ABSTRACT
The behaviour of the rockmass surrounding gold reef stopes at great depths is controlled by deformation on the fractures and the stability of the hangingwall is influenced by the fracture orientation. Rock type and its associated competency, sedimentary partings, faults, dykes, joints and extension gashes are the major primary and secondary geological features controlling fracture pattern, orientation and frequency. Boundary element techniques for the simulation of the fracture zone are being developed to identify potential hazards, assist in the selection of appropriate support and suggest safer mining methods. An evaluation of some results from the DIGS discrete fracture growth and random tessellation approaches versus selected Witwatersrand environments was undertaken. Predictions of fracture angles, distribution and persistence are similar to underground observations. The models are able to predict the influence of initial stresses and joint patterns on the mining induced fracturing. Further research is required to enable prediction of fracture intensities.
