Impala Platinum Limited operates a modified MF2 circuit treating UG2 ore in separate high and low grade streams. In 2003, plant management initiated an optimisation program and SUPASIM was chosen as one of the components to aid Impala in identifying areas of opportunity and improve flotation performance. Standard bench scale rougher and cleaner flotation rate tests were performed on a sample of primary mill feed to characterize the ore and predict the maximum possible plant recovery and grade at optimum performance. In 2002, prior to the optimisation program Impala conducted an 8000 ton trial conducted through a nearby plant (Crocodile River Mine) and in the latter half of 2003 an extensive pilot plant campaign was performed by Mintek at site on high grade circuit feed. SUPASIM was used to analyse these results and benchmark them against the performance of the main UG2 circuit. The model was used to identify which sections offer maximum recovery improvement potential, simulate the main plant, the CRM test and the pilot plant circuits, identify key metallurgical parameters of influence and determine an optimum flow sheet for the main plant. Due to the voluminous amount of data, analysis and simulations generated [Hay, M.P., 2003a. Analysis and benchmarking of Impala UG2 ore. Report IMP 30/2003. Submitted to Impala Platinum, November 2003; Hay, M P., 2004a. Analysis of Mintek's pilot plant campaign treating primary high grade feed at Impala's UG2 plant and determination of the circuit best suited to the ore. Report IMP 6/2004. Submitted to Impala Platinum, February; Hay, M.P., 2004b. Report IMP 20/2004. Benchmarking of primary high grade feed flotation performance 2004 ore vs. 2003 ore. Submitted to Impala Platinum, August] the paper provides only a summary of the reports submitted to Impala Platinum and describes SUPASIM's contribution to Impala's decision process. The first phase of Impala's optimisation program has resulted in an improvement of 3.7% in PGM recovery. Currently the second phase of the program is underway. (C) 2005 Elsevier Ltd. All rights reserved.