Determining the PGM bearing mineral phase in the UG2 ore

UG2 is a low grade PGM ore, with value concentration in the range of 1–2 ppm. In this paper, we aim to determine whether the PGM values in the UG2 ore are associated with a soft or hard mineral phase. The anticipated benefits of determining which mineral phase the PGMs are associated with is that such knowledge may be very useful in the efficient processing of the ore. We developed and successfully applied a simple model in order to achieve our objective. The development of our model is from fundamental first principles, in which we mathematically manipulate the component mass fraction ratio of a hard component in the ore to develop an expression that we used to predict the mass fraction of the hard component in UG2 ore remaining in the largest size class material after a specified milling duration. Our results show that as the mass fraction of the tracer element retained in the largest size class increases with grinding time, so does the predicted mass fraction of the hard component. This similarity in grinding behaviour and the linear relationship that exists between the tracer element and the hard component theoretically supports that the PGMs in the UG2 ore are associated with the hard mineral phase.