A numerical model describing blast fragmentation and damage in three dimensions has been developed at the Julius Kruuschnitt Mineral Research Centre (JKMRC) and applied to numerous blasting operations in mines throughout Australia. The model combines the rock structure (summarised by block size distribution) with blast strain energy and uses comminution theory to calculate the resultant block size distribution. The model distinguishes between rock breakage and failure, the former being defined as size reduction and the latter as block dissassembly. The background and basis of the model are discussed in detail and three case studies presented describing the application of the model to explosive performance evaluation, explosive selection and drill selection in Australian mining operations.