DOCSLIB.ORG

RHODES UNIVERSITY Grahamstown • 6 1 10* South Africa

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
RHODES UNIVERSITY Grahamstown • 6 1 10* South Africa RHODES UNIVERSITY Grahamstown • 6 1 10* South Africa Characterization of the distribution of Platinum Group Elements in Sulphide Ores within the Merensky Reef at Modikwa and Two Rivers Platinum Mines, Eastern Bushveld Complex, South Africa By Nosibulelo Julie Zilibokwe A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE (Economic Geology) MSc Exploration Geology Programme Geology Department Rhodes University P.O. Box 94 Grahamstown 6140 South Africa April 2017 Acknowledgements I would like to thank Almighty God for keeping me healthy and energetic from the start until the end of this journey. This thesis is dedicated to my mother Dorothy Zilibokwe, thank you mama-D for providing me with a sound education. I would like to express my appreciation to my supervisor Dr Napoleon Q. Hammond, now at the University of Limpopo, for your valuable professional guidance, advice and constructive suggestions during the planning and development of this dissertation. Thank you for believing in me Doc. I remain indebted to my manager Dr Stewart Foya at the Council for Geoscience, thank you for permitting me to carry out my studies and for also taking time out of your busy schedule to attend to my queries. You provided great personal guidance, encouragement and support throughout this journey. My gratitude is boundless and I thank you for making this all possible. Special gratitude to my co-supervisor Prof. R.E. “Jock” Harmer in the Geology Department at Rhodes University, for your advice, guidance and valuable support during the writing of this dissertation. Furthermore, I wish to thank the staff of the Geology Department at Rhodes for warmly welcoming me whenever I had any questions or queries. I would especially like to thank Mrs Ashley Goddard for your unconditional support and excellent administrative performance. In addition, I would like to thank the many lecturers who took the time to teach our class about their geological specialities and the staff at the mines across South Africa we were exposed to. Many thanks to the geological teams at Modikwa and Two Rivers Platinum Mines, in particular, Mr N. Machumele and Mr J. Khumalo for your assistance and warm welcome during the mine visits. This thesis would not have been possible without project data and drill-core samples supplied by Anglo Platinum and African Rainbow Minerals/Impala. I would also like to sincerely thank Mr Abdul Kenan from the Council for Geoscience, the funniest advisor who is always ready to assist, I have learnt several things from you. Thank you for your assistance in the drawing of the grade profiles. Your tremendous support, timely help and advice have been extremely valuable to me and I am indebted to you. 11 NwaNdwandwe (Valerie Nxumalo) from the Council for Geoscience, words cannot convey my full appreciation for the interest, involvement, support and selfless help extended by you during this research, you have greatly motivated me as a mentor. I cannot forget to thank my classmates who made this two-year journey unforgettable. It was fun to study with you guys. I greatly acknowledge the Mining Qualification Authority (MQA), the Councilfor Geoscience in collaboration with the Department of Science and Technology (DST) for funding my studies. I wish to extend my sincere thanks to the Council for Geoscience Laboratory staff, Mr N. Nxokwana (MK) and Mr L. Maema, without those thin sections this thesis would not have been possible. Many thanks to Dr Gelu Costin for your critical input during the microprobe analyses. The use of the Jeol JXA 8230 Superprobe instrument, sponsored by NRF/NEP Grant 40113 (UID 74464) is kindly acknowledged. I wish to humbly thank Mr T. Mothupi from Mintek for your warm welcome and advice on the Mineral Liberation Analyser (MLA) data presentation, together with Mr J. Chiliza for conducting the assay analyses. I have no words to thank my entire family and relatives for your love, care, prayers and encouraging words that facilitated me achieving my goals. To all my dearest friends, colleagues and well-wishers who I have not named above, you have been my pillar of strength and your best wishes greatly encouraged me during this research. Thank you all for the different roles you have played throughout this journey, (Yes You!). m Declaration I, Nosibulelo Julie Zilibokwe, declare that this dissertation is my own work. It is being submitted for the Degree of Master of Science at Rhodes University, Grahamstown. It has not been submitted before for any degree or examination at any other University. Signature of Candidate.. .Nosibulelo Julie Zilibokwe................................................................ Date: ............................... th day of April 2017......................................................................... Place.. .Silverton........Pretoria.................................................................................................... iv Abstract The distribution of the platinum group element (PGE), in the Merensky Reef was characterized by, first determining the occurrence of the platinum group minerals (PGM), then by establishing the PGE concentration in the base metal sulphides (BMS) associated with the PGE mineralization in the Merensky Reef from selected borehole intersections, at the Two Rivers (TRP) and Modikwa Platinum Mines in the Eastern Bushveld Complex. A mineral liberation analyser (MLA) was then used to identify the PGM phases; their silicate and base metal associations; and their grain size distribution. Electron microprobe quantitative analysis and mapping were then used to determine the compositional variation of the PGM and the PGE elemental distribution in the BMS, respectively. The study showed that the BMS including pyrrhotite, pentlandite, and chalcopyrite were the principal sulphides, where pyrrhotite was most prominent with minor quantities of pyrite. Orthopyroxene, clinopyroxene and plagioclase were the most abundant primary silicate minerals identified, while secondary silicates identified included talc, serpentine and amphibole. Platinum group minerals showed three distinct groups with respect to the mineralogical association with the PGE; (i) BMS association; (ii) chromite association; and (iii) silicate association. Of the BMS, chalcopyrite showed the most dominant association with the PGMs. All samples from both mines exhibited a wide range of PGMs, including maslovite, braggite, cooperate, laurite and PGE alloys such as ferroplatinum as well as other unidentified platinum and palladium sulphides, arsenides and bismuthides, while gold was present as electrum. The PGMs ranged in size from less than a micron to about 125 microns with an average of 20 microns. The close association of PGM with BMS along the margins of sulphides indicates that the PGMs were derived from the sulphide melt. PGE distribution in the sulphides at Modikwa showed pentlandite contained the highest concentrations of palladium (up to 379 ppm) and chalcopyrite hosting the highest rhodium concentrations (up to 793 ppm). Samples from Two Rivers revealed pentlandite as the principal host to both palladium and rhodium, with concentrations reaching up to 695 and 930 ppm, respectively. Magnetite at both Modikwa and Two Rivers showed significant rhodium content, reaching up to 982 and 930 ppm, respectively. v The pyrrhotite compared to other sulphides contained all the elements found in the platinum group (PPGE), namely, platinum, palladium and rhodium, with all the platinum identified found in the pyrrhotite. The concentrations for the iridium group (IPGE) namely, iridium, osmium, and ruthenium were below the detection limit. The PGE mineralization in the stratigraphy varied within each mine. The mineralization revealed top loading in the central sector (Modikwa) and bottom loading in the southern sector (Two Rivers). The sequence of the Merensky Reef at the two sectors of the Eastern Bushveld Complex showed a remarkable similarity in their mineralogy suggesting that these two sectors were formed from the same liquid or formed simultaneously within a single magma chamber; however the PGE distribution within the stratigraphy may have been controlled by the presence of cumulate sulphides. Keywords: Platinum group elements (PGE), Platinum group minerals (PGM), Merensky Reef, Bushveld Complex, Modikwa, Two Rivers. vi List of Abbreviations Amp Amphibole ARM African Rainbow Minerals ASSMANG Associated Manganese Mines of South Africa Limited ATP Annual Technical Report BCU Bastard Cyclic Unit Bio Biotite BMS Base Metal Sulphides BSE Back Scattered Electron Ccp Chalcopyrite CGS Council for Geoscience Chl Chlorite Chr Chromite Cpx Clinopyroxene CZ Critical Zone EPMA Electron Probe Micro Analyzer IPGE Iridium (Ir), Osmium (Os) and Ruthenium (Ru) IRUP Iron Rich Ultramafic Pegmatite JV Joint Venture LZ Lower Zone MZ Main Zone MaZ Marginal Zone MCU Merensky Cyclic Unit MLA Mineral Liberation Analyzer MPM Modikwa Platinum Mine MPX Merensky Pyroxenite Ol Olivine vii Opx Orthopyroxene OV Onverwacht PFP Pegmatoidal Feldspathic Pyroxenite PGE Platinum Group Elements PGM Platinum Group Minerals Phl Phlogopite Pn Pentlandite PPGE Platinum (Pt), palladium (Pd) and rhodium (Rh) PPL Plane Polarized Light RLS Rustenburg Layered Suite SEM-EDS Scanning Electron Microscopy-Energy Dispersive Spectrometry Srp Serpentine TRP Two Rivers Platinum UZ Upper Zone viii Table of Contents Acknowledgements..................................................................................................................ii
Load more

Recommended publications
  • Modikwa-SLP-2019-2023.Pdf
