Abstract
The objective of installing ground support is to mitigate the potential risk of ground instabilities by conserving and mobilizing the inherent strength of a rock mass such that it can become self-supporting. Ground support design requires an understanding of many factors including, the characteristics of the rock mass, stress conditions, the excavation geometry, and the required degree of stability based on the intended use of an excavation. Design and support optimization procedures can be complex given the inherent variability of the ground conditions and engineering parameters.
This paper describes a hazard-based approach to support design for underground mines which takes the spatial variability of ground conditions into consideration. The geotechnical site characterization and domain delineation relied on geotechnical scanline mapping data, a three-dimensional geological model, and three-dimensional stress modelling. While rock mass quality and the geological model are static input parameters, the three-dimensional stress modelling provided insight regarding the evolution of induced stresses over the life of mine. Empirical and kinematics tools were used to develop support standards that suit different categories of ground conditions for the standard drift development (permanent and temporary). Ground support maps were then developed for the planned mine workings to communicate the required spatial extent of each support category. Domain-based ground support planning (based on lithology, spatial variances in ground conditions and numerically predicted stress conditions) provides valuable guidance for mine planning and operational efficiencies.