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  • 1.
    Axelsson, Mikael
    et al.
    Luleå tekniska universitet.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Determination of major and trace elements in sphalerite using laser ablation double focusing sector field ICP-MS2001Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 72, nr 2, s. 81-89Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The analytical performance of laser ablation (LA) for the determination of Co, Fe, Cd, Ag, Mn, Cu and S in sphalerite was evaluated using double focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS). Samples were collected from Zinkgruvan, situated in the south central Sweden. The use of Zn for internal standardisation, together with correction for FeS impurities in sphalerite, allows straightforward quantification without using external methods for the determination of the actual Zn content. LA-ICP-SFMS results were compared with data obtained by conventional pneumatic nebulisation introduction of sample solutions following acid digestion. Good agreement between the two methods was obtained for homogeneously distributed elements. For the majority of the elements under consideration, LA-ICP-SFMS precision was better than 10% RSD.

  • 2.
    Dold, Bernhard
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Acid rock drainage prediction: A critical review2016Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 172, s. 120-132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acid rock drainage (ARD) prediction is a very important issue in order to predict and prevent environmental pollution associated with mining activities. Nowadays, simple tests are widely applied and established in the mining and consulting business for ARD prediction. These tests have many known errors and problems, as that they do not account for the complexity of the mineral assemblage of an ore deposit, and therefore are not able to predict the geochemical behavior accurately. This critical review has the aim of first, highlighting the geochemical processes associated to the problems of ARD prediction. Secondly, the errors and limitations of the standard static and kinetic tests are highlighted. The currently applied calculation factor of 31.25 for sulfide acid potential calculation overestimates the carbonate neutralization potential by 100% in its geochemical assumptions. Thus, the calculation factor 62.5, based on the effective carbonate speciation at neutral pH, is recommended. Additionally, standard ABA procedure ignore the acid potential of Fe(III) hydroxides and/or sulfates and do not distinguish between different carbonate minerals. This can be critical, as for example siderite can be a net acid producing carbonate. Therefore, it is crucial to count on accurate quantitative mineral data in order to be able to accurately predict ARD formation and potential liberation of hazardous trace elements to the environment.

    In many modern mining operations, quantitative mineral data is nowadays produced in order to enhance the recovery of the extraction process by the incorporation of geometallurgical information (e.g. quantitative mineralogy, mineral liberation, textural information, grain size distribution). Thus, the use of this very same existing data for ARD prediction can increase importantly the precision of ARD prediction, often without additional costs and testing. The only requirement is the interdisciplinary collaboration between the different divisions and data exchange in a modern mining operation.

  • 3.
    Ebenå, Gustav
    et al.
    Linköping University, Department of Biology.
    Hagberg, Jessika
    Örebro University, MTM, Department of Natural Sciences, Örebro.
    Carlsson, Erik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Origin and distribution of low molecular weight organic acids and bacteria in a depth profile of a soil covered tailings impoundment in northern Sweden2007Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 92, nr 2-3, s. 186-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The tailings at Kristineberg, northern Sweden, have a very low content of organic carbon, a feature common with many sulfidic tailing impoundments. Three different experiments were set-up to assess the role of carbon dioxide in a depth profile. Firstly, pore gas was collected in vials from ground water pipes at various points in the profile of a dry covered tailings impoundment and analyzed in the laboratory for CO2, O2, N2, H2, and CH4 contents. Secondly, pore water was extracted from tension lysimeters at various depths. This water was analyzed for numbers of bacteria (iron-oxidizing and sulfur-oxidizing, both by MPN), and low molecular weight organic acids. Thirdly, Acidithiobacillus ferrooxidans (Strain DSMZ No 1927) was grown on a mixture of irradiated tailings and sterile water. The amount of organic acids produced was monitored.The largest bacterial count of iron-oxidizing bacteria, 4.7 × 105/g tailings, was at the oxidation front, while the heterotrophic sulfur-oxidizing bacteria were mainly found in the unsaturated, oxidized zone, 2.65 × 104/g tailings. The oxidation front was also the location where the largest amount of organic acids was found in the field study (formate 0.83 mg/l and acetate 0.51 mg/l). The acetic acid found coincides with the highest count of iron-oxidizing bacteria.The intrusion of O2 and CO2 at the studied location is enough for microbiological activity, although the overall effect on AMD production is not addressed.The results from laboratory incubations indicate that the microbial community produces organic carbon with CO2 as the sole carbon source, up to 1.35 mg/l after 16 weeks measured as TOC.To conclude, we suggest that knowledge of the intrusion of both CO2 and O2 is vital for a full understanding of the microbial ecology, and thus the weathering processes, in a dry covered tailings impoundment. Hence, the CO2 produced in the till cover and entering the tailings ecosystem is crucial to the function of the ecosystem.

