Modern Mining June 2018

WEST AFRICA

The current processing facilities at the Baobab project were commissioned in 2016 and have a nameplate capacity of 500 kt/a. a cut-off grade of 10 % P 2 O 5 , with the inferred mineral resource estimated at 320 Mt at 16 % P 2 O 5 , also at a cut-off grade of 10 % P 2 O 5 .

bench scale flotation testing using actual mine water on various samples extracted from the Gadde Bissik open pit, plus set- tling and dewatering tests of tailings and final concentrate product by process tech- nology suppliers. Large samples of coarse and fine flotation feed material have also been prepared for upcoming pilot scale flotation runs for technology selection. Comminution testwork has been per- formed at FLSmidth’s Minerals Testing and Research Centre in Salt Lake City in Utah in the US to evaluate the hardness and abrasiveness characteristics of the larger rock sizes in Baobab’s ore from the Gadde Bissik mine and provide data for crushing and milling equipment selection and design. A number of appointments have been made to support the BFS. Ibrahima Gaye, a phosphate industry professional with over 35 years of experience in phosphate mining and beneficiation in Senegal, has joined the Baobab project team while Glenn Gruber, a phosphate beneficiation specialist with over 45 years’ experience in industrial minerals has joined the Wood team for the BFS as process expert. In addition, consultant Henry Lamb, a geologist with 40 years’ experience in the mining, geology and exploration of phosphate deposits and the operation and maintenance of phos- phate mineral projects in the US and internationally, is actively supporting the BFS work. Photos courtesy of Avenira

The expansion and upgrade project will include a flotation step and a mag- netic separation step to improve P 2 O 5 recovery from around 50 % currently to approximately 70 %, to reduce the silica assay and to control iron levels in the concentrate, as well as a drying process unit to control product moisture at the commercial target at all times, annual wet season included. The 2017 conceptual study estimated (to a ±30 % accuracy) that the project would involve an upfront capital expenditure of US$53,4 million. The magnetic separation step will ensure that Fe 2 O 3 content meets customer requirements. Magnetic separation test work has been carried out on both rare earth dry roll and on wet high-intensity technologies at Eriez Magnetics Central Test Laboratory in Erie, Pennsylvania in the US, with both types of processes achieving effective separation of ferrugi- nous particles from the rock concentrates at the laboratory scale. The flotation step will reduce the SiO 2 in the concentrate to the levels required by customers. Extensive laboratory scale flotation tests have been performed in Florida and have demonstrated at that scale that the target separation perfor- mance can be met by reverse flotation of silica (SiO 2 ) using amine-based reagents. Current testwork includes on-site

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