Platinum-group element-chromitite associations in the Bushveld Complex

Gruenewaldt, G. von; Hatton, C. J.; Merkle, R. K. W.

doi:10.2113/gsecongeo.81.5.1067

Cited by 117 publications

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“…This probably caused sulphur saturation in melt by decreasing sulphur solubility and helps concentration of PGE-Te-Au in sulphide melt. Similar observations have been made by different researchers in Bushveld complex and Xinjie layered intrusion in Emeishan LIP, SW China [47,48]. It is widely accepted that PGM exsolve over wide range of temperature from sulphide melt as it recrystallize from different sulphides during cooling [9].…”

Section: Discussionsupporting

confidence: 85%

Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

et al. 2014

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This paper reports the occurrence of Tsumoite (a bismuth telluride) in the Heti Cu-Ni-PGM prospect, Gondpipri mafic-ultramafic complex, Central India. The Gondpipri complex consists of several tectonically dismembered gabbronorite-gabbro-anorthositic gabbro -olivine gabbro -websterite disposed in~10 km long tonalite-trondhjemitegranodiorite (TTG) and charnockite-enderbite suite of rocks. The mineralization occurs in the sulphide zone hosted by gabbro variants. The host rocks have been deformed and metamorphosed to granulite grade and subjected to various degrees of hydrothermal alteration. The mineralization comprises chalcopyrite, pentlandite, pyrrhotite, cubanite, millerite, and pyrite. In addition to these, occur (1) tsumoite (2) PGM in the form of moncheite, merenskyite, Pd-mellonite, and Pt-Pd-Te-Bi-Fe-S alloy. The present study indicates that the mineralization occurs in two stages related to: (i) magmatic and (ii) hydrothermal remobilization and transport of Cu-rich sulphides, tsumoite and PGM, and their re-deposition in hydrosilicate alteration zones. It is possible that the mineralization at Heti formed at different stages of bismuth activity under variable fS 2 , T, and fTe 2 conditions due to change in total concentration of Te and S and /or cooling. Since the role of S is limited, Te and cooling are important factor influencing mineralogy and composition of tsumoite and associated mineralization. Mineralization occurs in two different modes of occurrences. The early mineralisation occur as blebs, specks and dissemination of sulphides, viz. pyrrhotite, chalcopyrite, pentlandite and minor pyrite ± PGM, whereas later mineralisation occur as stringers, minor veins of sulphides viz. pyrite, millerite, cubanite, sijenite, tsumoite and ± PGM. Mineral assemblages and textural relationships at Heti has indicated precipitation of tsumoite and associated PGM along fractures and secondary silicates, which confirms their hydrothermal origin.

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Section: Discussionsupporting

confidence: 85%

Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

et al. 2014

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“…4. Stratigraphic section (not drawn to scale) of the chromitite layers and their PGE contents, based on data from Lee & Tredoux (1986), Lee & Parry (1988), Scoon & Teigler (1994), von Gruenewaldt & Merkle (1995 and von Gruenewaldt et al (1986). Data are based on single analyses or averages of very few analyses, and so should not be considered quantitatively representative of the layers.…”

Section: Geology Of Pge-mineralized Layersmentioning

confidence: 99%

“…Assuming a typical value for Ru of 1.3 g/t, and allowing for minor Os, Ir and Au, the grade in this section would be about 7.5 g/t, in line with the other data. To the south, on the farm Maandagshoek, Gain (1986) quoted a grade of 9.5 ± 1.8 g/t over 0.55 m, whereas to the north, grades of 7 g/t over 0.87 m are given by Vermaak & van der Merwe (1999), both from exploration surveys. The Lebowa mine some 40 km to the north has an average grade of 7.8 g/t over 0.6 m (Hochreiter 2000).…”

Section: Pge and Pgm Associated With Discordant Pipesmentioning

confidence: 99%

“…Reef thicknesses are also indicated. Data are from Gain (1986), Table 1 This fluid either redissolved into a silicate magma, which triggered further PGE-rich sulfide immiscibility, or reacted with existing sulfide, low in PGE, in the precursor to the Merensky Reef ore. Each of these three processes ought to fractionate the PGE relative to each other. Such fractionation will depend upon relative values for the silicate liquid -sulfide liquid partition coefficients for the first stage.…”

Section: Fig 13 Variation In Pge Content Of the Ug2 Chromitite Frommentioning

confidence: 99%

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Relationship Between Pge and PGM in the Bushveld Complex

