This article presents an integrated methodology and main results of the geological and economic modeling of the Farim-Saliquinhé phosphate ore deposit, in Guiné-Bissau. This mineral mass was fi rst recognized in the 1980s, by the Bureau de Recherches Géologiques et Minières (BRGM) as sedimentary. The morphological characterization was performed by depth and thickness estimation of coverage and mineralized formations (main phosphate rock FPA, and carbo-phosphate FPB, secondary). The P2O5 grades were characterized by krigging and subsequently by geostatistical simulation, to infer the uncertainty and classify the reserves in terms of inferred, indicated and measured. Finally, the morphology and grades were converted into benefi ts and costs following a mineral exploitation scenario. With regard to the economic modeling, a pre-feasibility study is presented with sensitivity analysis, relative to the phosphate price, exploitation and transportation costs, and reduction on the phosphate price, if not concentrated. An estimate is also presented of the internal rate of return (IRR) of the project for a base scenario and one variant.
Phosphate; Farim- Saliquinhé; ore reserves evaluation; krigging; cut-off grade; cumulative and grade curves; pre-feasibility study
