Authors: Fuenzalida, MA; Orrego, C; Ghazvinian, E; Pierce, ME

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Fuenzalida, MA, Orrego, C, Ghazvinian, E & Pierce, ME 2022, 'Application of rock mass strength scale effect at Cadia East mine', in Y Potvin (ed.), Caving 2022: Proceedings of the Fifth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 951-962,

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The relevance of the scale effect when considering rock mass strength in different aspects of mine design in a caving mine is critical. A proper understanding of rock mass strength at different scales is required to appropriately forecast cave growth, subsidence, infrastructure and footprint stability. Evidence of rock mass strength scale effect is studied at Cadia East mine by performing a back-analysis of 1) the large-scale subsidence, and 2) stability performance of a crusher chamber. A methodology to account for the scale effect is proposed by fitting a power-law function to the results of the back-analysis. The fitted equation is then verified based on an improved rock mass knowledge derived from a recent systematic point load test campaign. The proposed approach serves as a framework to incorporate the scale effect in the rock mass strength in the design for future panels at Cadia East mine.

Keywords: scale effect, rock mass strength, subsidence, stability, crusher chamber

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