Variation in Platinum Group Mineral and Base Metal Sulfide Assemblages in the Lower Group Chromitites of the Western Bushveld Complex, South Africa
Bibliographic record
Abstract
Research Article| September 01, 2018 Variation in Platinum Group Mineral and Base Metal Sulfide Assemblages in the Lower Group Chromitites of the Western Bushveld Complex, South Africa Kai Bachmann; Kai Bachmann § Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany §Corresponding author e-mail address: k.bachmann@hzdr.de Search for other works by this author on: GSW Google Scholar Inga Osbahr; Inga Osbahr 3Deutsche Rohstoffagentur (DERA) at the Bundesanstalt für Geowissenschaften und Rohstoffe, Wilhelmstrasse 25-30, 13593 Berlin-Spandau, Germany Search for other works by this author on: GSW Google Scholar Raimon Tolosana-Delgado; Raimon Tolosana-Delgado Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany Search for other works by this author on: GSW Google Scholar Deshenthree Chetty; Deshenthree Chetty Mineralogy Division, Mintek, Malibongwe Drive, 2125 Randburg, South Africa Search for other works by this author on: GSW Google Scholar Jens Gutzmer Jens Gutzmer Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Kai Bachmann § Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany Inga Osbahr 3Deutsche Rohstoffagentur (DERA) at the Bundesanstalt für Geowissenschaften und Rohstoffe, Wilhelmstrasse 25-30, 13593 Berlin-Spandau, Germany Raimon Tolosana-Delgado Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany Deshenthree Chetty Mineralogy Division, Mintek, Malibongwe Drive, 2125 Randburg, South Africa Jens Gutzmer Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Bautzner Landstraße 400, 01328 Dresden, Germany §Corresponding author e-mail address: k.bachmann@hzdr.de Publisher: Mineralogical Association of Canada First Online: 11 Oct 2018 Online Issn: 1499-1276 Print Issn: 0008-4476 © 2018 Mineralogical Association of Canada The Canadian Mineralogist (2018) 56 (5): 723–743. https://doi.org/10.3749/canmin.1700094 Article history First Online: 11 Oct 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Kai Bachmann, Inga Osbahr, Raimon Tolosana-Delgado, Deshenthree Chetty, Jens Gutzmer; Variation in Platinum Group Mineral and Base Metal Sulfide Assemblages in the Lower Group Chromitites of the Western Bushveld Complex, South Africa. The Canadian Mineralogist 2018;; 56 (5): 723–743. doi: https://doi.org/10.3749/canmin.1700094 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyThe Canadian Mineralogist Search Advanced Search Abstract The Lower Group chromitites of the Bushveld Igneous Complex are mined for chromite as a primary product. The recovery of platinum group elements and base metals (Ni, Cu) as by products has the potential to add value to the chromite resources. This study focuses on the LG-6 and LG-6A chromitite seams at the Thaba mine located on the western limb of the Bushveld Complex. Platinum group minerals and base-metal sulfides are studied by mineral liberation analysis and electron microprobe analysis to define distinct assemblages and to evaluate the potential for beneficiation. Based on the results, two distinct major mineral assemblages are defined. The first assemblage is rich in platinum group element-sulfides, along with variable proportions of malanite/cuprorhodsite and alloys of Fe and Sn. The associated base metal sulfides are dominated by chalcopyrite and pentlandite, along with pyrite and subordinate millerite/violarite. Associated silicates are mainly primary magmatic orthopyroxene and plagioclase. The second assemblage is rich in platinum group element-sulfarsenides and -arsenides as well as -antimonides and -bismuthides and is associated with a base metal sulfide assemblage dominated by pentlandite and Co-rich pentlandite. The second assemblage is also marked by an abundance of alteration minerals, such as talc, serpentine, and/or carbonates, which are closely associated with the platinum group minerals. Statistical evaluation reveals that the two mineral assemblages cannot be attributed to their derivation from different chromitite seams but document the effects of pervasive hydrothermal alteration. Alteration evidently had similar effects on the different chromitite seams. The occurrence and distribution of the two characteristic assemblages has important implications for beneficiation. Assemblages rich in platinum group element-sulfides associated with base metal sulfides respond well to flotation, unlike the alteration assemblages rich in arsenides, antimonides, and bismuthides. The nature of the gangue minerals will also impact platinum-group mineral recovery, as high phyllosilicate abundances, such as those encountered in the alteration assemblage, may cause problems during flotation and lead to poor recoveries. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".