  • 4.
    Holmström, Henning
    et al.
    Luleå tekniska universitet.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Layers rich in Fe- and Mn-oxyhydroxides formed at the tailings-pond water interface, a possible trap for trace metals in flooded mine tailings2001Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 74, nr 1-3, s. 189-203Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Geochemical field studies of the flooded sulphide-rich mine tailings at Stekenjokk in northern Sweden have been performed. Minor diffusion of elements from the tailings to the pond water is occurring. The diffusion rate is higher where tailings that were oxidised before the flooding have been deposited. Layers rich in Fe-and Mn-oxyhydroxides have been developed close to the tailings surface, and a layer of natural sediments rich in organic material have developed on the tailings surface since the flooding. The oxyhydroxides adsorb and/or co-precipitate metals and function as a trap for released metals at the tailings-pond water interface, thereby decreasing the diffusion rate from the tailings pore water to the pond water at the sediment-water interface. This study shows that it is possible for a deposit of flooded tailings to reach a state when it almost functions as a natural lake in northerly areas, with Fe-and Mn-oxyhydroxide layers controlling the diffusion of metals into the overlying pond water, within a relatively short time after remediation

  • 5.
    Hällström, Lina
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Geochemical characterization of W, Cu and F skarn tailings at Yxsjöberg, Sweden2018Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 194, s. 266-279Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Little attention has been paid to tailings from skarn ore deposits and their environmental impact, even though they can contain elevated concentrations of elements of potential concern together with sulfides and fluorite. Historical skarn tailings at Yxsjöberg, Sweden, containing e.g. Be, Bi, Cu, F, Sn, S, W, and Zn were geochemically characterized as a first step to evaluate the environmental impact and the potential to re-mine the tailings. The tailings were deposited between 1897 and 1963 in the Smaltjärnen Repository without dams or a complete cover, and have been in contact with the atmosphere for >30 years. Four vertical cores throughout the tailings were taken and divided into 134 subsamples, which were analyzed for total concentrations and paste pH. Selected samples from different depths were mineralogically characterized using optical microscopy, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), Raman vibrational spectroscopy, and X-ray diffraction (XRD). Minerals, hand-picked from drilled rock cores, were analyzed for the element content, and a modified Element to Mineral Conversion (EMC) that pinpoints the quantitative distribution of elements between the minerals in the tailings was carried out. The average concentrations of Be, Bi, Cu, Sn, Zn, W, F and S in the tailings were 284, 495, 946, 559, 301, and 960 ppm, and 1.9 and 1.2 wt%, respectively. The tailings has reached a late stage development due to pyrrhotite oxidation resulting in low pH (<4) in the uppermost tailings, and formations of secondary minerals such as gypsum, hydrous ferric oxides (HFO) and orthogonal calcite. Secondary pyrite and magnetite, formed from monoclinic pyrrhotite was detected, and different weathering rates of secondary pyrite, hexagonal and monoclinic pyrrhotite was indicated, with secondary pyrite as the most stable and monoclinic pyrrhotite as the least. The rare and easily-weathered mineral danalite (Fe4Be3(SiO4)3S) was found in the drilled rock cores and by XRD in the tailings. However, the mineral could not be found by optical microscopy or SEM-EDS. This suggests that the mineral has been weathered to a great extent, which poses a high risk of releasing elements of potential concern to the groundwater since danalite contains approximately 40% of the total Be and Zn concentrations in the tailings. Fluorine was mainly found in fluorite, Cu in chalcopyrite, and Bi in bismuthinite; which all showed signs of weathering in acidic condition in the uppermost part, subsequent with decreased concentrations, followed by accumulation peaks deeper down in the tailings correlated with Al. Tungsten was mainly found in scheelite; most grains were unweathered, but a few grains had altered rims or HFO on the mineral surfaces. Tin was mainly found in ferrohornblende, hedenbergite and grossular. Beryllium, Cu, F, and Zn has high potential to be released to the surrounding environment from the Smaltjärnen Repository, while W, Bi and Sn are relatively stable in the tailings. Most of the scheelite is intact and re-mining could, therefore, be a suitable remediation method that would both reduce the environmental impact and simultaneously support the supply of critical raw materials in the EU.

