Developments in numerical modeling of blast induced rock fragmentation: updates from the HSBM project

Significant new developments in a 3D numerical model for blast-induced rock fragmentation have been made in the HSBM 2 project. The new code uses a unique combination of discrete and continuous numerical techniques to model detonation, dynamic wave propagation, rock fragmentation and muck pile formation. A continuum method is used to represent the near-borehole area and the detonation process. This is coupled to a DEM representation of the rock body, which models the wave propagation and initial fragmentation through to muck pile formation. The detonation process and axial borehole flow are modeled with a "programmed burn" approach in which the velocity of detonation, heat of reaction and product-phase behavior are supplied by an external code. The DEM representation uses a lattice-type method in which rock is represented as a collection of randomly located point masses connected by springs. The model reproduces the expected mechanisms occurring in the blasting process and is used to gain insight into the underlying physical processes. Models up to 27,000 cubic meters with several blastholes have been investigated. Several test blasts have been conducted in concrete as a validation of the model. The code compares well with physical experiments.