    1 | P a g e Table of Contents SECTION 1 ....................................................................................................................................................................................6 UNDERTAKING (Regulation 46 (f) ............................................................................................................................................6 INTRODUCTION ......................................................................................................................................................................7 ACRONYMS AND ABBREVIATIONS .......................................................................................................................................7 GLOSSARY................................................................................................................................................................................9 SECTION 2 ................................................................................................................................................................................. 12 PREAMBLE (Regulation 46 (a) ............................................................................................................................................... 12 2.1 LOCATION OF MINE .......................................................................................................................................................13 2.2 OWNERSHIP OF THE MINE ...........................................................................................................................................13
    [Show full text]
  • 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]
  • Integrated Annual Report 2020
    ANGLO AMERICAN PLATINUM LIMITED INTEGRATED ANNUAL REPORT 2020 REPORT ANNUAL INTEGRATED Integrated annual report 2020 Anglo American Platinum Limited Purpose: re-imagining mining to improve people’s lives We are grounded in our purpose to re-imagine mining to improve people’s lives. We are transforming the very nature of mining for a safer, cleaner, smarter future. We are using more precise technologies, less energy and less water; we are reducing our physical footprint for every ounce of PGM and base metal we produce. We are combining smart innovation with the utmost consideration for our people, their families, local communities, our customers, and the world at large – to better connect precious resources in the ground to all of us who need and value them. Our focus is on our four strategic priorities to deliver the next phase of value creation for stakeholders. – Stimulate new markets and leverage new capabilities – Embed anti-fragility across our business – Maximise value from our core – Be a leader in ESG Refers to other pages in this report Supporting documentation on the website Full annual financial statements (AFS) Full Ore Reserves and Mineral Resources report Environmental, social and governance (ESG) report Notice of annual general meeting www.angloamericanplatinum.com/investors/annual-reporting/2020 Contents 1 Our report 4 Strategy, PGM markets and 99 Our economic contribution in Zimbabwe business model in 2020 1 Approach to reporting 101 Mining and concentrator operations review 2 Reporting principles 38 Strategic priorities
    [Show full text]
  • Predictability of Pothole Characteristics and Their Spatial Distribution At
    79_Chitiyo:Template Journal 12/15/08 11:16 AM Page 733 Predictability of pothole characteristics J o and their spatial distribution at u Rustenburg Platinum Mine r n by G. Chitiyo*, J. Schweitzer*, S. de Waal*, P. Lambert*, and a P. Olgilvie* l P a p Synopsis thermo-chemical erosion of the cumulus floor by new influxes of superheated magma best explains the observed data. e Prediction of pothole characteristics is a challenging task, Partial to complete melting of the cumulate floor occurred in r confronting production geologists at the platinum mines of three phases. The first represents the emplacement of hot the Bushveld Complex. The frequency, distribution, size, magma. This magma, due to turbulent flow and high chemical shape, severity and relationship (FDS3R) of potholes has a and physical potential, aggressively attacks the existing floor huge impact on mine planning and scheduling, and (crystal mush on the magma/floor interface). Regional consequently cost. It is with this in mind that this study was erosion is manifested by large, often coalescing potholes. initiated. During the second phase, when the magma emplacement Quantitative analysis of potholes indicates that pothole process ceased and cooling in situ started, two distinct size (area covered) can be described by two partly periods of pothole formation ensued. The first is related to overlapping lognormal distributions. These are referred to as rapid cooling along the relatively steep part of the Newton Populations A (smaller) and B (larger). The range of Cooling Curve, when Population B potholes nucleated observed pothole sizes conforms to a simple double randomly and grew rapidly with concurrent convective exponential growth model based on Newton’s Cooling Curve.
