Characterization of the effect of micro-properties of rock on the correlation between Point Load strength index and comminution index tests

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Mining is an energy intensive industry. The majority of the energy consumed in mining industry is used for rock breakage in order to liberate valuable minerals from the gangue. In order to improve the energy efficiency in a mining operation, it is of vital importance to understand the heterogeneity and spatial variability of comminution characteristics of an orebody that is feeding the mill. A lack of resolution in the orebody's comminution characteristics (i.e. grindability index) can lead to inappropriate mill design, resulting in increased energy consumption. This research project aims to investigate the quantification of the spatial variability of orebody geometallurgical characteristics through correlations between Point Load rock strength index and comminution index properties. The Point Load test (PLT) is a simple, portable and easy to repeat testing method for characterizing the rock strength property of ore samples throughout a mine. The PLT index has been shown to correlate to ore breakage characteristics, which are required for design and modeling of mills. More specifically, the current study aims to determine the influence of rock micro-properties (i.e. grain size, shape, foliation, etc.) on the correlation between the PLT strength index and the comminution characteristics of ore in milling process. The study will utilize geological, geotechnical and comminution data from nine gold mines operated by Kinross Gold. This diverse set of geological and geomechanical information will be subjected to a statistical analysis to study the potential relationships between fundamental rock fabric variables (e.g. isotropy, fractures) and rock breakage characteristics for the different mine rock types and properties. A numerical modelling approach using the discrete element bonded particle model (BPM) will be utilized to simulate comminution and PLT tests of intact rocks.