  • 6.
    Jansson, Nils
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Zetterqvist, Anders
    Zetterqvist Geokonsult AB.
    Allen, Rodney
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. Boliden Mineral AB, Exploration Department.
    Malmström, Lars
    Zinkgruvan Mining AB.
    Geochemical vectors for stratiform Zn-Pb-Ag sulfide and associated dolomite-hosted Cu mineralization at Zinkgruvan, Bergslagen, Sweden2018Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 190, s. 207-228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Zinkgruvan deposit is the largest stratiform Zn-Pb-Ag mineralization in Sweden. The most recent genetic model attributes ore formation to the discharge of oxidized, near-neutral pH, metalliferous brines into a reduced basin, forming laterally extensive, stratiform sulfide mineralization on the seafloor. It has a known strike extent of 5 km and is underlain by a regionally extensive zone of K-altered metavolcanic rock and dolomitic marble, the latter hosting Cu-(Co-Ni) replacement mineralization near the inferred hydrothermal vent to the stratiform sulfides. The deposit is stratigraphically overlain by migmatized,  pyrrhotite- and graphite-rich pelite that is in turn overlain by a banded almandine-biotite-quartz-ferrosilite-bearing unit at the base of an regionally extensive metasedimentary succession. These laterally continuous units are interpreted as metamorphosed organic-rich sulphidic mudstone and silicate-dominated Fe formation, respectively.

    The favorable stratigraphic interval contains anomalously high Zn, Pb, Ag, Cu, K2O/(K2O+Na2O), Mn, Co, Tl, Ba and B relative to adjacent metatuffite. However, only Zn, Pb, Ag, K2O/(K2O+Na2O) and Mn are significantly enriched relative to adjacent strata beyond the known lateral extent of the ore. Elevated copper, Co and Tl only occur in the vent-proximal part of the deposit, whereas anomalous enrichments of Ba and B are sporadic and occur mainly in the stratigraphic footwall. Many elements such as Si, Fe, Mg, Ca and Cs are of limited use in vectoring due to low enrichment factors relative to inferred background compositions and/or strong lithological controls on their distribution.

    Although ore metal (Zn, Pb and Ag) enrichments are the best quantitative and qualitative guides to ore, K, Mn and Co enrichments also provide corroborative support. The most useful elements for vectoring have been synthesized into exploration indices. The Modified Sedex Metal Index (MSMI; Zn+3Pb+100Ag) is a vector towards stratiform Zn-Pb-Ag mineralization, whereas MSMI2 [Zn+3Pb+10(Cu+Co)] alsoallows targeting of proximal Cu mineralization.

    The banded iron formation and the pyrrhotite- and graphite-rich pelite of the stratigraphic hangingwall are consistently enriched in base metals (e.g. 500-1000 ppm Zn), total S and Mn throughout the entire Zinkgruvan area. However, these units are not known to grade laterally along strata into economic base metal sulfide mineralization, and they are not obviously products of the same hydrothermal system which formed the stratiform Zn-Pb-Ag deposit.

    In a vent-distal setting, the somewhat spurious metal anomalies of the hangingwall units can be difficult to distinguish from those of the favorable interval. The favorable stratigraphic interval can, however, be recognized by also taking into account that positive Zn anomalies are mainly coincident with positive anomalies in both K and Mn only in the favorable interval. Furthermore, samples from the favorable interval generally have Co/Ni > 1 and displays a positive Co/Ni vs. Zn trend, whereas samples of the pyrrhotite- and graphite-rich pelite have Co/Ni < 1 and define a negative Co/Ni vs. Zn trend. Thus, the index (Co/Ni)*Zn allows easy detection of weak Zn anomalies associated with the stratiform Zn-Pb-Ag mineralization.

  • 7.
    Kumpiene, Jurate
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Brännvall, Evelina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Taraškevičius, Ričardas
    Institute of Geology and Geography, Nature Research Centre.
    Aksamitauskas, Česlovas
    Vilnius Gediminas Technical University.
    Zinkutė, Rimantė
    Institute of Geology and Geography, Nature Research Centre.
    Spatial variability of topsoil contamination with trace elements in Preschools in Vilnius, Lithuania2011Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 108, nr 1, s. 15-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An investigation of the spatial variability of topsoil contamination level was performed in 49 preschool playgrounds located in Vilnius city and correlated with urban (height and age of the preschools and height of surrounding buildings) and natural (altitude) factors. Composite samples, consisting of 20-30 sub-samples, were collected from 10 cm topsoil layer with a 3-5 m distance from each other. Sieved fraction (< 0.63 mm) was ashed at 400 °C, ground to < 1.0 μm and analysed for the real total concentrations of 22 trace elements (Ag, B, Ba, Co, Cr, Cu, Ga, Li, Mn, Mo, Nb, Ni, Pb, Sc, Sn, Sr, Ti, V, Y, Yb, Zn and Zr) using optical atomic emission spectrophotometry. Information on construction year and height (number of building stories) of preschool and surrounding buildings was acquired from the Centre of Registers of Lithuania. Out of 22 analysed elements, 13 to a greater extent exceeded the background values in several areas and were used to calculate the total contamination index (Zs13). Out of 49 analysed areas, 21 had moderately hazardous to hazardous levels of contamination as indicated by Zs13. The main contaminating elements, exceeding the permissible concentrations were Ag, Cu, Mo, Pb, Sn and Zn, the origins of which coincide with city industry and traffic. Topsoil around the newer preschool buildings, despite their location, contained lower concentrations of contaminants, while areas at higher altitudes were more contaminated than those located at lower altitudes. The latter causality is biased, as the city industry, and hence the highest contamination, is in districts located higher above sea level than the remaining studied sites.

