| 1. |
- Alakangas, Lena, et al.
(författare)
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Norrbottens malm- och mineralresurs och dess potentiella betydelse för innovation, samhälle och miljö
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Gruvindustrins betydelse för samhällsutveckling och infrastruktur i Sverige och inte minst i Norrbottens län är mycket stor. De geologiska förutsättningarna att hitta nya brytvärda förekomster i Norrbotten är goda. Länet är tillsammans med Västerbotten en av Europas viktigaste regioner för utvinning av metaller. Det syns också i den nyligen framtagna regionala mineralstrategin för Norrbotten och Västerbotten. Visionen för den regionala mineralstrategin: ”Genom långsiktigt hållbart nyttjande av Norrbottens och Västerbottens läns mineralresurser har ytterligare tillväxt skapats i regionen och hela Sverige. Vi har utvecklat och stärkt vår ställning som ledande gruv- och mineralnation.”Eftersom framtidspotentialen för gruvnäringen är mycket god men okunnigheten hos både allmänhet och beslutsfattare om näringens betydelse för innovation och samhällsutveckling är stor, kopplat med en utbredd oro för miljöpåverkan, måste dessa viktiga framtidsfrågor belysas. Med finansiering från Länsstyrelsen i Norrbotten bedrevs därför under första hälften av 2014 en förstudie som syftade till att sammanfatta kunskapsläget om framtidens gruvindustri i Norrbotten. Resultaten av förstudien redovisas i den här rapporten. En viktig slutsats är att det under nästa strukturfondsperiod (med start 2015) behövs ett framtidsinriktat forskningsprogram för att belysa de möjligheter som finns. Denna förstudie utgör grund för en kommande ansökan till strukturfonderna. Kompetensen som finns vid Luleå tekniska universitet, Sveriges centrum för gruvrelaterad forskning och utbildning, bör användas för att studera troliga framtidsmöjligheter och hur de ska kunna användas för att få en så positiv utveckling som möjligt för länet. Projektet bör innehålla följande tre huvudinriktningar, som naturligtvis hör ihop:Vilka malm- och mineralresurser finns det potential för i Norrbotten, och vilka kommer sannolikt att exploateras i framtiden?Vad kommer den exploateringen att ha för betydelse för innovation och samhällsutveckling?Vad kommer den exploateringen att få för miljöeffekter och hur ska man göra för att minska miljöbelastningen?En annan slutsats är att nedlagda gruvområden inte måste ses som förstörd natur. Betydande mervärden som gruvturism skulle kunna skapas om vilja, kreativitet och beslutsamhet finns. Detta är ett givet utvecklingsområde där småföretag och entreprenörer kan göra stor insats om de politiska och myndighetsmässiga förutsättningarna finns. Dessa aspekter skulle också kunna belysas i det föreslagna forskningsprogrammet eller i ett eget projekt.
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| 2. |
- Andersson, Joel B.H., et al.
(författare)
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The tectonic overprint on the Per Geijer apatite iron ores in Kiruna, northern Sweden
- 2017
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Ingår i: Mineral Resources to Discover. - : Society for Geology Applied to Mineral Deposits. - 9782981689801 ; , s. 903-906
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Konferensbidrag (refereegranskat)abstract
- This ongoing project focusses on the structural evolution of the Per Geijer apatite iron ores in Kiruna, northern Sweden. The Per Geijer iron ores are situated in a NNE-SSW trending shear zone. This study indicate that the shear zone was active during D2 E-W compression giving rise to dip-slip and oblique slip components. The ductile fabric is overprinted by brittle structures carrying Cu, possibly representing traces of a separate Iron Oxide Copper Gold event in northern Norrbotten.
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| 3. |
- Anthony, Niklas, et al.
(författare)
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Laser-induced spallation of minerals common on asteroids
- 2021
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Ingår i: Acta Astronautica. - : Elsevier. - 0094-5765 .- 1879-2030. ; 182, s. 325-331
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Tidskriftsartikel (refereegranskat)abstract
- The ability to deflect dangerous small bodies in the Solar System or redirect profitable ones is a necessary and worthwhile challenge. One well-studied method to accomplish this is laser ablation, where solid surface material sublimates, and the escaping gas creates a momentum exchange. Alternatively, laser-induced spallation and sputtering could be a more efficient means of deflection, yet little research has studied these processes in detail. We used a 15-kW Ytterbium fiber laser on samples of olivine, pyroxene, and serpentine (minerals commonly found on asteroids) to induce spallation. We observed the process with a high-speed camera and illumination laser, and used X-ray micro-tomography to measure the size of the holes produced by the laser to determine material removal efficiency. We found that pyroxene will spallate at power densities between 1.5 and 6.0 kW cm−2, serpentine will also spallate at 13.7 kW cm−2, but olivine does not spallate at 1.5 kW cm−2 and higher power densities melt the sample. Laser-induced spallation of pyroxene and serpentine can be two- to three-times more energy efficient (volume removed per unit of absorbed energy) than laser-induced spattering, and over 40x more efficient than laser ablation.
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| 4. |
- Anthony, Niklas
(författare)
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Laser Interaction with Minerals Common on Asteroids
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Asteroids are worth studying for three reasons: planetary protection, industrial applications, and scientific knowledge. It is critical we develop technologies capable of diverting objects on collision courses with our planet. We can use the same technology to move or process asteroids and comets for materials to build structures or refuel in Low-Earth Orbit. Asteroids are also windows into the past; they were formed in the early Solar System, and could potentially have been the source of water and/or life on Earth. There are unique challenges to manipulating an asteroid or asteroid materials, which means that much of what we know about material processing needs to be revamped to fit the situation. One of the motivating drives of this research was that a laser would be an excellent tool to perform many tasks at an asteroid.One process of interest is laser drilling. The surface composition of asteroids is altered by aeons of space weathering; by studying the subsurface composition we can ascertain just how much it is altered and possibly by which processes. It is possible that hydrated minerals or ices exist below the surface as well, which are of great economic interest in asteroid mining. One of the greatest challenges to get under the surface of an asteroid is the low gravity: any forces or torques generated by a sampling mechanism may tip the spacecraft or launch it into deep space. A laser does not generate any significant forces, and can even be used without having to land; lasers do use a lot of electric power so the laser parameters need to be optimized to minimize the size and power requirements of the spacecraft. We found that nearly 1-cm deep holes can be made with as little as 18~J of energy using a 300-W laser.Laser ablation has been studied as a mechanism to redirect asteroids, but it is not particularly energy efficient at material removal. If the idea is to create a momentum exchange by removing surface material beyond an object's gravitational pull, then there could perhaps be more energy efficient mechanisms. One mechanism we investigated was spallation, where the shock wave of a laser pulse breaks off a relatively large chunk of material without having to melt and vaporize it. We found that spallation may be many times more energy efficient than ablation.Laser welding of metals has been of industrial interest for decades, though the welding of two different materials is still a challenge. We sought to develop a laser-based wire-attachment mechanism that can be used to anchor spacecraft to the surface of a small body or to maneuver boulders or small asteroids. When attempting to follow a traditional welding process, it was found that the two melt pools would not mix, and if it did, it was very weak. Instead, we used the laser to drill a hole and melt a wire while inserting it into the hole. This produced a solid anchor with a hold strength of up to 120~N.
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| 5. |
- Anthony, Niklas, et al.
(författare)
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Laser processing of minerals common on asteroids
- 2021
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Ingår i: Optics and Laser Technology. - : Elsevier. - 0030-3992 .- 1879-2545. ; 135
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Tidskriftsartikel (refereegranskat)abstract
- Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used a 300-W, pulsed Ytterbium fiber laser on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10 000 frames per second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material.
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| 6. |
- Barbosa, Leo, et al.
