DOCSLIB.ORG

On Cooperite, Braggite, and Vysotskitel

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
On Cooperite, Braggite, and Vysotskitel AmericanfrIineralogist, Volume 63 , pages832-839, I 978 On cooperite,braggite, and vysotskitel Louts J. Cesnt, J. H. Gllus Le,rLemltn,JoHN M. SrBwnRr Canada Centre for Mineral and Energy Technology 555Booth Street, Ottawa, CanadaKl A 0GI KsNr TunNsn INP BRtnNJ' SrtNNrn Department of Geology and Geophysics, Yale Uniuersity New Hauen, Connecticut06520 Abstract phase Detailedmineralogical analyses ol cooperite,braggite, and vysotskite,together with of equilibrium studies,reveal that, though there is no uncertaintyregarding the identity cooperite(PtS;P4r/mmc), one may considerbraggite (Pt,Pd)S and vysotskitePdS to be nicfeloanmembers of an isomorphoussolid-solution series (Pd,Pt)S (P4z/ m)' Theresults also the suggestthat this solid-solutionseries (braggite series) may be subdividedby restricting namevysotskite to thosemembers with lessthan about l0 molepercent PtS. Cooperite and is only braggitecan both form at magmatictemperatures of 1000"Cor above,but vysotskite fo.ir"a at submagmatictempiratures, possibly by crystallizationfrom a residualimmiscible sulfide-richmelt or by solid-statereaction. Introduction has since been reported, but not documentedin de- Montana (Cabri Cooperite,braggite, and vysotskiteare the only Pt- tail, from the Stillwater Complex of Isles deposit, Pd sulfide minerals with ideal compositions in the and Laflamme, 1974)and the Lac des system Pt-Pd-S. Cooperite is ideally PtS, braggite Ontario (Cabri and Laflamme,1976). (Pd,Pt)S,and vysotskitePdS. All analyses,however, In this note we report new data on all three miner- of report the presenceof significantamounts of Ni, so als from the Precambrian Stillwater Complex the variations mineralogicallythey must be consideredas being in Montana. Pageet al. (1976) discussed and ultramafic the system Pt-Pd-Ni-S. We aim to clarify the no- of PG-elementsin the different mafic identifiedby Page menclatureand to presentnew data on the composi- layersof the complex.In the layers Zones we have identi- tions of the minerals.It is a pleasureto be able to do et al. as the Banded and Upper minerals in the same so in the Frondel-Hurlbut issue of The American fied, for the first time, the three found in Mineralogist, becausethese two distinguished miner- deposit. The three minerals have not been doesnot alogists have clarified so many similarly confusing contact so it is probablethat the assemblage can issuesin the nomenclatureof minerals. representequilibrium, and its true significance Braggite and cooperite are both important plati- only be guessedat. num-group minerals (PG-minerals) and are known studies from many areasof'the world; in the great Merensky Previous mineralogical Reef deposits of the Bushveld Igneous Complex in Cooperite the Transvaalthey are major ore minerals.Vysotskite samples from the has not so far been found in sufficient quantities to be Cooperite was discovered in (1928) named by Wagner consideredan important ore mineral. First discov- Bushveld by Cooper and Mr. Wartenweiller ered in the Noril'sk deposits of the USSR and re- (lg2g) following a suggestionby a presentationof ported by Genkin andZvyagintsev(1962), vysotskite in a published discussionfollowing Cooper's paper. Bannister and Hey (1932) deter- with a : 4.91 and I MineralsResearch Program, Processing Contribution No. 88. mined the mineral to be tetragonal 832 CABRI ET AL: COOPERITE, BRAGGITE, AND VYS7TSKITE : c 6.10A.Though they recognizedthat this wasa c spacegroup P4r/m, Z : 8, and a compositionap- face-centeredcell and that the true primitivecell was proximating". (Pt,Pd,Ni)Scontaining about 20 : : p4r/mmc, a 