Abutment loading in deep cave mines: towards understanding susceptibility to strainbursts

Abstract

Deep cave mining is an inevitable requirement to meet the growing global demand for valuable minerals such as copper and gold. The experiences from historical and current deep mining suggest that the rock masses encountered at depth are more likely to be stronger, more brittle, and less jointed. While this may be a favourable condition for some mining and civil projects, under the high abutment loading associated with cave mining, the rock surrounding the mine drifts is susceptible to strainbursting, a sudden and high-energy failure mode. Loading conditions in cave mines can evolve rapidly over the course of mining, which can cause shifts in the susceptibility and triggers for strainbursting. Historical perspective on the strainbursting hazard in deep mining is presented in this paper, as well as a recent case study of the DMLZ mine where data-driven assessments have been applied to better understand the strainbursting hazard under the abutment loading condition. The strainbursting phenomenon can be difficult to manage in a complex cave mining environment. Therefore, tools and strategies for analysis of the occurrence of strainbursting that can be used to better constrain and manage the problem are discussed.