ABSTRACT
A rock mass is a three-dimensional discontinuous medium that can be thought of as an assembly of potential blocks that can be disaggregated by the excavation process. The size distribution, shape, and degree of interlock of the blocks are functions of the distribution and nature of usually at least three main discontinuity sets. Rock masses are rarely uniform or isotropic; even within the confines of a design area, there are likely to be major geological structures, significant changes of lithology, and a prevailing anisotropy. The nature and degree of this anisotropy and the heterogeneity of the rock mass properties are likely to exert considerable influence on the extent of damage to, and dilution from, the final stope walls.
