Process Development for the Marampa Iron Ore Tailings Project, Sierra Leone
London Mining Plc. is developing a unique iron ore project in Sierra Leone. The Marampa mine is a brownfield development effort, having been operated by others since the 1930’s until low iron ore prices forced closure. Peak production of the prior operations was approximately 2.5 mtpa in the 1960’s. Following civil war In Sierra Leone, London Mining obtained the mining license in 2006 and commenced activity to redevelop the Marampa mining and processing operations. There are two primary ore deposits of interest for development as well as a resource comprised of tailings from previous operations. The Marampa tailings operation is being implemented first with a 1.5 mtpa plant producing ~66% Fe sinter feed, expandable to 3 mtpa. The first phase is currently under construction. Further expansion to include development of the primary deposits is currently under prefeasibility study and targets 5-8 mtpa concentrate production.
Outotec partnered with London Mining on testing efforts to develop the magnetic separation flowsheet using SLon VPHGMS machines to process the Marampa hematite material. This paper explains the flowsheet development process commencing with sample characterization and preliminary testwork to evaluate SLon performance. Later work including detailed parametric investigations, lock-cycle tests and bulk sample processing efforts to confirm the process flowsheet are explored. The final flowsheet case is presented along with expected circuit recoveries and concentrates quality, clearly demonstrating the performance of the SLon VPHGMS circuit in iron ore tailings treatment.