3.47, c 6.10,4.,space group they percentPd and 5 percentNi . ." Braggiteis even neverthelessused the centeredcell in order to empha- more abundantthan cooperitein somemines of the size the relationshipto the unit cell of platinum. BushveldComplex. It averages35.9 volume percent Berryand Thompson(1962) reported a unit cellwith of the PG-mineralsfrom four areasin the Western : a: 3.48and c 6.llA, Z:2, in closeagreement Transvaal(Vermaak and Hendriks,1976) and 60 vol- with the primitivecell of Bannisterand Hey. In their umepercent at the Atok Platinummine in theeastern powder pattern,however, they observedbut could Bushveld(Schwellnus et al., 1976). not index three lines at 2.81(2),1.765(6), and The crystalstructure of braggitewas determined by 1.397A(Vr)respectively. Genkin (1968), reporting on Childsand Hall (1973)on a samplefrom the Potgie- cooperitefrom two differentlocations in theNoril'sk tersrustdistrict, Transvaal. They reported cell param- area,presented two new powder patterns.Neither etersof a : 6.380(l),c : 6.570(l)A,Z: 8. Childs pattern included the two weak lines (2.81 and andHall alsoproposedthat2 Pd atomswere ". the 1.397A)of Berry and Thompson,suggesting they minimum requirementin the formationof the pdS were probably due to impurity admixturesin the (braggiteor vysotskite)structure rather than the ptS Berry and Thompsonsample. Both of the Noril'sk (cooperite)structure." However, four of the sixbrag- samplepatterns contained the strongestline reported gite analysesreported by Schwellnuset al. (1976\ by Berry and Thompson,observed at 1.763and haveless than two atomsof Pd per cell,thus casting 1.770Arespectively, thus stronglysuggesting that it considerabledoubt on the Childs and Hall sugges- belongsto the pattern.The solutionto the problem ' tion. becomesapparent from the work of Grdnvold et al. (1960),who studiedsynthetic PtS, for which they Vysotskite : obtaineda cellwith q 3.4700and c :6.1096,{. The In 1962,Genkin andZvyagintsevreported the min- Grdnvoldpowder pattern contains a strongreflection eral vysotskite,for which theyindicated the formula at 1.7544,which is indexedas (103). (Pd,Ni)S,though they did not considerNi to be an Cooperitemakes up a significantfraction of the essentialconstituent. They found the mineralto be PG-mineralspresent in areasof the BushveldCom- tetragonalwith a : 6.371and c : 6.5404,and the plex wherethe MerenskyReef is mined le.g. 13.36 powderpattern was very similar to that reportedfor volumepercent average from four areasin the West- braggite.The powder pattern was also very similar to ern Transvaal,Vermaak and Hendriks(1976); 10.3 that of syntheticPdS, for whichGaskell (1937) had volumepercent at the WesternPlatinum mine, Bry- reporteda : 6.43(2)and c : 6.63(2)A,space group nardet al. (1976);and 25 volumepercent at the Atok P4r/m, Z : 8. Thesedata suggestedstrongly that Platinummine, Schwellnus el al. (1976)1.Inspite of braggiteand vysotskitewere membersof an iso- the significanceof cooperitein the MerenskyReef, morphousseries of which PdSwas the end-member the only publishedmicroprobe analyses are thoseof composition. Schwellnuset al. (1976)and Brynardet al. (1976), togetherwith a singleanalysis by A. M. Clark re- Phasesin the systemPt-Pd-S ported by Cabri (1972).The fivecooperite analyses of The ternaryphase relations for Pt-Pd-Sat 1000"C Schwellnuset al. (1976)are from samplesfrom the were reportedby Skinneret al. (1976).Those at easternBushveld, and they reveal a rangeofcomposi- 800'C havenow beencompleted and arereported in tion for Pd (by weight)from 0.15to 5.78percent and Figure l. No solidphases more sulfur-richthan PtS for Ni from 0.68to l.l8 percent;the analysesalso or PdSappear, thus we canconfine discussion to the revealPb (1.14to 