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Billström, K., Evins, P., Martinsson, O., Jeon, H. & Weihed, P. (2019). Conflicting zircon vs. titanite U-Pb age systematics and the deposition of the host volcanic sequence to Kiruna-type and IOCG deposits in northern Sweden, Fennoscandian shield. Precambrian Research, 321, 123-133
Open this publication in new window or tab >>Conflicting zircon vs. titanite U-Pb age systematics and the deposition of the host volcanic sequence to Kiruna-type and IOCG deposits in northern Sweden, Fennoscandian shield
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2019 (English)In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 321, p. 123-133Article in journal (Refereed) Published
Abstract [en]

The Northern Norrbotten region, and in particular the Kiruna area, hosts a number of large apatite iron oxide deposits (e.g. the huge Kiirunavaara ore) of significant economic importance. Age data from rock lithologies hosting these ores, represented by metamorphosed rocks of the Porphyrite and Kiirunavaara Groups, are complex to interpret. This is illustrated by (LA-ICP-MS) data for titanite, and to some extent for rutile, which scatter considerably yielding ages within a span from ca. 2.1 Ga to 1.7 Ga. These analysed hydrothermal minerals, characterized by complex BSE images revealing darker and brighter zones, are located in ore zones and associated with e.g. strong scapolitisation, albitisation and actinolitisation. Previous (TIMS) zircon ages of host rocks, on the other hand, define a more narrower age interval between ca. 1900 and 1870 Ma, and this is supported by new U-Pb zircon results presented here. Furthermore, one coherent set of SIMS data for titanite from the Luossavaara ore favour that crystallization took place at ca 1.88 Ga, although laser ICP data from the same locality are much more complex. An implication arising from published pre-1.9 Ga laser ablation ages for titanites is that the emplacement of host rocks started already at around 2.1 Ga. As the depositional time of these rocks is crucial for the understanding of the overall crustal formation in northern Norrbotten, additional rocks were selected for age dating. New zircon age data (LA-ICP-MS and SIMS) give support to a scenario where host rocks to ores started to develop at around 1900 Ma and this calls for a re-evaluation of published LA-ICP-MS data of hydrothermal mineral phases.

Here, we present four models that aim to explain how pre-1.9 Ga titanite ages, believed to have a questionable geological significance, may develop. The principal idea is that ≤2.1 Ga alteration events were not responsible for the crystallization of the hydrothermal minerals, instead it is believed that apparent old age domains carry excess radiogenic lead due to the effect of ≤1.9 Ga hydrothermal processes. Currently, the interpretation of U-Pb isotope data in the study area remains enigmatic, and further radiometric analyses are required.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
U-Pb age, Iron ore, Norrbotten, Sweden, Zircon, Titanite
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-72749 (URN)10.1016/j.precamres.2018.12.003 (DOI)000457657500008 ()2-s2.0-85058180697 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-01-31 (johcin)

Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-03-08Bibliographically approved
Alvarenga, R. A. .., Dewulf, J., Guinée, J., Schulze, R., Weihed, P., Bark, G. & Drielsma, J. (2019). Towards product-oriented sustainability in the (primary) metal supply sector. Resources, Conservation and Recycling, 145, 40-48
Open this publication in new window or tab >>Towards product-oriented sustainability in the (primary) metal supply sector
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2019 (English)In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 145, p. 40-48Article in journal (Refereed) Published
Abstract [en]

Consideration of sustainable supply of (primary) metals is increasingly influencing the policy agenda of western societies. Environmental sustainability can be managed from different perspectives, including a site-oriented one (strongly used by the mining sector) and a product-oriented one (as with life cycle assessment). The objectives of this article are to analyse and discuss the differences in these perspectives; to discuss potential benefits to the metal/mining sector of also considering the product-oriented perspective; and to propose ways for a smooth implementation. We made use of literature and expert knowledge, on top of interviews with different stakeholders, to identify why and how these perspectives are (not) used in the metal/mining sector. Moreover, we identified three key concerns related to the implementation of a product-oriented perspective in the sector (e.g., use of unrepresentative life cycle inventory (LCI) datasets for metal-based products) and proposed three corrective actions for all of them (e.g., increase the quantity and quality of LCI). Finally, we discuss how the corrective actions could be implemented in the sector in a smooth way and some potential benefits from its implementation.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Raw materials, Mining, Metal, Life cycle, Sustainability
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-73134 (URN)10.1016/j.resconrec.2019.02.018 (DOI)000466251200005 ()2-s2.0-85061805826 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-03-07 (johcin)