    [Show full text]
  • Exkursionen Excursions
    EXKURSIONEN EXCURSIONS 174 MITT.ÖSTERR.MINER.GES. 161 (2015) A GEOLOGICAL EXCURSION TO THE MINING AREAS OF SOUTH AFRICA by Aberra Mogessie, Christoph Hauzenberger, Sara Raic, Philip Schantl, Lukas Belohlavek, Antonio Ciriello, Donia Daghighi, Bernhard Fercher, Katja Goetschl, Hugo Graber, Magdalena Mandl, Veronika Preissegger, Gerald Raab, Felix Rauschenbusch, Theresa Sattler, Simon Schorn, Katica Simic, Michael Wedenig & Sebastian Wiesmair Institute of Earth Sciences, University of Graz, Universitaetsplatz 2, A-8010 Graz Frank Melcher, Walter Prochaska, Heinrich Mali, Heinz Binder, Marco Dietmayer-Kräutler, Franz Christian Friedman, Maximilian Mathias Haas, Ferdinand Jakob Hampl, Gustav Erwin Hanke, Wolfgang Hasenburger, Heidi Maria Kaltenböck, Peter Onuk, Andrea Roswitha Pamsl, Karin Pongratz, Thomas Schifko, Sebastian Emanuel Schilli, Sonja Schwabl, Cornelia Tauchner, Daniela Wallner & Juliane Hentschke Chair of Geology and Economic Geology, Mining University of Leoben, Peter-Tunner-Strasse 5, A-8700 Leoben Christoph Gauert Department of Geology, University of the Free State, South Africa 1. Preface Almost a year ago Aberra Mogessie planned to organize a field excursion for the students of the Institute of Earth Sciences, University of Graz. The choices were Argentina, Ethiopia (where we had organized past excursions) and South Africa. Having discussed the matter with Christoph Hauzenberger concerning geology, logistics etc. we decided to organize a field excursion to the geologically interesting mining areas of South Africa. We contacted Christoph Gauert from the University of Free State, South Africa to help us with the local organization especially to get permission from the different mining companies to visit their mining sites. We had a chance to discuss with him personally during his visit to our institute at the University of Graz in May 2014 and make the first plan.
    [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]
  • Sampling and Estimation of Diamond Content in Kimberlite Based on Microdiamonds Johannes Ferreira
    Sampling and estimation of diamond content in kimberlite based on microdiamonds Johannes Ferreira To cite this version: Johannes Ferreira. Sampling and estimation of diamond content in kimberlite based on micro- diamonds. Other. Ecole Nationale Supérieure des Mines de Paris, 2013. English. NNT : 2013ENMP0078. pastel-00982337 HAL Id: pastel-00982337 https://pastel.archives-ouvertes.fr/pastel-00982337 Submitted on 23 Apr 2014 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. N°: 2009 ENAM XXXX École doctorale n° 398: Géosciences et Ressources Naturelles Doctorat ParisTech T H È S E pour obtenir le grade de docteur délivré par l’École nationale supérieure des mines de Paris Spécialité “ Géostatistique ” présentée et soutenue publiquement par Johannes FERREIRA le 12 décembre 2013 Sampling and Estimation of Diamond Content in Kimberlite based on Microdiamonds Echantillonnage des gisements kimberlitiques à partir de microdiamants. Application à l’estimation des ressources récupérables Directeur de thèse : Christian LANTUÉJOUL Jury T M. Xavier EMERY, Professeur, Université du Chili, Santiago (Chili) Président Mme Christina DOHM, Professeur, Université du Witwatersrand, Johannesburg (Afrique du Sud) Rapporteur H M. Jean-Jacques ROYER, Ingénieur, HDR, E.N.S. Géologie de Nancy Rapporteur M.
