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  • 301.
    Martinsson, Olof
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Metallogeny of juvenile Palaeoproterozoic volcanic arcs and greenstone belts in rifted Archaean crust in the northern part of Sweden, Fennoscandian Shield1999Ingår i: Mineral deposits : processes to processing: proceedings of the Fifth biennial SGA meeting and the Tenth quadrennial IAGOD symposium, Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1999, s. 1329-1332Konferensbidrag (Refereegranskat)
  • 302.
    Martinsson, Olof
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Metallogeny of juvenile Palaeoproterozoic volcanic arcs and greenstone belts in rifted Archaean crust in the northern part of Sweden: Fenno-scandian Shield1999Ingår i: Mineral deposits, processes to processing: proceedings of the fifth biennial SGA Meeting and the tenth quadrennial IAGOD Symposium/London/United Kingdom/22-25 August 1999 / [ed] C.J. Stanley, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1999, Vol. 2, s. 1005-1008Konferensbidrag (Refereegranskat)
  • 303.
    Martinsson, Olof
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Stratiform-stratabound sulphide deposits2007Ingår i: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, s. 18-19Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 304.
    Martinsson, Olof
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öberg, E.
    LKAB, Research & Development, 983 81 Malmberget.
    Fredriksson, Andreas
    Mining Technology R and D, LKAB Kiruna Mine.
    Apatite for extraction: Mineralogy of apatite and ree in the kiirunavaara Fe-deposit2012Ingår i: XXVI International Mineral Processing Congress: IMPC 2012, New Delhi, India, September 24-28, 2012 : conference proceedings, New Dehli: The Indian Institute of Metals , 2012, s. 3287-3297Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Kiruna area is an important mining province in northern Sweden, which is dominated by Fe- and Cu-Au deposits. Economically most important for the region, are the apatite iron ores with an annual production of c. 43 M ton of crude Fe-ore and a total production of more than 2000 M ton of ore the last 100 years. The apatite iron ores in the Kiruna area are dominated by either Magnetite or Haematite and contain varying amounts of apatite giving them a content of Fe and P, which varies between 30-70 % and 0.05-5 %, respectively. A typical geochemical feature of the ores is the strong enrichment of REE that is caused by a high content of REE in apatite and the occurrence of Allanite and Monazite containing 22.4 and 69.8 wt% REO, respectively. At Kiirunavaara, the content of REE in apatite varies between 0.07 to 1.57 wt% REO with a dominance for the light rare earths. The variation in REE-content of apatite depending on textural and paragenetic aspects is not known but apatite grains may display a strong LREE-depletion due to hydrothermal alteration. Monazite occurs as rod-shaped or tabular inclusions in apatite and is suggested, to have formed in response to hydrothermal alteration of apatite after the emplacement of the ore. Inclusions are mainly found in the central part of apatite grains occurring in veins and schliren, while they are rare in apatite occurring disseminated in the ore. Monazite also occurs as larger grains outside apatite and together with Allanite is found in texturally and paragenetically different settings within the ore. These occurrences of REE-minerals may largely be a product of LREE mobilized by alteration of apatite after the emplacement of the ore. However, REE-minerals including Allanite and Monazite might also have formed directly from late magmatic fluids.

  • 305.
    Mellqvist, Claes
    et al.
    Luleå tekniska universitet.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Sjöberg, Hans
    Swedish Museum of Natural History.
    Some aspects on the subdivision of the Haparanda and Jörn intrusive suites in northern Sweden2003Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 125, nr 2, s. 77-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The geographical subdivision between the Haparanda and the Jörn suites of intrusive rocks in northern Sweden has not been very well defined. Early stratigraphical schemes placed these two granitoid suites in two separate orogenic cycles, where the Jörn belonged to the older cycle and Haparanda to the younger. Our present knowledge regarding the isotopic ages of these rocks in northern Sweden has changed this view, but has also made the distinction between the two suites less clear. Based on recent Sm–Nd isotopic work combined with geochemistry and some new U–Pb zircon data, we point out some similarities as well as some differences between the Jörn and Haparanda suites of rocks. Two U–Pb zircon age determinations performed give upper intercept ages of 1891±32 Ma and 1861±19 Ma which are interpreted as maximum ages. The two samples are taken from the Luleå area, on each side of the Archaean–Proterozoic boundary, as defined by Sm–Nd isotopic analyses of c.1.9 Ga old intrusive rocks combined with the southern limit of outcropping Archaean rocks. On the basis of new results together with results from previous studies of areas north and south of the Archaean–Proterozoic boundary, we also suggest how to separate the Haparanda and Jörn suites of rocks due to their geochemical, and isotope geochemical, characteristics. The Haparanda suite generally has negative εNd(t) values and was formed within or in marginal parts of the Archaean craton. The Jörn suite was formed in an juvenile, island-arc terrane, that was accreted to the Archaean craton during the later, collisional stages of the Svecokarelian orogeny. In a similar way, we connect the Haparanda suite of rocks with the Archaean craton, and the Jörn suite of rocks with Svecofennian juvenile crust.

  • 306.
    Mercier-Langevin, Patrick
    et al.
    Geological Survey of Canada.
    McNicoll, Vicky
    Geological Survey of Canada.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Blight, James H.S.
    Boliden Mineral, Exploration Department, Boliden.
    Dubé, Benoît B.
    Geological Survey of Canada.
    The Boliden gold-rich volcanogenic massive sulfide deposit, Skellefte district, Sweden: new U-Pb age constraints and implications at deposit and district scale2013Ingår i: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 48, nr 4, s. 485-504Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Boliden deposit (8.3 Mt at 15.9 g/t Au) is interpreted to have been formed between ca. 1894 and 1891 Ma, based on two new U-Pb ID-TIMS ages: a maximum age of 1893.9 + 2.0/-1.9 Ma obtained from an altered quartz and feldspar porphyritic rhyolite in the deposit footwall in the volcanic Skellefte group and a minimum age of 1890.8 ± 1 Ma obtained from a felsic mass-flow deposit in the lowermost part of the volcano-sedimentary Vargfors group, which forms the stratigraphic hanging wall to the deposit. These ages are in agreement with the alteration and mineralization being formed at or near the sea floor in the volcanogenic massive sulfide environment. These two ages and the geologic relationships imply that: (1) volcanism and hydrothermal activity in the Skellefte group were initiated earlier than 1.89 Ga which was previously considered to be the onset of volcanism in the Skellefte group; (2) the volcano-sedimentary succession of the Vargfors group is perhaps as old as 1892 Ma in the eastern part of the Skellefte district; and (3) an early (synvolcanic) deformation event in the Skellefte group is evidenced by the unconformity between the ≤1893.9 + 2.0/-1.9 Ma Skellefte group upper volcanic rocks and the ≤1890.8 ± 1 Ma Vargfors sedimentary and volcanic rocks in the Boliden domain. Differential block tilting, uplift, and subsidence controlled by synvolcanic faults in an extensional environment is likely, perhaps explaining some hybrid VMS-epithermal characteristics shown by the VMS deposits of the district