  • 8.
    Land, Magnus
    et al.
    Stockholm University, Department of Geology and Geochemistry.
    Thunberg, Jonas
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Trace metal occurrence in a mineralised and a non-mineralised Spodosol in northern Sweden2002Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 75, nr 1-3, s. 71-91Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to determine the metal-bearing phases with special emphasis on Cu, a sequential extraction has been carried out on seven soil samples from a sulphide-bearing spodosol profile in Liikavaara Ostra, close to the Aitik Copper Mine in northern Sweden. A reference spodosol profile with very low abundances of sulphides located far from anthropogenic emissions was also studied. Five fractions were selected for the extraction: (I) CH (sub 3) COONa-extractable (exchangeable/adsorbed/carbonate); (II) Na (sub 4) P (sub 2) O (sub 7) -extractable (labile organics); (III) 0.25 M NH (sub 2) OH.HCl-extractable (amorphous Fe oxyhydroxides/Mn oxides); (IV) 1 M NH (sub 2) OH.HCl-extractable (crystalline Fe oxides); and (V) KClO (sub 3) /HCl-extractable (organics and sulphides). The distribution of trace elements (Co, Cr, Cu, Ni, Pb and Zn) in the profile in Liikavaara Ostra is different from that in the reference profile. Possible explanations for these differences are (i) the presence of sulphides in the soil, (ii) atmospheric deposition of dust derived from mining activities at the Aitik Copper Mine, and (iii) mineralogical heterogeneities inherited from the deposition of the till. There is no straightforward correlation between the amount of the extracted phases and the metal extractability in the soils. This fact indicates that other factors are important for the retention of trace metals as well. The data presented in this study suggest that Co, Cr and Ni, to a fairly large extent, are associated with the organic matter in the B-horizon in both profiles, while in the C-horizon in Liikavaara Ostra, sulphides are probably the more important carriers of these elements. For Co and Ni, Fe oxyhydroxides seem to be important. Most of the Cr occurred in the residual remaining after the leaching procedure. Copper and Zn seem to be associated with the organic matter to some extent in the B-horizon. The concentration of Cu in the C-horizon in Liikavaara Ostra is high (2310 ppm), but only a very small fraction is likely to be hosted by sulphides. It is concluded that the major part of Cu in the C-horizon and a prominent fraction in the B-horizon in Liikavaara Ostra are associated with some secondary phase that is extractable during extractions III and IV. Possible candidates for this phase are goethite and inclusions of native Cu in weathered biotite

  • 9.
    Ljungberg, Johan
    et al.
    Boliden Mineral AB.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The geochemical dynamics of oxidizing mine tailings at Laver, northern Sweden2001Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 74, nr 1-3, s. 57-72Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    former Cu mine Laver in northern Sweden was selected for a study of the geochemical processes in mine tailings. The Laver mine was in operation between 1936 and 1946, producing approximately 1.2 Mt of tailings. This study of the tailings at Laver includes time series of groundwater and surface water chemistry, chemical and mineralogical studies of the tailings sand and geophysical investigations. The results allow a good understanding of the dynamic geochemical processes taking place within the tailings. Oxidation of sulphide minerals in the tailings has led to the development of a distinct chemical zonation. Metals released from oxidation and weathering of sulphide minerals are retained within the tailings impoundment. This retention mechanism is today very efficient and only 5-10% of the released masses of metals reaches the surface water system. Zn, Cd, Co and Ni are probably secondarily bound to the tailings with adsorption in a large mass of non-weathered tailings. Cu, on the other hand, is enriched in a distinct zone just below the front of oxidation. This distinct Cu-enrichment suggests precipitation of a secondary mineral phase, probably covellite. The downward movement of the front of oxidation advances at a rate of 2.8 cm/a, and displaces the secondary zone with Cu-enrichment at the same rate. When the oxidation front reaches the groundwater table, the oxidation of sulphide minerals will almost completely stop. The Cu-enrichment will, in this case, probably partly go into solution and be transported away by the groundwater movement. The seepage of acid water from the oxidation front will consume pH-buffering capacity of the tailings and the groundwater will eventually become more acidic. Such a low pH-environment in the tailings will force the adsorbed Zn, Cd, Co and Ni to go into solution and be transported away. A front of water with low pH and high concentrations of metals has been detected and is moving towards the outlets of the tailing impoundment. Due to the low hydraulic gradient and conductivity, the front of acid metal-rich water will be delayed in time by 10-30 years before it reaches the recipient.

