Safe Rapid Drifting – Water Jet Scaling
CIM Edmonton 2004
David Muldowney, Andre van Wageningen,
Safe rapid drift development results principally in reducing exposure of underground workers to the working face. This reduction in exposure is not achieved until either the rock walls have been suitably scaled or sufficient support has been put in place. Rapid drifting enables quicker access to orebodies (increasing returns), higher production rates and a resultant lower cost of mining. The Mining Innovation, Rehabilitation And Applied Research Corporation (MIRARCO) has been developing technology and a methodology for safe rapid drift development within the underground metalliferous mining industry.
In terms of rock scaling for underground metalliferous mining, there is still considerable use of manual and mechanical impact rock scaling techniques. Two main issues result from this approach. The first is that in highly stressed or highly fractured ground, a decision has to be made as to when sufficient scaling has taken place. This is not always easy to do and hence operator judgment is a crucial element in this approach. During a baseline study of current rock scaling practices, a wide range of scaling practices were observed within five different underground mining operations; this tends to support the difficulty in the rock scaling quality decision making process. The second issue is related to the exposure of workers to freshly created rock surfaces. In manual scaling techniques this is unavoidable and despite the best scaling practices, accidents still occur. In an attempt to provide an alternative scaling technology, MIRARCO has been investigating high pressure water jet scaling for removing loose rock as part of the drift advance process. This technology not only provides a means by which scaling practices can be engineered (remove the loose material you want to in a given rock mass condition) but is quicker and easily automated. Automating the scaling process removes workers from exposure to freshly created rock surfaces and also enhances the application of spray-on liners through improved adhesion of these support types with the rock surface.
This paper describes the water jet scaling technology research and methodology for safe rapid drifting within the underground metalliferous mining industry and highlights the key issues and major drivers behind their continued development at MIRARCO.
drift, Development, jet, scaling, Water