Tantalum-(niobium-tin) mineralisation in pegmatites and rare-metal granites of Africa

Research Article| March 01, 2017 Tantalum-(niobium-tin) mineralisation in pegmatites and rare-metal granites of Africa F. Melcher; F. Melcher Chair of Geology and Economic Geology, University of Leoben, Peter-Tunnerstraße 5, 8700 Leoben, Austria e-mail: frank.melcher@unileoben.ac.at Search for other works by this author on: GSW Google Scholar T. Graupner; T. Graupner Federal Institute for Geosciences and Natural Resources, Stilleweg 2, D-30655 Hannover, Germany e-mail: torsten.graupner@bgr.de; mut.oberthuer@yahoo.de; ph.schutte@gmail.com Search for other works by this author on: GSW Google Scholar T. Oberthür; T. Oberthür Federal Institute for Geosciences and Natural Resources, Stilleweg 2, D-30655 Hannover, Germany e-mail: torsten.graupner@bgr.de; mut.oberthuer@yahoo.de; ph.schutte@gmail.com Search for other works by this author on: GSW Google Scholar P. Schütte P. Schütte Federal Institute for Geosciences and Natural Resources, Stilleweg 2, D-30655 Hannover, Germany e-mail: torsten.graupner@bgr.de; mut.oberthuer@yahoo.de; ph.schutte@gmail.com Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2017) 120 (1): 77–100. https://doi.org/10.25131/gssajg.120.1.77 Article history first online: 10 Apr 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation F. Melcher, T. Graupner, T. Oberthür, P. Schütte; Tantalum-(niobium-tin) mineralisation in pegmatites and rare-metal granites of Africa. South African Journal of Geology 2017;; 120 (1): 77–100. doi: https://doi.org/10.25131/gssajg.120.1.77 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract Tantalum is an important metal for high-technology applications of the modern world. It is recovered from oxide minerals that are present as minor constituents in rare-metal granites (RMG) and granitic rare-element pegmatites (REP). Significant potential exists as a by-product of spodumene mining from pegmatites, and from Nb-Zr-rare earth element (REE) mining from carbonatites and peralkaline igneous rocks. Columbite-group minerals (CGM) account for the majority of the current Ta production; other Ta-Nb oxides such as tapiolite, wodginite, ixiolite, rutile and pyrochlore-supergroup minerals are of minor importance. The estimated Ta resources of Africa are >50,000 tons of contained Ta2O5, representing 16% of the world resources. Currently, the economically most important mining districts in Africa are located within the Kibara Belt (mainly Rwanda and the DR Congo), around the Kenticha mine (Ethiopia) and in the Alto Ligonha Province (Mozambique). Production from pegmatites and related placer deposits is mostly from hundreds of artisanal and small-scale workings with only a handful of semi-industrial Ta mines. Collectively, African operations are currently responsible for more than half of the world's primary Ta.Rare-metal granite and REP districts in Africa are part of Archaean, Palaeoproterozoic, Neoproterozoic, Palaeozoic and Mesozoic provinces. Each period of Ta ore formation is characterised by specific mineralogical and geochemical features. Compositions of CGM are variable: Fe-rich types predominate in the Man Shield (Sierra Leone), the Congo Craton (DR Congo), the Kamativi Belt (Zimbabwe) and the Jos Plateau (Nigeria);Mn-rich columbite-tantalite is typical of the Alto Ligonha Province (Mozambique), the Arabian-Nubian Shield (Egypt, Ethiopia) and the Tantalite Valley pegmatites (southern Namibia) andLarge compositional variations through Fe-Mn fractionation, followed by Nb-Ta fractionation are typical for pegmatites of the Kibara Belt of Central Africa, pegmatites associated with the Older Granites of Nigeria and many pegmatites in the Damara Belt of Namibia. Trace element concentrations in CGM and other Ta-Nb oxides are highly variable, with Ti, W, Sn, Zr, Hf, Y, Sc and REE displaying significant regional differences that may be used to discriminate Ta provinces. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.