1.35percent) and Bi (0.41to 0.71 phase-volumePtS-PdS-Pd-Pt. Four phasesappear: percent).Six analysesof cooperitefrom the western a continuousalloy from Pt to Pd, a liquid field lo- Bushveldby Brynardet al. (1976)have a narrower catedon the Pd-PdSjoin, andtwo sulfides.The first rangefor Pd from 0.5to 1.5percent, with Ni ranging sulfideis a solid solutionidentical with cooperite from 0.6 to 1.6percent and tracesof Rh. extendingfrom PtS,along the compositionjoin to- ward PdS, to (Pt'.zoPdo.a0)Sat 1000.C Braggite and (Pto.b4Pdo.G)Sat 800oC. The secondis a phaseidenti- Braggitewas named by Bannisterand Hey (1932) cal in propertiesto braggite.At 1000'Cthe braggite- : : for a tetragonalmineral with a 6.37,c 6.584, like phaseranges in compositionfrom (Pdo.ooPto60)5 834 CABRI ET AL,, COOPERITE, BRAGGITE, AND VYSOTSKITE S cumulate layer situated some 6 feet stratigraphically below the main olivine cumulate horizon (main marker) which contains large pyroxene oikocrysts; sample 2 came from the "dark anorthosite" which forms part of the ore horizon immediatelyabove the main marker; and sample4 camefrom an adjoining section of the same ore horizon, referred to as the "tri-colored anorthosite." The three samples pro- vided by the Corporation are located as follows: sample 5(1824-PP-20)is a sulfide concentrate milled and floated from a bulk sampletaken from the West Fork adit. Sample 6(DDH 77-73-13) is from the Camp zone, located within the lower part of the Banded zone and 4.7 miles WNW along strike from the West Fork adit. Sample 7(789-T-l-l) is from a pyroxenecumulate layer in a trench in the southeast corner of claim Coors 8, located 6.5 miles WNW along strike from the adit. The Lac des Islesvysotskite sample was discovered in a partly crusheddrill core sample,Pl4-7, and the Pt to il arroy r o ;-- Pd Rustenburg (M19398) and Potgietersrust(MI9388) from the Fig. l. Phase relations in the Pt-Pd-S system at 1000' and samples were PG-mineral concentrates 800'C. The braggite solid solution at 800"C includesvysotskite. Royal Ontario Museum collections' : PtS : PdS, in atomic percent, for specificpoints are: A : 70: 30; B The samplesthat neededcrushing and concentra- = : = 60:40; C 16:84; D 54:46:E 24:'76. tion were
Load more

Recommended publications
  • Mineral Profile
    Platinum September 2009 Definition, mineralogy and Pt Pd Rh Ir Ru Os Au nt Atomic 195.08 106.42 102.91 192.22 101.07 190.23 196.97 deposits weight opme vel Atomic Definition and characteristics 78 46 45 77 44 76 79 de number l Platinum (Pt) is one of a group of six chemical elements ra UK collectively referred to as the platinum-group elements Density ne 21.45 12.02 12.41 22.65 12.45 22.61 19.3 (gcm-3) mi (PGE). The other PGE are palladium (Pd), iridium (Ir), osmium e Melting bl (Os), rhodium (Rh) and ruthenium (Ru). Reference is also 1769 1554 1960 2443 2310 3050 1064 na point (ºC) ai commonly made to platinum-group metals and to platinum- Electrical st group minerals, both often abbreviated to PGM. In this su resistivity r document we use PGM to refer to platinum-group minerals. 9.85 9.93 4.33 4.71 6.8 8.12 2.15 f o (micro-ohm re cm at 0º C) nt Chemically the PGE are all very similar, but their physical Hardness Ce Minerals 4-4.5 4.75 5.5 6.5 6.5 7 2.5-3 properties vary considerably (Table 1). Platinum, iridium (Mohs) and osmium are the densest known metals, being significantly denser than gold. Platinum and palladium are Table 1 Selected properties of the six platinum-group highly resistant to heat and to corrosion, and are soft and elements (PGE) compared with gold (Au). ductile. Rhodium and iridium are more difficult to work, while ruthenium and osmium are hard, brittle and almost pentlandite, or in PGE-bearing accessory minerals (PGM).
