Stratiform chromitite layers are peculiar to large layered mafic intrusions. The origin of these chromitite layers has been widely debated. Some petrologists suggested that the layers formed as a result of the mixing of two compositionally different magmas whereas others suggest that the chromitite layers formed from changes in pressure. The former hypothesis is widely accepted, and states that chromitite forms when a more evolved magma is injected into the chamber occupied by a more primitive one. To evaluate this hypothesis, a study has been conducted on the silicate textures and major element geochemistry of the silicate-rich layers above and below the MG4 chromitite package in the Critical Zone of the Rustenburg Layered Suite, part of the Bushvel Complex in South Africa.The MG4 chromitite package consists of several chromitite seamsseparated by silicate layers. Orthopyroxene and plagioclase (interstitial plagioclase) are observed in large amounts throughout the silicate layer, with less abundant clinopyroxene and some trace amounts of biotite. Throughout the silicate-rich layers above and below the MG4 chromitite layers (MG4 pyroxenite), the orthopyroxene exhibits no major compositional variation in major elements (Mg#= 1.15-1.25). This is also observed in the clinopyroxene composition throughout the study area. However, plagioclase, which dominates the lower part of the stratigraphy, varies in composition with a decrease in the calcium content (Ca= 0.8-0.5) and a simultaneous increase in the sodium content (Na=0.2-0.5). These similarities between the rocks above and below the MG4 chromitite layers suggest that the chromitite layer originated from a single magma or a mixture of two magmas with similar composition. This model is supported by the observed thin sections where orthopyroxene occurs as euhedral grains throughout the section especially above the 63.13m depth lying above the plagioclase –rich layer. Trace element analysis further suggest that the magma that crystallized the plagioclase-rich lower part mixed with the influx of new magma rich in Mg to crystallize the rocks of the upper sequence dominated by orthopyroxene, clinopyroxene and Na-rich plagioclase. / Dissertation (MSc)--University of Pretoria, 2011. / Geology / unrestricted

Ce travail est consacré aux études cinétiques et thermodynamique des processus qui produisent les magmas basaltiques (basalte de dorsale océanique ou MORB et basalte de l'île océaniques ou OIB) dans la lithosphère, notamment lors de l'interaction du magma avec la lithosphère serpentinisée. Dans ce travail, nous avons testé l'hypothèse selon laquelle la genèse des chromitites de la zone de transition entre le manteau et la croute peut être la conséquence de l'interaction du magma basaltique avec le protolite du manteau serpentinisé. Une étude détaillée du corps de chromitites nodulaires dans les dunites hôtes de la région Maqsad de l'ophiolite d'Oman a été réalisée. Dans l'étude pétrologique, nous avons démontré une relation génétique étroite entre les dunites hôtes et les chromitites nodulaires et disséminées lors de la cristallisation sans équilibre des cristaux de chromite à partir de l'étude des inclusions piégées dans la chromite. Les expériences d'équilibre sur la saturation des liquides basaltiques et haplobasaltiques en chromite et en magnesiochromite comme la fonction de la fugacité d'oxygène (de ΔFMQ (-2) à ΔFMQ (+2)) ont été effectuées à une température constante de 1450 ° C et une pression de 0,1 MPa. Pour la première fois, les concentrations de chrome dans les liquides basaltiques saturés en magnesiochromite ont été mesurées. Les teneurs en Cr lors de la saturation en magnesiochromitre est de ~ 6800 ppm à ΔFMQ (-2), ~ 4500 ppm à ΔFMQ et 3500 ppm à ΔFMQ (+2), qui sont plus élevés par rapport à ceux (~ 6300 ppm à ΔFMQ (-2), 2900 ppm à ΔFMQ et 2000 ppm à ΔFMQ (+2)) de saturation en chromite (système contenant du Fe). Ce fait a une implication importante pour l'assimilation du manteau serpentinisé par des magmas basaltiques. Sur la base de toutes les données disponibles sur la saturation des liquides mafiques et ultramafiques en chromite, nous avons créé un nouveau modèle prévisible de solubilité de chromite et magnéstochromite dans les liquides en fonction de la température, de la fugacité d'oxygène et de la basicité optique du liquide : [X liq Cr tot]/[X Chr Cr2O3] = exp(a+b*lambda+c/T)*(1+fO2^(-0.25)*exp(d+k/T+g*lambda)), où [X liq Cr tot] est la fraction molaire du chrome dans le liquide silicaté, [X Chr Cr2O3] est la fraction molaire de l'oxyde de chrome dans le