  • 10. Malinovskiy, Dmitry
    et al.
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Axelsson, Mikael D.
    SGAB Analytica, Luleå.
    Baxter, Douglas
    Determination of rhenium and osmium concentrations in molybdenite using laser ablation double focusing sector field ICP-MS2004Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 81, nr 1-3, s. 71-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A technique for the in situ determination of Re and Os in molybdenite samples using direct solid sampling by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is described. The sample preparation is limited to molybdenite separation followed by grinding and pressing to pellets. For Re determination, the best results were obtained using external calibration in conjunction with internal standardization. Isotopes of both molybdenum and sulphur could be used as internal standards. This quantification approach provides precision levels generally better than 10% the relative standard deviation (RSD) with similar levels of accuracy. Os concentrations were derived from Re concentrations and measured isotopic ratios of intensities measured at masses 187 and 185, using W isotopes for on-line mass bias correction. As a rule, LA-ICP-MS results for Os agree with corresponding isotope dilution ICP-MS data to within 30%. Reproducibility is strongly dependent on the age of the molybdenite as well as on the precision of isotope ratio measurements, which in turn depend on Re and W concentrations. The proposed technique provides a rapid estimation of Re and Os concentrations for subsequent precise analysis by isotope dilution ICP-MS.

  • 11.
    Qureshi, Asif
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Maurice, Christian
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Potential of coal mine waste rock for generating acid mine drainage2016Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 160, s. 44-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acid mine drainage (AMD) due to the oxidation of sulphide bearing waste rock (WR) is a common environmental problem associated with coal extraction. Therefore, WRs from the Lakhra coal field in Pakistan, were studied to i) perform a mineralogical and chemical characterisation, ii) determine the AMD generating potential and iii) estimate the leachability of elements. The chemical and mineralogical composition was studied using ICP, XRF, XRD and SEM. Acid base accounting and weathering cell test determined the acid producing potential of WRs. Besides organic material, the WRs were composed of quartz, pyrite, kaolinite, hematite and gypsum with varying amounts of calcite, lime, malladerite, spangolite, franklinite and birnessite. The major elements Si, Al, Ca and Fe were in the range (wt.%) of 8–12, 6–9, 0.3–3 and 1–10, respectively, with high S concentrations (19.4–113.3 g/kg). Trace elements were in the range (mg/kg) As (0.3–8), Cd (0.2–0.4), Co (15–75), Cr (67–111), Cu (25–101), Hg (0.1–0.2), Ni (50–107), Pb (8–20) and Zn (75–135). The AMD potential of WRs ranged from − 70 to − 492 kg CaCO3/tonne. During the test period of 192 days, the pH of leachates from very acidic WRs was maintained from 1 to 2.5, whereas, the less acidic WRs produced leachates of mildly acidic (2.7) to neutral (7.3) pH. The leachates from very acidic WRs ranged in the element concentrations of Fe, SO42 − and Al from mg/L to g/L and As, B, Co, Cu, Mn, Ni and Zn from μg/L to mg/L. However, the leachates from less acidic WRs contained all major elements in mg/L and trace elements in μg/L concentrations except for B and Mn that ranged from μg/L to mg/L. The results show that the studied WRs have mild to strong acid producing potential and have the capacity to deteriorate natural water quality significantly. Therefore, necessary preventive or/and acid neutralising measures are strongly suggested.

  • 12.
    Sandrin, Alessandro
    et al.
    Luleå tekniska universitet.
    Edfelt, Åsa
    Waight, Tod E.
    University of Copenhagen.
    Berggren, Robert
    Elming, Sten-åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Physical properties and petrologic description of rock samples from an IOCG mineralized area in the northern Fennoscandian Shield, Sweden2009Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 103, nr 2-3, s. 80-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Tjårrojåkka Fe-Cu prospect in northern Sweden is considered an example of a Fe-oxide Cu-Au (IOCG) deposit and is hosted in metamorphosed Paleoproterozoic volcanic and intrusive rocks. Rock samples from 24 outcrops were collected for petrophysical analysis (magnetic susceptibility, remanent magnetization, variation of magnetic susceptibility with temperature, Curie temperature and density). The major Cu-prospect in the area has been studied by magnetic and electron microprobe analyses of four selected rock samples. The samples are from an exploration well that intersects the main Cu-mineralized body.The magnetic analyses show that magnetite is the dominant magnetic mineral, while hematite and other Fe-minerals are present in minor amounts. The electron microprobe observations confirm the presence of magnetite and further indicate that hematite is an alteration product of magnetite. Moreover, microprobe observations indicate that Fe-sulfides are present in negligible amounts in the samples from the Tjårrojåkka area. The strong spatial relationship of Cu-minerals (e.g., chalcopyrite) and the oxidation of magnetite to hematite suggest that the presence of rocks with low magnetic susceptibility in areas dominated by high susceptibility rocks may be a signal of related Cu-prospects.