    [Show full text]
  • New Mineral Names*,†
    American Mineralogist, Volume 104, pages 625–629, 2019 New Mineral Names*,† DMITRIY I. BELAKOVSKIY1 AND FERNANDO CÁMARA2 1Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18 korp. 2, Moscow 119071, Russia 2Dipartimento di Scienze della Terra “Ardito Desio”, Universitá di degli Studi di Milano, Via Mangiagalli, 34, 20133 Milano, Italy IN THIS ISSUE This New Mineral Names has entries for 8 new minerals, including fengchengite, ferriperbøeite-(Ce), genplesite, heyerdahlite, millsite, saranchinaite, siudaite, vymazalováite and new data on lavinskyite-1M. FENGCHENGITE* X-ray diffraction pattern [d Å (I%; hkl)] are: 7.186 (55; 110), 5.761 (44; 113), 4.187 (53; 123), 3.201 (47; 028), 2.978 (61; 135). 2.857 (100; 044), G. Shen, J. Xu, P. Yao, and G. Li (2017) Fengchengite: A new species with 2.146 (30; 336), 1.771 (36; 24.11). Single-crystal X-ray diffraction data the Na-poor but vacancy-dominante N(5) site in the eudialyte group. shows the mineral is trigonal, space group R3m, a = 14.2467 (6), c = Acta Mineralogica Sinica, 37 (1/2), 140–151. 30.033(2) Å, V = 5279.08 Å3, Z = 3. The structure was solved by direct methods and refined to R = 0.043 for all unique I > 2σ(I) reflections. Fengchengite (IMA 2007-018a), Na Ca (Fe3+,) Zr Si (Si O ) 12 3 6 3 3 25 73 Fenchengite is the Fe3+ analog of eudialyte with a structural difference (H O) (OH) , trigonal, is a new eudialyte-group mineral discovered in 2 3 2 in vacancy dominant N5 site and splitting its Na site N1 into N1a and the agpaitic nepheline syenites and its pegmatite facies near the Saima N1b sites.
    [Show full text]
  • STRATIFORM and ALLUVIAL Plafl NUM MINERALIZATION in THE
    LU3 The Canadian M iner alog is t Vol. 33,pp. 1023-lM5(1995) STRATIFORMAND ALLUVIALPLAfl NUM MINERALIZATION IN THENEW CALEDONIA OPHIOLITE COMPLEX THIERRY AUGE lNI PIERREMATIRZOT BRGM'Metallogeny and Geotynarnics", B.P. 6009, 45060 Orldans Cedex 2, France ABSTRA T An unusualtype offt mineralizationhas beenfound in the New Caledoniaophiolite complex, associatedwitl stratiform chromite-bearingrocks at the baseof the cumulateseries (close to the transition zone betweendunite and pyroxene-bearing rocks) and with cbromite-richpyroxenite dykes from the samezone. Two placer deposis, both enrichedin Fl also have been recognized one derived from the chromite-rich horizons and the other a cbromitiferous beach sand of unknown origin. Chromite-bearingrocks aremarked by a very strongenrichment in Pt relative to fhe other platinum-groupelements (PGE), $'ith a rrardmunconcentration of 11.5ppm (average3.9 ppm). The Pt enrichmenttakes the form of platinum-groupminerals (PGM) included in chromite crystals and is interpretedas being pdlrar'/. The following minerals have been identified: ft-Fe{u alloys (isoferroplatinum,tulame€nite, tetraferroplatinum and undeterminedphases), cooperite, laurite, bowieite, malanite, cuprorhodsite,unnamed PGE oxides, and base-metalsulfides with PGE in solid solution. The associatedplacers show a slightly different mineral association,with isoferroplatinum,tulameenite, and rare cooperite,sperrylite, Os-k-Ru alloys and PGE oxides. A more complex paragenesishas been identified in the beach san4 with isoferroplatinum,cooperite, laurite, erlichmanite, Os-Ir-Ru alloys, bowieite, ba$ite, hollingworthire, sperrylite, stibiopalladinite, and unnamed Rh sulfide, Pt-Ru-Rh alloy and PGE oxides. This type of mineralization, which differs markedly from the Os-Ru-h mineralization previously recognized in podiform cbromitite in New Caledonia, shows several analogies with Alaskan-type PGE mineralization.The host chromitite,with typical cumulustextwes, is markedby Ti and Feh emichmentdue to derivationfrom an evolved liquid.
