®) and the results of geochemical characterizations by atomic absorption spectroscopy (AAS), LECO® furnace, and sequential extractions). For the QEMSCAN® results, biases were observed in the proportions of pyrite and calcium sulfate minerals detected. An analysis of the results indicated that the problems observed were likely associated with polished section preparation. Therefore, six different sample preparation protocols were tested and evaluated using three samples from the previous study. One of the methods, which involved particle size reduction and transverse section preparation, was identified as having the greatest potential for correcting the errors observed in the mineralogical analyses. Further, the biases in the quantities of calcium sulfate minerals detected were reduced through the use of ethylene glycol as a polishing lubricant. It is recommended that the sample preparation methodology described in this study be used in order to accurately quantify percentages of pyrite and calcium sulfate minerals in environmental mineralogical studies which use automated mineralogical analysis

  • 4.
    Ghosh, Rajib
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Gustafson, Anna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Monitoring of Drill System Behavior for Water-Powered in-the-hole (ITH) drilling2017Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 7, nr 7, artikkel-id 121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A detailed understanding of the drilling system and the drilling control is required to correctly interpret rock mass conditions based on monitored drilling data. This paper analyses data from hydraulic in-the-hole (ITH) drills used in LKAB’s Malmberget mine in Sweden. Drill parameters, including penetration rate, percussive pressure, feed pressure, and rotation pressure, are monitored in underground production holes. Calculated parameters, penetration rate variability, rotation pressure variability, and fracturing are included in the analysis to improve the opportunity to predict rock mass conditions. Principal component analysis (PCA) is used to address non-linearity and variable interactions. The results show that the data contain pronounced hole length-dependent trends, both linear and step-wise linear, for most parameters. It is also suggested that monitoring can be an efficient way to optimize target values for drill parameters, as demonstrated for feed force. Finally, principal component analysis can be used to transfer a number of drill parameters into single components with a more straightforward geomechanical meaning

  • 5.
    Greberg, Jenny
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Salama, Abubakary
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Gustafson, Anna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Skawina, Bartlomiej
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Alternative Process Flow for Underground Mining Operations: Analysis of Conceptual Transport Methods Using Discrete Event Simulation2016Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 6, nr 3, artikkel-id 65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the near surface deposits are being mined out, underground mines will increasingly operate at greater depths. This will increase the challenges related to transporting materials from deeper levels to the surface. For many years, the ore and waste transportation from most deep underground mines has depended on some or all of the following: truck haulage, conveyor belts, shafts, rails, and ore pass systems. In sub-level caving, and where ore passes are used, trains operating on the main lower level transport the ore from ore passes to a crusher, for subsequent hoisting to the surface through the shaft system. In many mines, the use of the ore pass system has led to several problems related to the ore pass availability, causing production disturbances and incurred cost and time for ore pass rehabilitation. These production disturbances have an impact on the mining activities since they increase the operational costs, and lower the mine throughput. A continued dependency on rock mass transportation using ore passes will generate high capital costs for various supporting structures such as rail tracks, shaft extensions, and crushers for every new main level. This study was conducted at an existing underground mine and analyzed the transport of ore from loading areas at the lower levels up to the existing shaft points using trucks without employing ore passes. The results show that, when the costs of extending ore passes to lower levels become too great or ore passes cannot be used for production, haul trucks can be a feasible alternative method for transport of ore and waste up the ramp to the existing crusher located at the previous main level. The use of trucks will avoid installing infrastructure at the next main level and extending the ore passes to lower levels, hence reducing costs.

  • 6.
    Guntoro, Pratama Istiadi
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ghorbani, Yousef
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Koch, Pierre-Henri
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    X-ray Microcomputed Tomography (µCT) for Mineral Characterization: A Review of Data Analysis Methods2019Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, nr 3, artikkel-id 183Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The main advantage of X-ray microcomputed tomography (µCT) as a non-destructive imaging tool lies in its ability to analyze the three-dimensional (3D) interior of a sample, therefore eliminating the stereological error exhibited in conventional two-dimensional (2D) image analysis. Coupled with the correct data analysis methods, µCT allows extraction of textural and mineralogical information from ore samples. This study provides a comprehensive overview on the available and potentially useful data analysis methods for processing 3D datasets acquired with laboratory µCT systems. Our study indicates that there is a rapid development of new techniques and algorithms capable of processing µCT datasets, but application of such techniques is often sample-specific. Several methods that have been successfully implemented for other similar materials (soils, aggregates, rocks) were also found to have the potential to be applied in mineral characterization. The main challenge in establishing a µCT system as a mineral characterization tool lies in the computational expenses of processing the large 3D dataset. Additionally, since most of the µCT dataset is based on the attenuation of the minerals, the presence of minerals with similar attenuations limits the capability of µCT in mineral segmentation. Further development on the data processing workflow is needed to accelerate the breakthrough of µCT as an analytical tool in mineral characterization.

