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  • 1.
    Lamberg, Pertti
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Minz, Friederike
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mwanga, Abdul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Parian, Mehdi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Building a Geometallurgical Model in Iron Ores using a Mineralogical Approach with Liberation Data2013In: Geomet13: The Second AusIMM International Geometallurgy Conference 2013 / [ed] Simon Dominy, Parkville, Victoria: The Australasian Institute of Mining and Metallurgy, 2013, p. 317-324Conference paper (Refereed)
    Abstract [en]

    A geometallurgical model is currently built in two different ways. The first and the most common way relies on geometallurgical testing, where a large number of samples are analysed for metallurgical response using small-scale laboratory tests, eg Davis tube testing. The second, mineralogical approach focuses on collecting mineralogical information over the orebody and building the metallurgical model based on mineralogy. At Luleå University of Technology,Sweden, the latter method has been adopted and taken further in four ongoing PhD studies. The geological model gives modal composition by the help of element-to-mineral conversion and Rietveld X-ray diffraction. Texturally, the orebody is divided into different archetypes, and liberation measurements for each of them are carried out in processing fineness using IncaMineral, a SEM-based technique. The grindability and liberation spectrum of any given geological unit (sample, ore block, domain) are extrapolated from the archetypes. The process model is taken into a liberation level by mass balancing selected metallurgical tests using the particle tracking technique. The approach is general and can be applied to any type of ores. Examples of ongoing studies on iron and massive sulfide ores are given.

  • 2.
    Minz, Friederike
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mineralogical characterisation of the Rockliden antimony-bearing volcanic-hosted massive sulphide deposit, Sweden2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Rockliden is a polymetallic Zn-Cu volcanic-hosted massive sulphide (VHMS) deposit. It is located in north-central Sweden about 150 km south of the Skellefte ore district. Two major challenges to mining and production were identified soon after Rockliden was discovered in the 1980’s. Firstly, the geographic distance to Boliden’s main ore deposits and existing concentrator in the Skellefte district will set additional financial and logistic constrains for the processing of the ore. Secondly, the locally high Sb grade in the ore potentially lowers the quality of the Cu-Pb concentrate sent to the Cu smelter. To face the second challenge to mining and production, it is necessary to use information from three disciplines: ore geology, mineral processing and process metallurgy. The three disciplines build the geometallurgical framework of the Rockliden ore characterisation. The purpose of this investigation is to outline which mineralogical factors are the cause of the elevated Sb content in the Cu-Pb concentrate. Determining such factors will help to predict the Sb content of this product and thus outline the tools required before decisions may be reached with regard to selection between various processing alternatives for the Rockliden ore. Hydrometallurgical treatment of the Cu-Pb concentrate has previously been studied by Awe (2013) and it was found that alkaline sulphide leaching can be used to lower the Sb content.A qualitative characterisation of the ore forms the main focus of this licentiate thesis. Minerals have been identified and their chemical composition has been obtained with micro-analytical tools (SEM/EDS & EPMA/WDS) to study the mineralogical distribution of major (e.g. Zn, Cu, Fe), penalty (e.g. Sb) and bonus (e.g. Ag) metals. Furthermore, mineral textures and associations have been studied in ore samples by optical microscopy and SEM/BSE imaging. Ore types are preliminary classified based on the sulphide mineralogy, i.e. the relative content of pyrite, pyrrhotite, magnetite, sphalerite and chalcopyrite estimated by reflected light microscopy. As sphalerite and chalcopyrite form the main Cu- and Zn-bearing minerals at Rockliden, the content of these two minerals can be approached with element-to-mineral conversion based on standard drill core assays (including S, Cu, Zn, Pb, As, Sb and Ag). The mineralogy of Sb-bearing minerals is complex and a single thin section can contain more than three different Sb-bearing phases. Thus, the element-to-mineral conversion is not applicable in directly calculating the modal mineralogy of the Sb-bearing mineral fraction based on drill core assays. Additionally, it is shown that the mineral association of the Sb-bearing minerals is complex. Products from initial flotation tests have been studied and the preliminary conclusion is that the complex intergrowths with various minerals influence the distribution of Sb-bearing minerals between the flotation products. Thus, a more detailed petrographic study on the massive sulphides and their host rocks was conducted. The sulphide and non-sulphide mineralogy of the host rocks and ore types are shown to be variable. It is also shown that the host rock types can be distinguished based on their trace element eochemistry, supporting the geological classification based on drill core logging.Based on petrographic and mineralogical observations done in this study, potential process-relevant rock-intrinsic factors are outlined. However, to evaluate the impact of such parameters on the beneficiation process, these parameters have to be quantified throughout the Rockliden deposit and this is the focus of continued studies. SEM-based automated mineralogy tools will be essential in measuring the important parameters such as modal mineralogy and mineral liberation. Quantitative information will then be used in a larger framework to build a geometallurgical model usable for production planning.

