The Falémé deposits, Republic of Senegal – an old kid, new on the iron ore block

Abstract

The Falémé iron ore deposits are located in the so-called 'Birrimian' volcano-sedimentary complex that extends in a general NE-SW direction across Eastern Senegal and part of Mali and Guinea. The rocks underwent folding and greenschist facies metamorphism, as well as various events of granitoid emplacement. The deposits formed part of the Dialé-Daléma Series of the Birrimian Supergroup and were subjected to contact metamorphism. The Fe-mineralisation occurs as primary magnetite within the metamorphic aureole. Supergene oxidation (martitisation) of this mineralisation produced the hematite-rich iron deposits that can be seen as prominent hills across the plains of this southeastern corner of Senegal. The Bureau de Recherches Géologiques et Minières of France and Société des Mines de Fer du Sénégal Oriental have conducted several phases of prospecting since 1957. Their aim was to delineate the primary magnetite and oxidised ore (hematite) deposits and to assess the grade, beneficiation characteristics and marketability of the iron ore. A hematite feasibility study by Fluor Daniel was completed in 1992. Results indicated that, at the time, the resource could not compete in the international arena in terms of size and accessibility. The growing iron ore market and additional available resources in the area now challenge the 1992 feasibility study results and put the old kid back on the iron ore block. The project faces some mining challenges, such as the amount of magnetite in the hematite product that will be acceptable to the market. Previous project evaluations only considered the secondary hematite deposits as economically viable. It is therefore important to accurately delineate the magnetite/hematite contact zone to optimise the resource tonnage. Project logistic constraints also exist in terms of railway access and harbour facilities. The resource is, however, well situated for the European iron ore market and aims to find a place in the rapidly expanding iron ore seaborne trade.