    [Show full text]
  • ECONOMIC GEOLOGY RESEARCH INSTITUTE HUGH ALLSOPP LABORATORY University of the Witwatersrand Johannesburg
    ECONOMIC GEOLOGY RESEARCH INSTITUTE HUGH ALLSOPP LABORATORY University of the Witwatersrand Johannesburg CHROMITITES OF THE BUSHVELD COMPLEX- PROCESS OF FORMATION AND PGE ENRICHMENT J.A. KINNAIRD, F.J. KRUGER, P.A.M. NEX and R.G. CAWTHORN INFORMATION CIRCULAR No. 369 UNIVERSITY OF THE WITWATERSRAND JOHANNESBURG CHROMITITES OF THE BUSHVELD COMPLEX – PROCESSES OF FORMATION AND PGE ENRICHMENT by J. A. KINNAIRD, F. J. KRUGER, P.A. M. NEX AND R.G. CAWTHORN (Department of Geology, School of Geosciences, University of the Witwatersrand, Private Bag 3, P.O. WITS 2050, Johannesburg, South Africa) ECONOMIC GEOLOGY RESEARCH INSTITUTE INFORMATION CIRCULAR No. 369 December, 2002 CHROMITITES OF THE BUSHVELD COMPLEX – PROCESSES OF FORMATION AND PGE ENRICHMENT ABSTRACT The mafic layered suite of the 2.05 Ga old Bushveld Complex hosts a number of substantial PGE-bearing chromitite layers, including the UG2, within the Critical Zone, together with thin chromitite stringers of the platinum-bearing Merensky Reef. Until 1982, only the Merensky Reef was mined for platinum although it has long been known that chromitites also host platinum group minerals. Three groups of chromitites occur: a Lower Group of up to seven major layers hosted in feldspathic pyroxenite; a Middle Group with four layers hosted by feldspathic pyroxenite or norite; and an Upper Group usually of two chromitite packages, hosted in pyroxenite, norite or anorthosite. There is a systematic chemical variation from bottom to top chromitite layers, in terms of Cr : Fe ratios and the abundance and proportion of PGE’s. Although all the chromitites are enriched in PGE’s relative to the host rocks, the Upper Group 2 layer (UG2) shows the highest concentration.
    [Show full text]
  • Thirty-Fourth List of New Mineral Names
    MINERALOGICAL MAGAZINE, DECEMBER 1986, VOL. 50, PP. 741-61 Thirty-fourth list of new mineral names E. E. FEJER Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD THE present list contains 181 entries. Of these 148 are Alacranite. V. I. Popova, V. A. Popov, A. Clark, valid species, most of which have been approved by the V. O. Polyakov, and S. E. Borisovskii, 1986. Zap. IMA Commission on New Minerals and Mineral Names, 115, 360. First found at Alacran, Pampa Larga, 17 are misspellings or erroneous transliterations, 9 are Chile by A. H. Clark in 1970 (rejected by IMA names published without IMA approval, 4 are variety because of insufficient data), then in 1980 at the names, 2 are spelling corrections, and one is a name applied to gem material. As in previous lists, contractions caldera of Uzon volcano, Kamchatka, USSR, as are used for the names of frequently cited journals and yellowish orange equant crystals up to 0.5 ram, other publications are abbreviated in italic. sometimes flattened on {100} with {100}, {111}, {ill}, and {110} faces, adamantine to greasy Abhurite. J. J. Matzko, H. T. Evans Jr., M. E. Mrose, lustre, poor {100} cleavage, brittle, H 1 Mono- and P. Aruscavage, 1985. C.M. 23, 233. At a clinic, P2/c, a 9.89(2), b 9.73(2), c 9.13(1) A, depth c.35 m, in an arm of the Red Sea, known as fl 101.84(5) ~ Z = 2; Dobs. 3.43(5), D~alr 3.43; Sharm Abhur, c.30 km north of Jiddah, Saudi reflectances and microhardness given.