  • 307.
    Metzger, Nicolai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Structural controls on the shear zone hosted, IOCG-style Kiskamavaara Cu-Co-Au mineralization2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Sweden is the largest producer of iron ore in the European Union, as well as amongst the top producers for base and precious metals. Much of its mineral wealth derives from northern Norrbotten, type locality of the Kiruna-type-magnetite-apatite ores. Besides the massive iron ore bodies, the region is further recognized as important iron-oxide-copper-gold (IOCG) province, with the world class, Aitik Cu-Au-Ag-(Mo) deposit as its most prominent example (1061 Mt with 0,22% Cu; 0,15ppm Au; 1.3ppm Ag), (Wanhainen et al. 2012, Boliden 2017). The close spatial relation between Aitik, further IOCG style mineralization and the Nautanen Deformation Zone (NDZ), a crustal-scale, approximately N-S trending shear system provides important insights into the complex connection between deformation, reactivated fault systems and the different mineralizing events affecting the area during the Svecofennian period (1.9-1.8 Ga). Whereas this connection is well constrained within the Gällivare mining district (c.f. Martinsson and Wanhainen 2004, Wanhainen et al. 2012, Bauer et al. 2018, Lynch et al. 2018), the northern and southern continuations of the NDZ and its potential to host further mineralization remain unknown. During this study, an area around the Kiskamavaara Cu-Co-Au mineralization was investigated to link its tectonic evolution with regional metallogenic events and compare its alterations and structural regime to that of the highly prospective NDZ. It is suggested that the region was affected by at least two deformation events, D1 and D2, both causing a characteristic alteration assemblage, structural patterns and related mineralization. The identification of pseudotachylitic structures and supergene mineralization argues for a late, brittle, upper crustal event with hydrothermal character during D2. Constraining the Kiskamavaara Cu-Co-Au mineralization to this event allows to propose a genetic link to the known IOCG-style mineralization in the Nautanen area that are generally related to a late, 1.80 Ga period of hydrothermal activity. It is suggested that the Cu-Au mineralization in the Kiskamvaara and Nautanen area formed under similar conditions, hence arguing for a single high strain zone in favor over several locally constrained zones of crustal weakening. If supported in further studies, this finding of a highly prospective NDZ beyond its known extend, might justify more intense exploration in highly strained lithologies between the Kiskamavaara and Nautanen area, as well as north of Mattavaara and south of Gällivare.

  • 308.
    Minz, Friederike
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Mineralogical characterisation of the Rockliden antimony-bearing volcanic-hosted massive sulphide deposit, Sweden2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 309.
    Minz, Friederike
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Mineralogical Controls on the Recovery of Antimony in Base-Metal Flotation – Outlining the Framework of a Geometallurgical Model for the Rockliden VHMS Deposit, Sweden2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 310.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bohlin, Nils-Johan
    Boliden, Division of Process Technology.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Detailed characterisation of antimony mineralogy in a geometallurgical context at the Rockliden ore deposit, North-Central Sweden2013Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 52, s. 95-103Artikel i tidskrift (Refereegranskat)
    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.

  • 311.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bolin, Nils-Johan
    Boliden Mineral AB, Luleå tekniska universitet.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Distribution of Sb minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden2015Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 82, s. 125-135Artikel i tidskrift (Refereegranskat)
    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.

  • 312.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bolin, Nils-Johan
    Boliden Mineral AB, Luleå tekniska universitet.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    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 tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Distribution of Sb-bearing minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden2014Konferensbidrag (Övrigt vetenskapligt)
  • 313.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bolin, Nils-Johan
    Division of Process Technology, Boliden Mineral AB.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    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 Sweden2017Ingår i: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 126, nr 4, s. 212-223Artikel i tidskrift (Refereegranskat)
    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.

  • 314.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    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 Sweden2015Ingår i: Mineral resources in a sustainable world / [ed] A.S. André-Meyer; M. Cathelineau; P. Muchez; E. Pirard; S. Sindern, 2015, s. 1439-1442Konferensbidrag (Refereegranskat)
    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.

  • 315.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lasskogen, Jonas
    Boliden Mines, Exploration Department.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lithology and mineralisation types of the Rockliden Zn–Cu massive sulphide deposit, north-central Sweden: Implications for ore processing2014Ingår i: Transactions - Institution of Mining and Metallurgy. Section B. Applied earth science, ISSN 0371-7453, E-ISSN 1743-2758, Vol. 123, nr 1, s. 2-17Artikel i tidskrift (Refereegranskat)
    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.

  • 316.
    Minz, Friederike
    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.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    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 Sweden2013Ingår i: 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, s. 340-343Konferensbidrag (Refereegranskat)
    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.

  • 317. Montelius, Cecilia
    The genetic relationship between rhyolitic volcanism and Zn-Cu-Au deposits in the Maurliden volcanic centre, Skellefte district, Sweden: volcanic facies, lithogeochemistry and geochronology2005Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The Skellefte district is one of three major ore provinces in Sweden and contains more than 80 Zn-Cu-Au-Ag massive sulphide deposits. The Maurliden area in the central part of the district represents a subaqueous, constructional and relatively topographic high silicic volcanic centre. It hosts four sulphide deposits and was active during around 1885 Ma. The tholeiitic to transitional Maurliden volcanic centre developed in an extensional arc region in the Skellefte district that probably developed on an immature (relatively thin) continental arc crust. The four Maurliden Zn- Cu-Au massive to stringer sulphide deposits are hosted within the same quartz-feldspar porphyritic pumice breccia-sandstone unit (QFP pumice unit) and were formed by replacement and infilling of this unit together with seafloor precipitation/exhalation. The QFP pumice unit was generated by explosive subaqueous eruptions and was sedimented on the seafloor as a succession of subaqueous mass-flow pulses. Field relationships and geochemistry indicate a close relationship between massive sulphide deposition and host rock in composition, intensity of volcanism and sedimentation during the evolution of the Maurliden volcanic centre. The volcanic activity before ore deposition was dominated by felsic extrusive volcanism associated with both terrestrial to shallow marine breccia-conglomerates and siltstone-sandstone turbidites deposited below wave base. At the same time or slightly after this stage, there was a stage of quartz-feldspar porphyritic rhyolitic extrusive and explosive volcanism. At this stage the ore-host, the QFP pumice unit, was subaqeously erupted and emplaced. The waning stage of the felsic volcanic activity was accompanied by deposition of massive sulphide and siltstone-sandstone. Most mafic rocks are post-ore dykes. The similar geochemical composition of the felsic rocks suggests that they were derived from a common magma source. Trace element and rare earth element characteristics suggest that these magmas were relatively primitive. The coeval felsic volcanic activity and the strong facies control on massive sulphide deposition, suggest that massive sulphide deposition was intimately linked to the magmatic evolution of the Maurliden volcanic centre. The QFP pumice unit has a strong control on the location of sulfide mineralization in the Maurliden area, and represents a new VMS horizon in the central Skellefte district and it is possible that this horizon occurs in other unexplored parts of the Maurliden domain.

  • 318.
    Montelius, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Volcanology of the paleoproterozoic Maurliden area and its four unusual massive sulphide deposits, Skellefteå district, Sweden2001Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The Skellefte district is one of three major ore provinces in Sweden and contains more than 85 Zn-Cu-Au-Ag massive sulphide deposits. The Maurliden area is situated in the central part of the district and is a subaqueous volcanic dominated area with four Zn-Pb-Cu-Au-Ag sulphide deposits. The stratigraphy is characterised by felsic coherent intrusions, lavas and their clastic facies, sulphide mineralisations and fine to coarse grained stratified to graded volcaniclastic sedimentary rocks. Facies analysis of the Maurliden domain involving mapping and drillcore logging in a number of areas, but mainly in the central mineralised part where most drill-cores and outcrops occur, has led to a better understanding of the palaeovolcanology. Coherent felsic intrusions, lavas and their clastic facies and minor sedimentary and mafic rocks characterize the area. These rocks are tightly to closely upright folded and the massive sulphide deposits are situated in the northern and southern limbs of a major synform. The principal sedimentary facies are; 1) mudstone and sandstone turbidites; 2) pebbly sandstone and sand to siltstone turbidites; 3) graded to stratified breccia/conglomerate and 4) locally derived breccia/conglomerates. The volcanic and sedimentary facies together reflect a dynamic interplay between subsidence and uplift and between volcanism and tectonism. This resulted in adjacent and juxtaposed deep and shallow water depositional environments at different stratigraphic levels. The four massive to network sulphide deposits occur in and above stratigraphic intervals containing sedimentary facies emplaced below wave base, but shallow water facies are widespread and occur close to and stratigraphically below the mineralizations. Based on field relationships, petrographic and textural evidence are all four Maurliden mineralizations interpreted to be hosted in the same strongly quartz-feldspar porphyritic rhyolite. Intrusive contact relationships and high crystal content of this rhyolite suggest that it is an intrusion. The Maurliden sulfide deposits show several features typical of seafloor VHMS such as well-developed stringer zones, metal zonation, potential ore bearing sub-aqueous sedimentary horizon, colloform pyrite and polymetallic composition. However, other features such as intrusive host facies, extensive hydrothermal brecciation, disseminated and vein mineralizations are more typical of porphyry and high sulfidation deposits. The Maurliden deposits with all these different features form a transition between these hydrothermal end members.