  • 13.
    Villain, Lucile
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The effects of backfilling and sealing the waste rock on water quality at the Kimheden open-pit mine, northern Sweden2013Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 134, s. 99-110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Evaluating the water quality at reclaimed mines affected by acid mine drainage is an essential step in assessing and improving the performance of mitigation techniques. At the Kimheden copper mine in northern Sweden, reclamation involved the progressive backfilling of waste rock into the two small open pits and, in 1996, the application of a till dry cover that included a sealing layer. The data from both the long-term water quality monitoring by the mining company and the repeated sampling of the surface water and groundwater in 2009 and 2010 were used to assess the success of the reclamation in mitigating the acid mine drainage production from the mine waste. A substantial decrease in the concentrations of copper, zinc and sulphate ions by 95%, 81% and 81%, respectively followed by a rapid stabilisation of element concentrations was observed at the outlet of the receiving stream since early reclamation times. This trend initially suggested successful results for the reclamation, though another explanation for the diminution of contaminant release through depletion of the limited sulphidic source could not be neglected. However, in spite of the decrease, post-reclamation metal concentrations in the stream are still not satisfactory for the discharge of the mine drainage into the natural environment, indicating that the mitigation measures were insufficient. Seepage from one of the pits in 2009 had dissolved copper, aluminium and zinc concentrations of 1.6 mg/L, 4.4 mg/L and 0.45 mg/L, respectively and a pH of 3.0. Relatively high dissolved oxygen concentrations in the groundwater of the backfill in 2009 and 2010 (> 2 mg/L) suggest that the mixed outcome of the mitigation actions is due to on-going oxidation in the backfilled waste rock despite the dry cover. Moreover, stream discharge and dissolved sulphate and magnesium used as natural tracers in the drainage showed that water management in the form of ditches is not appropriate. In particular, due to poor sealing of the ditches, whilst a measurable part of the contaminated drainage in the collecting ditch is leaking to groundwater and dispersing in the surrounding natural areas, the water discharged to a treatment pond at the outlet of the stream is mostly uncontaminated background water.

  • 14. Weihed, Pär
    Lithogeochemistry, metal and alteration zoning in the Proterozoic Tallberg porphyry-type deposit, northern Sweden1991Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 42, nr 2-3, s. 301-325Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Tallberg porphyry-type deposit is situated in the Early Proterozoic, syntectonic Jörn Granitoid Complex (JGC). The occurrence shows similarities with Phanerozoic porphyry type deposits: (a) low grade (0.27% Cu) and large tonnage, 44 × 106 metric tonnes, (b) stockwork as well as disseminated sulphides, (c) hydrothermal propylitic and phyllic alterations, (d) sulphides spatially associated to tectonic lineaments, and (e) genetically related to granitoid porphyry stocks. Lithogeochemical investigations indicate a metal zonation with (Mo+Cu+S) → (Zn+Pb±Au) → (As) from centre outwards. The host granitoid shows similarities with modern I-type granitoids, and the high primary content of Cu and Fe is possibly a discriminant factor for exploration for similar porphyry-type occurrences in Early Proterozoic volcanic arc terrains. Late shear zones adjacent to postmineral dykes have high Au contents (2-3 g/t), which are interpreted as gold mobilized from the porphyry-type deposit.