    [Show full text]
  • The Expansion of Platinum Mining in South Africa the Expansion Rustenburg Blue Ridge
    2898_JM03_14_17 5/13/03 11:36 AM Page 1 Supplies A period of unprecedented growth In 1998 – before the most recent phase of expansions – the UG2 The South African platinum industry is currently expanding at an reef accounted for around 38 per cent of the ore processed by South unprecedented rate in order to meet projected increases in demand. African platinum mines. By 2002, that proportion had risen above With the exception of Northam, all existing producers have 50 per cent and in 2006 we expect UG2 to account for over 60 per ambitious expansion plans. They will be joined by several new cent of the total ore processed. entrants as the South African government’s policy of black economic The Merensky Reef reserves on the western Bushveld were empowerment leads to the greater involvement of black-led exploited in preference to those on the more remote eastern limb companies in the platinum mining sector, mainly in the form of joint because grades in the west tend to be higher and access and ventures with existing producers. Additional investment is also infrastructure was easier to develop. However, higher platinum expected from non-South African companies, such as the UK’s Cluff prices, the prospect of rising demand, and above all the depletion Mining and Canada’s SouthernEra. of the most attractive ore reserves on the western Bushveld have As a result of this expansion activity, platinum output is set to rise begun to offset these disadvantages. The eastern limb accounted for substantially over the next four years. If all new projects reach their a mere 6 per cent of platinum production in 2002; by 2006, that targets, refined production from South African platinum mines could proportion will be around 18 per cent and by the end of this decade, be as high as 6.3 million oz in 2006, with Anglo Platinum alone could be as high as 30 per cent.
    [Show full text]
  • The Centenary of the Discovery of Platinum in the Bushveld Complex (10Th November, 1906)
    CAWTHORN, R.G. The centenary of the discovery of platinum in the Bushveld Complex (10th November, 1906). International Platinum Conference ‘Platinum Surges Ahead’, The Southern African Institute of Mining and Metallurgy, 2006. The centenary of the discovery of platinum in the Bushveld Complex (10th November, 1906) R.G. CAWTHORN School of Geosciences, University of the Witwatersrand, South Africa The earliest authenticated scientific report of the occurrence of platinum in rocks from the Bushveld Complex appears to be by William Bettel on 10th November 1906. Thereafter, prospecting of the chromite-rich rocks for platinum proved frustrating. I suggest that the resurgence of interest shown by Dr Hans Merensky in 1924 resulted from his realization that newly-panned platinum had a different grain size from that in the chromite layers and indicated a different source rock, which he located and it became known as the Merensky Reef. Merensky’s discoveries in Johannesburg). He found it contained ‘silver, gold, The story of Dr. Hans Merensky’s discoveries of the platinum and iridium (with osmium)’. Hence, the presence platinum-rich pipes and the Merensky Reef itself in 1924 of the platinum-group elements (PGE) in South Africa in have been well documented (Cawthorn, 1999; Scoon and minor amounts was well-established by the end of the Mitchell, 2004, and references therein), but the events that nineteenth century. preceded it have not been summarized. In the probable centenary year of the first report of platinum in the In situ platinum Bushveld it is appropriate to review the events between In his article Bettel reported that he had ‘recently’ (i.e.
    [Show full text]
  • Pdf 358.5 Kb
    Seventy-fifth Anniversary of the Discovery of the Platiniferous MerenskvJ Reef THE LARGEST PLATINUM DEPOSITS IN THE WORLD By Professor R. Grant Cawthorn Department of Geology, University of the Witwatersrand, South Africa The Merensky Reef is a thin layer of igneous rock in the Bushveld Complex in South Africa, which, with an underlying layer, the Upper Group 2 chromitite, contains 75 per cent of the world’s known platinum resources. It was discovered in September 1924 by Hans Merensky, and by early 1926 had been traced for about 150 km. However, large-scale mining of the reef did not develop until aproliferation of uses for theplatinumgroup metals in the 1950s increased demand and price. Successful extraction of metal from the Upper Group 2 chromitite had to wait until the 1970s for metallurgical developments. In 1923 platinum was discovered in the rivers. In early June 1924, a white metal was Waterberg region of South Africa, and alerted panned in a stream on a small farm called geologists to its presence there, see Figure 1. At Maandagshoek, 20 km west of Burgersfort, see that time world demand for platinum was not Figure 2, by a farmedprospector called Andries great, and the economic slump during the years Lombaard. Suspecting it was platinum, he of the Great Depression, which followed soon sent it to Dr Hans Merensky for confirmation. afterwards, reduced demand and price still fur- Hans Merensky was a consulting geologist and ther. Consequently, the discovery in 1924 was mining engineer in Johannesburg. Together, almost before its time. Lombaard and Merensky followed the “tail” of Platinum, like gold and diamonds, has a high platinum in their pan upstream into some hills density and forms stable minerals, which accu- on Maandagshoek, where they finally found mulate at the sandy bottoms of streams and platinum in solid rock on 15th August 1924.
