ABSTRACT
The mine design and layout of a Shaft should be based on the geotechnical parameters of the specific mining block. This should include the impact of both regional and secondary geological structures exposed in the underground mining operations. Anomalous or unexpected conditions encountered could contribute to large-scale Falls of Grounds (FOG’s), unstable beam behaviour, unpredictable pillar behaviour or support failure. All of these incidents could significantly impact on the health and safety of mine workers as well as cause detrimental financial losses as a result of the instability risk and loss in production.
On many operations, mining layouts are inherited from best practices on a mine or to accommodate a specific mining method. The consequence of mining in unfavorable conditions is often only realized once significant instabilities are experienced. A case study is presented in this paper based on instabilities experienced on Lonmin. The contributing geological structures, associated behaviour and resulting failure mechanisms are discussed. The intent is to share the design strategies and the early identification of areas with a potential for a fall of ground risk ahead of mining to prevent occurrences.
