Mackenzie, S, de Kever, N, Smedley, E & Gregory, S 2016, 'Mine waste characterisation — complexities with assessing the physical properties of rock', in AB Fourie & M Tibbett (eds), Mine Closure 2016: Proceedings of the 11th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 677-690, https://doi.org/10.36487/ACG_rep/1608_50_Mackenzie (https://papers.acg.uwa.edu.au/p/1608_50_Mackenzie/) Abstract: The aim of mine waste characterisation is to assess the geochemical and physical properties of rock in order to identify deleterious or beneficial materials. Mine waste geochemistry is generally well understood and there are accepted procedures to assess the geochemical properties of rock. Predicting the physical properties of mine waste is more difficult and practitioners are achieving mixed results with varied methods. Routine soil science techniques are commonly applied to assess the physical properties of rock. Such techniques measure the resultant properties of rock, without considering the geological factors that control those properties. Such testwork results can be unreliable in predicting erosion potential of rock. Furthermore, practitioners may fail to develop a working appreciation of deposit scale geology prior to sample collection and testwork. In many cases such limitations result in incorrect predictions relating to the physical properties of rock. There are five geological factors that control the physical properties of rock: petrology/lithology, alteration, mineralogy, weathering and structural deformation. The interplay between these factors in determining the as-dumped erosion stability of rock on a mining landform can be complex. This paper considers the geological factors that control the physical properties of rock, the effectiveness of current assessment methods and opportunities to advance current practice. Field data is used to support observations where applicable. Keywords: Mine waste characterisation, waste rock, erosion potential, physical properties