  • 319. Montelius, Cecilia
    et al.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Crystal-rich Rhyolitic Pumice Flows and Domes: Evidence for Submarin Explosive and Extrusive Volcanism in the 1.9 Ga Maurliden Volcanic Centre, Skellefte District, Sweden2004Konferensbidrag (Refereegranskat)
  • 320. Montelius, Cecilia
    et al.
    Allen, Rodney
    Svenson, S. A.
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The Maurliden volcanogenic Zn-Cu-Au-Ag massive- and network-sulfide deposits, Skellefte District, Sweden2000Ingår i: Volcanic environments and massive sulfide deposits / [ed] J. Bruce Gemmell; June Pongratz, Hobart: Colonialism and its Aftermath, University of Tasmania, 2000, s. 135-136Konferensbidrag (Övrigt vetenskapligt)
  • 321. Montelius, Cecilia
    et al.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Svenson, S. Å.
    Weihed, Pär
    Volcanology of a palaeoproterozoic shallow marine region with unusual massive sulphide deposits: potential for a gold-bearing system, Maurliden, Skellefte district, Sweden1999Ingår i: Gold 99 Trondheim: Precambrian gold in the Fennoscandian and Ukrainian shields and related areas : abstract volume / [ed] Nigel J. Cook; Krister Sundblad, Trondheim: American Speech-Language-Hearing Association, 1999, s. 123-124Konferensbidrag (Övrigt vetenskapligt)
  • 322. Montelius, Cecilia
    et al.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Svenson, Sven-Åke
    Boliden Mineral AB.
    Weihed, Pär
    Facies architecture of the Palaeoproterozoic VMS-bearing Maurliden volcanic centre, Skellefte district, Sweden2007Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 129, nr 3, s. 177-196Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The four Maurliden massive to network sulphide deposits are hosted by a silicic volcanic succession in the Palaeoproterozoic Maurliden domain in the central part of the Skellefte district, northern Sweden. The bedrock in the Maurliden domain can be divided into primary volcanic rocks and volcaniclastic sedimentary rocks. The primary volcanic rocks comprise coherent rhyolitic, dacitic, andesitic and mafic volcanic facies and their related autoclastic and pumiceous breccia facies. The volcaniclastic sedimentary rocks include monomict to slightly polymict breccia-conglomerates, which are related to terrestrial to shallow marine erosion of domes, and sandstone turbidites and mudstones, which indicate submarine settings below wave base. The primary volcanic rocks and volcaniclastic sedimentary rocks collectively define a submarine volcanic centre. This volcanic centre was characterized by the emplacement of rhyolitic domes and cryptodomes, accompanied by subordinate explosive activity. It was developed in the ensialic back-arc or intra-arc basin of the Skellefte district. The facies architecture shows that prior to massive sulphide deposition, feldspar porphyritic rhyolitic volcanism, and both terrestrial/shallow marine and below wave base environments characterized the volcanic centre. At the time of massive sulphide deposition the Maurliden volcanic centre was characterized by quartz-feldspar porphyritic rhyolite volcanism and below wave base environment. This volcanism resulted in strongly quartz-feldspar porphyritic rhyolite cryptodomes, domes and quartz-feldspar porphyritic pumice breccia-sandstone (QFP pumice unit). The QFP pumice unit erupted explosively and was rapidly sedimented on the sea floor as a series of subaqueous mass-flows. All four Maurliden sulphide deposits are hosted within this QFP pumice unit, which suggest a genetic connection between eruption of the QFP pumice unit and formation of the sulphide deposits.

  • 323. Montelius, Cecilia
    et al.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Svenson, Sven-Åke
    Weihed, Pär
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Intrusion-Hosted, Polymetallic Massive and Network Sulfide Deposits, Maurliden, Skellefte District, Sweden2004Ingår i: Svecofennian Ore-Forming Environments Field Trip Volcanic-associated Zn-Cu-Au-Ag and magnetite-apatite, sediment-hosted Pb-Zn, and intrusion-associated Cu-Au deposits in northern Sweden, Littleton, Colorado: Society of Economic Geologists, 2004, s. 95-Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 324.
    Möller, Charlotte
    et al.
    Department of Geology, University of Lund.
    Bingen, Bernard
    Geological Survey of Norway, Trondheim.
    Andersson, Jenny
    Geological Survey of Sweden.
    Stephens, Michael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Viola, Giulio
    Geological Survey of Norway, Trondheim.
    Scherstén, Anders
    Department of Geology, University of Lund.
    A non-collisional, accretionary Sveconorwegian orogen: comment2013Ingår i: Terra Nova, ISSN 0954-4879, E-ISSN 1365-3121, Vol. 25, nr 2, s. 165-168Artikel i tidskrift (Refereegranskat)
  • 325.
    Nilsson, Bruno
    Luleå tekniska universitet.
    Two topics in electromagnetic radiation field prospecting1978Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Different kinds of electrical methods have been used for a considerable time in the field of Applied Geophysics. In common these methods have almost exclusively been based on stationary or slow-varying electromagnetic fields. With a slow-varying field is meant a field whose wavelength is much larger than the characteristic dimensions of the body under study. That is, the field may be regarded as homogeneous in volumes of interest. In practice, a field with a frequency below let say 50 kHz may be regarded as slow~ varying. A certain class of electromagnetic fields is of the radiating type. In this case a considerable part of the electromagnetic energy will leave the near-zone of the transmitting antenna, and propagate as electromagnetic waves. In this dissertation, the author presents some of his research connected to electromagnetic radiation field prospecting carried out at the GeoPhysics Laboratory at Boliden Metall AB. In part 1 "Geophysical prospecting by radar" the possibilities in using HF, VHF and UHF frequencies are studied. These frequencies are found at the extreme high end of the electromagnetic spectrum, from a geophysical point of view. A particular interest is paid to the pulse-radar principle. In part 2 "New instrumentation for VLF radiation field prospecting" the technical details of the prospecting systems VLF-72/73 and WIMP-30 are presented. These systems utilize radiation fields at the extreme low end of the electromagnetic spectrum, in order to measure the apparent resistivity of the ground.

