The effect of grinding environment on the flotation behaviour of sulphide-poor platinum group element (PGE) ores was studied with 3 different ores containing Ni, Cu and PGE. The sulphur content of the investigated ore samples varied from 0.3% to 0.6%. Grinding tests were performed with a Magotteaux Mill (R) which is instrumented for measurement and monitoring of pulp properties. Flotation tests were done with a 5L Magotteaux float cell. Pulp potential, pH and dissolved oxygen (DO) levels were measured continuously during grinding. Pulp oxidation-reduction potential (ORP) and DO were adjusted by the addition of CO2, N-2 and nitric acid. Iron or 30% chrome containing balls were used in grinding. In this study, a number of grinding and flotation tests were done with natural ore samples into which 1 g of synthetic sperrylite was added. This study presents some aspects of the effect of a reducing grinding environment on the flotation response of low-S content PGE containing ores. Highly reducing grinding environment created with CO2 was found to have a positive effect on flotation behaviour of PGE minerals from low-S content ores. (C) 2012 Elsevier Ltd. All rights reserved.