Joel Gray Senior Mining Engineer – Operations, Cannington Mine, South32 Several paste backfill bulkhead failures over the space of 12 months demanded that paste inrush risk at Cannington be re-evaluated. The resulting risk assessment led to the introduction of a set of new operating rules for high risk filling conditions to ensure safer use of the popular backfill method at the mine. This paper will talk operators through the high potential incidents which occurred, the primary causes and the risk assessment which followed. Implementable actions utilised at Cannington are shared, while challenging other operations to consider their own current level of risk with regards to the use of paste backfill.

Chris Hall Superintendent Geotechnical, Cannington Mine, South32 Cannington mine is a silver lead zinc operation located in north west Queensland. The operation has been in production since 1997. Ore is primarily moved through an underground material handling system comprising of a crusher, conveyor and hoist. The underground crusher and conveyor system were sited in lower grade ore when the mine was first commissioned and a mine design exclusion zone was established around them. As the mine matured, stopping fronts advanced towards the crusher, resulting in an increase in damage of rock mass and ground support within infrastructure areas in the lower parts of the mine. In response to preliminary observations of crusher chamber deformation, additional ground support was designed and installed. As the rate of damage began to exceed the rate of rehabilitation, monitoring of rock mass became the predominant control to ensure that exposure to personnel working in the crusher chamber was appropriately safe. The intensity of the monitoring regime continued to increase as the rockmass deformed to the point that new laser scanning technology was implemented to provide short interval monitoring. Ultimately, the monitoring system enabled a safe and controlled closure of the chamber.

Stephen Williams Engineering Manager, Connec High Voltage Coupler Systems High voltage (HV) electricity is one of the primary sources of energy within underground coal mines, the effective control of which is fundamental to maintaining a safe working environment. Furthermore, the equipment typically used in HV transmission and distribution is heavy, requiring manual handling to facilitate installation in what can be deemed a confined and harsh working environment. HV cable coupler and connection systems are an integral and necessary part of mining electrical systems. Underground mining especially has a frequent need to connect and disconnect cables as a result of both the mining process and cable/connector inspection, maintenance and testing regimes. However, current coupler designs which have been in use for several decades consist primarily of a heavy metallic body that inherently limits methods for “testing for dead” prior to touching the coupler. This presentation describes at a relatively high level the various associated safety benefits that have been incorporated into developing these polymer coupler systems, including the ability to reliably “test for dead” prior to disconnecting a coupler and the substantial weight reductions that allow for improved manual-handling. Having been supported by ACARP from the outset, Connec has developed the world’s first polymer-based Restrained (≤3.3 kV) and Bolted (≤11 kV) HV coupler systems that are both ANZEx and IECEx certified for use in underground coal mining environments.