CALGARY, ALBERTA -- (Marketwired) -- 07/10/13 -- Mkango Resources Ltd. (TSX VENTURE: MKA) (the "Corporation" or "Mkango") is pleased to announce a base case metallurgical flow sheet for the Songwe Hill rare earth project. Proof of concept test work on a bench scale has demonstrated that the flow sheet has potential to produce a high grade mixed rare earth carbonate or hydroxide product.
-- Proof of concept test work produced a high grade mixed rare earth carbonate product (59% TREO(1), 7% HREO(2)/TREO) and a cerium depleted, heavy rare earth enriched mixed rare earth hydroxide product (55% TREO, 18% HREO/TREO) on a bench scale.-- The proposed base case flow sheet uses conventional technology comprising flotation, followed by leaching of the mineral concentrate with hydrochloric acid, then precipitation and purification.-- Songwe's favourable mineralogy, comprising synchysite and apatite that is anomalously enriched in heavy rare earths, allows for a simple, low temperature acid leaching process to achieve good recoveries. There is an added benefit of the higher value critical and heavy rare earths leaching more effectively than light rare earths such as lanthanum and cerium.-- In contrast to other rare earth deposits containing monazite or xenotime, high capital and energy intensive kilns are not required in the proposed Songwe Hill processing flow sheet. Mkango anticipates that the plant design will be modular, using plastics or composite materials for tanks and pipework. With a design largely comprised of conventional technology, using tanks, pumps and filters, there is the potential for lower capital expenditure and ease of future expansion.-- Mkango is now proceeding with further optimisation and demonstration of the flow sheet, in advance of commencing plant engineering studies. Alternative hydrometallurgical flow sheets are being evaluated in parallel to confirm that the current flow sheet represents the optimal base case and to evaluate different product options.
William Dawes, Chief Executive of Mkango, stated "This is a major milestone in the development of the Songwe Hill rare earth project and the company is now well positioned to further progress discussions with potential strategic investors, separation facilities and off-take partners. Mkango has delineated a significant Indicated and Inferred rare earth resource at Songwe and is spearheading development of a major, world class rare earth mineral province in Malawi."
(1) TREO - total rare earth oxides including yttrium oxide; (2) HREO - heavy rare earth oxides including yttrium oxide
A comprehensive three year program of mineralogical studies formed the basis for the program of scoping metallurgical testwork. Mineralogical work included an investigation by High Definition Mineralogy incorporating QEMSCAN completed by SGS Minerals Services, scanning electron microscope (SEM), electron microprobe and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analyses completed at the Natural History Museum, Aberystwyth University, Camborne School of Mines and the British Geological Survey. Further mineralogical work (SEM) on mineral concentrate was completed at Mintek and the Camborne School of Mines.