chromite, T est la température en Kelvins et fO2 est la fugacité de l'oxygène (en bars), lambda est la basicité optique du liquide, a (-7.01), b (13.72 ), c (-12404.92), d (24.46), k (24394.65), g (-23.59) sont des constantes. Des expériences cinétiques sur l'interaction serpentinite-basalte ont été effectuées à des températures entre 1200 et 1300 C et la pression de 0,2 à 1,0 GPa. Les données impliquent que la réaction est contrôlée par un mécanisme à plusieurs étapes: (i) une transformation métamorphique prograde de la serpentinite en harzdurgite (Fo92-95 mol. %) à spinelles riches en Cr (ii) la dissolution progressive de l'assemblage de harzburgite avec la formation des liquides basaltique à andésitique et (iii) l'assimilation finale de l'association de harzburgite par le basalte avec la formation du liquide basique hydraté appauvri ('depleted' et enrichi en Mg, Cr) à 0,5 - 1,0 GPa (51% pds de SiO2, 12 à 13% pds de MgO). / This work is devoted to kinetic and thermodynamic investigation of processes happening during basaltic (mid-ocean ridge basalt, MORB and ocean island basalt, OIB) magma genesis and evolution in the lithosphere, in particular, during the magma interaction with the serpentinized lithosphere. In this work, we tested hypothesis that the chromitite genesis at the Moho transition zone may be consequence of interaction of basaltic magma with serpentinized mantle protolith. Detailed field investigation of the nodular chromitites ore body in the host dunite at Maqsad area of the Oman ophiolite has been performed. In the petrologic investigation, we have demonstrated close genetic relationship between the host dunites and the nodular and disseminated chromitites during non-equilibrium crystallization of chromites based on investigation of chromite-hosted inclusions. Equilibrium experiments on chromite and magnesiochromite saturation in basaltic and haplobasaltic melts as function of oxygen fugacity (from ΔFMQ(-2) to ΔFMQ(+2)) were performed at a constant temperature of 1450 C and pressure of 0.1 MPa. For the first time, chromium concentrations in basaltic melts at magnesiochromite saturation were determined. The Cr contents at magnesiochromitre saturation are from ~6800 ppm at FMQ(-2), ~4500 ppm at FMQ and 3500 ppm at ΔFMQ(+2), that are higher compared to those (~ 6300 ppm at ΔFMQ(-2), 2900 ppm at ΔFMQ and 2000 ppm at ΔFMQ(+2)) of chromite saturation in Fe-bearing system. This fact has an important implication for serpentinized mantle assimilation by basaltic magmas. Based on all available data on chromite saturation in mafic and ultramafic melts, we created a new predictable model of chromite and magnesiochromite solubility depending on temperature, oxygen fugacity and the melt optical basicity: [X liq Cr tot]/[X Chr Cr2O3] = exp(a+b*lambda+c/T)*(1+fO2^(-0.25)*exp(d+k/T+g*lambda)), where [X liq Cr tot] is molar fraction of chromium in the silicate liquid, [X Chr Cr2O3] is molar fraction of the chromium oxide in the chromite, T is temperature in Kelvins and fO2 is oxygen fugacity (in bars), lambda is optical basicity, a (-7.01), b (13.72), c (-12404.92), d (24.46), k (24394.65), g (-23.59) are constants. Kinetic experiments on serpentinite-basalt interaction have been performed at temperatures of 1200 - 1300 C and pressure range from 0.2 to 1.0 GPa. The data imply that the reaction is controlled by multi-stage mechanism: (i) prograde metamorphic transformation of serpentinite to Cr-rich spinel-bearing harzdurgite (Fo92-95 mol.%) (ii) progressive dissolution of harzburgite assemblage with formation of hydrous basaltic to andesite melts and (iii) the final assimilation of the harzburgite association by basalt with formation of hydrous depleted basaltic melts at 0.5 - 1.0 GPa (51 wt% of SiO2, 12 - 13 wt.% of MgO contents). We experimentally demonstrate that serpentinite assimilation by basaltic melt at 0.5 - 1.0 GPa happening at average rate of 4.3 × 10-10 m2/s at 1300°C is controlled by silica diffusion in hydrous basaltic melt. Our experimental work provides incontestable evidence that depleted MORB melts, depleted high-Mg-Cr cumulates, and oceanic andesites can be routinely produced from "normal" mid-ocean ridge melts by chemical reaction with serpentinized lithospheric mantle. Our study prevents routine interpretation of depleted and primitive oceanic melts (MORB and OIB) as uniquely derived from a deep mantle. The data obtained in this work confirm that serpentinites, which may have been important constituents of the Hadean crust as a whole were possibly involved in the generation of the first continental crust.

