Orebody cavability prediction challenges in block caving mining — a review

A traditional block caving mine considers the development of an undercut level that allows blocky or veined rock masses to fracture, fail, and unravel when the undercut area is large enough. Once caving initiates, the rock mass progressively fails when induced stresses overcome the rock mass strength and when fractured rock masses unravel under gravity into the undercut and draw points. If the ability of a rock mass to cave is not enough, the cave will not propagate efficiently, thereby affecting fragmentation and ore recovery with the potential to upset safety and productivity if there are hang-ups in draw points. Therefore, cavability is critical for the success of a caving operation. Despite improving technological trends, most of the empirical approaches used for designing block caving mines were proposed 40 years ago, and their updates do not include most of the new understanding of mining geomechanics acquired since then. More importantly, the role of geology is often overlooked. This paper critically reviews the state of the art in orebody cavability prediction and explores whether traditional and statistical techniques can be applied for predicting cavability better. The review highlights the importance of geology that is often overlooked in orebody cavability prediction.