    [Show full text]
  • Platinum Group Minerals in Eastern Brazil GEOLOGY and OCCURRENCES in CHROMITITE and PLACERS
    DOI: 10.1595/147106705X24391 Platinum Group Minerals in Eastern Brazil GEOLOGY AND OCCURRENCES IN CHROMITITE AND PLACERS By Nelson Angeli Department of Petrology and Metallogeny, University of São Paulo State (UNESP), 24-A Avenue, 1515, Rio Claro (SP), 13506-710, Brazil; E-mail: [email protected] Brazil does not have working platinum mines, nor even large reserves of the platinum metals, but there is platinum in Brazil. In this paper, four massifs (mafic/ultramafic complexes) in eastern Brazil, in the states of Minas Gerais and Ceará, where platinum is found will be described. Three of these massifs contain concentrations of platinum group minerals or platinum group elements, and gold, associated with the chromitite rock found there. In the fourth massif, in Minas Gerais State, the platinum group elements are found in alluvial deposits at the Bom Sucesso occurrence. This placer is currently being studied. The platinum group metals occur in specific Rh and Os occur together in minerals in various areas of the world: mainly South Africa, Russia, combinations. This particular PGM distribution Canada and the U.S.A. Geological occurrences of can also form noble metal alloys (7), and minerali- platinum group elements (PGEs) (and sometimes sation has been linked to crystallisation during gold (Au)) are usually associated with Ni-Co-Cu chromite precipitation of hydrothermal origin. sulfide deposits formed in layered igneous intru- In central Brazil there are massifs (Americano sions. The platinum group minerals (PGMs) are do Brasil and Barro Alto) that as yet are little stud- associated with the more mafic parts of the layered ied, and which are thought to contain small PGM magma deposit, and PGEs are found in chromite concentrations.
    [Show full text]
  • The Bushveld Igneous Complex
    The Bushveld Igneous Complex THE GEOLOGY OF SOUTH AFRICA’S PLATINUM RESOURCES By C. A. Cousins, MSC. Johannesburg Consolidated Investment Company Limited A vast composite body of plutonic and volcanic rock in the central part of the Transvaal, the Bushveld igneous complex includes the platinum reef worked by Rustenburg Platinum Mines Limited and constituting the world’s greatest reserve of the platinum metals. This article describes the geological and economic aspects of this unusually interesting formation. In South Africa platinum occurs chiefly in square miles. Two of these areas lie at the the Merensky Reef, which itself forms part of eastern and western ends of the Bushveld and the Bushveld igneous complex, an irregular form wide curved belts, trending parallel to oval area of some 15,000 square miles occupy- the sedimentary rocks which they overlie, and ing a roughly central position in the province dipping inwards towards the centre of the of the Transvaal. A geological map of the Bushveld at similar angles. The western belt area, which provides the largest known has a flat sheet-like extension reaching the example of this interesting type of formation, western boundary of the Transvaal. The is shown on the facing page. third area extends northwards and cuts out- The complex rests upon a floor of sedi- side the sedimentary basin. Its exact relation- mentary rocks of the Transvaal System. This ship to the other outcrops within the basin floor is structurally in the form of an immense has not as yet been solved. oval basin, three hundred miles long and a As the eastern and western belts contain hundred miles broad.