M.Sc. / This study focuses on the Merensky Reef (MR) occurring within the Two Rivers Platinum mine property in the farm Dwarsriver 372 KT, on the Southern sector of the Eastern Limb of the Bushveld Complex. Five MR exploratory drill core intersections were obtained. Petrographic and mineral chemical characteristics of these drill core samples focused on the characterization of minerals like clinopyroxene, orthopyroxene, plagioclase, chromite and olivine. Data of the cryptic variation of orthopyroxene, plagioclase and chromite, from a 10 m interval (approximate thickness of the section studied); from footwall through the MR to the hangingwall lithologies at Dwarsriver are described in this study. Locally the vertical cryptic variation of these minerals is broadly consistent with regional trends of the RLS. The lateral variation (i.e. along strike) is less pronounced; however, locally these minerals appear to be chemically evolving moving to the south of the property. Footwall orthopyroxene compositions vary from a minimum of En66 and reach a maximum of En84. Those of the MR range from En71 to En85. Hangingwall orthopyroxene compositions range from En60 and reach a maximum of En80. Plagioclase compositions in the footwall units range from a minimum of An69 and reach a maximum of An85. Those of the MR range from a minimum of An35 to a maximum of An84. This wide range in plagioclase compositions is believed to be as a result of the increased presence of fluids within the MR interval. The hangingwall plagioclase compositions range from An64 to An84. By analogy of the Western Limb, where the lithologies of the Northwestern sector are believed to be proximal to the feeder of this limb; the local lateral variation in the present study suggests that the lithologies of either the Central or Western sectors are most probably proximal to the feeder for the Eastern Limb. PGM assemblages associated with and adjacent to the MR chromitite stringers were evaluated using an MLA. Data obtained from this technique is in broad agreement with regional studies of the MR. With the aid of wholerock PGE assays the MLA technique has proven to be a powerful tool in evaluating PGM assemblages relatively quickly, from a few carefully selected samples. The mineralogical associations of the PGM with the gangue and host minerals have shown three main associations. These are the associations of chromite, BMS and silicates with the PGM, of which the base metal sulfide (BMS) association is remarkable given that these have a relatively low modal abundance. The relatively high mineralogical association of the BMS with PGM has been explained by a model involving a base metal sulfide liquid which possibly scavenged chalcophile and siderophile elements. Chromite chemistry and modal analyses of MR secondary silicate phases, which peak adjacent to the chromitite stringers, suggests elevated fluid overprinting within and adjacent to the chromitite stringers. The upper chromitite stringers, however, have higher abundances of PGM phases that are believed to be secondary in origin relative to the basal chromitite stringers. Generally the PGM associated with the upper chromitite stringers are also bigger in size averaging 70 μm as opposed to 27 μm for those associated with the basal chromitite stringers. The increase in grain size of the PGM along with the higher modal abundance of secondary PGM phases associated with the upper stringers is believed to be as a result of fluids. These fluids although affecting both the upper and basal chromitite stringers, appear to have had a relatively higher influence on the upper chromitite stringers. The most common PGMs encountered in this study are isoferroplatinum, sperrylite, michenerite, maslovite, cooperite, laurite and braggite.