    [Show full text]
  • GSA TODAY Conference, P
    Vol. 10, No. 2 February 2000 INSIDE • GSA and Subaru, p. 10 • Terrane Accretion Penrose GSA TODAY Conference, p. 11 A Publication of the Geological Society of America • 1999 Presidential Address, p. 24 Continental Growth, Preservation, and Modification in Southern Africa R. W. Carlson, F. R. Boyd, S. B. Shirey, P. E. Janney, Carnegie Institution of Washington, 5241 Broad Branch Road, N.W., Washington, D.C. 20015, USA, [email protected] T. L. Grove, S. A. Bowring, M. D. Schmitz, J. C. Dann, Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA D. R. Bell, J. J. Gurney, S. H. Richardson, M. Tredoux, A. H. Menzies, Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa D. G. Pearson, Department of Geological Sciences, Durham University, South Road, Durham, DH1 3LE, UK R. J. Hart, Schonland Research Center, University of Witwater- srand, P.O. Box 3, Wits 2050, South Africa A. H. Wilson, Department of Geology, University of Natal, Durban, South Africa D. Moser, Geology and Geophysics Department, University of Utah, Salt Lake City, UT 84112-0111, USA ABSTRACT To understand the origin, modification, and preserva- tion of continents on Earth, a multidisciplinary study is examining the crust and upper mantle of southern Africa. Xenoliths of the mantle brought to the surface by kimber- lites show that the mantle beneath the Archean Kaapvaal Figure 2. Bouguer gravity image (courtesy of South African Council for Geosciences) craton is mostly melt-depleted peridotite with melt extrac- across Vredefort impact structure, South Africa. Color scale is in relative units repre- senting total gravity variation of 90 mgal across area of figure.
    [Show full text]
  • Tackling Tax Evasion: Transfer Price Manipulation, Extractive Natural Resources and a Strategy for the Southern African Customs Union
    University of Denver Digital Commons @ DU Electronic Theses and Dissertations Graduate Studies 1-1-2012 Tackling Tax Evasion: Transfer Price Manipulation, Extractive Natural Resources and a Strategy for the Southern African Customs Union Patrick Grant McLennan University of Denver Follow this and additional works at: https://digitalcommons.du.edu/etd Part of the African Studies Commons, Economics Commons, International Relations Commons, and the Natural Resource Economics Commons Recommended Citation McLennan, Patrick Grant, "Tackling Tax Evasion: Transfer Price Manipulation, Extractive Natural Resources and a Strategy for the Southern African Customs Union" (2012). Electronic Theses and Dissertations. 422. https://digitalcommons.du.edu/etd/422 This Thesis is brought to you for free and open access by the Graduate Studies at Digital Commons @ DU. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Digital Commons @ DU. For more information, please contact [email protected],[email protected]. Tackling Tax Evasion: Transfer Price Manipulation, Extractive Natural Resources and a Strategy for the Southern African Customs Union __________ A Thesis Presented to the Faculty of the Josef Korbel School of International Studies University of Denver __________ In Partial Fulfillment of the Requirements for the Degree Master of Arts __________ by Patrick G. McLennan August 2012 Advisor: Dr. Barry B. Hughes Author: Patrick G. McLennan Title: Tackling Tax Evasion: Transfer Price Manipulation, Extractive Natural Resources and a Strategy for the Southern African Customs Union Advisor: Dr. Barry B. Hughes Degree Date: August 2012 ABSTRACT An increase in the number of multinational enterprises (MNEs) has increased the attention on cross-border challenges, such as transfer price manipulation (TPM).
    [Show full text]