(författare)
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Gold mineralization in the Lappberget deposit, Garpenberg mine, Sweden: towards a geometallurgical approach
- 2022
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Ingår i: Geological Society of Sweden, 150 year anniversary meeting: Abstract volume. ; , s. 116-117
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study investigates the mineralogy and texture of gold-bearing phases in the Lappberget deposit, Garpenberg Mine, and how these characteristics affect gold recovery during mineral processing. Multiple methods such as optical microscopy, SEM-EDS, EPMA, LA-ICP-MS, and bulk chemical analysis were applied on drill core samples, and samples from the processing plant’s Knelson gravity concentrator. Electrum-type alloys were recognized as the most common gold hosts.
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| 7. |
- Bark, Glenn, et al.
(författare)
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Textural setting of gold and its implications on mineral processing: preliminary results from three gold deposits in northern Sweden
- 2013
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Ingår i: Mineral deposit research for a high-tech world. - Uppsala : Sveriges Geologiska Undersökning. - 9789174032079 ; , s. 302-305
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Konferensbidrag (refereegranskat)abstract
- Within the European Union (EU27) the two most important gold producers are Finland and Sweden, covering more than two thirds of the European market. Due to the high gold prize mining companies are looking to extract more of the metal by improving recovery. We have done textural analysis on three gold-bearing deposits to better understand how the gold-textures seen in drill cores might affect the processing of different gold-ore types. In the Nautanen IOCG deposit, gold deportment is different whether gold is associated with pyrite or magnetite, and this must be considered when optimising the future mine and process planning. In the VMS-type Kristineberg deposit, the gold is associated with pyrite, sphalerite, and galena. Low gold recoveries from flotation could be explained by the occurrence of gold-inclusions in the pyrite. In the epigenetic Svartliden lode gold deposit, the gold is rather coarse-grained and associated with arsenopyrite-löllingite, and silicates. The relatively large grain size of gold can result in incomplete breakdown of the largest gold grains in the cyanide leaching process. To properly understand gold deportment in ores and to be able to improve mine planning and predict metal recoveries a comprehensive textural analysis of gold in drill core-samples is essential.
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| 8. |
- Bauer, Tobias, Associate professor, 1982-, et al.
(författare)
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Structural Controls on Iron Oxide Copper-Gold Mineralization and Related Alteration in a Paleoproterozoic Supracrustal Belt: Insights from the Nautanen Deformation Zone and Surroundings, Northern Sweden
- 2022
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Ingår i: Economic geology and the bulletin of the Society of Economic Geologists. - : Society of Economic Geologists. - 0361-0128 .- 1554-0774. ; 117:2, s. 327-359
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Tidskriftsartikel (refereegranskat)abstract
- The Nautanen deformation zone in the Gällivare area of northern Sweden is a highly Cu-mineralized, magnetite-rich, large-scale shear zone with a long-lived (~100 m.y.) deformation, hydrothermal alteration, and mineralization history. This composite structure hosts the Aitik porphyry Cu-Au-Ag ± Mo deposit and several Cu-Au ± Fe ± Ag ± Mo occurrences assigned to the iron oxide copper-gold (IOCG) deposit class. The Nautanen deformation zone was a locus for polyphase deformation and intermittent metasomatic-hydrothermal activity that overprinted middle Orosirian (ca. 1.90–1.88 Ga) continental arc-related volcanic-plutonic rocks. The deformation zone is characterized by intense shearing fabrics that form a series of subvertical to moderately W-dipping, NNW-SSE–trending, first-order shear zones with oblique reverse kinematics and related NNE-SSW–oriented second-order shear zones that control hydrothermal alteration patterns and Cu-Au mineralization.Hydrothermal alteration in the study area formed during several phases. Volcanic-volcaniclastic rocks to the east and west of the Nautanen deformation zone display low to moderately intense, pervasive to selectively pervasive (i.e., patchy zones or bands, disseminations) sericite ± feldspar, amphibole + biotite + magnetite ± tourmaline, and K-feldspar + hematite alteration. Both the amphibole + biotite and K-feldspar + hematite associations occur adjacent to NNW- and NE-oriented deformation zones and are locally associated with minor sulfide. Within the deformation zone, a moderate to intense biotite + amphibole + garnet + magnetite + tourmaline + sericite alteration assemblage is typically associated with chalcopyrite + pyrrhotite + pyrite and forms linear and subparallel, mainly NNW-oriented seams, bands, and zones that locally appear to overprint possibly earlier scapolite + sericite ± feldspar alteration. Late-stage epidote ± quartz ± feldspar alteration (retrograde saussuritization) forms selectively pervasive zones and epidote veinlets across the area and is partly related to brittle faulting.A magnetite-amphibole-biotite–rich, penetrative S1 foliation records shortening during early Svecokarelian-related deformation (D1) and can be related to ca. 1.88 to 1.87 Ga arc accretion processes and basin inversion that overlaps with regional peak metamorphism to near mid-amphibolite facies conditions and a potential initial Cu mineralization event. Folding and repeated shearing along the Nautanen deformation zone can be assigned to a second, late-Svecokarelian deformation event (D2 stage, ca. 1.82–1.79 Ga) taking place at a higher crustal level. This D2 deformation phase is related to late-stage accretionary processes active during a transition to a stage of postorogenic collapse, and it was accompanied by abundant, syntectonic intrusions. D2-related magmatism produced high-temperature and low-pressure conditions and represents a regional magmatic-hydrothermal event that controlled the recrystallization/remobilization of magnetite, biotite, and amphibole. Associated shear zone reactivation during D2 favors the utilization of the Nautanen deformation zone as a fluid conduit, which preferentially controlled the siting and formation of epigenetic Cu-Au mineralization with distinctive IOCG characteristics within second-order shear zones.
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| 9. |
- Billström, Kjell, et al.
(författare)
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IOCG and related mineral deposits of the northern Fennoscandian Shield
- 2011
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Ingår i: Hydrothermal iron oxide copper-gold & related topics. - Adelaide : PGC Publishing. ; , s. 381-414
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The northernmost Fennoscandian shield comprises Archaean and Palaeoproterozoic rocks. Unlike most other shield areas, economic mineral deposits are largely restricted to its Palaeoproterozoic parts. The latter are characterised by intracratonic basin evolution between ca. 2.5 and 2.0 Ga, involving recurrent mantle hotspot activity with numerous layered intrusions, komatiite and picrite eruptions, but no signs of accretionary phases or formation of major new felsic crust. Accretion and continent-continent collision followed from ca. 1.9 to 1.8 Ga, during the Svecofennian orogeny. A range of mineralisation styles are hosted by extensive ca. 2.5 to 2.0 Ga greenstone belts and younger, subduction-related 1.9 to 1.8 Ga Svecofennian intrusive and extrusive settings. These mineralisation styles partially overlap, and individual deposits may not readily be placed into genetic classification schemes. A provisional grouping of observed mineralisation styles comprises (1) stratiform-stratabound sulphide, (2) apatite-iron, (3) skarn-related iron and BIF, and (4) epigenetic(±syngenetic?) Au and Cu-Au deposits. The descriptive section of this paper also highlights features that may relate to orogenic-gold, IOCG and 'atypical metal association' categories of mineralisation. The assumption made is that the deposition of a diverse range of ore deposits was made possible by a long and complex geological evolution. This involved an initial (sowing) stage where iron, and to some extent copper and gold, were concentrated during 2.3 to 2.1 Ga (Karelian) rock-forming processes. Following this, ore elements were mobilised during two younger (Svecofennian) stages at 1.92 to 1.87 and 1.85 to 1.79 Ga, respectively. The latter were triggered by metamorphic and magmatic episodes, and fluids liberated during these stages precipitated IOCG and related deposits when fluids met structural and chemical traps in suitable host rocks. Ore fluids are generally saline, and their development probably involved incorporation of evaporates and, at least locally, also felsic magmatism may have played a role. Skarn-related mineralisation, hosted by ca. 2.1 Ga greenstones, occurs both as a BIF type in Sweden (formed at around 2.1 Ga), and as a gold-copper enriched variety (the result of Svecofennian epigenetic processes) in the Kolari region of Finland. The huge Kiirunavaara deposit is the type example of apatite iron ores, and is here considered to have formed from a magma at ca. 1.88 Ga, although it also has features best explained by a magmatic-hydrothermal overprint. A younger, less prominent, stage of apatite iron ore formation took place at approximately 1.78 Ga. Epigenetic gold and copper-gold deposits are particularly hard to classify as these show mixed ore characteristics, and to some extent this is likely to be due to multiple mineralisation stages (cf. the huge, low grade Aitik deposit in Sweden which is interpreted to be a hybrid porphyry-IOCG-type of ore). Structurally controlled, orogenic-gold mineralisation is common in the Central Lapland greenstone belt, although there are also gold deposits with enhanced contents of e.g., copper, cobalt and uranium (e.g., at Saatopoora). The latter, sometimes referred to as being of an 'atypical metal association' type, could potentially also include syngenetic mineralisation (e.g., at Juomasou). The range of epigenetic (±syngenetic) gold and copper-gold deposits could possibly be related to a vague east-west trend defined by gold-rich deposits in the east (Finland), followed by IOCG (copper±gold) and more iron-dominant ore types near the Finnish-Swedish border and further west into Sweden.