  • 326.
    Nissen, Johan
    Luleå tekniska universitet.
    Versatile programs for geoelectromagnetic interpretation1986Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 327.
    Nordin, Roger
    et al.
    Boliden Mineral AB.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Aaltonen, Riikka
    Boliden Mineral AB.
    Day 5: Gruvberget and Aitik deposits. Stop 2 - Aitik Cu-Au-Ag mine2007Ingår i: Metallogeny and tectonic evolution of the Northern Fennoscandian Shield: field trip guidebook, Espoo: Geological Survey of Finland , 2007, s. 78-84Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 328.
    O'Brien, Joshua J
    et al.
    Department of Geological and Atmospheric Sciences, Iowa State University.
    Spry, Paul
    Department of Geological and Atmospheric Sciences, Iowa State University.
    Raat, Hein
    Boliden Mines, Exploration Department.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Frank, Katherine S
    Department of Geological and Atmospheric Sciences, Iowa State University.
    Jansson, Nils
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The major-trace element chemistry of garnet in metamorphosed hydrothermal alteration zones, Proterozoic Stollberg Zn-Pb-Ag-(Cu-Au) ore field, Bergslagen district, Sweden: implications for exploration2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Altered and exhalative rocks are used as exploration guides to ore deposits since they are generally more extensive than the massive sulfide target. Major and trace element compositions of silicates (e.g., garnet) and oxides (e.g., gahnite and magnetite) in meta-exhalites have recently been used as a vectoring tool in the search for metamorphosed massive sulfide deposits. Here, we evaluate the major-trace element chemistry of garnet in altered (i.e., gedrite-albite, garnet-biotite, and garnet-pyroxene-carbonate alteration) and unaltered (i.e. rhyolitic ash-siltstone) rocks spatially associated with volcanogenic massive sulfide Zn-Pb-Ag-(Cu-Au) and magnetite deposits in the Stollberg ore field (metamorphosed to the amphibolite facies), to determine the spatial distribution of major/trace element compositions of garnet and the potential of garnet chemistry as a guide to ore. Garnet in garnet-biotite alteration (extends intermittently for ~8 km along strike) and high-grade sulfides is Fe-rich (almandine) whereas garnet in skarn and garnet-pyroxene alteration contains significantly higher amounts of Ca (grossular), and Mn (spessartine). Concentrations (425 analyses) of trace elements in garnet were obtained from 38 samples in the Dammberget (n = 14), Gränsgruvan (n = 17), and Tvistbo (n = 7) deposits. Garnet contains elevated concentrations of Sc, Ti, V, Cr, Co, Zn, Ga, Ge, Y, and rare earth elements (REEs). Chondrite-normalized rare earth element patterns of garnet are depleted in light REEs (LREEs) and enriched in heavy REEs (HREEs). Garnet in sulfide-bearing altered rocks (i.e., garnet-biotite and garnet-pyroxene alteration) show a strong positive Eu anomaly, regardless of its major element composition, and contains elevated Zn (> 100 ppm) and Ga (> 15 ppm) contents, and low concentrations of Ti (<200 ppm). Garnet-biotite alteration adjacent to unaltered rhyolitic ash-siltstone contains garnet which is LREE depleted, HREE enriched, and typically shows no Eu anomaly, or in some cases, minor negative Eu anomalies. In sulfide-free quartz-garnet-pyroxene rocks, garnet possesses no Eu anomaly and contains elevated concentrations of Ga (> 10 ppm), Sc (> 5 ppm), and Ti (> 100 ppm), but low concentrations of Co (< 1 ppm), Cr (< 5 ppm), and V (< 20 ppm). Garnet in gedrite albite alteration exhibits a relatively flat chondrite-normalized REE profile, and contains elevated (> 10 ppm) Sc content, and low concentrations of V (< 2 ppm), Cr (< 3 ppm), and Zn (< 30 ppm). Garnet in mafic dikes and marbles contain the highest Cr (> 10 ppm), Co (> 5 pm), V (25-250 ppm) and Ti contents, whereas garnet in rhyolitic ash-siltstone typically shows no Eu anomaly, and low concentrations of Zn (< 100 ppm), Ga (< 15 ppm), Cr (< 5 ppm), and V (< 3 ppm). Garnet in massive sulfides and sulfide-bearing alteration assemblages can be distinguished from sulfidepoor or sulfide-free rocks of the same alteration type on the basis of their positive Eu anomaly, and Zn, Ga, and Ti content, which suggests garnet chemistry may be used as a vectoring tool to ore in the Stollberg ore field, and elsewhere in the Bergslagen district.

  • 329.
    O’Carroll, Conor
    et al.
    European Research Area Steering Group on Human Resources and Mobility, Newry.
    Scholz, Beate
    Scholz Consulting, Bonn, Germany.
    Nogueira, Maria Manuela
    European Science Foundation, Strasbourg, France.
    Avellis, Gianna
    InnovaPuglia, Valenzano, Italy, m-WiSET Working Group of the Marie Curie Fellows Association, Brussels.
    Marin, Laura
    Swedish Research Council, Stockholm, Sweden.
    Dan, Maria Bostenaru
    Ion Mincu University of Architecture and Urbanism, Bucharest, Romania.
    Chmielowski, Riia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Trapani, Antonella di
    European Research Council Executive Agency, Brussels.
    Theodoridou, Magdalini
    University of Cyprus, Nicosia.
    Careers: Virtual mobility can drive equality2014Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 511, nr 292, s. 292-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    At a EuroScience Open Forum meeting last month, scientists, policy-makers and the public discussed ‘virtual mobility’. Could it replace the conventional geographical mobility of earlycareer researchers between labs? (See also R. Garwood Nature 510, 313; 2014.) The group concluded that virtual mobility would work, but should be combined with short-term visits to other labs to allow face-to-face contact, which in our view is crucial for building trust and for working across cultures. However, more than half of scientists questioned in a European Commission survey (www.more-2.eu) considered that virtual mobility would make short-term visits unnecessary. Meeting participants agreed that virtual mobility would provide equal access to and for researchers with physical disabilities, would help those on parental leave to maintain contact with their national and international networks, and would enable researchers in poorer regions to access wellresourced labs and to collaborate internationally. We maintain that virtual mobility should be considered on the same footing as mobility between disciplines, sectors and geographical regions, and that it should be seen as a driver of equal opportunities. Peer review and evaluation structures need to acknowledge these new mobility concepts.

  • 330. Oghazi, Pejman
    et al.
    Lund, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Applying traceability in a mine-to-mill context by using particle texture analysis2010Ingår i: SME Annual Meeting and Exhibit 2010: Phoenix, Arizona, USA, 28 February - 3 March 2010, Red Hook, NY: Curran Associates, Inc., 2010, s. 7-11Konferensbidrag (Refereegranskat)
    Abstract [en]

    It is possible to have traceability in the mining industry, by parameters and signatures like particle mineralogy, mineral association, texture and mineral liberation. The study is on an apatite-iron ore deposit at Malmberget, Sweden, and characterises an ore body both mineralogically and texturally in a quantitative manner by using analytical methods like optical microscopy, microprobe (EMPA) and an automatic SEM based system, Particle Texture Analysis (PTA). The mineralogy was evaluated by PTA and characterized by modal mineralogy, mineral liberation and mineral associations. Magnetite has a simple outline and straight grain boundaries and the gangue minerals have a finer particle size with a more complicated texture. The PTA analysis also shows that apatite is associated to magnetite as mixed particles, while smaller grains of magnetite are inclusions in feldspar. Result from particle texture analysis shows that there is a connection which link to the mine-to-mill context, and it may be used to create traceability. This link is not the associations of the main ore mineral magnetite, nor the modal mineralogy. Instead, it is the mineral associations of contaminating minerals (apatite and feldspar) that appear to be most promising since they survive from mine to mill. The modal mineralogy may be used to understand how contaminating minerals break into or out of particle size fraction during grinding.

