Bewick, R & Moss, A 2024, 'The new normal of deep caving', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 1093-1102.
(https://papers.acg.uwa.edu.au/p/2435_H-03/)
Abstract: Caving is a fragile mining method resulting from several factors, including investment magnitudes and limited optionality when production problems are encountered. The deeper high-production caves amplify this fragility due to the significant stresses and stress changes in and around the cave and the large active mining volumes that must be managed. Further challenges arise from the more massive, veined rock masses observed with increasing depth due to the decay in the frequency of open joints. Thus, there is a change in response from joint-controlled mechanisms that dominate the performance of shallower caves to brittle response with the massive, veined rock masses that become more prevalent with depth. These changes require a shift in emphasis during both design and operations. Better techniques are required to describe the make-up of deeper rock masses, while caution is required in applying the empirical approaches that have served the industry well in shallower operations during the design process. Similarly, substantial rigour is required to manage stress, seismicity and ground conditions in the production and development areas at the operational level. 

The authors explore these changes (deep ground response, ground management, and deep rock mass characterisation) and discuss the processes required for more robust design and reliable operations. The concepts of fragility, production reliability, excavations as major assets, and operational governance are introduced.