Available from: 2019-03-07 Created: 2019-03-07 Last updated: 2019-06-18Bibliographically approved
Ericsson, M., Drielsma, J., Humphreys, D., Storm, P. & Weihed, P. (2019). Why current assessments of ‘future efforts’ are no basis for establishing policies on material use: a response to research on ore grades. Mineral Economics, 32(1), 111-121
Open this publication in new window or tab >>Why current assessments of ‘future efforts’ are no basis for establishing policies on material use: a response to research on ore grades
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2019 (English)In: Mineral Economics, ISSN 2191-2203, E-ISSN 2191-2211, Vol. 32, no 1, p. 111-121Article in journal, Editorial material (Refereed) Published
Abstract [en]

The concept of declining availability due to declining primary resource quality has been investigated for various resource categories to try to determine the effort needed in future to either extract the resource or to treat it for intended use. The concept of ‘future efforts’ due to declining primary resource quality is explored by Vieira et al. (2016, 2017). They suggest that a specific burden associated with the production of each primary material should be taken into account and that this can be done by studying the costs of production or ore requirements of the material and by projecting forward likely costs into the future. For the purpose of the analysis, they employ mine cost data for 2000–2013 and reserve data published by the US Geological Survey. We will argue below that this approach is not correct and, with this comment, we wish to make it clear that—contrary to what is suggested in much of the Life Cycle Assessment literature—the future efforts concept is not an established rule of natural resource extraction. For mineral resources, it is quite impossible to proceed with extraction in the ordered way that this approach suggests because nobody has a comprehensive view of the entire natural resource. Secondly, there is no evidence available to support the idea that extracting a mineral resource today causes a decrease in availability of that mineral tomorrow. On the contrary, the weight of evidence suggests that where declines in ore grades have been observed, they are overwhelmingly due to technology development in response to high demand and have been accompanied by increased mining efficiency and increased availability of the resource to successive generations. Grade is a rather arbitrary measure since the grade of mined ore ultimately has to do with the relationship of costs and revenues. It is not only the technology employed which matters but also how smartly this technology is applied. Thirdly, the future efforts approach entirely overlooks the potential availability of mineral materials from secondary (scrap) sources, sources which are expected to become increasingly important to mineral supply in the future. Our conclusion from the discussion is that we as humans have been able to economically access ever-increasing amounts of material from often lower and lower-grade sources. What is impossible to conclude from this is that the environment no longer contains any of the higher-grade sources. In fact, all the available evidence suggests that higher-grade deposits are still out there. We remain critical optimists.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Future efforts, Ore grade, Declining availability, Life Cycle Assessment, “Type 3”, Hotelling, Surplus cost
National Category
Geology Economics
Research subject
Ore Geology; Economics
Identifiers
urn:nbn:se:ltu:diva-73814 (URN)10.1007/s13563-019-00175-6 (DOI)000464850300008 ()
Available from: 2019-05-02 Created: 2019-05-02 Last updated: 2019-05-02Bibliographically approved
Abdelnasser, A., Kumral, M., Zoheir, B., Karaman, M. & Weihed, P. (2018). REE geochemical characteristics and satellite-based mapping of hydrothermal alteration in Atud gold deposit, Egypt. Journal of African Earth Sciences, 145, 317-330
Open this publication in new window or tab >>REE geochemical characteristics and satellite-based mapping of hydrothermal alteration in Atud gold deposit, Egypt
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2018 (English)In: Journal of African Earth Sciences, ISSN 0899-5362, Vol. 145, p. 317-330Article in journal (Refereed) Published
Abstract [en]

