Open Stope Design at Normandy Golden Grove Operations

摘要

The empirical stope design techniques developed by Mathews et al(1981) and refined by Potvin (1988) and others, have gained rapid acceptance in Australia in the 1990s as a simple, 'first-pass' means of designing primary stopes. However, it is recognised that these 'stability graph' methods can only provide broad design guidelines. Recently published stability graphs (Hutchinson and Diederichs, 1996) encompass a wide range of geological environments, which are not discussed, and the influence of time and blasting practices cannot be easily reviewed. The 'scatter' in the graphs must reflect, to some degree, different operating practices as well as subtle but important differences in the pre-mining conditions that are not adequately accounted for in the 'modified stability number'. Development of a 'local', site-specific stability graph may overcome some of these problems. At Normandy's Golden Grove Operations, Western Australia, detailed reviews of stope stability performance, including Cavity Monitoring System (CMS) surveys, are undertaken for every stope, with the objeclive of developing a series of local stability graphs, customised to site conditions and calibrated in terms of 'Average Falloff Thickness' (AFT).