French Guiana

The three sectors are all mainly composed of shales from the Orapu series. This group is mainly composed of grey to purplish red clayey sericitoschists depending on the degree of alteration.

Tantalum mineralization comes either from the Crab granites or the Galibi granites present within the PER zones or along the edge. Streams and tropical rains erode these granites. The tantaliferous elements resulting from this erosion, due to their high density, are concentrated in the flats very close to their source.

The PER known as "Voltaire" with a surface area of 34 km² is the last permit requested by SUDMINE. It was obtained in 2019.

The limits of this PER originate from the Voltaire index discovered in the 1960s by BRGM. More than a hundred wells have been drilled and have made it possible to determine the significant potential of the sector. Thus the sampled content is 440 g/m³ of columbite-tantalite. The estimated potential is 38 tonnes of columbite-tantalite.

The PER known as "Basse-Mana" with a surface area of 48 km² was granted in 2018. It has a proven potential for alluvio-electrolytic columbite-tantalite.

The boundaries of this PER include three important tantaliferous showings discovered by BRGM. The Valentin showing is rich in Ta2O5 (55%) with grades of around 250 g/m³ and an estimated potential of 2 tonnes of columbite-tantalite. In the 1980 mining inventory of French Guyana, the Belle-Etoile index is cited as "an alluvial deposit of 235,000 m³ with an average grade of 1,255 g/m³", i.e. a potential of 295 tonnes of columbite-tantalite. Finally, the Agami-Maïpouri showing has high grades (1,100 g/m³) for an estimated potential of 8 tonnes of columbite-tantalite.

The PER known as "Kourou" was the first requested by SUDMINE (2016) and was granted in 2018. With a surface area of 34 km², it is located 15 km south-west of Kourou and has proven potential for alluvio-eluvial colombo-tantalite mineralisation.

The boundaries of this PER include two colombo-tantalite showings discovered by BRGM. The first is that of Passoura-Cariacou with an estimated potential of more than 350 tonnes of columbite-tantalite and grades in excess of 700 g/m³ of columbite-tantalite (12.9% Ta2O5 and 49.3% Nb2O5). The second, the Monkey Mountain index, has tantalum (Ta2O5) contents above 60%.

This area also has anomalies in rutile (up to 350 g/m³ TiO2), ilmenite (up to 3,000 g/m³ FeTiO3) as well as beryl and lithium.