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Nb-Ta-Minerals Resources

In nature tantalum and niobium are rare since they are depleted in the continental crust (Nb < 10 ppm; Ta < 1 ppm). Usually they occur together as a result of their chemical similarity. Main ore minerals are oxides with columbite-tantalite, pyrochlore, wodginite and loparite being the principal pay minerals.

Three main types of niobium/tantalum deposits are distinguished: carbonatite complexes, alkaline to peralkaline rocks and pegmatites.

All three deposit types have in common that they are hosted in rocks that preferentially accommodate incompatible elements such as niobium, rare earth elements etc. which do not occur in common rock forming minerals.

Carbonatite complexes are host to the world’s most significant niobium deposits. It is either mined in the lateritic caps of such carbonatite complexes in which pyrochlore has been strongly concentrated by tropical weathering as in Araxá and Catalão deposits in Brazil or it is mined from mineralized lenses as is the case in Saint-Honoré in Canada. Brazil accounts for more than 90% of the global niobium production with Canada and Africa accounting for the rest.

Alkaline to peralkaline rocks can also host significant niobium occurrences as in the Kvanefjeld project in the Illimaussaq complex in Greenland. Typically deposits in this kind of geological setting are enriched in zirconium, rare earth elements and niobium with only minor amounts of tantalum.

Historically rare element pegmatites located in Canada (Bernic Lake) and Australia (Greenbushes and Wodgina) have been important sources of tantalum. Nowadays most of the tantalum produced comes from artisanal mining in central Africa. Tantalum is also recovered from placer deposits as a by-product of tin mining.

Main producers of tantalum are located in Africa (>60%) and Brazil (20%), followed by less significant producers in Australia, Canada and Malaysia.