Geotechnical analyses for risk management of a large scale failure at Century mine, Northwest Queensland

Abstract

The occurrence of large scale instability in open cut mines can have a detrimental impact to both safety and business of a mining company. As such it is crucial that the instability is effectively understood, communicated and managed to reduce both the likelihood and consequences of the failure and to keep the mine operational. During the period of January 2013 to December 2014, MMG’s Century mine successfully operated under a large-scale progressive wall failure and recovered more than 1.8 millions of tonnes of ore; with no incidents or near misses related to the numerous failures that propagated in this area during this time. This paper briefly describes the investigations undertaken to understand the failure mechanisms, as well as the expected size and extents of the failures. It further describes how the geotechnical team used this information, in conjunction with various forms of monitoring, to effectively reduce both safety and business exposure to the risks of wall failures.