London-listed Berkeley Mineral Resources (BMR) has scrapped the definitive feasibility study- (DFS-) recommended multispiral gravity separation in favour of leach processing for its Kabwe project’s pilot plant, in Zambia.
The shift in methodology for the recovery of zinc and lead from the washplant tailings (WPT) and leach plant residue (LPR) tailings emerged after a peer review of the DFS and relevant metallurgical and mineralogical testwork over the past few months showed flaws in using the gravity separation.
The company now expected to finalise the design parameters for the pilot plant in the next few weeks, with its establishment expected later this year, BMR chairperson Alex Borrelli said in a statement on Thursday.
The DFS had been commissioned in August 2013 after the DFS results, which Borrelli said did not provide an “acceptable basis” for the choice in technology, were “accepted without sufficient challenge” by the former board.
The study’s “impractical and more costly” processing recommendation failed to replicate the stated potential recoveries or grades of the zinc and lead in the final product, while the metal recoveries were materially inferior to those reported in the DFS.
The company tasked South Africa-based spiral process specialists to test a 5 t WPT sample using a full multispiral gravity separation plant.
“Although the pilot plant is yet to be costed and ordered, the board is confident that BMR has sufficient resources to initiate pilot processing without recourse to BMR’s shareholders,” said Borrelli.