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| 10. |
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| 11. |
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| 12. |
- Ghorbani, Sasan, et al.
(författare)
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A new rock hardness classification system based on portable dynamic testing
- 2022
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Ingår i: Bulletin of Engineering Geology and the Environment. - : Springer. - 1435-9529 .- 1435-9537. ; 81:5
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Tidskriftsartikel (refereegranskat)abstract
- Hardness is one of the critical physical characteristics of minerals and rocks, which indicates the resistance of the rock to penetration, scratch, or permanent deformation. As a basic concept, rock hardness has a significant role in rock mechanics and geological engineering and is an appropriate diagnostic tool for the classification of minerals and rocks. The main purpose of this study is to guide rock engineers to measure the rock hardness faster, easier, and more accurately using Leeb’s dynamic hardness test. Accordingly, this paper presents a new rock hardness classification system based on the Leeb dynamic and portable hardness testing method. It is a well-known method for its fast and straightforward procedure testing equipment. A set of 33 different rock types were collected and tested during this study. Next, in-depth microscopic mineralogical studies were performed to determine the precise Mohs hardness value. The Mohs hardness was considered the leading hardness benchmark during the experimental studies, and the Leeb hardness was adopted to classify based on this hardness. A series of laboratory studies and statistical analysis was performed to predict the Shore and Vickers hardness using Leeb hardness. Finally, based on the comparative studies, it is recommended to classify the rocks considering the Leeb hardness method in six different categories: extremely soft (1–250), soft (250–450), moderately soft (450–750), moderately hard (750–850), hard (850–920), and extremely hard (920–1000). The provided classification could be useful in a vast range of rock engineering applications, especially for feasibility studies of rock engineering projects and engineering geology.
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| 13. |
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| 14. |
- Holsti, Mari, 1963-, et al.
(författare)
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Circulating Vascular Basement Membrane Fragments are Associated with the Diameter of the Abdominal Aorta and Their Expression Pattern is Altered in AAA Tissue
- 2018
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Saunders Elsevier. - 1078-5884 .- 1532-2165. ; 56:1, s. 110-118
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Abdominal aortic aneurysm (AAA) is characterised by enhanced proteolytic activity, and extracellular matrix (ECM) remodelling in the vascular wall. Type IV and XVIII collagen/endostatin are structural proteins in vascular basement membrane (VBM), a specialised ECM structure. Here the association between plasma levels of these collagens with the aortic diameter and expansion rate is studied, and their expression in aortic tissue characterised. Methods: This was a retrospective population based cohort study. Type IV and XVIII collagen/endostatin were analysed in plasma by ELISA assay in 615 men, divided into three groups based on the aortic diameter: 1) normal aorta <= 25 mm, 2) sub-aneurysmal aorta (SAA) 26-29 mm, and 3) AAA >= 30 mm. Follow up data were available for 159 men. The association between collagen levels and aortic diameter at baseline, and with the expansion rate at follow up were analysed in ordinal logistic regression and linear regression models, controlling for common confounding factors. Tissue expression of the collagens was analysed in normal aorta (n = 6) and AAA (n = 6) by immunofluorescence. Results: Plasma levels of type XVIII collagen/endostatin (136 ng/mL [SD 29] in individuals with a normal aorta diameter, 154 ng/ml [SD 45] in SAA, and 162 ng/ml [SD 46] in AAA; p = .001) and type IV collagen (105 ng/mL [SD 42] normal aorta, 124 ng/ml [SD 46] SAA, and 127 ng/ml [SD 47] AAA; p = .037) were associated with a larger aortic diameter. A significant association was found between the baseline levels of type XVIII/endostatin and the aortic expansion rate (p = .035), but in the multivariable model, only the initial aortic diameter remained significantly associated with expansion (p = .005). Altered expression patterns of both collagens were observed in AAA tissue. Conclusion: Plasma levels of circulating type IV and XVIII collagen/endostatin increase with AAA diameter. The expression pattern of VBM proteins is altered in the aneurysm wall.
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| 15. |
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| 16. |
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| 17. |
- Johansson, Björn, et al.
(författare)
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Flotation and leach tests performed within a geo-metallurgical project on gold in the Aitik Cu-Au-Ag-(Mo) deposit
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 73-84
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Laboratory flotation tests were done with all samples after 7 and 11 minutes of grinding. Tail products from the laboratory flotation tests were leached for Au using cyanide. Different ore types could be distinguished from their particle size distribution after grinding. Similar mineralogical structures could be tied to samples with a lower than expected Cu-recovery and mineralogical explanations for high and low Au recoveries are given in this paper.
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| 18. |
- Kampmann, Tobias Christoph, 1987-, et al.
(författare)
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Syn-tectonic sulphide remobilization and trace element redistribution at the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, Bergslagen, Sweden
- 2018
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Ingår i: Ore Geology Reviews. - : Elsevier. - 0169-1368 .- 1872-7360. ; 96, s. 48-71
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Tidskriftsartikel (refereegranskat)abstract
- Mineralization types at the Palaeoproterozoic Falun base metal sulphide deposit are predominantly pyritic Zn-Pb-Cu-rich massive sulphide mineralization, disseminated to semi-massive Cu-Au mineralization, auriferous quartz veins, and mineralized shear zones of talc-chlorite-dominated schist. The massive and disseminated to semi-massive sulphide mineralization types were subject to polyphase ductile deformation (D1 and D2) and metamorphism under low-P, lower-amphibolite facies conditions, which led to the development of ore textures and paragenetic relationships indicating both mechanical and chemical remobilization of sulphides. In the massive sulphide mineralization, rare inclusion-rich pyrite occurs as relic cores inside inclusion-poor metamorphosed pyrite. Imaging and spot analysis using multielement laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) reveal that inclusion-poor pyrite was depleted in trace elements, which were originally present as non-stoichiometric lattice substitutions or in mineral inclusions. The inclusion-rich pyrite was shielded from depletion and, at least partly, retained its initially higher trace element concentrations, including Au.Gold is also associated with chalcopyrite in the disseminated to semi-massive Cu-Au mineralization and in the system of auriferous quartz veins hosted therein, the latter being also affected by the D2 ductile strain. It is inferred that emplacement of the vein system took place after the peak of metamorphism, which occurred between D1 and D2, but prior to and possibly even shortly after completion of the D2 deformational event. Similarities in trace element signatures in chalcopyrite are compatible with the interpretation that the quartz veins formed by local chemical remobilization of components from the Cu-Au mineralization. Transport of liberated Au from pyrite during grain growth in the massive sulphide mineralization may have upgraded the Au endowment in the quartz veins, leading to the additional formation of native gold in the veins. A strong correspondence between elements liberated from pyrite (e.g. Pb, Bi, Se and Au) and those forming discrete and characteristic mineral phases in the quartz veins (Pb-Bi sulphosalts, native gold) supports this hypothesis.Trace element signatures for the main sulphide minerals pyrite, chalcopyrite, sphalerite and galena are similar to previously published data from other metamorphosed massive sulphide deposits. The association of the Falun mineralization with elevated Bi is reflected by its occurrence in sulphide minerals (e.g. galena) and in abundant mineral inclusions of Pb-Bi sulphosalts (e.g. weibullite), especially in the disseminated to semi-massive Cu-Au mineralization. Elevated Sn concentrations in the lattice and/or as cassiterite inclusions in chalcopyrite, sphalerite and galena are compatible with a hot, acidic and reducing fluid during formation of the syn-volcanic, base metal sulphide mineralization and associated host-rock alteration.