  • 3.
    Minz, Friederike
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mineralogical Controls on the Recovery of Antimony in Base-Metal Flotation – Outlining the Framework of a Geometallurgical Model for the Rockliden VHMS Deposit, Sweden2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The results presented in this thesis are a case study on the polymetallic Zn–Cu volcanic-hosted massive sulphide (VHMS) deposit at Rockliden. The Rockliden mineralisation is located in north-central Sweden, about 150 km south of the Skellefte district. Exploration at Rockliden started in the 1980’s despite the relative remote location of the deposit from processing facilities in the Skellefte ore district. During the first exploration period, flotation tests wereconducted which indicated that the locally high Sb grade in the mineralisation would increase the Sb content of the Cu–Pb concentrate and lower its quality at the smelter. In 2007 exploration was resumed at the Rockliden site andmassive sulphide mineralisation was found to extend toward the depth. The average Sb grade in the mineralisation decreases with depth; it is approximately 0.13 wt% above 400m below surface and only 0.06 wt% Sb below 400m. The focus of this PhD study was to evaluate mineralogical controls on the distribution of Sb minerals in base-metal flotation, which influences the Sb grade and hence the quality of the Cu–Pb concentrates. Modelling the Sb grade of the Cu–Pb concentrates is expected to be helpful in flowsheet design, e.g. for decision making on when to usehydrometallurgical treatment to reduce the Sb grade of this product prior to submission to the smelter. The first part of the study was to characterise the massive sulphides and the immediate host rocks with special reference to Sb mineralogy. The mineralogy and mineral associations were documented by optical and scanning electron microscopy (SEM). Micro-analytical tools (such as wavelength-dispersive X-ray spectroscopy at an electron probe microanalyser) were used to study the mineralogical distribution of major, minor and trace elements (e.g., Zn, Cu, Fe, Sb). Sphalerite and chalcopyrite are the main base-metal minerals in the massive sulphides. Antimony (Sb) is a minor to trace element bound in different minerals. The Sb mineralogy is complex; the most common Sb-bearing phases include gudmundite and Cu- and Pb-bearing Sb sulphosalts; tetrahedrite, bournonite, and meneghinite. Furthermore, the Sb minerals were found to occur partly locked with base-metal sulphides and gangue in flotation products from initial flotation tests. Mineralogical parameters such as grain size, degree of liberation and locking (mineral association in particles) were outlined as potential controls on the distribution of the Sb minerals. The second part of this study was to quantify mineralogical parameters influencing the distribution of the Sbminerals in a laboratory flotation test. For this purpose composites blended from drill core samples were collected and tested, and the flotation products were analysed with MLA measurement. The measurements were massbalancedby a particle tracking technique and the impact of the mineralogical parameters controlling the Sb distribution was evaluated. The laboratory flotation test showed that Cu- and Pb-bearing Sb sulphosalts show different flotation behaviour than gudmundite and that locking of gudmundite with Cu- and Pb-bearing minerals influences its distribution. Further, chemical, bulk mineralogical and particle information was used to build Sb distribution models based on a first-order kinetic process using HSC Chemistry Sim software. Chemical assays alone were insufficient to simulate the Sb grades of flotation products, since they do not distinguish between the various Sb minerals. The simulation indicated that a model using bulk mineralogy (e.g. collected by Scanning Electron Microscopy based measurements) would be sufficient for estimating the Sb recovery and grade of the Cu–Pb concentrate in the exploration or scoping stage of the Rockliden deposit The following components are required for a complete particle-based geometallurgical model of Rockliden: a process-adapted geological model, a particle-breakage model, and a unit process model. Implementing full particle information in the HSC Chemistry Sim software would improve the flotation model for Sb distribution, i.e. unit process model. Further, suggestions on building a process-adapted geological model and a particle breakage modelare given based on the demands of a corresponding flotation model. The potential of the particle-based approach to provide a holistic view on the deposit by connecting ore geology, mineral processing and process metallurgy aspects of the Rockliden deposit was shown in this study.