  • 15.
    Yousefi, Fazilat
    et al.
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Sadeghian, Mahmoud
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ghasemi, Habibollah
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Frei, Dirk
    Department of Earth Science, Faculty of Natural Science, University of the Western Cape.
    Geochemistry, petrogenesis and tectonic setting of middle Eocene hypabyssal rocks of the Torud–Ahmad Abad magmatic belt: An implication for evolution of the northern branch of Neo-Tethys Ocean in Iran2017Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 178, s. 1-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Torud–Ahmad Abad magmatic belt is located in the south-southeast of Shahrood (East of Semnan Province, NE Iran) and lies in the northern part of the Central Iran Structural Zone (CISZ), where a thick sequence of Paleocene to middle Eocene volcanic and volcanosedimentary rocks cropped out. This sequence was intruded by numerous dikes, hypabyssal igneous domes and one small gabbrodioritic intrusion, with compositions ranging from trachybasaltic andesite, trachyandesite, dacite, trachyte, gabbro, diorite and syenite. Various enclaves (cogentic and noncogenetic) with different composition, size and shape have been found in these domes and dikes. These enclaves are evidence of magma mixing and crustal contamination. Geochemically, the studied rocks exhibit a calc-alkaline to high potassium calc-alkaline affinity, and are enriched in LREE and LILE and depleted in HREE and HSFE. Other geochemical characteristics, such as a silica content varying between 59–63 wt% and 51–59 wt%, a Na2O content > 3 wt%, Al2O3 content > 16 wt%, Yb < 1.8 ppm, and Y < 18 ppm, make it possible to classify these rocks as high silica adakite in the Ahmad Abad region and low silica adakite in the Sahl-Razzeh region or at least, adakitic like rocks. Also, depletion of Nb and Ti, and high enrichment in Rb, Ba, K and Th, imply crustal contamination of the mentioned adakitic domes. The petrographical and geochemical evidence show that the magma forming of the high silica adakites has been originated from partial melting of the subducted oceanic slab of Neo-Tethys (Sabzevar–Darouneh branch) in amphibolite to eclogite facies and the low silica adakites formed by partial melting of the metasomatized or modified mantle wedge, above the subduction zone. Gabbroic to syenitic rocks are the products of fractional crystallization of basic magma which originated from a nearly non-modified mantle wedge above the subducted oceanic slab. U-Pb dating of the dacitic and andesitic rocks belong to hypabyssal rocks yielded age of 41.4 ± 0.3 Ma, and 35.5 ± 0.2 Ma respectively and consistent to Middle to Late Eocene.

  • 16.
    Yousefi, Fazilat
    et al.
    Faculty of Earth Sciences, Shahrood University of Technology.
    Sadeghian, Mahmoud
    Faculty of Earth Sciences, Shahrood University of Technology.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ghasemi, Habibollah
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Lambrini, Papadopoulou
    Department of Mineralogy-Petrology-Economic Geology, Aristotle University of Thessaloniki.
    Bark, Glenn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rezaei-Kahkhaei, Mehdi
    Department of Petrology and Economic Geology, Faculty of Earth Sciences, Shahrood University of Technology.
    Koroneos, Antonis
    Department of Mineralogy-Petrology-Economic Geology, Aristotle University of Thessaloniki.
    Mineral chemistry and P-T conditions of the adakitic rocks from Torud–Ahmad Abad magmatic belt, S-SE Shahrood, NE Iran2017Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 182, nr A, s. 110-120Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Torud-Ahmad Abad magmatic belt is located 175 km east and southeast of Shahrood in the northern part of the Central Iran Structural Zone and includes a thick sequence of Paleocene to middle Eocene volcanic and volcanosedimentary rocks. This magmatic belt was formed by numerous hypabyssal igneous adakitic domes constituting basaltic andesite, andesite, trachyandesite, dacite, trachydacite, and dacite. The investigated rocks are mainly composed of pyroxene, amphibole, and plagioclase, with minor biotite and opaque minerals. Mineral chemical analysis reveals that plagioclase composition varies from albite to labradorite, clinopyroxene varies from diopside to augite, and amphibole varies from Mg-hastingsite to Mg-hornblende.

    Amphibole geothermobarometry suggests crystallization temperatures of 850–1050 °C, at 2–6 kbar and the temperature of 920–970 °C, at a pressure of 3–4.5 kbar, which are conditions in agreement with andesite and dacite formation. Clinopyroxene crystallized at temperatures of 1020–1170 °C, at 2–10 kbar, indicating crystallization at crustal depths of maximum 30 km for the studied intrusive rocks in the Torud-Ahmad Abad magmatic belt.