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| 19. |
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| 20. |
- Lamberg, Pertti, et al.
(författare)
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Building a Geometallurgical Model in Iron Ores using a Mineralogical Approach with Liberation Data
- 2013
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Ingår i: Geomet13. - Parkville, Victoria : The Australasian Institute of Mining and Metallurgy. - 9781921522901 ; , s. 317-324
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Konferensbidrag (refereegranskat)abstract
- A geometallurgical model is currently built in two different ways. The first and the most common way relies on geometallurgical testing, where a large number of samples are analysed for metallurgical response using small-scale laboratory tests, eg Davis tube testing. The second, mineralogical approach focuses on collecting mineralogical information over the orebody and building the metallurgical model based on mineralogy. At Luleå University of Technology,Sweden, the latter method has been adopted and taken further in four ongoing PhD studies. The geological model gives modal composition by the help of element-to-mineral conversion and Rietveld X-ray diffraction. Texturally, the orebody is divided into different archetypes, and liberation measurements for each of them are carried out in processing fineness using IncaMineral, a SEM-based technique. The grindability and liberation spectrum of any given geological unit (sample, ore block, domain) are extrapolated from the archetypes. The process model is taken into a liberation level by mass balancing selected metallurgical tests using the particle tracking technique. The approach is general and can be applied to any type of ores. Examples of ongoing studies on iron and massive sulfide ores are given.
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| 21. |
- Lu, Jinmei, et al.
(författare)
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Metal mobilization under alkaline conditions in ash-covered tailings
- 2014
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 139, s. 38-49
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine element mobilization and accumulation in mill tailings under alkaline conditions. The tailings were covered with 50 cm of fly ash, and above a sludge layer. The tailings were geochemically and mineralogically investigated. Sulfides, such as pyrrhotite, sphalerite and galena along with gangue minerals such as dolomite, calcite, micas, chlorite, epidote, Mn-pyroxene and rhodonite were identified in the unoxidized tailings. The dissolution of the fly ash layer resulted in a high pH (close to 12) in the underlying tailings. This, together with the presence of organic matter, increased the weathering of the tailings and mobilization of elements in the uppermost 47 cm of the tailings. All primary minerals were depleted, except quartz and feldspar which were covered by blurry secondary carbonates. Sulfide-associated elements such as Cd, Fe, Pb, S and Zn and silicate-associated elements such as Fe, Mg and Mn were released from the depletion zone and accumulated deeper down in the tailings where the pH decreased to circum-neutral. Sequential extraction suggests that Cd, Cu, Fe, Pb, S and Zn were retained deeper down in the tailings and were mainly associated with the sulfide phase. Calcium, Cr, K and Ni released from the ash layer were accumulated in the uppermost depletion zone of the tailings
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| 22. |
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| 23. |
- Lundberg, Christina, 1972-
(författare)
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Screening for Atherosclerosis with Magnetic Resonance Imaging and Ultrasound
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atherosclerosis is a major cause of death and disability worldwide. Although traditional risk factors can identify the healthy or severely affected individuals, sudden lethal outcome is still frequent in those suggested as intermediate in risk for cardiovascular events (CVE). Adding imaging to the traditional scoring systems might improve risk stratification.This thesis investigates whether the addition of magnetic resonance imaging (MRI) and ultrasound (US) to traditional risk factors might render atherosclerosis suitable for mass screening, selective screening or screening in research settings.In paper I the carotid arteries were assessed in six different manners (carotid intima media thickness (CIMT) in two different locations, presence of plaque, number of plaques, plaque size and plaque composition) using US. More than 800 Caucasian subjects were assessed at ages 70 and 75, and outcome examined at 80 years of age. Plaques with an area exceeding 10mm2 in the bulb were found to be most closely related to CVE.Paper II established that carotid plaque volume measured with MRI did not correlate with carotid plaque area assessed with US. MRI reached the highest levels of reproducibility of the two methods.Paper III used the previously created total atherosclerotic score (TAS), a scoring system based on whole body magnetic resonance angiography (WBMRA) that assesses global atherosclerosis. TAS was found to predict CVE in 305 PIVUS-subjects at age 70 years during 5 years of follow-up. The risk for CVE was found to be eightfold with TAS>0.In paper IV CIMT was assessed with US at ages 70 and 75 years. CIMT at baseline, but not the change in CIMT over five years, was significantly related to TAS, thus suggesting carotid changes to correlate with atherosclerosis throughout the body.In conclusion, in research settings WBMRA and MRI, as well as US, can be used for screening and following up of atherosclerotic changes, as their predictive values and reproducibility are good. US might be feasible in selective screening but none of these methods are as of now suitable for mass screening.
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| 24. |
- Lundberg, Jan, et al.
(författare)
-
Measurements of friction coefficients between rails lubricated with a friction modifier and the wheels of an IORE locomotive during real working conditions
- 2015
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 324-325, s. 109-117
-
Tidskriftsartikel (refereegranskat)abstract
- The real friction coefficients between the rails and the wheels on a 360. t and 10,800. kW IORE locomotive were measured using the locomotive׳s in-built traction force measurement system. The locomotive consisted of two pair-connected locomotives had a CoCo+CoCo bogie configuration, and hauled a fully loaded set of 68 ore wagons (120. t/wagon). The measurements were performed both on rails in a dry condition and on rails lubricated with a water-based top-of-rail (ToR) friction modifier on the Iron Ore Line between the cities of Kiruna and Narvik in Northern Sweden and Norway, respectively. Since full-scale measurements like these are costly, the friction coefficients were also measured at the same time and place using a conventional hand-operated tribometer, with and without the ToR friction modifier. The most important results are that the real friction coefficient is definitely not constant and is surprisingly low (0.10-0.25) when the ToR friction modifier is used, and that it is also significantly dependent on the amount of ToR friction modifier. A large amount will reduce the friction coefficient. Furthermore, it is concluded that the real friction coefficients are in general lower than the friction coefficients measured with the hand-operated tribometer. A final remark is thus that the use of a water-based ToR friction modifier can give excessively low friction, which can result in unacceptably long braking distances.
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| 25. |
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| 26. |
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| 27. |
- Martinsson, Olof, et al.
(författare)
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Day five field guide : Cu-Au Deposits in the Gällivare Area
- 2004
-
Ingår 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. - : Society of Economic Geologists. ; , s. 161-166
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 28. |
- Martinsson, Olof, et al.
(författare)
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Economic potential of battery metals and minerals in Sweden
- 2022
-
Ingår i: Proceedings volume for the 16th SGA Biennial Meeting. - : Society for Geology Applied to Mineral Deposits (SGA). ; , s. 227-230
-
Konferensbidrag (refereegranskat)abstract
- The potential for battery metal production in Sweden is difficult to predict with the present geological knowledge. The Swedish bedrock are known to containnumerous occurrences of lithium, cobalt, nickel, manganese, vanadium, and graphite, but a waste majority of them have not been studied in any detail recently and data to estimate their potential is therefore limited. However, known alum shales and graphite schists probably constitute world class deposits of vanadium and graphite if extracted and processed in an economically feasible and environmentally responsible manner, while the potential to find significant manganese and cobalt deposits in Sweden is probably low. These metals, as well as vanadium, could rather be extracted from the waste material of active and historic mines. The geology of parts of Sweden also suggests that significant sulphidic nickel deposits might exist, as well as lithium-pegmatites similar to those in the same crustal domain in Finland.
