The Farim phosphate deposit is a flat-lying sedimentary phosphatic bed, which underlies an area greater than 60 km2. The geological sequence at Farim displays the following lithological units from top to bottom:
• sandy-argillaceous overburden with soft, alternating sandy, clayey and sandy-clayey layers
• phosphatic interval (FPO)
• upper dolomitic limestone
• decarbonized phosphate unit (FPA) corresponding to the Saliquinhé phosphate deposit
• calcareous phosphate member (FPB)
• limestone at the footwall of the phosphate sequence, white, soft and porous.
Two main types of phosphate, differentiated by their petrography and chemical composition, have been identified on the Farim property:
• FPA layer – A de-carbonated phosphate matrix with very high P2O5 content of about 30% P2O5, formed exclusively in the shallow water of the Saliquinhé basin
• Lower grade FPB layer – Highly carbonated phosphate, generally containing 5 to 15% P2O5 (mean 13% P2O5) with some values up to 20%.
Deposit Geology and Mineralization
The three phosphate-bearing horizons referred to as FPO, FPB and FPA are located below a variable thickness of overburden.
Overburden
The overburden waste at Farim typically consists of a layer of reddish-brown laterite gravel, followed by cream-colored clay with occasional cobbles and boulders of cemented orange sand and brown clay. This is followed by a layer of stiff brown to ora ........
