Economic Geology Models 2. Tantalum and Niobium: Deposits, Resources, Exploration Methods and Market – A Primer for Geoscientists

Abstract

The world’s main tantalum (Ta) resources are in pegmatites (e.g. Wodgina, Australia), rare element-enriched granites (e.g. Abu Dabbab, Egypt), peralkaline complexes (e.g. Nechalacho, Canada), weathered crusts overlying the previously mentioned deposit types, and in placers. Niobium (Nb) resources with the highest economic potential are in weathered crusts that overlie carbonatite complexes (e.g. Catalão I and II, Brazil). Brazil accounts for 90% of the global Nb mine production with another 9% coming from the Niobec Mine, Canada (a hard-rock underground mine). However, at least 17 undeveloped carbonatite complexes outside of Brazil have NI-43-101 compliant Nb resource estimates (e.g. Aley carbonatite, Canada). Concentrates from most carbonatites are used to produce ferroniobium (Fe–Nb alloy), and Ta is not recovered. The Ta and Nb contents of some carbonatites (e.g. Upper Fir deposit and Crevier dyke, Canada) are of the same order of magnitude as that of pegmatite ores; however, concentrates from carbonatites have a higher Nb/Ta ratio. Historically, 10–12% Ta2O5 in Nb concentrates has not been recovered in ‘western’ smelters because of the hydrofluoric acid cost. Western countries perceive Ta and Nb supplies to be at risk. Tantalum market downturns resulted in several mines in Australia and Canada closing, at least temporarily, and a resultant shortfall has been filled by what is now recognized as ‘conflict-free columbite-tantalite’ from Central Africa. The lack of ore will not be a key factor in future Ta and Nb supply disruption. For example, more than 280 Nb- and 160 Ta-bearing occurrences are known in Canada alone, and more resources will likely to be discovered as geophysical and geochemical exploration methods are optimized.RÉSUMÉLes principales sources mondiales en tantale (Ta) sont les pegmatites (par ex. Wodgina, Australie), les granites enrichis en éléments rares (par ex. Abu Dabbab, Égypte), les complexes hyperalcalins (par ex. Nechalacho, Canada), les croûtes altérées recouvrant les types de gisements déjà mentionnés, et les placers. Les sources en niobium (Nb) ayant le meilleur potentiel économique se trouvent dans les croûtes altérées qui recouvrent les complexes de carbonatite (par ex. Catalão I et II, Brésil). Le Brésil est la source de 90% de la production minière mondiale de Nb, et 9% provient de la mine Niobec, au Canada (une mine souterraine). Cela dit, il existe au moins 17 complexes de carbonatite non développés à l'extérieur du Brésil dont les estimations de ressources en Nb sont conformes à la norme NI-43-101 (par ex. Aley carbonatite, Canada). Les concentrés de la plupart des carbonatites sont utilisés pour produire du ferroniobium (alliage Fe-Nb), et le Ta n'est pas récupéré. Les teneurs en Ta et Nb de certaines carbonatites (par ex. le gisement de Upper Fir et le dyke Crevier, Canada) sont du même ordre de grandeur que celles des minerais depegmatite; cependant, les concentrés de carbonatites ont une proportion Nb/Ta plus élevée. Historiquement, 10 à 12% du Ta2O5 des concentrés de Nb n'ont pas été récupérés dans les fonderies de l'Ouest en raison du coût de l’acide fluorhydrique. Les pays occidentaux estiment que les approvisionnements en Ta et Nb sont à risque. Le fléchissement du marché du tantale a entraîné la fermeture, au moins temporaire, de plusieurs mines en Australie et au Canada, et la pénurie qui en résulte a été comblée par ce qui est maintenant reconnu comme étant du minerai de colombite-tantalite «sans conflit» d'Afrique centrale. Le manque de minerai ne sera pas un facteur clé des perturbations à venir de l'approvisionnement en Ta et Nb. Par exemple, plus de 280 occurrences minérales contenant du Nb et 160 occurrences minérales contenant du Ta sont connues au Canada seulement, et davantage de ressources seront probablement découvertes à mesure que les méthodes d'exploration géophysique et géochimique seront optimisées.

Carbonatites: related ore deposits, resources, footprint, and exploration methods

“…The rate of discovery increased significantly between 1956 and 1966 due to technical improvements in airborne radiometric and magnetic survey technology in combination with aerial photointerpretation. This mid-century surge in the rate of discovery is apparent from the numbers of known carbonatites reported in a series of consecutive review studies: Pecora (1956), Heinrich (1958), Heinrich (1966) and Woolley and Simandl et al (2018). Most grade and tonnage references are available in Mackay and Simandl (2014a).…”

Geology and Petrogeochemistry of Lijiapuzi Nb-Ta Granitic Pegmatite Deposit: Implications for Ore Genesis and Prospecting

“…Rare metals are essential to modern industry, especially high-tech industries such as micro-electronics, specialty alloys and high-strength low-alloys etc., [1][2][3][4], which are regarded as strategic and critical metals [3][4][5][6]; however, their production has long been limited in a few countries, and thus their resources, types of deposit, origin, genesis, and tectonic settings attract attention worldwide [7][8][9][10]. Globally the Ta resources mainly occur in pegmatites and rare element-enriched peraluminous granites [3,4,6]; consequently, pegmatites had long been the foci of metallogenic research.…”

Liberation Characteristics of Ta–Sn Ores from Penouta, NW Spain

“…Tantalum and niobium occur together in nature. Most of the tantalum comes from the exploitation of pegmatites and rare metal granites [19]. However, the shortage of primary Ta deposits makes it necessary to look for other sources of this metal, such as the tailings of some old tin mines, which may have a high potential for Ta.…”