  • 4.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bohlin, Nils-Johan
    Boliden, Division of Process Technology.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Detailed characterisation of antimony mineralogy in a geometallurgical context at the Rockliden ore deposit, North-Central Sweden2013In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 52, p. 95-103Article in journal (Refereed)
    Abstract [en]

    The antimony (Sb) content of the Rockliden complex Zn–Cu massive sulphide ore lowers the quality of the Cu–Pb concentrate. The purpose of this study is to characterise the Sb mineralogy of the deposit. The Sb-bearing minerals include tetrahedrite (Cu,Fe,Ag,Zn)12Sb4S13, bournonite PbCuSbS3, gudmundite FeSbS and other sulphosalts. On a microscopic scale these minerals are complexly intergrown with base-metal sulphides in the ore. Based on these observations mineralogical controls on the distribution of Sb-bearing minerals in a standard flotation test are illustrated. Deposit-scale and rock-related variation in the Sb-content and distribution of Sb-bearing minerals were found. This underlines the importance in understanding the geological background as a basis of a 3D geometallurgical model for Rockliden. Such a model is expected to predict the Sb content of the Cu–Pb concentrate, among other process-relevant factors, and helps to forecast when the Cu–Pb concentrate has to be treated by alternative processes, such as alkaline sulphide leaching, before it is sold to the smelter.

  • 5.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bolin, Nils-Johan
    Boliden Mineral AB, Luleå tekniska universitet.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Bachmann, Kai
    TU Bergakademie Freiberg, Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology.
    Gutzmer, Jens
    TU Bergakademie Freiberg, Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Distribution of Sb minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden2015In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 82, p. 125-135Article in journal (Refereed)
    Abstract [en]

    The Rockliden massive sulphide Zn–Cu deposit contains minor amounts of Sb minerals. The Sb mineralogy is complex in terms of composition, micro textures and mineral associations. The main Sb minerals comprise tetrahedrite, bournonite, gudmundite and Sb–Pb sulphides such as meneghinite. The presence of these minerals is especially critical to the quality of the Cu–Pb concentrate. To study how they are distributed in a simplified flotation circuit and what controls their process behaviour Sb-rich drill core samples were selected from the Rockliden deposit and a standard laboratory flotation test was run on the composite samples. Scanning electron microscope-based automated mineralogy was used to measure the Sb mineralogy of the test products, and the particle tracking technique was applied to mass balance the different liberation classes to finally trace the distribution of liberated and locked Sb minerals. The mineralogical factors controlling the distribution of Sb minerals are mineral grain size, the degree of liberation, and associated minerals. Similarities in the distribution of specific particle types from the tested composites point towards systematics in the behaviour of particles and predictability of their distribution which is suggested to be used in a geometallurgical model of the deposit.

  • 6.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bolin, Nils-Johan
    Boliden Mineral AB, Luleå tekniska universitet.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Bachmann, Kai
    TU Bergakademie Freiberg, Helmholtz Institute Freiberg for Resource Technology.
    Gutzmer, Jens
    TU Bergakademie Freiberg, Helmholtz Institute Freiberg for Resource Technology.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Distribution of Sb-bearing minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden2014Conference paper (Other academic)
  • 7.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bolin, Nils-Johan
    Division of Process Technology, Boliden Mineral AB.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bachmann, Kai
    Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology, Freiberg.
    Gutzmer, Jens
    Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology, Freiberg.
    Particle-based Sb distribution model for Cu–Pb flotation as part of geometallurgical modelling at the polymetallic Rockliden deposit, north-central Sweden2017In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 126, no 4, p. 212-223Article in journal (Refereed)
    Abstract [en]

    The polymetallic Cu–Zn ore of the Rockliden massive sulphide deposit in the Skellefte District in north-central Sweden contains a number of deleterious elements in relevant concentrations. Of particular concern is the amount of antimony (Sb) reporting to the Cu–Pb concentrate. The aim of this study was to compare different model options to simulate the distribution of Sb minerals in a laboratory flotation test based on different degrees of details in the mineralogical information of the flotation feed. Experimental data obtained from four composites were used for the modelling and simulation. The following different simulation levels were run (sorted from least to highest level of detail of their mineralogical information): chemical assays, unsized bulk mineralogy, sized bulk mineralogy and particle information. It was shown that recoveries simulated based on bulk mineralogy are mostly within the error margin acceptable in the exploration stage of the Rockliden deposit. Unexpected high deviation in the simulation using particle information from the original recovery has been partly attributed to the fact that recovery of non-liberated particles cannot be modelled appropriately in the present version of the modelling and simulation software. It is expected that the implementation of full particle information in simulation will improve the Sb distribution model for the mineralogically complex Rockliden deposit.

