Technical Summary of
Port Loko Bauxite
Bauxite in the Port Loko area occurs as a series of elongate lenses/pods in various low lying plateaus / blocks at an elevation of 60 to 80m.
The bauxite is gibbsitic in nature and amenable to dry and wet beneficiation processes. Similar types of bauxite formed on Kasila series of rocks are being mined and beneficiated at Gondama&Mokanji area of SMHL.
Bauxite areas are generally buried beneath anoverburden of between 1 and 5 m of soft soil mixed with lateritic gravel. The thickness of thebauxite layer varies from 3 to 11 m and on average is around 5 m. The three main bauxite areas within the Port Loko concession are, from north tosouth, Mange-Gbonkomakent, Yenkisa-Tekeya-Lungi, and Mamaliki. The subject of mostexploration is the Yenkisa-Tekeya-Lungi area.
Dry beneficiation of Bauxite to produce exportable grade DSO production years 1 through to 3. The quality of crushed, dried and screened bauxite will be 45% Al2O3 and 4% SiO2 with less than 0.5% alumina as Boehmite. Deposits and blocks of Port Loko bauxite are identified for mining of bauxite, suitable for dry beneficiation. The equipment and process flow-sheet for dry beneficiation is finalized for the production of 3 million tonnesof DSO per annum for export. The dry beneficiated bauxite will haveless than 3% reactive silica and more than 40% Available Alumina.
In the second phase, the ROM will be crushed, washed followed by attrition scrubbing and classification by vibrating screens / hydro-cyclones to remove Kaolinite and Goethite rich fines from bauxite. Initial tests were conducted in AKW, Germany and further pilot scale trials are planned to achieve the targeted quality of ore. The objective of washing of bauxite is to produce ore with about 48% Al2O3 and below 3% silica. as produced in SMHL/VIMETCO. The raw ore washing will commence in Year 3 of mining i.e. initial higher gradematerial will not require washing. Theenvisaged Washed Bauxite production is about 0.5 Mtpa (year 3), and 3 Mtpa year 4 onwards.