New geochemical data of the hydrothermal alteration zones associated with gold-bearing quartz veins at Atud mine are used for better understanding the ore evolution and exploration vectoring. ASTER and Landsat 8 OLI data are used to elucidate the distribution of gold-associated alteration zones. Three alteration zones are defined; zone 1 (sericite-kaolinite-quartz-pyrite), zone 2 (quartz-sericite-albite-pyrite), and zone 3 (chlorite-carbonate-epidote ± pyrite). Sericite and hydrothermal quartz are confined to the mineralized quartz veins. Fe-OH and OH-bearing minerals are observed along NW- and NE-trending shear zones in the Main Atud mine. The association of gold-bearing quartz veins and sericite alteration is constrained by processing ASTER- and OLI-imagery data. The geochemical data of the ore-enveloping hydrothermally altered rocks are used to assess the behavior of the REEs during the mineralization process. Mild enrichment in LREE and significant enrichment in the HREE are associated with sericite in zones (1) and (2) alterations. Carbonate alteration (zone 3) is enriched in LREE and in immobile HREE. Moreover, LREE and Eu anomalies have negative correlated with the Alteration Index (A.I.) and K2O index (K.I.) in zones 1 and 2, suggesting high mobility of LREE in K-rich hydrothermal fluids. On the other hand, HREE anomalies with increasing MgO index (M.I.) in alteration zone 3 may imply low solubility of these elements in alkaline solutions. Au anomalies linked to sericite/silica alteration is a rather meaningful vector for further exploration in the area.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-67608 (URN)10.1016/j.jafrearsci.2018.01.013 (DOI)000439403600025 ()2-s2.0-85041926005 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-07-23 (inah)

Available from: 2018-02-12 Created: 2018-02-12 Last updated: 2019-03-27Bibliographically approved
Zeballos, A., Weihed, P., Blanco, M. & Machaca, V. (2017). Characterization of some nonmetallic resources in Bolivia: an overview of their potentiality and their application in specialized formulations. Environmental Earth Sciences, 76(22), Article ID 754.
Open this publication in new window or tab >>Characterization of some nonmetallic resources in Bolivia: an overview of their potentiality and their application in specialized formulations
2017 (English)In: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 76, no 22, article id 754Article in journal (Refereed) Published
Abstract [en]

Bolivia has several nonmetallic occurrences widespread in the country. Unfortunately, they are poorly studied and slightly characterized. In the present work, several nonmetallic occurrences located in La Paz, Oruro, Potosí and Santa Cruz were studied. The results of the chemical and mineralogical characterization of the materials will be presented, in order to approach their applicability in specialized industrial formulations. A preliminary test of the final products besides an overview of their potentiality will be exposed and a current view of the commercialization as well.

Place, publisher, year, edition, pages
Springer, 2017
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-66733 (URN)10.1007/s12665-017-7094-7 (DOI)000416820300022 ()2-s2.0-85034744509 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-11-23 (andbra)

Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2018-09-14Bibliographically approved
Kampmann, T. C. & Weihed, P. (2017). Debatt: Falu gruvas 1,9 miljarder år gamla geologiska processer kan säkra samhällets framtida behov av metaller. Dala-Demokraten, Article ID 20 maj.
Open this publication in new window or tab >>Debatt: Falu gruvas 1,9 miljarder år gamla geologiska processer kan säkra samhällets framtida behov av metaller
2017 (Swedish)In: Dala-Demokraten, ISSN 1103-9183, article id 20 majArticle in journal, News item (Other (popular science, discussion, etc.)) Published
Place, publisher, year, edition, pages
Mittmedia, 2017
Keywords
Geologi, Falu Gruva, Världsarvet Falu Gruva, Gruvbrytning, Luleå tekniska universitet
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-63489 (URN)
Projects
Structural evolution, hydrothermal alteration and tectonic setting of the Falun base metal and gold deposit, Bergslagen region, Sweden
Funder
The Geological Survey of Sweden (SGU)
Available from: 2017-05-22 Created: 2017-05-22 Last updated: 2018-11-20Bibliographically approved
Kampmann, T. C., Stephens, M. & Weihed, P. (2016). 3D modelling and sheath folding at the Falun Zn-Pb-Cu-(Au-Ag) massive sulphide deposit and implications for exploration in a 1.9 Ga ore district, Fennoscandian Shield, Sweden (ed.). Paper presented at . Mineralium Deposita, 51(5), 665-680
Open this publication in new window or tab >>3D modelling and sheath folding at the Falun Zn-Pb-Cu-(Au-Ag) massive sulphide deposit and implications for exploration in a 1.9 Ga ore district, Fennoscandian Shield, Sweden
2016 (English)In: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 51, no 5, p. 665-680Article in journal (Refereed) Published
Abstract [en]