    [Show full text]
  • Detrital Platinum-Group Minerals (PGM) in Rivers of the Bushveld Complex, South Africa – a Reconnaissance Study
    Detrital Platinum-Group Minerals (PGM) in Rivers of the Bushveld Complex, South Africa – A Reconnaissance Study Thomas Oberthür, Frank Melcher, Lothar Gast, Christian Wöhrl and Jerzy Lodziak Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover, Germany e-mail: [email protected] Introduction Regional geology The initial major discovery of platinum in Sampling concentrated on stream the Bushveld Complex, which subsequently led to sediments of rivers in the vicinity of the original the discovery of the Merensky Reef, was made in discovery of the Merensky Reef on the farm 1924 by panning in a river bed on the farm Maandagshoek close to Burgersfort in the Eastern Maandagshoek in the Eastern Bushveld (Merensky Bushveld (Fig. 1). The localities investigated by 1924, 1926, Wagner 1929, Cawthorn 1999a, 1999b, Cawthorn (1999b, 2001), i. e. those documented by 2001). Wagner (1929) also reports on a number of Merensky (1924) as Pt-bearing, and additional alluvial diggings in the Bushveld Complex that places along the Moopetsi river were sampled. The produced some platinum. However, as mining river valley runs approximately north-south, commenced on the rich pipes and reef-type deposits subparallel to the layering of the Mafic Phase of the of the Bushveld, alluvial PGM soon became Bushveld Complex, and is between 2 and 3 km forgotten and no published information on the wide. On the farm Maandagshoek, the Merensky placer PGM is available. Cawthorn (1999b, 2001) Reef and the UG2 are about 2 km apart and crop performed geochemical investigations of stream- out on the western and eastern side, respectively, of sediments at and close to the 1924 discovery site the Moopetsi river.
    [Show full text]
  • Platinum-Group Element and Minerals in the Lower and Middle Group Chromitites of the Western Bushveld Complex, South Africa
    Helmholtz-Zentrum Dresden-Rossendorf (HZDR) Platinum-group element and minerals in the Lower and Middle Group chromitites of the western Bushveld Complex, South Africa Junge, M.; Oberthür, T.; Osbahr, I.; Gutter, P.; Originally published: August 2016 Mineralium Deposita 51(2016)7, 841-852 DOI: https://doi.org/10.1007/s00126-016-0676-6 Perma-Link to Publication Repository of HZDR: https://www.hzdr.de/publications/Publ-26567 Release of the secondary publication based on the publisher's specified embargo time. Platinum-group elements and minerals in the Lower and Middle Group chromitites of the western Bushveld Complex, South Africa Malte Junge1, Thomas Oberthür1, Inga Osbahr2 and Paul Gutter3 1Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover, Germany; [email protected] 2Helmholtz Institute Freiberg for Resource Technology, Halsbrücker Strasse 34, 09599 Freiberg, Germany 3SYLVANIA Platinum Ltd., P.O. Box 976, Florida Hills 1716, South Africa Abstract The chromitites of the Bushveld Complex in South Africa contain vast resources of platinum- group elements (PGE). However, knowledge of the distribution and the mineralogical siting of the PGE in the Lower Group (LG) and Middle Group (MG) chromitite seams of the Bushveld Complex is limited. We studied concentrates from the LG-6 and MG-2 chromitites of the western Bushveld Complex by a variety of microanalytical techniques. The dominant PGM are sulfides, namely laurite, cooperite-braggite and malanite-cuprorhodsite, followed by PGE-sulfarsenides, sperrylite, and Pt-Fe alloys. Laurite is the most abundant PGM (vol%). The matching sets of PGM present in the LG and MG chromitites of both the western and the eastern Bushveld Complex, and in the UG-2 chromitite, show strong similarities which support the assumption of a characteristic and general chromitite-related PGM assemblage.