  • 331.
    Olsson, Olle
    Luleå tekniska universitet.
    Scattering of electromagnetic wave by a perfectly conducting half plane below a stratified overburden1978Ingår i: Radio Science, ISSN 0048-6604, E-ISSN 1944-799X, Vol. 13, nr 2, s. 391-397Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By expanding the electromagnetic field into plane wave eigenfunctions, an integral equation is obtained which describes the coupling between an overburden, consisting of an arbitrary number of plane layers and an arbitrary object beneath a stratified half space. As an example of the technique, a perfectly conducting half plane inclined to the strata in a substratum is discussed. In this case the kernel of the integral equation may be expressed in terms of elementary functions. Numerical results are discussed for a plane wave incident on the ground

  • 332.
    Olsson, Olle
    Luleå tekniska universitet.
    Scattering of electromagnetic waves by a perfectly conducting half plane below a stratified overburden1978Ingår i: Radio Science, ISSN 0048-6604, E-ISSN 1944-799X, Vol. 13, s. 391-397Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By expanding the electromagnetic field into plane wave eigenfunctions, an integral equation is obtained which describes the coupling between an overburden, consisting of an arbitrary number of plane layers and an arbitrary object beneath a stratified half space. As an example of the technique, a perfectly conducting half plane inclined to the strata in a substratum is discussed. In this case the kernel of the integral equation may be expressed in terms of elementary functions. Numerical results are discussed for a plane wave incident on the ground.

  • 333.
    Olsson, Olle
    Luleå tekniska universitet.
    Scattering of electromagnetic waves by a perfectly conducting half plane below a stratified overburden and applications to geophysical prospecting by VLF1978Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The present paper is an introduction to and a summary of a thesis consisting of the following papers:1. Scattering of electromagnetic waves by a perfectly conducting half plane below a stratified overburden. Radio Sci. (1978), Vol. 13, No. 2, p. 391-397.II. VLF anomalies from a perfectly conducting half plane below an overburden. Accepted for publication in Geophysical Prospecting.The thesis also containsIII. VLF5 program documentationIV. Program listing of VLF5-MO.Electromagnetic methods have been used in geophysical prospecting since the beginning of the twentieth century. Since the first field tests there has been a tremendous development and refinement of field methods and instrumentation. The electromagnetic methods have proved to be an efficient tool for the localization of conductive zones in the earths crust, e.g. mineral deposits, shales and fracture zones. Even though the electromagnetic methods have been in extensive use for such a long time the intrepretation of the field data has been more an art than a science. This has to a large extent been due to lack of appropriate theoretical models amenable to computation that would explain the field data. For a long time the only theoretical models available were those where boundaries between media of different conductivity were defined by a constant on a coordinate axis such as a sphere, cylinder, half plane, or a horizontally stratified earth. Beginning in the nineteensixties when large digital computers came into more general use there has been an increased effort put into solving electromagnetic problems relevant to geophysics. Since about 1970 there has been a series of pertinent papers published by different workers on the subject. The problems have been attached by different analytical and numerical methods such as integral equation methods, finite element methods, and finite difference methods. The present thesis is a development of the integral-equation technique to deal with the problems often encountered in geophysical prospecting where a subsurface conductor in conducting host rock is situated below a stratified overburden. The electric and magnetic field is represented by the Hertz vectors. As has been discussed by Stratton (1941) it is sufficient with a single component of each Hertz vector. The fields are thus expressed through two scalar potentials satisfying the scalar Helmholtz equation. These scalar potentials may in certain cases be identified with the two polarizations of the electromagnetic field. To solve the boundary equations at the horizontal boundaries in the stratified overburden the potential functions are expanded into plane waves. In the plane wave representation the overburden is completely described through its reflection and transmission coefficients for each plane wave. For an arbitrary number of layers in the overburden the reflection and transmission coefficients are easily obtained through a recursion formula. When a plane wave propagating downward strikes an anomalous object situated in the halfspace below the overburden the secondary field generated by this object will consist only of upgoing waves at any horizontal surface above the anomalous object. The secondary field generated by the anomalous region may thus be completely represented by the scattering matrix for the plane waves. In certain cases the scattering matrix is fairly easy to calculate e.g. a sphere, cylinder, or halfplane (as will be shown below). In a series of papers Waterman (1965, 1971) has developed a method to calculate the scattering matrix for more complicated structures. The boundary equations at the bottom surface of the overburden gives an integral equation for the plane wave amplitudes where the kernel of the equation is the scattering matrix multiplied by the reflection coefficient of the overburden. To find the scattering matrix of the perfectly conducting halfplane the Hertz potentials are expanded into modified Bessel functions. After several manipulations the scattering matrix is found to be simple and its elements consist of elementary functions. The integral equation is approximated by a matrix equation which is solved by standard iterative methods. When the plane wave amplitudes at the bottom of the overburden have been obtained the wave amplitudes at the ground surface are readily obtained and the field components may be calculated. Numerical calculations have been carried out for the perfectly conducting halfplane when the incident field is a plane wave, with special application to VLF prospecting. The VLF method makes use of the electromagnetic field from radio transmitters in the frequency range 10-30 kHz. The VLF transmitter can usually be considered as a vertical electrical dipole situated at the ground surface. The transmitted field will thus have a magnetic field component which is approximately tangential to the surface of the earth. When the VLF field is considered in a limited region a few wavelengths from the transmitter the primary field is usually well approximated by a plane TM wave incident almost tangentially along the ground. The use of the VLF-method in mineral exploration started around 1960, since then the VLF-method has become an extensively used tool in mineral exploration and geological mapping. The method has proved to be an efficient tool in localizing structures of enhanced conductivity, e.g. mineralization, fracture zones, graphite shists, and shales. For many of these cases the halfplane can be considered to be an appropriate model. The VLF anomalies have been computed for different overburden conductivity and thickness and also for different dip angles of the halfplane. The anomaly curves, which are displayed as tilt and ellipticity of the polarization ellipse, show a fairly complicated behavior. However the qualitative behavior of the curves is mainly due to the phase shift and attenuation of the field caused by the conductivity of the overburden and the host rock. From the anomaly curves it is possible to define the apparent depth to the top of the conductor as the distance between the up-dip peak value and the cross-over of the real component. The apparent depth is usually larger than the actual depth, but it is possible to determine the actual depth to the conductor from the relation between the peak to peak anomaly and the apparent depth. When the peak to peak anomaly is fairly large it is also possible to make estimates of the dip angle. In a specific case the theoretical calculations are shown to be in good agreement with measured data.

  • 334.
    Olsson, Olle
    Luleå tekniska universitet.
    VLF anomalies from a perfectly conducting half plane below an overburden1980Ingår i: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 28, nr 3, s. 415-434Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A theoretical solution to the electromagnetic problem of a perfectly conducting half plane below a conducting overburden has been obtained. The VLF anomalies have been computed for different overburden conductivity and the thickness and also for different dip angles of the half plane. In the computations the contribution to the secondary magnetic field from the electric Hertz potential has been neglected. From the anomaly curves it is possible to define the apparent depth to the top of the conductor as the distance between the peak value and the cross-over of the real component. It is possible to determine the actual depth to the conductor from the relation between the peak-to-peak anomaly and the apparent depth. When the peak-to-peak anomaly is fairly large, it is also possible to make estimates of the dip angle