Cawthorn¹,

Lee²,

Schouwstra³

et al. 2002

The Canadian Mineralogist

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The abundances of the platinum-group elements (PGE), and their relative proportions, are summarized for all the mines exploiting the Merensky Reef on both western and eastern limbs of the Bushveld Complex, in South Africa. Grades for the mined reef interval are uniform over 100 km of strike length, at 5-7 g/t, except for Union mine, where it is currently 8 g/t. The relative proportions of the various PGE are extremely constant over this same distance. In contrast, the platinum-group minerals (PGM) vary enormously. On a regional scale around the western limb, the mineralogy ranges from alloy-dominated in the northwest to sulfide-or telluride-arsenide-dominant in the southeast. Local features that are important in terms of mining are potholes and discordant ultramafic bodies. Comparative studies of the PGE from close to and within such structures again show constant absolute and relative abundances. Limited data on the PGE from PGE-mineralized pipes (Onverwacht, Mooihoek and Driekop) suggest that they are Pt-dominated, and have a totally different relative pattern of distribution of the PGE than that in the stratiform mineralization. The PGM in the vicinity of these pipes also tends to be dominated by alloys, and in potholes by alloys and tellurides and arsenides. Hence, on both a regional scale and very local scale associated with disturbances in the reef, there is a dichotomy between the constancy of the PGE and the variability of the PGM. These observations suggest that the primary mechanism concentrating the PGE is a first-order process, and that the evolution of the PGM is the result of secondary processes related to cooling, local changes in f(S 2 ) in the crystallization environment, and subsolidus re-equilibration. The debate as to whether the PGE are derived by fluid scavenging of a footwall succession or have accumulated from supernatant magma is reexamined, and unresolved problems pertaining to both processes are highlighted.Keywords: Bushveld Complex, platinum-group elements, platinum-group mineralogy, Merensky Reef, potholes, pipes, mineralization, South Africa. SOMMAIRELe niveau de concentration des éléments du groupe du platine (EGP), ainsi que leurs proportions relatives, sont examinés pour toutes les mines exploitant le banc de Merensky, dans les secteurs ouest et est du complexe de Bushveld, en Afrique du Sud. Les teneurs des sections exploitées de ce banc sont uniformes, entre 5 et 7 g/t, sur une distance de 100 km, sauf à la mine Union, où la teneur est présentement 8 g/t. Les proportions relatives des EGP sont d'une constance frappante sur cette distance. En revanche, les assemblages de minéraux du groupe du platine varient énormément. Sur une échelle régionale autour du secteur ouest, ces minéraux vont d'alliages dans le nord-ouest aux minéraux sulfurés ou bien aux tellurures et arséniures vers le sud-est. Les "nidsde-poule" et les venues ultramafiques discordantes sont des accidents locaux qui exercent une influence sur les activités minières. Des études comparatives des EGP près de ...

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“…PGMs are usually associated with chromite and has been known since the early 1920s [1,2]. Detail studies of this reef by the following researchers ; McLaren and De Villiers [3], Von Gruenewaldt et al, [4] and Gain [5] has also shown the association of PGMs and chromite. The UG-2 and Merensky ores are the main sources of PGMs in South Africa, the Merensky ore has less chromium compared to the UG-2 known to contain about 10% chromite, meaning that most of the PGMs lost in process tailings such as flotation are contained in chromite gangue [6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Recovery of Pt and Pd from PGM Mine Tailings by Magnetic Separation

Rabatho

Tongamp

Takasaki

et al. 2010

Int.J.Soc.Mater.Eng.Resour.

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Application of dry magnetic separation process to recover platinum (Pt) and palladium (Pd) contained in PGM (platinum group metals) flotation tailings (Mixture of Merensky and UG-2 from operations in South Africa was investigated in this work. Ore from UG-2 mainly contains chromite where PGMs are associated with and report to tailings during flotation. Concentrating chromite by magnetic separation can allow possible recovery of the PGMs into chromite product and further recovered by using NiS-FA process. The content of Pt and Pd in the tailings was 0.7 g/t and 0.2 g/t contained in mainly MgSiO 3 and MgCr 2 O 4 minerals. A dry coil magnetic separator with its strength varied from 120 to 240 mT was used to separate the tailings into magnetic, middling and non-magnetic fractions in a two-stage operation. Up to around 2 wt% of the tailings was recovered as magnetic fraction in the final stage with Pt and Pd contents exceeding 42 g/t and 13 g/t respectively with total recovery of about 30% and 34%. About 8 wt% of the tailings reported to the middling section giving Pt and Pd contents at 8.3 g/t and 5.33 g/t with a total recovery of 5.9% and 13.2% respectively. XRD studies of the three fractions from magnetic separation show MgCr 2 O 4 and MgSiO 3 as main phases in the magnetic and middling fractions indicating that Pt and Pd are contained in MgCr 2 O 4 . The results indicate that a dry magnetic separation process could be used to concentrate Pt in PGM flotation tailings to over 40 g/t and offer as the additional resource for recovering Pt and Pd.

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Platinum-group element-chromitite associations in the Bushveld Complex

Cited by 117 publications

References 0 publications

Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

Tsumoite (BiTe) and associated Ni-PGE mineralization from Gondpipri mafic-ultramafic complex, Bastar Craton, Central India: mineralogy and genetic significance

Relationship Between Pge and PGM in the Bushveld Complex

Recovery of Pt and Pd from PGM Mine Tailings by Magnetic Separation

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