Measurement of the fragmentation efficiency of rock mass blasting and its mining applications

A new approach in evaluating the fragmentation efficiency of rock mass blasting is presented. It differs from most of the methods as it is predicated on a pre-existing in situ block size distribution in the rock mass as defined by the natural discontinuity network. Blasting therefore accomplishes the supplementary fragmentation of the already fragmented rock mass, the efficiency of which depends on the blasting parameters employed. The blasting efficiency is evaluated through comparison of the block size distributions of the rock mass and the corresponding muck pile. The estimate of the former is achieved by discontinuity network modelling in three dimensions with the aim of identifying the in situ blocks formed and measuring their volumes. For the muck pile, image analysis techniques applied to 'randomly-taken' photos are used to derive the resulting block size distribution. Validation of the proposed method on various mines is presented as well as its significant and practical mining applications.