Ni-laterites have the potential to become unconventional ore deposits for platinum group elements (PGE). This study was conducted to determine enrichment trends of PGE as a result of the Ni-laterization process. 6 samples were selected by mine workers from the protolith, saprolite, and limonite horizons of the Ni-laterite profile from the Acoje ophiolite block, Luzon, Philippines, and sent to Luleå University of Technology (LTU). 2 samples representing the protolith are described as dunite having undergone serpentinization, 1 sample is a massive chromitite from the saprolite layer of the laterite profile, 1 sample is a massive chromitite from the limonite layer of the laterite profile, and 2 samples are limonitic soils. Total PGE contents of the investigated Acoje samples range from 161-1180 ppb with the highest contents of PGE occurring in the limonite hosted chromitite, and the lowest contents in the saprolite hosted chromitite. C1 chondrite-normalized patterns reveal distinct trends of the PGE in the different sample types: dunite samples have a positive trend from Ir-Pd, the chromitite samples have a negative trend from Ru-Pd with a negative Ir anomaly and the limonite samples have a strong positive trend from Ir-Pd. Rare earth elements (REE) chondrite-normalized patterns of the samples show a negative Ce anomaly in the limonite while the dunite and saprolite-hosted chromitite have negative Eu anomalies. Cr# (Cr/[Al+Cr]) and Mg# (Mg/[Fe2++Mg]) were analyzed using automated mineralogy and produced Cr# values ranging from 0.67 – 0.77 and Mg# values from 0.46 – 0.59.  17 platinum group minerals (PGM) were identified from the Acoje samples: 9 from the dunite, 1 from the saprolite-hosted chromitite, 6 from the limonite-hosted chromitite and 1 from the limonite. Laurite ((Ru,Os)S2) was identified in samples A-02 and A-07 and is the only primary mineral identified. Secondary PGM, thought to have formed due to alteration processes during serpentinization, were identified as alloys composed of: Cu-Pd, Cu-Pt, Pt-Ni-Cu, Pt-Fe, Ir-Ni-(Pt,Fe), and Cu-Pt-Au-(Pd-Ag). PGM are small, measuring consistently <10 µm in diameter. Laurite occurs as inclusions in unfractured chromite. PGM alloys in the dunite samples occur along the boundary of sulfide minerals or within serpentine. PGM identified in the limonite-hosted chromitite occur along interstitial fractures within chromitite or in a Fe-Al oxide matrix within pore spaces.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Pt mineralization within the Bushveld Complex is strikingly focused on the chromitite reefs, despite these horizons being associated with low volumes of base metal sulphide relative to Pt grade. Partitioning of Pt (Dsil/sulp) from silicate magma into immiscible sulphide liquid appears unable to explain Pt concentrations in chromitite horizons, due to the mismatch that exists between very large R factor required and the relevant silicate rock volume. Consequently, in this experimental study we attempt to gain better insight into possible Pt grade enhancement processes that may occur with the Bushveld Complex (BC) sulphide magma. We investigate the wetting properties of sulphide melt relevant to chromite and silicate minerals, as this is a key parameter controlling sulphide liquid percolation through the cumulate pile. Additionally, we have investigated how fractionation of the sulphide liquid from mono-sulphide-solid-solution (Mss) crystals formed within the overlying melanorite might affect sulphide composition and Pt grades within the evolved sulphide melt. Two sets of experiments were conducted: Firstly, at 1 atm to investigate the phase relations between 900OC and 1150OC, within Pt-bearing sulphide magma relevant to the BC; Secondly, at 4 kbar, between 900OC to 1050OC, which investigated the downwards percolation of sulphide magma through several layers of silicate (melanorite) and chromitite. In addition, 1atm experiments were conducted within a chromite dominated chromite-sulphide mixture to test if interaction with chromite affects the sulphide system by ether adding or removing Fe2+. Primary observations are as follows: We found sulphide liquid to be extremely mobile, the median dihedral angles between sulphide melt and the minerals of chromitite and silicate layers are 11O and 33O respectively. This is far below the percolation threshold of 60O for natural geological systems. In silicate layers sulphide liquid forms vertical melt networks promoting percolation. In contrast, the extremely effective wetting of sulphide liquid in chromitites restricts sulphide percolation. Inter-granular capillary forces increase melt retention, thus chromitites serve as a reservoir for sulphide melt. Sulphide liquid preferentially leaches Fe2+ from chromite, increasing the Fe concentration of the sulphide liquid. The reacted chromite rims are enriched in spinel end-member. This addition of Fe2+ to the sulphide magma prompts crystallization Fe-rich Mss, decreasing the S-content of sulphide melt. This