  • 7.
    Jafari, Mohammad
    et al.
    School of Mining Engineering, University of Tehran, Tehran, Iran.
    Shafaei, Said Zia Aldin
    School of Mining Engineering, University of Tehran, Tehran, Iran.
    Abdollahi, Hadi
    School of Mining Engineering, University of Tehran, Tehran, Iran.
    Gharabaghi, Mahdi
    School of Mining Engineering, University of Tehran, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, USA.
    A comparative study on the effect of flotation reagents on growth and iron oxidation activities of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans2017Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 7, nr 1, artikkel-id 2Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recently, extraction of metals from different resources using a simple, efficient, and low-cost technique-known as bioleaching-has been widely considered, and has turned out to be an important global technology. Leptospirillum ferrooxidans and Acidithiobacillus (Thiobacillus) ferrooxidans are ubiquitous bacteria in the biomining industry. To date, the effects of commercial flotation reagents on the biooxidation activities of these bacteria have not been thoroughly studied. This investigation, by using various systematic measurement methods, studied the effects of various collectors and frothers (collectors: potassium amylxanthate, potassium isobutyl-xanthate, sodium ethylxanthate, potassium isopropylxanthate, and dithiophosphate; and frothers: pine oil and methyl isobutyl carbinol) on L. ferrooxidans and A. ferrooxidans activities. In general, results indicate that in the presence of these collectors and frothers, L. ferrooxidans is less sensitive than T. ferrooxidans. In addition, the inhibition effect of collectors on both bacteria is recommended in the following order: for the collectors, potassium isobutyl-xanthate > dithiophosphate > sodium ethylxanthate > potassium isobutyl-xanthate > potassium amylxanthate; and for the frothers, methyl isobutyl carbinol > pine oil. These results can be used for the optimization of biometallurgical processes or in the early stage of a process design for selection of flotation reagents.

  • 8.
    Leiva, Claudio A.
    et al.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Arcos, Katheryn V.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Poblete, Diego A.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Serey, Eduardo A.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Torres, Cynthia M.
    Department of Metallurgical and Mining Engineering, Universidad Católica del Norte, Chile.
    Ghorbani, Yousef
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Design and Evaluation of an Expert System in a Crushing Plant2018Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, nr 10, artikkel-id 469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This document presents a proposal for designing an expert system in the Gabriela Mistral Division’s crushing plant belonging to Codelco (Chile) with the objective of maximizing stacked tonnage, allowing the improvement of operational variables that directly interact with the crushing process. In addition, this study considers the impact that occurs in both the process and operational continuity regarding the standardization of the system. In the first stage, a survey and analysis of historic operation data was carried out, which allowed the definition of benchmarking indicators. Subsequently, both modalities of operation were compared, monitoring processed tonnage and detentions related to operational failures. As a result, significant differences were observed in the performance of the critical line operating with expert control, with a 55% reduction in the detentions referred to operational failures. Added to this is the benefit of low cost and improved quality as the control provides an analysis of the variables in reduced time intervals, which is superior to human control.

  • 9.
    Lishchuk, Viktor
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lund, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Miroshnikova, Elena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    Simulation of a Mining Value Chain with a Synthetic Ore Body Model: Iron Ore Example2018Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, nr 11, artikkel-id 536Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reconciliation of geological, mining and mineral processing information is a costly and time demanding procedure with high uncertainty due to incomplete information, especially during the early stages of a project, i.e., pre-feasibility, feasibility studies. Lack of information at those project stages can be overcome by applying synthetic data for investigating different scenarios. Generation of the synthetic data requires some minimum sparse knowledge already available from other parts of the mining value chain, i.e., geology, mining, mineral processing. This paper describes how to establish and construct a synthetic testing environment, or “synthetic ore body model” by integrating a synthetic deposit, mine production, constrained by a mine plan, and a simulated beneficiation process. The approach uses quantitative mineralogical data and liberation information for process simulation. The results of geological and process data integration are compared with the real case data of an apatite iron ore. The discussed approach allows for studying the implications in downstream processes caused by changes in upstream parts of the mining value chain. It also opens the possibility of optimising sampling campaigns by investigating different synthetic drilling scenarios including changes to the spacing between synthetic drill holes, composite length, drill hole orientation and assayed parameters.