  • 335.
    Parian, Mehdi
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Particle-based Process Models in Mineral Processing2016Konferensbidrag (Övrigt vetenskapligt)
  • 336.
    Pašava, Jan
    et al.
    Czech Geological Survey.
    Ackerman, Lukáš
    Institute of Geology of the Czech Academy of Sciences .
    Halodová, Patricie
    Czech Geological Survey.
    Pour, Ondrej
    Czech Geological Survey.
    Durišová, Jana
    Institute of Geology of the Czech Academy of Sciences.
    Zaccarini, Frederica
    Department of Applied Geosciences and Geophysics, University of Leoben.
    Aiglsperger, Thomas
    Department of Crystallography, Mineralogy, and Ore Deposits, University of Barcelona.
    Vymazalová, Anna
    Czech Geological Survey.
    Concentrations of platinum-group elements (PGE), Re and Au in arsenian pyrite and millerite from Mo-Ni-PGE-Au black shales (Zunyi region, Guizhou Province, China): results from LA-ICPMS study2017Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 29, nr 4, s. 623-633Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lower Cambrian Mo-Ni sulphidic black shales from the Huangjiawan mine (Guizhou Province, south China) have anomalous platinum-group element (PGE) concentrations (up to ~1 ppm in total). We used LA-ICPMS to study the distribution of PGE in pyrite and Ni-sulphide (millerite) and FE-SEM/EDS for determination of As in pyrite. A sulphide concentrate was produced by innovative hydroseparation techniques from one representative sample, which contained 162 ppb Pt, 309 ppb Pd, 12.2 ppb Ru, 11.3 ppb Rh, 1.5 ppb Ir, 11 212 ppb Re and 343 ppb Au. Mineralogical analysis revealed that pyrite forms ~12 vol%, which corresponds to a calculated ~18.4 wt% of all mineral phases in mineralized black shale. We found that pyrite contains on average (144 analyses) 0.10 ppm Pt, 0.11 ppm Re and 1.40 ppm Au (Ru, Rh, Pd, Os and Ir were below detection limit). It also contains from ~0.5 to ~1.8 wt% As and can be therefore classified as arsenian pyrite. Millerite (77 analyses) showed PGE, Re and Au values below detection limit. We suggest that pyrite represents a dominant Au carrier, containing between 64 and 83% Au of the total Au mineralised rock budget. Conversely, pyrite does not bear any significant amount of Re and Pt, contributing up to ~0.2% and ~12.5% to their whole rock budgets, respectively. Time resolved LA-ICPMS spectra in pyrite indicate that Pt, Re and Au behave as typical lattice-bound elements, with only Re locally forming micro-inclusions. Arsenic is heterogeneously distributed in pyrite and the Au/As ratio (much lower than 0.02) is in support of Au to be structurally bound in solid solution. © 2017 E. Schweizerbart’sche Verlagsbuchhandlung.

  • 337.
    Pašava, Jan
    et al.
    Czech Geological Survey.
    Zaccarini, Frederica
    Department of Applied Geosciences and Geophysics, University of Leoben.
    Aiglsperger, Thomas
    University of Barcelona.
    Vymazalová, Anna
    Czech Geological Survey.
    Platinum-group elements (PGE) and their principal carriers in metal-rich black shales: An overview with a new data from Mo-Ni-PGE black shales (Zunyi region, Guizhou Province, south China)2013Ingår i: Journal of Geosciences, ISSN 1802-6222, E-ISSN 1803-1943, Vol. 58, nr 3, s. 213-220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lower Cambrian Mo–Ni sulfidic black shales from the Huangjiawan mine (Guizhou Province, south China) have anomalousplatinum-group elements (PGE) concentrations (up to ~1 ppm in total). In order to identify principal PGE carriers,we used heavy mineral separates which were produced by innovative hydroseparation techniques. Subsequent detailedmineralogical study using electron microprobe did not result in the identification of discrete platinum-group minerals.Pyrite (grainy, not framboidal), millerite and gersdorffite that were found in our heavy concentrate were analyzed forPGE and Re. We found that they contain the following concentrations of PGE and Re: pyrite (up to 490 ppm Pt, 390ppm Pd and 220 ppm Rh), millerite (up to 530 ppm Pt, 430 ppm Pd and 190 ppm Rh) and gersdorffite (up to 410 ppmPt and 320 ppm Pd; no Rh detected). Rhenium was detected only in grainy pyrite (up to 1060 ppm). It was found thatdespite anomalous PGE concentrations, the Mo–Ni black shales do not contain any platinum-group minerals and thatthe PGE are bound to pyrite and Ni-sulfides (millerite and gersdorffite).

  • 338.
    Perdahl, Jan-Anders
    et al.
    Luleå tekniska universitet.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Korvi, Bo-Göran
    Mining Technology R and D, LKAB Kiruna Mine.
    Chemistry in the Kiirunavaara iron ore and related alternations1993Ingår i: Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå / [ed] Jan-Anders Perdahl, Luleå: Högskolan i Luleå , 1993, s. 156-Konferensbidrag (Övrigt vetenskapligt)
  • 339.
    Persson, Lena
    Luleå tekniska universitet.
    An investigation of the topographic effect and a comparison of staked an insulated receiver antennas in the VLF method1995Licentiatavhandling, monografi (Övrigt vetenskapligt)
  • 340.
    Petersson, Jesper
    et al.
    Vattenfall Research & Development.
    Stephens, Michael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Mattsson, Håkan
    Geovista AB.
    Möller, Charlotte
    University of Lund.
    Albitization and quartz dissolution in Paleoproterozoic metagranite, central Sweden: implications for the disposal of spent nuclear fuel in a deep geological repository2012Ingår i: Lithos, ISSN 0024-4937, E-ISSN 1872-6143, Vol. 148, s. 10-26Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrothermal alteration resulting in albitization and quartz dissolution has been identified in Paleoproterozoic metagranites down to − 1000 m elevation at Forsmark, Sweden. The alteration features were discovered during investigations to locate a site for the disposal of spent nuclear fuel in a deep geological repository. In general, albitization occurs extensively, but it is also observed locally adjacent to minor intrusive bodies of amphibolite. The altered rocks show a marked decrease in K-feldspar and an increase in quartz relative to the unaltered equivalents, resulting in an epitonalitic composition. Plagioclase is metamorphic in character and generally richer in albite than in the unaltered rocks. It is inferred that albitization was triggered by the input of basic or intermediate melts into the crust during igneous activity close to the peak of regional metamorphism at 1.87–1.86 Ga. The mineralogy of the epitonalites gives rise to an increased thermal conductivity and, thereby, a positive influence for the design and safety of a deep geological repository for spent nuclear fuel. However, the increased frequency of low conductive amphibolite in the albitized volumes, consistent with the proposed mechanism for alteration, gives a negative influence. In sharp contrast to the albitization, a majority of the occurrences of quartz dissolution, which resulted in the formation of episyenite, are located along fracture zones. Quartz dissolution took place between or after 1.8–1.7 Ga, when the bedrock was able to respond to deformation in a brittle manner. Most of the vugs left after the removal of quartz are, to a variable extent, refilled by hydrothermal assemblages, including quartz, albite, K-feldspar, hematite, chlorite and calcite. The geometry and spatial distribution of episyenite argue against an extreme fluid/rock ratio and it is inferred that the fluids had at least a moderate salinity with a temperature in excess of 300 °C. The dissolution process was promoted by the generation of secondary permeability localized in columnar or pipe-like volumes. The close spatial connection to fracture zones provides a basis to avoid bedrock affected by this type of alteration and, thereby, reduce the negative mechanical and hydrogeological aspects for a deep geological repository.