lowers Pt solubility and leads to the formation of Pt alloys within the chromitite layer. Eventually, Cu-rich sulphide melt escapes through the bottom of the chromitite layer. These observations appear directly applicable to the mineralized chromitite reefs of the Bushveld complex. We propose that sulphide magma, potentially injected from the mantle with new silicate magma injections, percolated through the silicate cumulate overlying the chromitite and crystallized a significant volume of Fe-Mss. Chromitite layers functioned as traps for percolating, evolved, Cu-, Ni- and Pt-rich sulphide liquids. This is supported by the common phenomenon that chromitites contain higher percentages of Ni, Cu and Pt relative to hanging wall silicate layers. When in contact with chromite, sulphide melt is forced to crystallize Mss as it leaches Fe2+ from the chromite, thereby further lowering the S-content of the melt. This results in precipitation, as Pt alloys, of a large proportion of the Pt dissolved in the sulphide melt. In combination, these processes explain why chromitite reefs in the Bushveld Complex have Pt/S ratios are up to an order of magnitude higher that adjacent melanorite layers. / AFRIKAANSE OPSOMMING: Pt mineralisasie in die Bosveld Kompleks is kenmerkend gefokus op die chromatiet riwwe, alhoewel die riwwe geassosieer is met lae volumes basismetaal sulfiedes relatief tot Pt graad. Verdeling van Pt (Dsil/sulp) vanaf silikaat magma in onmengbare sulfiedvloeistof is klaarblyklik onvoldoende om Pt konsentrasies in chromatiet lae te verduidelik, a.g.v. die wanverhouding wat bestaan tussen ‘n baie groot R-faktor wat benodig word en die relatiewe silikaat rots volumes. Gevolglik, in die eksperimentele studie probeer ons beter insig kry oor moontlike Pt graad verhogingsprosesse wat plaasvind in die BK sulfied magma. Ons ondersoek die benattingseienskappe van sulfied vloeistof relevant tot chromiet- en silikaat minerale, omdat dit die sleutel maatstaf is vir die beheer van sulfied vloeistof deursypeling deur die kumulaat opeenhoping. Addisioneel het ons ook ondersoek hoe die fraksionering van sulfied vloeistof vanaf MSS kristalle, gevorm binne die hangende melanoriet muur, moontlik die sulfied samestelling en Pt graad binne ontwikkelde sulfied smelt kan beïnvloed. Twee stelle van eksperimente is gedoen: Eerstens, by 1 atm om ondersoek in te stel oor fase verwantskappe tussen 900OC en 1150OC, binne ‘n Pt-verrykte sulfied magma samestelling relevant tot die BK; Tweedens, by 4 kbar, tussen 900OC tot 1050OC, wat die afwaartse deursypeling van sulfied magma deur veelvuldige lae van silikaat minerale en chromatiet. Addisionele 1 atm eksperimente is gedoen binne ‘n chromiet gedomineerde chromiet-sulfied mengsel, om te toets of interaksie met chromiet die sulfied sisteem affekteer deur Fe2+ te verwyder of by te dra. Primêre observasies is soos volg: Ons het bevind sulfiedsmelt is uiters mobiel, die mediaan dihedrale hoek tussen sulfiedsmelt en minerale van chromiet en silikaat lae is 11O en 33O onderskydelik. Dit is ver onder die deursypelings drumpel van 60O vir natuurlike geologiese stelsels. In silikaatlae vorm die sulfiedsmelt vertikale netwerke wat deursypeling bevorder. Inteendeel, uiters effektiewe benatting van sulfiedsmelt binne chromatiete vertraag sulfied deusypeling. Tussen kristal kapilêre kragte verhoog smelt retensie, dus dien chromatiete as ‘n opgaarmedium vir sulfiedsmelt. S oorversadigte sulfied vloeistof loogsif Fe2+ vanuit chromiet en veroorsaak ‘n verhoging in Fe-konsentraie. Die gereageerde chromiet buiterante is daarvolgens verryk in Cr-spinêl eind-ledemaat. Die addisionele byvoeging van Fe2+ aan sulfied magma veroorsaak die kristalisasie van Fe-ryke Mss en verlaag dus die S-konsentrasie van die sulfied smelt. Dit verlaag Pt oplosbaarheid en lei tot die formasie van Py allooie binne-in chromatiete. Ten einde, ontsnap Cu-ryke sulfied smelt deur die onderkant van die chromatiet lae. Die observasies is direk van toepassing op die gemineraliseerde chromatiet riwwe van die Bosveld Kompleks. Ons stel voor dat sulfied magma, potensiaal ingespuit vanuit die mantel saam nuwe inspuitings van silikaat magma, deur die hangende silikaat kumulaat bo chromatiet lae deurgesypel het en ‘n betekenisvolle volume Fe-Mss gekristalliseer het. Chromatiet lae het gefunksioneer as lokvalle vir afwaartsbewegende, ontwikkelde, Cu-, Ni-, en Pt-ryke sulfied vloeistowwe. Dit word ondersteun deur die algemene verskynsel dat chromatiete hoër persentasies van Ni, Cu en Pt relatief teenoor die hangende muur silikaat lae het. Wanneer sulfied smelt in kontak is met chromiet, word dit geforseer om Mss te kristalliseer soos Fe2+ geloogsif word, waarvolgens die smelt se S konsentrasie verder verlaag word. Dit veroorsaak die presipitasie, as Pt allooie, van groot proporsies opgeloste Pt vanuit sulfied smelt. Deur die prosesse te kombineer, kan dit moontlik verduidelik word hoekom chromatiet riwwe in die Bosveld Kompleks Pt/S verhoudings veel hoër is as aanrakende melanoriet lae.