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| 29. |
- Martinsson, Olof, et al.
(författare)
-
Iron oxide-Cu-Au deposits in the northern part of the Fennoscandian shield
- 2008
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The northern part of the Fennoscandian Shield, which formed during repeated extensional and compressional events at 3.1-1.8 Ga, is an ore province characterized by regionally developed albite and scapolite alteration and the occurrence of world class Fe-oxide (Kiirunavaara) and Cu-Au deposits (Aitik). It host several styles of Fe-oxide-Cu-Au deposits, including skarn and apatite-iron style deposits, many of them with features that also warrant classification as iron oxide-copper-gold (IOCG) deposits.The apatite-iron ores are economically most important with a total production of c. 1900 Mt from 10 mines during the last 100 years and with a total pre-mining resource of c. 4100 Mt. In these deposits, the Fe and P content vary between 30-70 % and 0.05-5 %, respectively. The ore minerals magnetite and hematite occur in lenses or as breccia infill. The ores are usually enriched in LREE, sulphides are rare but subeconomic amounts of Cu may occur.Skarn-like iron occurrences consisting of magnetite and Mg and Ca-Mg silicates have been less important with c. 20 Mt mined from 6 deposits and a pre-mining resource of 760 Mt. Most of them occur as conformable lenses with a banded internal structure. Pyrite, pyrrhotite and minor chalcopyrite are commonly present disseminated or as veinlets. Typical grades are 30-55% Fe, 0.2-3.5 % S, 0.05-0.3% Cu, 0.005-1g/t Au and 0.02-0.2% P. A few of the deposits are also enriched in LREE. Epigenetic Cu±Au occurrences include the porphyry-style giant Aitik deposit with a pre-mining resource of 2000 Mt at 0.3% Cu and 0.2 g/t Au and a total production of 465 Mt. Other deposits vary in style from disseminated to breccia infill or veins. Chalcopyrite is the most important ore mineral but bornite, pyrite, pyrrhotite, magnetite, molybdenite and native gold may occur in varying amounts. The skarn-like ores occur in 2.1Ga Karelian greenstones in association to carbonate rocks, BIF and graphite schist. The apatite iron ores are hosted by 1.9 Ga Svecofennian intermediate to felsic porphyries. The epigenetic Cu±Au deposits occur in both Karelian and Svecofennian volcanic and sedimentary rocks and 1.9 Ga intrusive rocks. The two last type of deposits show similar alteration styles including albite, K-feldspar, biotite, scapolite, carbonate, amphibole and tourmaline, whereas the skarn-like deposits are associated with diopside, amphibole, scapolite and biotite alteration.Deposit studies and geochronological data reveal a multiphase origin of the Fe oxide and Cu±Au occurrences with multiple sources of the ore fluids and peaks of mineralization at c. 1.88 and 1.77 Ga. These events are temporally related to major orogenic stages in the evolution of the Fennoscandian Shield. This implies that mineralization formed in different tectonic settings, and with different magmatic associations. Thus, the IOCG deposits are not uniform in origin, which may well explain their diverse features and also makes a simple genetic model for them dubious.
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| 30. |
- Martinsson, Olof, et al.
(författare)
-
Metallogeny of the Northern Norrbotten Ore Province, northern Fennoscandian Shield with emphasis on IOCG and apatite-iron ore deposits
- 2016
-
Ingår i: Ore Geology Reviews. - : Elsevier BV. - 0169-1368 .- 1872-7360. ; 78, s. 447-492
-
Forskningsöversikt (refereegranskat)abstract
- The Northern Norrbotten Ore Province in northernmost Sweden includes the type localities for Kiruna-type apatite iron deposits and has been the focus for intense exploration and research related to Fe oxide-Cu-Au mineralisation during the last decades. Several different types of Fe-oxide and Cu-Au +/- Fe oxide mineralisation occur in the region and include: stratiform Cu +/- Zn +/- Pb +/- Fe oxide type, iron formations (including BIF's), Kiruna-type apatite iron ore, and epigenetic Cu +/- Au +/- Fe oxide type which may be further subdivided into different styles of mineralisation, some of them with typical IOCG (Iron Oxide-Copper-Gold) characteristics. Generally, the formation of Fe oxide +/- Cu +/- Au mineralisation is directly or indirectly dated'between-2.1 and 1.75 Ga, thus spanning about 350 m.y. of geological evolution. The current paper will present in more detail the characteristics of certain key deposits, and aims to put the global concepts of Fe-oxide Cu-Au mineralisation into a regional context. The focus will be on iron deposits and various types of deposits containing Fe-oxides and Cu-sulphides in different proportions which generally have some characteristics in common with the IOCG style. In particular, ore fluid characteristics (magmatic versus non magmatic) and new geochronological data are used to link the ore-forming processes with the overall crustal evolution to generate a metallogenetic model. Rift bounded shallow marine basins developed at similar to 2.1-2.0 Ga following a long period of extensional tectonics within the Greenstone-dominated, 2.5-2.0 Ga Karelian craton. The similar to 1.9-1.8 Ga Svecofennian Orogen is characterised by subduction and accretion from the southwest. An initial emplacement of calc-alkaline magmas into similar to 1.9 Ga continental arcs led to the formation of the Haparanda Suite and the Porphyrite Group volcanic rocks. Following this early stage of magmatic activity, and separated from it by the earliest deformation and metamorphism, more alkali-rich magmas of the Perthite Monzonite Suite and the Kiirunavaara Group volcanic rocks were formed at similar to 1.88 Ga. Subsequently, partial melting of the middle crust produced large volumes of similar to 1.85 and 1.8 Ga S-type granites in conjunction with subduction related A-/I-type magmatism and associated deformation and metamorphism. In our metallogenetic model the ore formation is considered to relate to the geological evolution as follows. Iron formations and a few stratiform sulphide deposits were deposited in relation to exhalative processes in rift bounded marine basins. The iron formations may be sub-divided into BIF-(banded iron formations) and Mg rich types, and at several locations these types grade into each other. There is no direct age evidence to constrain the deposition of iron formations, but stable isotope data and stratigraphic correlations suggest a formation within the 2.1-2.0 Ga age range. The major Kiruna-type ores formed from an iron-rich magma (generally with a hydrothermal over-print) and are restricted to areas occupied by volcanic rocks of the Kiirunavaara Group. It is suggested here that 1.89-1.88 Ga tholeiitic magmas underwent magma liquid immiscibility reactions during fractionation and interaction with crustal rocks, including metaevaporites, generating more felsic magmatic rocks and Kiruna-type iron deposits. A second generation of this ore type, with a minor economic importance, appears to have been formed about 100 Ma later. The epigenetic Cu-Au +/- Fe oxide mineralisation formed during two stages of the Svecofennian evolution in association with magmatic and metamorphic events and crustal scale shear zones. During the first stage of mineralisation, from 1.89-1.88 Ga, intrusion-related (porphyry style) mineralisation and Cu-Au deposits of IOCG affinity formed from magmatic-hydrothermal systems, whereas vein-style and shear zone deposits largely formed at c. 1.78 Ga. The large range of different Fe oxide and Cu-Au +/- Fe oxide deposits in Northern Norrbotten is associated with various alteration systems, involving e.g. scapolite, albite, K feldspar, biotite, carbonates, tourmaline and sericite. However, among the apatite iron ores and the epigenetic Cu-Au +/- Fe oxide deposits the character of mineralisation, type of ore- and alteration minerals and metal associations are partly controlled by stratigraphic position (i.e. depth of emplacement). Highly saline, NaCl + CaCl2 dominated fluids, commonly also including a CO2-rich population, appear to be a common characteristic feature irrespective of type and age of deposits. Thus, fluids with similar characteristics appear to have been active during quite different stages of the geological evolution. Ore fluids related to epigenetic Cu-Au Fe oxides display a trend with decreasing salinity, which probably was caused by mixing with meteoric water. Tentatively, this can be linked to different Cu-Au ore paragenesis, including an initial (magnetite)-pyrite-chalcopyrite stage, a main chalcopyrite stage, and a late bornite stage. Based on the anion composition and the Br/Cl ratio of ore related fluids bittern brines and metaevaporites (including scapolite) seem to be important sources to the high salinity hydrothermal systems generating most of the deposits in Norrbotten. Depending on local conditions and position in the crust these fluids generated a variety of Cu-Au deposits. These include typical IOCG-deposits (Fe-oxides and Cu-Au are part of the same process), IOCG of iron stone type (pre-existing Fe-oxide deposit with later addition of Cu-Au), IOCG of reduced type (lacking Fe-oxides due to local reducing conditions) and vein-style Cu-Au deposits. From a strict genetic point of view, IOCG deposits that formed from fluids of a mainly magmatic origin should be considered to be a different type than those deposits associated with mainly non-magmatic fluids. The former tend to overlap with porphyry systems, whereas those of a mainly non-magmatic origin overlap with sediment hosted Cu-deposits with respect to their origin and character of the ore fluids.
