CSIRO researchers have been involved in the development of predictive metallurgical indices as a tool in the hydro- and geometallurgy fields. Rapid, small-scale, cost effective tests and protocols have been developed for comparative ranking of attributes relevant to leach performance, e.g. leach index (relative indication of leach performance), recovery, impurity deportment, reagent consumption and mineralogy of samples for their relative ranking. Results from these tests can be used for plant design or process optimisation to maximise the commercial value of an ore body and to minimise the social and environmental impact of mining operations. The motivation for development of these tests includes the reduction in use of traditional mineralogical tools, be they for reasons of accessibility, cost, speed or scale-up for processing of large sample numbers. Mineralogical analysis remains essential for validating leach results in the development of test protocols and as a means of quality control. This paper presents an accurate, robust statistical method for QEMSCAN data analysis that has been developed for use in conjunction with the geometallurgical leach tests. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.