  • 10.
    Mwanga, Abdul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Testing of Ore Comminution Behavior in the Geometallurgical Context: A Review2015Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 5, nr 2, s. 276-297Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Comminution tests are an important element in the proper design of orebeneficiation plants. In the past, test work has been conducted for particular representative reference samples. Within geometallurgy the entire ore body is explored in order to further identify the variation within the resource and to establish spatial geometallurgical domains that show the differential response to mineral processing. Setting up a geometallurgical program for an ore deposit requires extensive test work. Methods for testing the comminution behavior must therefore be more efficient in terms of time and cost but also with respect to sample requirements. The integration of the test method into the geometallurgical modeling framework is also important. This paper provides an overview of standard comminution test methods used for the investigation of ore comminution behavior and evaluates their applicability and potential in the geometallurgical context.

  • 11.
    Mäkitalo, Maria
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Maurice, Christian
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Jia, Yu
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Characterization of Green Liquor Dregs, Potentially Useful for Prevention of the Formation of Acid Rock Drainage2014Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 4, nr 2, s. 330-344Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using alternative materials such as residual products from other industries to mitigate the negative effects of acid rock drainage would simultaneously solve two environmental problems. The main residual product still landfilled by sulphate paper mills is the alkaline material green liquor dregs (GLD). A physical, mineralogical and chemical characterization of four batches of GLD was carried out to evaluate the potential to use it as a sealing layer in the construction of dry covers on sulphide-bearing mine waste. GLD has relatively low hydraulic conductivity (10−8 to 10−9 m/s), a high water retention capacity (WRC) and small particle size. Whilst the chemical and mineralogical composition varied between the different batches, these variations were not reflected in properties such as hydraulic conductivity and WRC. Due to relatively low trace element concentrations, leaching of contaminants from the GLD is not a concern for the environment. However, GLD is a sticky material, difficult to apply on mine waste deposits and the shear strength is insufficient for engineering applications. Therefore, improving the mechanical properties is necessary. In addition, GLD has a high buffering capacity indicating that it could act as an alkaline barrier. Once engineering technicalities have been overcome, the long-term effectiveness of GLD should be studied, especially the effect of aging and how the sealing layer would be engineered in respect to topography and climatic conditions.

  • 12.
    Reinhardt, Nils
    et al.
    Institute of Mineralogy, Technische Universität Bergakademie Freiberg, Germany;Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain; Institute of Applied Mineralogy and Economic Geology (IML), RWTH Aachen University, Germany.
    Proenza, Joaquín A.
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain.
    Villanova-de-Benavent, Cristina
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain;School of Environment and Technology (SET), University of Brighton, UK.
    Aiglsperger, Thomas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain.
    Bover-Arnal, Telm
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain.
    Torró, Lisard
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain;Especialidad Ingeniería Geológica, Sección Ingeniería de Minas, Pontificia Universidad Católica del Perú, Peru.
    Salas, Ramon
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Spain.
    Dziggel, Annika
    Institute of Applied Mineralogy and Economic Geology (IML), RWTH Aachen University, Germany.
    Geochemistry and Mineralogy of Rare Earth Elements (REE) in Bauxitic Ores of the Catalan Coastal Range, NE Spain2018Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, nr 12, artikkel-id 562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Karst bauxite deposits are currently investigated as a new resource for rare earth elements (REE) in order to avoid present and future supply shortfalls of these critical metals. The present work focuses on the geochemistry and mineralogy of the REE in karst bauxite deposits of the Catalan Coastal Range (CCR), NE-Spain. It is revealed that the studied bauxitic ores have a dominant breccia and local ooido-pisoidic and pelitomorphic texture. The bauxitic ores are mostly composed of kaolinite and hematite, as well as of lesser amounts of boehmite, diaspore, rutile and calcite. The mineralogy and major element composition indicate incomplete bauxitization of an argillaceous precursor material possibly derived from the erosion of the Mesozoic Ebro massif paleo-high. The studied bauxites are characterized by ∑REE (including Sc, Y) between 286 and 820 ppm (av. 483 ppm) and light REE to heavy REE (LREE/HREE) ratios up to 10.6. REE are mainly concentrated in phosphate minerals, identified as monazite-(Ce) and xenotime-(Y) of detrital origin and unidentified REE-phosphates of a possible authigenic origin. REE remobilization presumably took place under acidic conditions, whereas REE entrapment in the form of precipitation of authigenic rare earth minerals from percolating solutions was related to neutral to slightly alkaline conditions. During the bauxitization process no significant REE fractionation took place and the REE distribution pattern of the bauxitic ores was governed by the REE budget of the precursor material. Finally, adsorption as a main REE scavenging mechanism in the studied CCR bauxite deposits should not be considered, since the presented data did not reveal significant REE contents in Fe-and Mn-oxyhydroxides and clay minerals.