The Falun pyritic Zn-Pb-Cu-(Au-Ag) deposit, situated in the Palaeoproterozoic (1.9–1.8 Ga) Bergslagen lithotectonic unit in the south-western part of the Fennoscandian Shield, is one of the major base metal sulphide deposits in Sweden. Altered rocks and ore types at Falun have been metamorphosed and deformed in a heterogeneous ductile manner, strongly modifying mineral assemblages in the original hydrothermal alteration system and the geometry of the deposit. Using a combined methodological approach, including surface mapping of lithologies and structures, drill core logging and microstructural investigation, the polyphase character (D1 and D2) of the ductile deformation is demonstrated and a 3D model for the deposit created. F2 sheath folding along axes that plunge steeply to the south-south-east, parallel to a mineral stretching lineation and the dip direction of the S2 foliation, is suggested as a key deformation mechanism forming steeply plunging, rod-shaped ore bodies. This is in contrast to previous structural models involving fold interference and, in turn, has implications for near-mine exploration, the occurrence of hanging-wall components to the ore body being questioned. Typical rock-forming minerals in the Falun alteration aureole include quartz, biotite/phlogopite, cordierite, anthophyllite and minor almandine, andalusite and chlorite, as well as dolomite, tremolite and actinolite. Where observable, the silicate minerals in the alteration rocks show growth patterns during different phases of the tectonothermal evolution, considerable static grain growth occurring between D1 and D2 and even after D2. A major high-strain zone, characterized by the mineral assemblage talc-chlorite-(quartz-biotite/phlogopite) defines a boundary between northern and southern structural domains at the deposit, and is closely spatially associated with the polymetallic massive sulphide ores. A possible role as a metal-bearing fluid conduit during ore genesis is discussed.

National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-9197 (URN)10.1007/s00126-016-0638-z (DOI)000377024500007 ()2-s2.0-84955598369 (Scopus ID)7c293c1b-cd76-47eb-85c5-e1cf3a56f6d9 (Local ID)7c293c1b-cd76-47eb-85c5-e1cf3a56f6d9 (Archive number)7c293c1b-cd76-47eb-85c5-e1cf3a56f6d9 (OAI)
Projects
Structural evolution, hydrothermal alteration and tectonic setting of the Falun base metal and gold deposit, Bergslagen region, Sweden
Note
Validerad; 2016; Nivå 2; 20150212 (tobkam)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Tavakoli, S., Bauer, T., Rasmussen, T. M., Weihed, P. & Elming, S.-å. (2016). Deep massive sulphide exploration using 2D and 3D geoelectrical and induced polarization data in Skellefte mining district, northern Sweden (ed.). Geophysical Prospecting, 64(6), 1602-1619
Open this publication in new window or tab >>Deep massive sulphide exploration using 2D and 3D geoelectrical and induced polarization data in Skellefte mining district, northern Sweden
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2016 (English)In: Geophysical Prospecting, ISSN 0016-8025, E-ISSN 1365-2478, Vol. 64, no 6, p. 1602-1619Article in journal (Refereed) Published
Abstract [en]

Geoelectrical and induced polarization data from measurements along three profiles and from one 3D survey are acquired and processed in the central Skellefte District, northern Sweden. The data were collected during two field campaigns in 2009 and 2010 in order to delineate the structures related to volcanogenic massive sulphide deposits and to model lithological contacts down to a maximum depth of 1.5 km. The 2009 data were inverted previously, and their joint interpretation with potential field data indicated several anomalous zones. The 2010 data not only provide additional information from greater depths compared with the 2009 data but also cover a larger surface area. Several high-chargeability low-resistivity zones, interpreted as possible massive sulphide mineralization and associated hydrothermal alteration, are revealed. The 3D survey data provide a detailed high-resolution image of the top ∼450 m of the upper crust around the Maurliden East, North, and Central deposits. Several anomalies are interpreted as new potential prospects in the Maurliden area, which are mainly concentrated in the central conductive zone. In addition, the contact relationship between the major geological units, e.g., the contact between the Skellefte Group and the Jörn Intrusive Complex, is better understood with the help of 2010 deep-resistivity/chargeability data. The bottommost part of the Vargfors basin is imaged using the 2010 geoelectrical and induced polarization data down to ∼1-km depth.