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| 31. |
- Minz, Friederike, et al.
(författare)
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Detailed characterisation of antimony mineralogy in a geometallurgical context at the Rockliden ore deposit, North-Central Sweden
- 2013
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 52, s. 95-103
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 32. |
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| 33. |
- Minz, Friederike, et al.
(författare)
-
Distribution of Sb minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden
- 2015
-
Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 82, s. 125-135
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 34. |
- Minz, Friederike, et al.
(författare)
-
Geological background and qualitative ore characterisation for the geometallurgical project at Rockliden, north-central Sweden
- 2013
-
Ingår i: Mineral deposit research for a high-tech world. - Uppsala : Sveriges Geologiska Undersökning. - 9789174032079 ; , s. 340-343
-
Konferensbidrag (refereegranskat)abstract
- The Rockliden Zn-Cu massive sulphide mineralisation is located at the stratigraphic top of altered rhyolitic-dacitic volcanic rocks, which in turn are intercalated by meta-sedimentary rocks of the Bothnian Basin, north-central Sweden. After the discovery, in the 1980’s, the project was put on hold due to metallurgical and geometallurgical challenges. Exploration drilling restarted in 2007 and resources have increased since then. However, little is known about the mineralogical variability of the ore and how that will affect the processing of the mineralised material. Examples of rock-intrinsic process-relevant parameters are the mineral grain size, the texture of the minerals and the mineral associations, i.e. the mode of occurrence of minerals in the different types of mineralisation, and also the presence and distribution of penalty and bonus elements. Rock-intrinsic parameters and their spatial variability are considered in this study and will form the basis of a 3D-geometallurgical model for the Rockliden mineralisation.
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| 35. |
- Minz, Friederike, et al.
(författare)
-
Lithology and mineralisation types of the Rockliden Zn–Cu massive sulphide deposit, north-central Sweden : Implications for ore processing
- 2014
-
Ingår i: Transactions - Institution of Mining and Metallurgy. Section B. Applied earth science. - 0371-7453 .- 1743-2758. ; 123:1, s. 2-17
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 36. |
- Minz, Friederike, et al.
(författare)
-
Mineralogical controls on the distribution of antimony in a base-metal flotation test at the Rockliden massive sulphide deposit, north-central Sweden
- 2015
-
Ingår i: Mineral resources in a sustainable world. ; , s. 1439-1442
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 37. |
- Minz, Friederike, et al.
(författare)
-
Particle-based Sb distribution model for Cu–Pb flotation as part of geometallurgical modelling at the polymetallic Rockliden deposit, north-central Sweden
- 2017
-
Ingår i: Mineral Processing and Extractive Metallurgy. - : Taylor & Francis. - 0371-9553 .- 1743-2855. ; 126:4, s. 212-223
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 38. |
- Nina, Lidia, et al.
(författare)
-
Anoxic oceanic conditions during the late Permian mass extinction-evidence from the Chutani formation, Bolivia
- 2020
-
Ingår i: Journal of South American Earth Sciences. - : Elsevier. - 0895-9811 .- 1873-0647. ; 103
-
Tidskriftsartikel (refereegranskat)abstract
- We analyze diagenesis of carbonate rocks from the Late Permian Chutani Formation of western Bolivia (San Pablo de Tiquina section) in the southern Lake Titicaca zone, which is a sedimentary succession of semiarid tidal flat comprised of mixed carbonate and siliciclastic units. The diagenetic study includes petrographic analysis (conventional petrography and cathodoluminescence) and geochemical analysis (carbon and oxygen isotopes and minor element chemistry). An integrated study of lithofacies and isotope stratigraphy of carbonates shows a succession of five types of depositional environments: tidal barrier, tidal flat, shoal coastal and shoreface. The Chutani Formation was subjected to different diagenetic processes including micritization, cementation, mechanical compaction, dissolution, neomorphism, dolomitization and dedolomitization that occurred during marine to shallow burial stages. Carbon isotope (δ13C) values range between −7 and 2.9‰ (VPDB) with variations linked to stratigraphic changes. The transgressive stage of the basin exhibits an upwards decreasing trend of δ13C values whereas regression is marked by an increase in such values. The oxygen isotope values (δ18O) vary from −16.6 to −1‰ VPDB with lighter values towards the top of the stratigraphy. The transgressive trend may reflect mixing of meteoric water and/or volcanic-hydrothermal fluids with seawater or progressive oxygenation with enhanced circulation conditions. Heavier values during regression may reflect more evaporitic and anoxic conditions towards the Permian-Triassic boundary. Significant variation in isotope values among neighbouring samples is observed, especially during trangression, which may be the result of different diagenetic processes.
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| 39. |
- Nina, Lidia, et al.
(författare)
-
Diagenesis of the Pennsylvanian –Lower Permian Copacabana Formation, western Bolivian Altiplano
- 2020
-
Ingår i: Journal of South American Earth Sciences. - : Elsevier. - 0895-9811 .- 1873-0647. ; 100
-
Tidskriftsartikel (refereegranskat)abstract
- This contribution presents the diagenetic evolution of limestone deposits in the Copacabana Formation that occurs in the northern Altiplano, in the Lake Titicaca area of western Bolivia. The best-exposed stratigraphic succession of the Copacabana Formation occurs in the Yampupata section, and its division into five facies successions is based on petrographic analysis, cathodoluminescence, x-ray fluorescence analysis (chemical composition) and stable isotope data (δ18O and δ13C). The results showed that the carbonate rocks experienced early marine diagenetic processes such as micritization during or after the deposition (eogenesis). The initial burial event (mesogenesis 1), characterized by stabilization of temperature-water carbonates by freshwater, and represented by bladed calcite-cement, equant calcite cement, dissolution, dolomitization, neomorphism, silicification and compaction (physical), occurred in shallow burial conditions. During the second burial episode (mesogenesis 2), in deeper burial environment the processes include: compaction (physical and chemical) and neomorphism. Diagenetic processes have affected reservoir quality in the Copacabana Formation during the mesodiagenesis, and reduced the conditions for development of high-quality conventional hydrocarbon reservoirs. Depleted O and C stable isotope signatures indicate that these carbonate rocks deposits underwent both meteoric and burial diagenesis including moderate water-rock interaction.