  • 13.
    Svartsjaern, Mikael
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Saiang, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Discrete Element Modelling of Footwall Rock Mass Damage Induced by Sub-Level Caving at the Kiirunavaara Mine2017Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 7, nr 7, artikkel-id 109Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Kiirunavaara mine is one of the largest sub-level-caving (SLC) mines in the worldand has been in underground operation for more than 50 years. The mine has been the focus ofseveral case studies over the years. The previous works have either focused on the caving of thehanging wall, using the footwall as a passive support, or focused on the footwall using the hangingwall to apply a passive load. In this updated study the findings of the previous case studies arecombined to study the interaction between the caving hanging wall, the developing cave rock zoneand the footwall. The geological data for the rock types in the mine area are used to derive upperand lower limits for the geomechanical parameters calibrated for numerical models in the previousstudies. The calibrated parameters are used as inputs to a numerical model constructed usingItasca’s Particle-flow-code (PFC) encompassing a mine-scale 2D section at the mid portion of themine. The model captures the failure locations well in the footwall underground and indicatesdamage development without a coherent large-scale failure. The trend in subsidence data on thehanging wall is adequately simulated but the magnitude of deformation is underestimated. Theinput strength for the hanging wall was lowered to study the impact of hanging wall strength onfootwall damage development. It is shown that when the footwall strength is kept constant, whilelowering the hanging wall strength, the extent of damage and magnitude of displacements in thefootwall increases. From these observations it is argued that the hanging wall and footwall cannotbe studied independently for the Kiirunavaara mine since the cave rock zone significantly affectsthe damage development in both walls.

  • 14.
    Tohry, Arash
    et al.
    Yazd University, Yazd, Iran.
    Dehghan, R.
    Yazd University, Yazd, Iran.
    Chelgani, Saeed Chehreh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rahmani, O.
    Chadormalu Mining and Industrial Company, Yazd, Iran.
    Selective Separation of Hematite by a Synthesized Depressant in Various Scales of Anionic Reverse Flotation2019Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, nr 2, artikkel-id 124Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. Reverse anionic flotation by using sodium silicate (SS) as an iron oxide depressant is one of the techniques for iron ore processing. This investigation is going to present a synthesized reagent “sodium co-silicate (SCS)” for hematite depression through a reverse anionic flotation. The main hypothesis is the selective depression of hematite and, simultaneously, modification of the pulp pH by SCS. Various flotation experiments, including micro-flotation, and batch flotation of laboratory and industrial scales, were conducted in order to compare the depression selectivity of SS versus SCS. Outcomes of flotation tests at the different flotation scales demonstrated that hematite depression by SCS is around 3.3% higher than by SS. Based on flotation experiment outcomes, it was concluded that SCS can modify the pH of the process at ~9.5, and the plant reagents (including NaOH, Na2CO3, and SS gel) can be replaced by just SCS, which can also lead to a higher efficiency in the plant. 

  • 15.
    Wanhainen, Christina
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nigatu, Wondowossen
    Gunnarn Explorat AB.
    Selby, David
    University of Durham, Department of Earth Science.
    McLeod, Claire L
    University of Houston, Department of Earth & Atmospheric Science.
    Nordin, Roger
    Boliden Mineral AB, Boliden AB.
    Bohlin, Nils-Johan
    Boliden, Division of Process Technology.
    The Distribution, Character, and Rhenium Content of Molybdenite in the Aitik Cu-Au-Ag-(Mo) Deposit and Its Southern Extension in the Northern Norrbotten Ore District, Northern Sweden2014Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 4, nr 4, s. 788-814Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molybdenite in the Aitik deposit and its southern extension was studied through mineralogical/chemical analysis and laboratory flotation tests. It is demonstrated that molybdenite varies considerably in grain size, ranging from coarse (>20 m) to very fine (<2 m) and occurs predominantly as single grains in the groundmass of the rocks, as grain aggregates, and intergrown with chalcopyrite and pyrite. The dominating molybdenite-bearing rocks are the mica schists, the quartz-monzodiorite, and the Salmijarvi biotite-amphibole gneiss, the latter containing mostly medium-coarsegrained molybdenite. Later geological features, such as garnet-magnetite-anhydrite-K feldspar alteration and pegmatite dikes appear to be responsible for a significant part of the distribution pattern of molybdenite. Molybdenite grains contain up to 1587 ppm Re, with an average of 211 +/- 10 ppm in Aitik molybdenite and 452 +/- 33 ppm in Salmijarvi molybdenite. The higher Re concentrations are found in molybdenite associated with sericite- and quartz-amphibole-magnetite altered rocks, whereas low Re values occur in rocks in which potassic alteration is prominent. Molybdenite recovery is influenced by the mineralogy of the host rock and the alteration grade; hence both of these factors will have an impact on potential recoveries. The recovery of molybdenite was lower from flotation feeds with significant amounts of Mg-bearing clay-micas.

