Fines circuit performance evaluation

The Mafube processing plant encountered significant discrepancies between the actual yield of middling product compared to the yield predicted by the geological model. This triggered a review of the performance of the coarse-fines circuit given its significant contribution to the middlings product. This paper presents the results of performance measurements conducted on the coarse-fines circuit performance to understand existing performance and improvements required. The Mafube coarse-fines circuit beneficiates coarse-fines within the particle size range from -0.50mm to 0.150mm and consist of the low-cut density three product (LC3) spirals and the teetered bed separator (TBS). The LC3 spirals operate as the primary beneficiation circuit of the coarse-fines whereas the TBS serves as a secondary upgrade stage, to achieve a target overall coarse-fines calorific value (CV) upgrade of 5 MJ/kg. The LC3 spirals results indicated an efficient performance in the primary beneficiation circuit with a CV upgrade of 3.2 MJ/kg with an ash yield of 51%. The secondary beneficiation stage in TBS indicated a further coarse-fines upgrade CV of 1.55 MJ/kg, thus yielding an overall coarse-fines CV upgrade of 4.82 MJ/kg from the Mafube coarse-fines circuit. Notably, the TBS discard stream showed a CV quality of 21.90 MJ/kg which still meets the Mafube middlings product specifications, thus indicating additional potential to capture the Mafube coarse-fines circuit's discard stream as middlings product. A further feasibility study must be conducted to evaluate the potential gains of capturing the Mafube coarse-fines product for the RB2 export stream and the coarse-fines discard for the RB4 middlings stream.