National Category
Geophysics Geology
Research subject
Exploration Geophysics; Ore Geology
Identifiers
urn:nbn:se:ltu:diva-15251 (URN)10.1111/1365-2478.12363 (DOI)000386158100014 ()2-s2.0-84961572568 (Scopus ID)ebf80035-8141-4c62-94db-d97a3d1a5641 (Local ID)ebf80035-8141-4c62-94db-d97a3d1a5641 (Archive number)ebf80035-8141-4c62-94db-d97a3d1a5641 (OAI)
Note

Validerad; 2016; Nivå 2; 2016-11-21 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Drielsma, J. A., Russell-Vaccari, A. J., Drnek, T., Brady, T., Weihed, P., Mistry, M. & Simbor, L. P. (2016). Erratum to: Mineral resources in life cycle impact assessment: defining the path forward (ed.). Paper presented at . The International Journal of Life Cycle Assessment, 21(1), 133
Open this publication in new window or tab >>Erratum to: Mineral resources in life cycle impact assessment: defining the path forward
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2016 (English)In: The International Journal of Life Cycle Assessment, ISSN 0948-3349, E-ISSN 1614-7502, Vol. 21, no 1, p. 133-Article in journal (Refereed) Published
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-16131 (URN)10.1007/s11367-015-1006-4 (DOI)000367522200012 ()2-s2.0-84952630822 (Scopus ID)fb6fa330-a4cc-4d19-b3f9-7536e38e7e7f (Local ID)fb6fa330-a4cc-4d19-b3f9-7536e38e7e7f (Archive number)fb6fa330-a4cc-4d19-b3f9-7536e38e7e7f (OAI)
Note
Godkänd; 2015; 20151207 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zeballos, A., Weihed, P., Blanco, M. & Machaca, V. (2016). Geological, mineralogical and chemical characterization of Devonian kaolinite-bearing sediments for further applications in the ceramic (tiles) industry in La Paz, Bolivia (ed.). Environmental Earth Sciences, 75(7), Article ID 546.
Open this publication in new window or tab >>Geological, mineralogical and chemical characterization of Devonian kaolinite-bearing sediments for further applications in the ceramic (tiles) industry in La Paz, Bolivia
2016 (English)In: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 75, no 7, article id 546Article in journal (Refereed) Published
Abstract [en]

Clay minerals are widely distributed in Bolivia; among them, illitic clays are most common in the Altiplano where they are mined for use in the ceramic industry that has been growing in the last few years. In addition to illitic sediments, kaolinitic sediments have been recently discovered in sedimentary units in the Bolivian Altiplano. Residual ball clay occurrences in Devonian sedimentary units were studied as part of this work. Geological mapping and geophysical studies (ERT and GPR) were done for better understanding the origin of the deposits and were part of a preliminary study of the mineral potential to define the relationship with the host rock. Chemical and mineralogical techniques such as X-Ray Diffraction, Scanning Electron Microscopy and Inductively Coupled Plasma analyses were performed in samples from the studied area to verify the presence of kaolinite. Atterberg limits and behaviour of the raw material in ceramic specimens supported by chemical analyses show that this material is suitable for manufacturing tile ceramics. This study provides fundamental knowledge for deposit exploitation and future generation of an alternative source of employment for the inhabitants of Micaya

National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-11311 (URN)10.1007/s12665-015-5212-y (DOI)000373635400005 ()2-s2.0-84961744633 (Scopus ID)a40d5b37-9ee7-4bfb-9efb-4907e6261f2f (Local ID)a40d5b37-9ee7-4bfb-9efb-4907e6261f2f (Archive number)a40d5b37-9ee7-4bfb-9efb-4907e6261f2f (OAI)
Note

Validerad; 2016; Nivå 2; 20160411 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3879-3897

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