  • 341.
    Proenza, J. A.
    et al.
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona, C/Martí i Franquès s/n, 08028, Barcelona, Spain.
    González-Jiménez, J. M.
    Departamento de Mineralogía y Petrología, Universidad de Granada, Facultad de Ciencias, Fuentenueva s/n 18002, Granada, Spain.
    Garcia-Casco, A.
    Departamento de Mineralogía y Petrología, Universidad de Granada, Facultad de Ciencias, Fuentenueva s/n 18002, Granada, Spain; Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avda. de las Palmeras 4, E-18100, Armilla, Granada, Spain.
    Belousova, E.
    ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS), GEMOC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney.
    Griffin, W. L.
    ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS), GEMOC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney.
    Talavera, C.
    John de Laeter Centre, Curtin University, Perth, WA 6102, Australia.
    Rojas-Agramonte, Y.
    Geocycles-Earth System Research Center, Institut für Geowissenschaften, Johannes Gutenberg-Universität, Becherweg 21, D-55099 Mainz, Germany; Departamento de Geociencias, Universidad de los Andes, Bogotá, Colombia.
    Aiglsperger, Thomas
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona, C/Martí i Franquès s/n, 08028, Barcelona, Spain.
    Navarro-Ciurana, D.
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona, C/Martí i Franquès s/n, 08028, Barcelona, Spain.
    Pujol-Solá , N.
    Departament de Mineralogia, Petrologia i Geologia Aplicada, Universitat de Barcelona, C/Martí i Franquès s/n, 08028, Barcelona, Spain.
    Gervilla, F.
    Departamento de Mineralogía y Petrología, Universidad de Granada, Facultad de Ciencias, Fuentenueva s/n 18002, Granada, Spain; Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR), Avda. de las Palmeras 4, E-18100, Armilla, Granada, Spain .
    O’Reilly, S. Y.
    ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS), GEMOC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney.
    Jacob, D. E.
    ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS), GEMOC National Key Centre, Department of Earth and Planetary Sciences, Macquarie University, Sydney.
    Cold plumes trigger contamination of oceanic mantle wedges with continental crust-derived sediments: Evidence from chromitite zircon grains of eastern Cuban ophiolites2018Ingår i: Geoscience Frontiers, ISSN 1674-9871, Vol. 9, nr 6, s. 1921-1936Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The origin of zircon grains, and other exotic minerals of typical crustal origin, in mantle-hosted ophiolitic chromitites are hotly debated. We report a population of zircon grains with ages ranging from Cretaceous (99 Ma) to Neoarchean (2750 Ma), separated from massive chromitite bodies hosted in the mantle section of the supra-subduction (SSZ)-type Mayarí-Baracoa Ophiolitic Belt in eastern Cuba. Most analyzed zircon grains (n = 20, 287 ± 3 Ma to 2750 ± 60 Ma) are older than the early Cretaceous age of the ophiolite body, show negative εHf(t) (−26 to −0.6) and occasional inclusions of quartz, K-feldspar, biotite, and apatite that indicate derivation from a granitic continental crust. In contrast, 5 mainly rounded zircon grains (297 ± 5 Ma to 2126 ± 27 Ma) show positive εHf(t) (+0.7 to +13.5) and occasional apatite inclusions, suggesting their possible crystallization from melts derived from juvenile (mantle) sources. Interestingly, younger zircon grains are mainly euhedral to subhedral crystals, whereas older zircon grains are predominantly rounded grains. A comparison of the ages and Hf isotopic compositions of the zircon grains with those of nearby exposed crustal terranes suggest that chromitite zircon grains are similar to those reported from terranes of Mexico and northern South America. Hence, chromitite zircon grains are interpreted as sedimentary-derived xenocrystic grains that were delivered into the mantle wedge beneath the Greater Antilles intra-oceanic volcanic arc by metasomatic fluids/melts during subduction processes. Thus, continental crust recycling by subduction could explain all populations of old xenocrystic zircon in Cretaceous mantle-hosted chromitites from eastern Cuba ophiolite. We integrate the results of this study with petrological-thermomechanical modeling and existing geodynamic models to propose that ancient zircon xenocrysts, with a wide spectrum of ages and Hf isotopic compositions, can be transferred to the mantle wedge above subducting slabs by cold plumes.

  • 342.
    Pålsson, Bertil
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fredriksson, Andreas
    Mining Technology R and D, LKAB Kiruna Mine.
    Unlocking Rare Earth Elements from European apatite‐iron ores2014Ingår i: ERES 2014 - 1st International Conference on European Rare Earth Resources: Book of Proceedings / [ed] Efthymios Balomenos; Dimitrios Panias; Ioannis Paspaliaris, Santorini: Heliotopos Conferences Ltd. , 2014, s. 211-220Konferensbidrag (Refereegranskat)
    Abstract [en]

    Rare Earth Elements are known to occur within apatite‐magnetite ores of the Kiruna type. Previously it was assumed that the REE was associated to the apatite part of the ore. It is now shown that the REE follows the apatite to a much less degree, and that the REE are contained in the minerals monazite, allanite and some unknown REE‐phase still to be identified. Monazite occurs as inclusions in the apatite as well as free particles. Allanite is to some degree in mixed grains with magnetite but also in free particles. Monazite mainly reports to the apatite concentrate while allanite largely goes to the tailings. Laboratory flotation also shows some preferential concentration of heavy REE over light REE to the apatite concentrate. A new EU project, REEcover, will characterise the REE phases in this type of iron ore and among the different process streams within the mineral beneficiation chain.

  • 343.
    Pålsson, Bertil
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Recovery of Rare Earth Elements from Electronic Waste by Cryo-grinding2015Konferensbidrag (Refereegranskat)
  • 344.
    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 Spain2018Ingår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, nr 12, artikel-id 562Artikel i tidskrift (Refereegranskat)
    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.

  • 345.
    Renström, Viktor
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    The influence of weakness zones on the tunnel stability based on investigations in Bodøtunnelen2016Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    When planning for a tunnel, the ground conditions in which the tunnel is going to be excavated through will be investigated to different extent. Lack of relevant pre-investigation data or misinterpretations of the available data can cause both economical and/or unexpected stability problems.

    Weakness zones that are expected to cross the tunnel could be investigated thoroughly with a variety of methods. Refraction seismicity survey and 2D resistivity survey are two geophysical methods that are common in Norway for obtaining information about the rock quality in weakness zones. In this work, a twin tunnel under construction in Bodø (northern Norway) called the Bodøtunnel is studied. The predictions based on the pre-investigation for crossing of some expected weakness zones are compared to the actual conditions encountered during tunneling. Tunneling observations (Geological mapping and photos), rock samples and measurement while drilling (MWD) were used to describe the weakness zones that were encountered during tunneling.

    Rock samples were collected from two weakness zones and the general rock mass. These samples were tested in a point bearing machine for determination of their uniaxial compressive strength (UCS). These results indicated that the rock samples gathered from the weakness zones had significantly lower UCS than the samples from the rock mass. This was exceedingly clear for the samples of fault rock gathered in connection with a shear zone. The results from this work demonstrate that refraction seismicity had a high success rate for locating weakness zones, with the exception for the crossed narrow zones that were interpreted lacking a shear component. Empirical formulas relating Q-value and UCS with the seismic wave speed were used for calculating these factors for some interesting locations. The empirically calculated UCS was similar to the obtained UCS from the point bearing tests, while the empirically calculated Q-value showed large deviations from the mapped Q-value.

    The resistivity measurements had a low success rate so far in this project; the reason for this could be disturbances in the ground and the location of the resistivity profiles, which had to adapted to the nearby railroad. It should be noted that only one full resistivity profile has been crossed and the rest of the profiles are expected to be more accurate. Based on the results from the crossed profile(s), the suitability of resistivity survey 2D in urban areas can be brought to question. This work also stumbled upon problems regarding the definition of weakness zones. Shear/fault zones are one of the more common type of weakness zones encountered in tunneling. These kind of zones often consists of different parts. Depending on which parts are regarded as a weakness zone by the responsible engineers, the Q-value might differ due to the SRF.

