Por: PhD Kyu-Seok Woo. Senior Geotechnical Consultant for AMC Mining Consultants (Canada).

Introduction

The use of block caving to mine deep, massive, low-grade ore bodies is gaining increasing attention from the mining industry given its achievements in terms of safety, tonnage produced and costs which may be compared to those of open-pit operations. However, the undercutting and bulk extraction of ore through caving (Kendorski, 1978; Brown, 2003), leads to the development of significant surface subsidence above the developing cave (see Figure 1), potentially impacting the integrity of surface infrastructure and environment. To mitigate these impacts, it is important to predict the extent and scales of this subsidence with reasonable accuracy (e.g. Moss et al, 2006). While most of the research on mining-induced subsidence topic has been directed towards longwall coal mining and continuous subsidence, block cave mining produces discontinuous subsidence due to the high extraction intensity. This results in large differential movements controlled by geologic faults, rock mass heterogeneity, and irregular surface topography.