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| 40. |
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| 41. |
- Nyström, Elsa, et al.
(författare)
-
Occurrence and release of trace elements in pyrite-rich waste rock
- 2021
-
Ingår i: Minerals. - : MDPI. - 2075-163X. ; 11:5
-
Tidskriftsartikel (refereegranskat)abstract
- Waste rock can contain high concentrations of deleterious trace elements, which upon oxidation can be released, having a significant impact on water quality. Therefore, knowledge about their occurrence and overall mobility is crucial to ensure suitable environmental protection measures. Sulfide-rich waste rock was characterized and quantified using automated mineralogy (QEMSCAN). Selected pyrite grains were analyzed for trace element occurrence using LA-ICP-MS before, during, and after leaching the waste rock in 10 L small-scale test cells for two years to assess trace element occurrence and mobility. Sequential extraction was used to estimate elemental sequestration during the experiment. The high abundance of pyrite (66%) and scarcity of buffering minerals resulted in low pH (<1.3) leachate with high concentrations of trace elements such as As (21 mg/L), Cu (20 mg/L), Hg (13 µg/L, Pb (856 µg/L), Sb (967 µg/L), Tl (317 µg/L ), and Zn (23 mg/L) in solution with limited retention in secondary minerals, primarily due to these elements’ association with pyrite either as inclusions or impurities showing an average abundance of 193 ppm As, 15 ppm Cu, 13 ppm Hg, 20 ppm Pb, 24 ppm Sb, 26 ppm Tl, and 74 ppm Zn in the waste rock. The occurrence of Cu and Zn as inclusions associated with the pyrite led to their extensive mobilization of 79% and 72%, respectively, despite their low abundance in the waste rock. Provided the overall leachability of S (11%) and limited formation of secondary minerals, the average oxidation rate suggests depletion of the pyrite within approximately 18 years. In conclusion, this study shows the importance of detailed mineralogical investigations and early preventive measures of waste rock to ensure sustainable mine waste and water management.
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| 42. |
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| 43. |
- Pålsson, Bertil, et al.
(författare)
-
Unlocking Rare Earth Elements from European apatite‐iron ores
- 2014
-
Ingår i: ERES 2014 - 1st International Conference on European Rare Earth Resources. - Santorini : Heliotopos Conferences Ltd.. - 9789606746154 ; , s. 211-220
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 44. |
- Riegler, Thomas, et al.
(författare)
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Petrographic and mineralogical study of the Kilmacoo gold occurrence, Avoca District, Southeast Ireland
- 2019
-
Ingår i: Proceedings of the 15th SGA Biennial Meeting, 27-30 August. - : University of Glasgow Publicity Services. ; , s. 323-326
-
Konferensbidrag (refereegranskat)abstract
- Petrographic investigation of the quartz vein hosted Kilmacoo gold occurrence spatially associated with the copper rich Avoca massive sulphide ore body evidenced a close association between gold and sulphides. Visible electrum grains are frequently observed within chalcopyrite, and more rarely as minute inclusions in both arsenopyrite and pyrite. Mineralogical investigations also revealed complex sulphide paragenetic succession from framboidal pyrite to colloform and idiomorphic cements with overall a low arsenopyrite content. We also documented the presence of hydrothermal phosphates (apatite and monazite) subsequently altered in aluminum phosphate sulphate minerals, as well as a broad diversity of phyllosilicates. These observations as well as the cross cutting relationships tend to indicate a brittle deformation event involving possible remobilization of some of the copper mineralization from the main VMS ore body. At the present time the source of gold is still under investigation to determine the possible contribution from both local and distal sources.
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| 45. |
- Rincon, Jonathan, 1991-, et al.
(författare)
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Mineralogy, textural characteristics and mineral chemistry of remobilised sulphides and sulphosalts in the Rävliden Norra VMS deposit, Skellefte district, northern Sweden
- 2020
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Ingår i: EGU General Assembly 2020. - : Copernicus GmBH.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Remobilisation of sulphides in metamorphosed volcanic-hosted massive sulphide deposits has been investigated in many VMS districts with regards to scale, mineral assemblages, texture and relative competence of minerals under certain p-t conditions (Gilligan & Marshall, 1987; Marshall & Gilligan, 1987). Examples of syn-tectonic remobilisation can be found at the Rävliden Norra (RVN) volcanic-hosted massive sulphide in the Skellefte district. At Rävliden, polymetallic sulphide mineralization occurs at the transition from meta-volcanic rocks of the Skellefte group rocks to the overlying Vargfors group, comprising volcaniclastic metasedimentary rocks and graphitic shales. This contribution details features of mesoscale (0.1-50 cm) remobilisation of sulphides, such as sulphide-rich veins, tension gashes, ball-ore, massive sulphides with cataclastic texture, and micro-scale features such as infilling of pressure shadows, displaying evidences of brittle and ductile deformation. Sulphide-rich veins containing sphalerite, galena, and a relative high content of Ag-sulphosalts (e.g. freibergite, pyrargyrite, pyrostilpnite) are hosted in the hanging wall (HW) of the RVN mineralization. Brittle deformation is shown in accessory quartz and calcite as bulging recrystallization, grain boundary migration and deformation lamellae or twinning. Ductile expressions include ball-ore (i.e. “durchbewegung”) textures, typically made up of two components, one composed of clasts of graphite shale or tremolite-, actinolite-, talc-altered meta-volcanic rocks and the other comprising a matrix of massive sulphide mineralization. In the massive sulphide matrix of sphalerite, chalcopyrite or pyrrhotite, micro-scale tension gashes and/or pressure shadows occur around clasts infilled by pyrrhotite, chalcopyrite, galena, freibergite, boulangerite, or gudmundite. A similar mineralogy is observed in ore lenses in the ore zone, comprising sphalerite, galena and Ag-Sb-As sulphosalts, hosted structurally above chalcopyrite + pyrrhotite stringer zones in the footwall (FW). Sulphosalts and galena present a high silver content relative to other VMS deposits in the district. This is evidenced by SEM and EMPA analysis in both HW and FW ore lenses. Argentopyrite, sternbergite and stephanite are also locally present in the HW as minor silver species hosted in veins. Inclusions of freibergite in galena contain Ag with average values of 18.4 wt. % in the HW (n=5), 18 wt. % in the massive sphalerite and ball-ore (n= 15), and 20.2 wt. % in the chalcopyrite + pyrrhotite stringer zone (n= 5). Similarly, Pb is 0.2 wt. %, 0.3 wt. %, and 0.4 wt. %, respectively. For sphalerite, Fe is on average 8.0 wt. % (n=3), 7.4 wt. % (n = 11), and 8.3 wt. % (n=3), respectively. Our preliminary results suggest that mineralization in the HW is remobilized from the main ore and textural relationships support a hypothesis that remobilisation involved a relative silver-enrichment in paragenetically later assemblages. At least two stages of deformation in the deposit can be recognized. In the first stage, sphalerite- and chalcopyrite-rich mineralization was deformed along with tremolite and talc to form a S1 foliation. The second stage involved folding of S1, and remobilisation of galena, chalcopyrite and Ag-Sb-As sulphosalts as veins or breccia infill in the HW or filling tension gaps or ball-ore, in the FW. These are often parallel to S2 crenulation or axial planes.
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| 46. |
- Rincon, Jonathan, 1991-, et al.