    Different scenarios were also evaluated with numerical modeling for the expected remaining major weakness zones. This analysis highlights the importance of differentiation between more fractured zones and zones containing fault rock, such as breccia. The width of the zone had a major impact on the stability while the dip for wide zones had a minor impact on the stability, as long the zones dip is not so small that both tunnels are intersected at the same time. The rock mechanical parameter of the weakness zones that had the most impact on the overall stability was the cohesion.

  • 346.
    Rincon, Jonathan
    et al.
    University of Liege, GeMMe – Minerals Engineering and Recycling, Sart-Tilman Campus-B52, Liège, Belgium.
    Gaydardzhiev, Stoyan
    University of Liege, GeMMe – Minerals Engineering and Recycling, Sart-Tilman Campus-B52, Liège, Belgium.
    Stamenov, Lachezar
    Dundee Precious Metals Chelopech, Village of Chelopech, Bulgaria.
    Coupling comminution indices and mineralogical features as an approach to a geometallurgical characterization of a copper ore2019Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 130, s. 57-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A production block of the underground mine exploiting the Chelopech high sulphidation epithermal copper-gold deposit was subjected to geometallurgical modelling. This study details the procedure used based on traditional comminution and mineralogical indices. Drop weight and batch grinding tests were performed on representative samples to yield parameters related to Axb and operating work OWi indices. These were further correlated with the ore mineralogical features using principal component analysis. Modal mineralogy data processed by a set of linear equations enabled the estimation of the aforementioned indices with a deviation of ±2.4 for Axb and ±9.08 kWh/t for OWi respectively. Based on ore textural characteristics and non-sulphide gangue (NSG) minerals content, two geometallurgical domains were identified as a first approach to modelling of the studied block.

  • 347.
    Rincon, Jonathan
    et al.
    University of Liege, GeMMe – Minerals Engineering and Recycling, Sart-Tilman Campus-B52, Liège, 4000, Belgium.
    Gaydardzhiev, Stoyan
    University of Liege, GeMMe – Minerals Engineering and Recycling, Sart-Tilman Campus-B52, Liège, 4000, Belgium.
    Stamenov, Lachezar
    Dundee Precious Metals Chelopech, Village of Chelopech, 2087, Bulgaria.
    Investigation on the flotation recovery of copper sulphosalts through an integrated mineralogical approach2019Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 130, s. 36-47Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Investigation on the flotation behaviour of enargite (Cu3AsS4) and tennantite ((Cu, Fe)12As4S13) during selective copper flotation was performed using an integrated mineralogical approach. To this end, samples taken from a production block at the Chelopech mine were subjected to a laboratory scale flotation and products characterized through multi-element chemical analyses and mineral mapping using a SEM-based automated mineralogy. Chemistry, modal mineralogy, copper-sulphosalts’ liberation and associations were quantified. Principal component analysis (PCA) was employed to look for relationships between mineralogical features and flotation recovery. High variability in head copper grade was observed in the studied block, with deportment results attributing it to the varied content of enargite and tennantite. Chalcopyrite content was low in the majority of the samples. The close association and the frequently observed interlocking of pyrite and Cu-sulphosalt grains can explain pyrite (and gold) recovery during copper cleaner flotation. Linear equations based on PCA results allow the prediction of Cu-sulphosalts’ recovery with a root mean square error of ±1.32%.

  • 348.
    Rincon, Jonathan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Jansson, Nils
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Kaiser, Christiane
    Boliden Mineral AB, Exploration department, Boliden, Sweden.
    Thomas, Helen
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Persson, Mac
    Boliden Mineral AB, Exploration department, Boliden, Sweden.
    Textural and chemical characterization of sulphide minerals for improved beneficiation and exploration at the Rävliden Norra VMS deposit, Skellefte district, Sweden2020Ingår i: Abstracts and Proceedings of the Geological Society of Norway / [ed] Hans Arne Nakrem and Ann Mari Husås, Oslo: Norsk Geologisk Forening, 2020, Vol. 1, s. 179-180Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Rävliden Norra VMS deposit, represents one of the most important new discoveries in the Skellefte district (SD) in this decade. The mineralization is hosted at the transition between Skellefte group rocks (SG), dominated by coherent rhyolitic and dacitic meta-volcanic rocks, and the Vargfors group (VG), composed of metasedimentary graphitic shale interbedded with crystal-rich, monomictic to polymictic, clast-supported mass flow deposits. The ore lenses contain massive sphalerite + galena + pyrite + pyrrhotite + chalcopyrite ± Ag-Sb-Pbsulphosalts, structurally and stratigraphically above chalcopyrite + pyrrhotite stringer mineralization. The hanging wall rocks (VG) host pyrite + pyrrhotite ± arsenopyrite mineralization. Alteration in the footwall rocks, consists of sericite, chlorite, quartz, pyrite, tremolite, actinolite, carbonate and talc. The hanging wall is less altered with limited sericite or chlorite associated with minor carbonate alteration. Post ore modifications occur as, e.g. sulphides in pressure shadows, infilling of syntectonic tension gashes, “durchbewegung” texture, and sulphide-rich veins that crosscut hanging wall rocks. Significant changes in the distribution and deportment of trace and precious elements within the deposit are evident, however the implications of these on mineral processing performance and exploration vectoring has not previously been assessed in other VMS deposits in the SD. To this end, the presence of pyrite and remobilised sulphides in both hanging wall and footwall of the Rävliden Norra mineralizations, provides an opportunity to evaluate enrichment or depletion of elements hosted in the sulphide lattices or as inclusions using LA-ICP-MS. In-situ SIMS analyses in sulphide phases will allow discrimination between sedimentary and hydrothermal sulphur in the system. An investigation into the deportment of In, Ga and Ge in sphalerite and galena, will be the first assessment of these critical elements in a VMS deposit in the SD. Ultimately, integration of elemental distribution and mineral features, such as modal mineralogy, liberation degree, and grain size, with processing variables, e.g. mineral recovery, grade or flotation kinetics; will provide a better understanding of the ore performance during concentration and beneficiation.

  • 349.
    Rio, L.M. Suárez Del
    et al.
    Department of Petrology, Faculty of Geology, University of Oviedo.
    Norin, J.
    Luleå tekniska universitet.
    Bending tests and acoustic emission for heated avesta-gneiss1985Ingår i: International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, ISSN 0148-9062, E-ISSN 1879-2073, Vol. 22, nr 1, s. 47-50Artikel i tidskrift (Refereegranskat)
  • 350.
    Ripa, Magnus
    et al.
    Geological Survey of Sweden.
    Kampmann, Tobias Christoph
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hellström, Fredrik
    Geological Survey of Sweden.
    SIMS U-Pb (zircon) geochronology at the Kuså Ni-Cu deposit, south-central Sweden2017Ingår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 139, nr 3, s. 233-240Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Kuså orthomagmatic Ni-Cu sulphide deposit is situated c. 13 km west of Falun in Bergslagen, southcentral Sweden. Ion probe data on zircon from the mafic to ultra-mafic host rocks yield a 207Pb/206Pb weighted average age of 1798 ± 4 Ma, suggesting a genetic connection to intrusive activity forming theTransscandinavian Igneous Belt (TIB-1 phase). TIB-1 ages have recently been reported also for the Kleva deposit of similar type in Southern Sweden. The presence of these two occurrences suggests prospectivity potential for Ni-Cu mineralisation in mafic to ultramafic members of the areally extensive TIB.

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