Modelling of incremental rock breakage by impact – For use in DEM models

DEM simulations of AG and SAG mills indicate that breakage in a single impact is almost certainly a rare event. However, there are many events which might cause some damage. Hence it becomes important to be able to model how damage might accumulate and with what severity a particle is likely to break after accumulating sufficient damage. estigation of incremental impact breakage of a well characterized ore sample has been carried out by Whyte (2005) [Whyte, R., 2005. Measuring incremental damage in rock breakage by impact. BE (honours) Thesis, The University of Queensland (unpublished)]. The outcomes of this work are encouraging. A modified version of a JKMRC developed equation – which relates severity of breakage to specific energy input – also provides a good description of the degree of incremental breakage for each size range of particles which was tested when breakage does occur. her factor of interest for a DEM model is the probability of survival after a number of impact events. The work of Vogel and Peukert (2004) [Vogel, L., Peukert, W., 2004. Determination of material properties relevant to grinding by practicable labscale milling tests, International Journal of Minerals Processing, 74S, S329–S338] provides a useful model for multiple impacts with identical energies. This model has been modified and extended to different input energy levels. odel proposes a minimum specific impact energy E0 below which no damage is accumulated by the body of the particle. s the most important insight from this work is a way to quantify energy inefficiency of breakage in comminution devices. Each successive impact after the first one fails to utilize E0 because the particle must be loaded again to E0 before any further damage can be achieved. e ore tested, achieving a similar degree of severity of incremental breakage using multiple impacts typically required substantially more total energy than was required for a single impact. However, even very small interactions will still cause some surface damage and generate fine progeny.