LAUSR

Abstract Comminution indices are used to represent the grindability of a combination of minerals treated by specific processes. If two rock samples with similar values for an index are treated in the same comminution process, they are expected to have a similar behavior during grinding. However, indices are obtained assuming the breakage of homogeneous and continuous materials without considering minor scale mineral and geological textural characteristics. Eventual differences in the process could be related to those properties and may not be explained by comminution indices by itself. In the present study, two different copper ores samples with similar Bond Work index were used to evaluate the influence of mineralogy and geological texture at meso and micro scale in a ball grinding process at laboratory scale. Samples were characterized through geological texture analysis at micro-scale using petrographic microscopy, hyperspectral characterization, X-ray diffraction, and X-ray fluorescence. The effect of mineral properties on grinding was assessed through controlled grinding kinetics performed in a Magotteaux Mill®. Results show that the BWi allows to describe the transition between initial and final states at long grinding times, but it cannot reproduce the entire grinding kinetic, while textural properties, such as grain size and matrix-grain mineralogical composition, may be linked to P80 variation over time and the variation of cumulative particle size distributions at different grinding times. Results suggest that geological texture may be considered as a complement to traditional grindability indices to evaluate the grinding performance.