  • 17.
    Zhang, Wei
    et al.
    College of Land and Environment, Shenyang Agricultural University.
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wei, Zhongyi
    College of Land and Environment, Shenyang Agricultural University.
    Long, Jinghua
    Research Institute of Land Reclamation and Ecological Restoration, China University of Mining and Technology (Beijing).
    Geochemical evaluation of heavy metal migration in Pb-Zn tailings covered by different topsoils2016Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 165, s. 134-142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heavy metal migration was evaluated in Pb-Zn tailings covered by different topsoil constructions. The four topsoil constructions each had different interlayers: one with direct topsoiling above the tailings (CT); the second had a limestone interlayer between the tailings and topsoil with two geotextile layers set above and below the interlayer (SLS); the third had a lime interlayer, also with two geotextile layers (SL); and the fourth had a clay interlayer with two geotextile layers (SC). The topsoils were evaluated in a 210-day laboratory column leaching experiments and in a 3-year field cover application at an abandoned Pb-Zn tailings pond (northeastern China). The contents of Pb, Zn and Cd in the soils, leachates, interlayers and leaves of Amorpha fruticosa L. were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES).Results showed that the pH values of the leachates from the columns increased with time, from 6.5 to the range of 7.5 to 8.03, and the maximum in pH in C1 (tailings), C2 (CT), C3 (SLS), C4 (SL) and C5 (SC) appeared after the 180th day, at 7.85, 7.89, 7.78, 8.03, and 7.89, respectively. The topsoil effectively reduced the concentrations of Pb, Zn and Cd in the leachate, and the addition of a limestone or lime interlayer enhanced the efficiency, especially for Zn and Cd. The Pb, Zn and Cd concentrations in the topsoil that directly cover the tailings were appreciably less than the initial concentrations, resulting from the eluviation. The presence of a limestone or lime interlayer reduced the mobility of Zn and Cd, and a clay interlayer was effective in preventing the migration of Pb and Zn but had less impact on Cd.During the 3-year field experiment, the pH values of the topsoil increased slightly with time, from 7.15 to the range of 7.67 to 8.20. At the end of the experiment, Pb, Zn and Cd concentrations in the topsoil at the SLS, SL and SC plots showed little change compared with the initial value in 2012. Acid-soluble Pb, Zn and Cd concentrations of the upper soil (0–0.1 m) at CT increased from 0.19, 1.95 and 0.11 mg kg− 1 in 2012 to 1.82, 32.87 and 0.56 mg kg− 1 in 2015, indicating that acid-soluble heavy metals migrated from tailings to topsoil. Acid-soluble Cd in topsoil and in the interlayer showed a small increase at plot SC, indicating that Cd may migrate through the clay layer to topsoil with pore water. The Pb contents in leaves at SLS and SL were 2.38 and 3.04 mg kg− 1, which were appreciably lower than at CT and SC, and the Zn and Cd contents in leaves at CT were 45.78 and 0.26 mg kg− 1, which were higher than at SLS, SL and SC. Topsoiling with an interlayer could be a reliable technique for preventing toxic elements from moving downward or upward during ecological restoration of tailings ponds.

  • 18.
    Öhlander, Björn
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Müller, Barbara
    Institute of Geotechnical Engineering, ETH Hönggerberg, Zürich.
    Axelsson, Mikael
    Varian Analytical Instruments, Solna.
    Alakangas, Lena
    An attempt to use LA-ICP-SMS to quantify enrichment of trace elements on pyrite surfaces in oxidizing mine tailings2007Inngår i: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 92, nr 1, s. 1-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metals released from oxidation and weathering of sulphide minerals in mine tailings are to a high degree retained at deeper levels within the tailings themselves. To be able to predict what could happen in the future with these secondarily retained metals, it is important to understand the retention mechanisms. In this study an attempt to use laser ablation high-resolution ICP-MS (LA-ICP-SMS) to quantify enrichment of trace elements on pyrite surfaces in mine tailings was performed. Pyrite grains were collected from a profile through the pyrite-rich tailings at the Kristineberg mine in northern Sweden. At each spot hit by the laser, the surface layer was analyzed in the first shot, and a second shot on the same spot gave the chemical composition of the pyrite immediately below. The crater diameter for a laser shot was known, and by estimating the crater depth and total pyrite surface, the total enrichment on pyrite grains was calculated. Results are presented for As, Cd, Co, Cu, Ni and Zn. The results clearly show that there was an enrichment of As, Cd, Cu and Zn on the pyrite surfaces below the oxidation front in the tailings, but not of Co and Ni. Arsenic was also enriched on the pyrite grains that survived in the oxidized zone. Copper has been enriched on pyrite surfaces in unoxidized tailings in the largest amount, followed by Zn and As. However, only 1.4 to 3.1% of the Cd and Zn released by sulphide oxidation in the oxidized zone have been enriched on the pyrite surfaces in the unoxidized tailings, but for As and Cu corresponding figures are about 64 and 43%, respectively. There were many uncertainties in these calculations, and the results shall not be taken too literally but allowed the conclusion that enrichment on pyrite surfaces is an important process for retention of As and Cu below the oxidation front in pyrite rich tailings. Laser ablation is not a surface analysis technique, but more of a thin layer method, and gives no information on the type of processes resulting in enrichment on the pyrite surfaces. Although only pyrite grains that appeared to be fresh and without surface coatings were used in this study, the possibility that a thin layer of Fe-hydroxides occurred must be considered. Both adsorption to the pyrite directly or to Fe-oxyhydroxides may explain the enrichment of As, Cd, Cu and Zn on the pyrite surfaces, and, in the case of Cu, also the replacement of Fe(II) by Cu(II) in pyrite.

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