(författare)
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Ore Remobilization History of the Metamorphosed Rävliden North Volcanogenic Massive Sulfide Deposit, Skellefte District, Sweden
- 2024
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Ingår i: Economic geology and the bulletin of the Society of Economic Geologists. - : Society of Economic Geologists. - 0361-0128 .- 1554-0774. ; 119:4, s. 907-934
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Tidskriftsartikel (refereegranskat)abstract
- The Skellefte district in northern Sweden hosts many volcanogenic massive sulfide (VMS) deposits and is considered one of the most important European mining districts for Cu, Zn, Pb, Ag, and Au. The volcanic and sedimentary rocks that the VMS deposits are hosted in were deformed during the Svecokarelian orogeny, with three documented regional deformation phases. These events imparted a distinct attitude and geometry to the deposits, their host succession, and discordant zones of synvolcanic hydrothermal alteration. Few studies have investigated the detailed deformation effects on the sulfide minerals.In this contribution, we document the structural characteristics and remobilization history of mineralization at the Rävliden North Zn-Pb-Cu-Ag deposit—one of the most important recent discoveries in the district consisting of 8.5 million tonnes (Mt) grading 1.01% Cu, 3.45% Zn, 0.53% Pb, 78.60 g/t Ag, and 0.23 g/t Au. At Rävliden, massive to semimassive sphalerite-rich mineralization with lesser pyrrhotite, galena, pyrite, and silver minerals occurs structurally above stringer-type mineralization dominated by chalcopyrite, pyrrhotite, and pyrite. These mineralization types exhibit evidence of deformation and remobilization such as (1) sulfide-alignment parallel to tectonic foliations; (2) rounded wall-rock tectonoclasts in a ductile deformed sulfide matrix (“ball ore” or durchbewegt ore); and (3) sulfides in tension gashes, strain shadows, piercement veins, and late, straight veinlets crosscutting tectonic fabrics. These features are attributed to polyphase deformation during the D1, D2, and D3 events at temperature ranging from 200° to 550°C. Remobilization of sulfides was mostly within the bounds of the main mineralization (i.e., 10–100 m), with few local external occurrences. A combination of solid-state and fluid-assisted remobilization processes are inferred.Rare brittle veinlets and zeolite-cemented breccias with sphalerite, galena, and silver minerals occur in the stratigraphic hanging wall, where they crosscut all Svecokarelian structures. This mineralization type is highly reminiscent of Phanerozoic low-T vein- and breccia-hosted Pb-Zn deposits of the Lycksele-Storuman area west of Rävliden North, which have been linked to far-field effects associated with the opening of the Iapetus Ocean (0.7–0.5 Ga). We suggest that this Zn-Pb mineralizing event led to the formation of the late sulfide-zeolite veinlets and breccias at Rävliden North, and that elements such as Ag and Sb within this mineralization were locally remobilized from Rävliden.
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| 47. |
- Rincon, Jonathan, 1991-, et al.
(författare)
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Pyrite and sphalerite trace element redistribution during metamorphism of the Rävliden North VMS deposit, northern Sweden
- 2022
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Ingår i: Geological Society of Sweden, 150 year anniversary meeting: Abstract volume. ; , s. 154-157
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Rävliden North volcanogenic massive sulphide (VMS) deposit and its host rocks exhibit a shared history of metamorphism during the 1.88–1.86 Ga deformation phases of the Svecokarelian orogeny. Predominantly internal sulphide remobilisation produced minor modifications to the overall pre-metamorphic trace element distribution including remobilisation. Post-Svecokarelian sulphide-bearing zeolite- and calcite veinlets cross-cut the stratigraphic hanging wall suggesting mobilisation of sulphides in a fluid phase during an overprinting later event unrelated to the VMS mineralisation.
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| 48. |
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| 49. |
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| 50. |
- Rincon, Jonathan, 1991-
(författare)
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Textural and chemical characterization of sulphide minerals at the Rävliden North VMS deposit, Skellefte district, Sweden
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The discovery of new mineral deposits is essential to meet the increasing demand for metals in our society. The Skellefte mining district in Northern Sweden is one of the main producers of polymetallic ores of Cu, Zn, Pb,Ag, Au, and Te in Europe. Discovery of new deposits in the Skellefte district has become increasingly challenging due to exhaustion of near surface deposits, and general difficulties when applying traditional exploration methods at depth. This has stimulated an interest in alternative methods, such as utilizing the trace element chemistry of sulphide minerals (e.g. pyrite) in metasedimentary and metavolcanic rocks to vector in on massive sulphide deposits. Meanwhile, there is a near complete paucity of trace element data from the massive sulphide deposits of the Skellefte district, and a global shortage of data from Palaeoproteroizoic, polydeformed and metamorphosed volcanogenic massive sulphide deposits (VMS).The Rävliden North Zn-Pb-Cu-Ag VMS deposit in the western most part of the Skellefte district, offers a great opportunity for combine in-situ trace element studies with paragenetic analysis to assess if vectors to mineralisation can be defined, and the effects of deformation and metamorphism. The deposit is hosted at the transition from the mainly felsic metavolcanic rocks of the Skellefte group to the mainly pelitic metasedimentary and mainly mafic – intermediate metavolcanic rocks of the Vargfors group. Rävliden North was significantly affected by deformation and greenschist – lower amphibolite facies metamorphism during the 1.88 – 1.86 Gadeformation phases of the Svecokarelian orogeny. Sphalerite-rich mineralisation associated with pyrrhotite, galena, pyrite and Ag-minerals is situated structurally and stratigraphically above stringer-type chalcopyrite-richmineralisation with lesser pyrrhotite, pyrite and minor amounts of Ag-minerals. Analysis of the textural and structural paragenesis of the mineralisations in the deposit show that sulphides range from aligned sub-parallel to three foliations (SC, S2, S2L), to hosted by tectonic structures such as tension gashes, piercement veins, veinlets, breccias and plastically deformed sulphide ore with rounded tectonoclasts (‘ball ore’). Sulphide occurrences associated with quartz veinlets and sulphide-cemented breccias cross-cutting poly-stage ductile structures could be the result of remobilisation under brittle conditions during the late stages of the Svecokarelian orogeny or afterwards. In-situ minor and trace element data from sphalerite, pyrite, sulphosalts, tellurides, antimonides and amalgams indicate trace element distribution patterns that can be related to primary ore formation followed by subsequent redistribution during the main phases of metamorphism and deformation.Sphalerite from the stringer-type chalcopyrite-rich mineralisation has a higher In, Co, Cu content, and a lower Mn content compared with sphalerite from the sphalerite-rich mineralisation. This trace element zonation resembles that of common VMS deposits, and is thus interpreted as retained from primary mineralisation. The Feand Cd content in sphalerite shows little variation in the sphalerite-rich mineralisation compared with the chalcopyrite-rich mineralisation, and do not exhibit any systematic variation relative to deformation textures. This can be explained by syn-metamorphic recrystallisation that could have equilibrated the composition of sphalerite. Sulphosalts, tellurides, antimonides, and amalgams are associated with galena and chalcopyrite in syn- to post-tectonic structures relative the main phase of deformation. The Ag-mineralogy seem to have formed during the retrograde phase of metamorphism as exsolutions from α-galena when temperatures decreased from 500 to 200C. However, LA-ICP-MS imaging of pyrite grains reveal co-precipitation of early syngenetic pyrite, base metalsulphides, and silver-rich minerals, and subsequent syn-metamorphic pyrite growth and remobilisation of the latter. This suggest that besides causing a significantly higher Ag content in paragenetically younger mineralisation types, syn-metamorphic remobilisation may have not extensively modified the mineralisations at Rävliden North.Sphalerite associated with low temperature Ag-sulphosalt-, zeolite- and calcite-bearing veinlets and breccias in the stratigraphic hanging wall contain the highest contents of Ga, Ge, Sb and Cu in the area. Comparison with sphalerite in similar style of mineralisation in the Lycksele-Storuman area, west of Kristineberg, suggest a contemporaneous origin. They possibly formed as a result of a mineralising event related to the opening of the Iapetus Ocean (0.7 – 0.5 Ga) or the waning stages of the Timanian orogeny (0.6 – 0.5 Ga). Although unrelated to the VMS deposit, the late-stage veins in the stratigraphic hanging wall of Rävliden North can still be of some aid during mineral exploration as they likely contain some components that were sourced locally via remobilisation (e.g. Ag and Sb).
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