An effective numerical method to understand different aspects of cave preconditioning

Abstract

Full-scale forward geomechanical modelling of the caving process, remains problematic, challenging the key principles of numerical analysis applied to rock engineering problems: i) a model is not and cannot be a perfect imitation of reality; and ii) numerical modelling is driven by questions. This paper presents a simpler numerical solution that follows fundamental modelling principles, whereby simple models are used to analyse different aspects of a given problem and to determine which process need to be considered explicitly and which can be represented in an average way. Synthetic cave models (SCM) are introduced as a suitable modelling approach for optimising hydrofracturing design and draw strategy by investigating a range of possible scenarios. The SCMs can be considered a scaled down version of a large, although simplified, mine scale problem. In the current paper, we have used SCM at different scale in terms of the adopted width of the simulated undercut. All modelling scenarios consider the development of a relatively deep cave located at a depth of 1,400 m. Due to their simple and conceptual nature, these models allow us to analyse different aspects of cave mechanics, including cave initiation, cave propagation, effectiveness of preconditioning, draw sequence and caving rates.