  • 8.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bolin, Nils-Johan
    Boliden, Division of Process Technology.
    Bachmann, Kai
    TU Bergakademie Freiberg.
    Gutzmer, Jens
    TU Bergakademie Freiberg.
    Mineralogical controls on the distribution of antimony in a base-metal flotation test at the Rockliden massive sulphide deposit, north-central Sweden2015In: Mineral resources in a sustainable world / [ed] A.S. André-Meyer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, p. 1439-1442Conference paper (Refereed)
    Abstract [en]

    The Rockliden Zn-Cu massive sulphide mineralisation shows elevated concentrations of critical elements. In particularly the presence of Sb in the Cu–Pb concentrate causes metallurgical challenges in the treatment of this flotation product. The Sb mineralogy at Rockliden is complex, comprising of four main Sb minerals. For this study one mafic dyke and three Sb-rich massive sulphide samples with different base-metal and Sb mineralogy were collected and subjected to a simplified flotation test. The Sb mineralogy of the flotation products was analysed using scanning electron microscope-based image analysis. The distribution of liberated and locked Sb minerals between the flotation products was studied using a particle tracking technique. A comparison of results from the different mineralisation types indicates systematic behaviour of specific particle types, pointing towards the predictability of distribution of the Sb minerals during base-metal flotation.

  • 9.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lasskogen, Jonas
    Boliden Mines, Exploration Department.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lithology and mineralisation types of the Rockliden Zn–Cu massive sulphide deposit, north-central Sweden: Implications for ore processing2014In: Transactions - Institution of Mining and Metallurgy. Section B. Applied earth science, ISSN 0371-7453, E-ISSN 1743-2758, Vol. 123, no 1, p. 2-17Article in journal (Refereed)
    Abstract [en]

    The Rockliden Zn–Cu volcanic-hosted massive sulphide deposit is located approximately 150 km south of the Skellefte ore district, north-central Sweden. Most of the mineralisation is found at the altered stratigraphic top of the felsic volcanic rocks, which are intercalated in the metamorphosed siliciclastic sedimentary rocks of the Bothnian Basin. Mafic dykes cross-cut all lithological units, including the massive sulphides, at the Rockliden deposit. The relatively high Sb grade of some parts of the mineralisation results in challenges in handling of the Cu–Pb concentrate in the smelting process. The aim of this study is to characterise different host rock units and ore types by their main mineralogy, as well as by their trace mineralogy with focus on the Sb-bearing minerals. Ore types are distinguished largely on the basis of their main base-metal bearing sulphide minerals, which are chalcopyrite and sphalerite. Several Sb-bearing minerals are documented and differences in the trace mineralogy between rock and ore types are highlighted. Based on the qualitative ore characterisation, rock- and ore-intrinsic parameters, such as the pyrite, pyrrhotite and magnetite content of the massive sulphides, the trace mineralogy and its association with base-metal sulphide minerals, are outlined and discussed in terms of relevance to the ore processing.

  • 10.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Lasskogen, Jonas
    Boliden Mines, Exploration Department.
    Raat, Hein
    Boliden Mines, Exploration Department.
    Geological background and qualitative ore characterisation for the geometallurgical project at Rockliden, north-central Sweden2013In: Mineral deposit research for a high-tech world: Proceedings of the 12th Biennial SGA Meeting, 12–15 August 2013, Uppsala, Sweden, Uppsala: Sveriges Geologiska Undersökning , 2013, p. 340-343Conference paper (Refereed)
    Abstract [en]

    The Rockliden Zn-Cu massive sulphide mineralisation is located at the stratigraphic top of altered rhyolitic-dacitic volcanic rocks, which in turn are intercalated by meta-sedimentary rocks of the Bothnian Basin, north-central Sweden. After the discovery, in the 1980’s, the project was put on hold due to metallurgical and geometallurgical challenges. Exploration drilling restarted in 2007 and resources have increased since then. However, little is known about the mineralogical variability of the ore and how that will affect the processing of the mineralised material. Examples of rock-intrinsic process-relevant parameters are the mineral grain size, the texture of the minerals and the mineral associations, i.e. the mode of occurrence of minerals in the different types of mineralisation, and also the presence and distribution of penalty and bonus elements. Rock-intrinsic parameters and their spatial variability are considered in this study and will form the basis of a 3D-geometallurgical model for the Rockliden mineralisation.

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