    [Show full text]
  • Braggite (Pt, Pd, Ni)S
    Braggite (Pt, Pd, Ni)S c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Tetragonal. Point Group: 4/m or 4. As prisms, to 2 cm, and rounded grains. Twinning: Rarely observed. Physical Properties: Hardness = n.d. VHN = 946–1064, 997 average (100 g load). D(meas.) = ∼10 D(calc.) = 9.383 Optical Properties: Opaque. Color: White in reflected light. Luster: Metallic. Anisotropism: Distinct, in purplish and pinkish shades of gray and brown. R1–R2: (400) 41.3–41.8, (420) 41.8–42.4, (440) 42.1–43.0, (460) 42.4–43.4, (480) 42.5–43.8, (500) 42.7–44.1, (520) 42.7–44.2, (540) 42.6–44.2, (560) 42.5–44.2, (580) 42.4–44.2, (600) 42.3–44.1, (620) 42.2–44.1, (640) 41.9–44.0, (660) 41.9–43.9, (680) 41.9–43.8, (700) 41.5–43.8 Cell Data: Space Group: P 42/m. a = 6.367 c = 6.561 Z = 8 X-ray Powder Pattern: Potgietersrus district, South Africa; can be confused with vysotskite. 2.86 (100), 2.93 (30), 2.64 (30), 1.852 (30), 1.423 (30), 1.713 (20), 1.595 (2) Chemistry: (1) (2) (1) (2) Pt 63.2 62.1 Ni 4.4 2.0 Pd 15.4 19.0 S 17.4 16.9 Total 100.4 100.0 (1) Potgietersrus district, South Africa; by electron microprobe, corresponding to (Pt0.60Pd0.27 Ni0.14)Σ=1.01S1.00. (2) Stillwater complex, Montana, USA; by electron microprobe, corresponding to (Pt0.60Pd0.34Ni0.06)Σ=1.00S1.00.
    [Show full text]
  • Sulfide Minerals in the G and H Chromitite Zones of the Stillwater Complex, Montana
    Sulfide Minerals in the G and H Chromitite Zones of the Stillwater Complex, Montana GEOLOGICAL SURVEY PROFESSIONAL PAPER 694 Sulfide Minerals in the G and H Chromitite Zones of the Stillwater Complex, Montana By NORMAN J PAGE GEOLOGICAL SURVEY PROFESSIONAL PAPER 694 The relationship of the amount, relative abundance, and size of grains of selected sulfide minerals to the crystallization of a basaltic magma UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1971 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of CongresR catalog-card No. 70-610589 For sale by the Superintendent of Documents, U.S. Government Printin&' Otrice Washin&'ton, D.C. 20402 - Price 35 cents (paper cover) CONTENTS Page Abstract------------------------------------------------------------------------------------------------------------ 1 Introduction________________________________________________________________________________________________________ 1 Acknowledgments--------------------------------------------------------------------------------------------------- 4 Sulfide occurrences-------------------------------------------------------------------------------------------------- 4 Sulfide inclusions in cumulus minerals_____________________________________________________________________________ 4 Fabrtc______________________________________________________________________________________________________ 5 Phase assemblages__________________________________________________________________________________________
    [Show full text]
  • The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (Pgms) in South Africa and Russia
    minerals Review The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South Africa and Russia Cyril O’Connor 1,* and Tatiana Alexandrova 2 1 Department of Chemical Engineering, Centre for Minerals Research, University of Cape Town, Cape Town 7701, South Africa 2 Department of Minerals Processing, St Petersburg Mining University, St Petersburg 199106, Russia; [email protected] * Correspondence: [email protected] Abstract: Russia and South Africa are the world’s leading producers of platinum group elements (PGEs). This places them in a unique position regarding the supply of these two key industrial commodities. The purpose of this paper is to provide a comparative high-level overview of aspects of the geological occurrence, mineralogy, and processing by flotation of the platinum group minerals (PGMs) found in each country. A summary of some of the major challenges faced in each country in terms of the concentration of the ores by flotation is presented alongside the opportunities that exist to increase the production of the respective metals. These include the more efficient recovery of minerals such as arsenides and tellurides, the management of siliceous gangue and chromite in the processing of these ores, and, especially in Russia, the development of novel processing routes to recover PGEs from relatively low grade ores occurring in dunites, black shale ores and in vanadium-iron-titanium-sulphide oxide formations. Keywords: Russia; South Africa; PGMs; geology; mineralogy; flotation Citation: O’Connor, C.; Alexandrova, T. The Geological Occurrence, Mineralogy, and Processing by Flotation of Platinum Group Minerals (PGMs) in South 1. Introduction Africa and Russia.
    [Show full text]