Summary

Deposit type

• Sedimentary

Summary:

The Yatela mine comprises the Yatela and Alamoutala deposits located in northwest Mali within the Keniéba-Kedougou Inlier, a major Paleoproterozoic- Birimian inlier along the northeast margin of the Kenema-Man shield. The Yatela deposit is located in the north of the inlier and is hosted in sedimentary rocks of the Kofi Formation, which have been intruded by numerous felsic to intermediate intrusives. The sedimentary rocks consist of fine-grained greywackes, pelites and impure limestones with minor tuffs and acid volcanics. The primary gold mineralisation is hosted along a sheared contact between predominantly dolomitic carbonate rocks of the Kofi Formation to the west and a dioritic intrusion to the east. The secondary mineralisation was concentrated to economic grades through dissolution of the carbonate and subsequent concentration of the gold by eluvial processes and supergene enrichment.

Karst development at Yatela has formed deep pot holes, collectively named the Yatela Basin, which were gradually filled by sandstones and conglomerates during peneplanation of the Proterozoic rocks. Chaotic collapse during karstification, coupled with the infill sediments resulted in the deposit being hosted in a melange-type of rocks made up of sedimentary rocks and dissolution residues. Gold is disseminated in the unconsolidated ferruginous, clastic layer with sandy-clayey matrix that lines the bottom and walls of a deep trough with steep margins. The karst margin dips steeply on the west wall and more gently to the west on the east wall, following a keel-like geometry with tight closure on the folded diorite towards the south. The supergene enrichment of low-grade primary gold mineralisation associated with the karstification is the most important geological feature to the economics of the Yatela deposit.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Commodity Production