Magister Scientiae - MSc (Earth Science) / This study area is situated within the Eastern Bushveld complex at Dwarsrivier chrome mine, which is approximately 30 km from Steelpoort and 60km from Lydenburg in the Mpumalanga province. The primary aim of the project is to identify the petrological and geochemical characteristics that can be used to distinguish the various rock types of feldspathic pyroxenites, chromitites, anorthosites and chromitite pyroxenites and determine whether the various rock types are from the MG2 package and MG3 package were formed from a single or multiple magma pulses. The geochemical and mineralogical variation studies were carried out using cores from borehole DWR74 and DWR172 located on the farm Dwarsrivier 372 KT. Using the combination of various multivariate statistical techniques (factor, cluster and discriminant analysis) multi element diagrams and trace element ratios, the outcome of the study demonstrated that each of the four rock types can be sub-divided into two groups.

Thesis (M.Sc. (Geology)) -- University of Limpopo, 2022 / The Two Rivers Platinum Mine (TRP) located in the Eastern Bushveld Igneous Complex is currently exploiting platinum-group elements (PGE) in the Upper Group 2 chromitite (UG2) Reef at the Dwarsrivier Farm. TRP has acquired a new prospect (at the Buffelshoek Farm) and is currently planning to mine the UG2 Reef and potentially also the Merensky Reef (MR). Three drill-cores which intersected the UG2 Reef and MR at the Buffelshoek Farm made available by TRP were sampled for mineralogical studies using complementary techniques including reflected light microscopy, mineral liberation analyser and electron microprobe. The platinum group minerals (PGM) which host the PGE exhibit variability in their flotation rates and consequently variable PGE recoveries that is mostly attributed to the not so well understood PGM distributions and characteristics. The purpose of the study was to investigate the PGE process mineralogical characteristics such as the PGM phases, their modal abundances and mineral associations, as well as the grain size distributions within the UG2 Reef and MR at the Buffelshoek Farm. The observed PGM phases are broadly grouped into PGE sulphides, PGE arsenides, PGE bismuth-tellurides, PGE antimonides and PGE alloys. The PGM phases are largely dominated by PGE-sulphides (average of 80%) in the UG2 Reef and PGE-arsenides (average of 39%) in the MR. Although the UG2 Reef and MR are mineralogically different, the PGM observed are similar in composition, but vary in their proportions. The PGM are mostly associated with base metal sulphides typically, pentlandite in the UG2 Reef and silicates, which are dominated by amphiboles in the MR. The PGM grain sizes generally range between 2 and 22 microns in the UG2 Reef and range between 2 and 32 microns in the MR. The concentrations of platinum are the highest in both the UG2 Reef and MR, and with the platinum largely deported in PGE-sulphides (about 69 - 84.9%) in the UG2 Reef and PGE-arsenides in the MR. Palladium is mostly deported in the PGE sulphides (about 52.3 - 69.2%) in the UG2 Reef and mostly deported in PGE antimonides (about 43%) and PGE bismuth-tellurides (about 37%) in the MR. Rhodium (Rh) is entirely deported in the PGE sulphides in the UG2 Reef and deported in PGE sulphides (about 86.5%) and PGE bismuth-tellurides (about 13.5%) in the MR. Expected recoveries of PGM ranges from 76 to 89% for PGE sulphides and arsenides in the UG2 Reef and 61.3% in the MR, which is considered good. PGE bismuth-tellurides, PGE antimonides and PGE alloys are expected to be variably to poorly recovered, requiring suitable reagents to be well recovered both in the UG2 Reef and MR. / Faculty of Science and Agriculture Research Division Geological Society of South Africa North West University's School of Geo- and Spatial Science