  • 16.
    Warlo, Mathis
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bark, Glenn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Butcher, Alan
    Geological Survey of Finland/Geologian tutkimuskeskus, Espoo, Finland.
    McElroy, Iris
    Boliden AB.
    Brising, Dominique
    Boliden AB.
    Rollinson, Gavyn
    Camborne School of Mines, University of Exeter.
    Automated quantitative mineralogy optimized for simultaneous detection of (precious/critical) rare metals and base metals in a production-focused environment2019Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, nr 7, artikkel-id 440Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Automated Scanning Electron Microscopy (ASEM) systems are applied in the mining industry to quantify the mineralogy of the ore feed and products. With society pushing towards sustainable mining, this quantification should be comprehensive and include trace minerals since they are often either deleterious or potential by-products. Systems like QEMSCAN® offer a mode for trace mineral analysis (TMS mode); However, it is unsuitable when all phases require analysis. Here, we investigate the potential of detecting micron-sized trace minerals in fieldscan mode using the QEMSCAN® system with analytical settings in line with the mining industry. For quality comparison, analysis was performed at a mining company and a research institution. This novel approach was done in full collaboration with both parties. Results show that the resolution of trace minerals at or below the scan resolution is difficult and not always reliable due to mixed X-ray signals. However, by modification of the species identification protocol (SIP), quantification is achievable, although verification by SEM-EDS is recommended. As an add-on to routine quantitative analysis focused on major ore minerals, this method can produce quantitative data and information on mineral association for trace minerals of precious and critical metals which may be potential by-products in a mining operation

  • 17.
    Wonyen, Darius G.
    et al.
    University of Liberia, Monrovia, Liberia.
    Kromah, Varney
    University of Liberia, Monrovia, Liberia.
    Gibson, Borbor
    University of Liberia, Monrovia, Liberia.
    Nah, Solomon
    University of Liberia, Monrovia, Liberia.
    Chelgani, Saeed Chehreh
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A Review of Flotation Separation of Mg Carbonates (Dolomite and Magnesite)2018Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, artikkel-id 354Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is well documented that flotation has high economic viability for the beneficiation of valuable minerals when their main ore bodies contain magnesium (Mg) carbonates such as dolomite and magnesite. Flotation separation of Mg carbonates from their associated valuable minerals (AVMs) presents several challenges, and Mg carbonates have high levels of adverse effects on separation efficiency. These complexities can be attributed to various reasons: Mg carbonates are naturally hydrophilic, soluble, and exhibit similar surface characteristics as their AVMs. This study presents a compilation of various parameters, including zeta potential, pH, particle size, reagents (collectors, depressant, and modifiers), and bio-flotation, which were examined in several investigations into separating Mg carbonates from their AVMs by froth flotation.

  • 18.
    Öhlander, Björn
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Chatwin, Terrence
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Management of sulfide-bearing waste: a challenge for the mining industry2012Inngår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 2, nr 1, s. 1-10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxidation of iron sulfides in waste rock dumps and tailings deposits may result in formation of acid rock drainage (ARD), which often is a challenging problem at mine sites. Therefore, integrating an ARD management plan into the actual mine operations in the early phases of exploration, continuing through the mine life until final closure might be successful and decrease the environmental impact. A thorough characterization of ore and waste should be performed at an early stage. A detailed knowledge of mineralogical composition, chemical composition and physical properties such as grain size, porosity and hydraulic conductivity of the different waste types is necessary for reliable predictions of ARD formation and efficiency of mitigation measures. Different approaches to prevent and mitigate ARD are discussed. Another key element of successfully planning to prevent ARD and to close a mining operation sustainably is to engage the mine stakeholders (regulators, community and government leaders, non-governmental organization (NGOs) and lenders) in helping develop and implement the ARD management plan.

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