Staged calibration of a cave-scale numerical model for the New Afton C-Zone block cave

Authors: Cancino, C; Fuenzalida, M; Yanagimura, Y Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2645_92

Cite As:
Cancino, C, Fuenzalida, M & Yanagimura, Y 2026, 'Staged calibration of a cave-scale numerical model for the New Afton C-Zone block cave', in A van As, D Cumming-Potvin & J Wesseloo (eds), Caving 2026: Proceedings of the Sixth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-11, https://doi.org/10.36487/ACG_repo/2645_92



Abstract:
Numerical models are widely applied in block caving operations to support design and operational decisionmaking. However, their reliability depends on robust calibration to observed cave behaviour and rock mass response. Calibration remains challenging due to the complex interaction between cave propagation, stress redistribution, rock mass strength, progressive damage and structural controls. This paper presents a staged calibration methodology applied to a cave-scale numerical model of the C-Zone block cave at the New Afton mine, located at approximately 1,150 m depth. The model was developed in FLAC3D and coupled with MassFlow to assess breakthrough timing into the overlying B3 lift and to simulate upward cave propagation. Initial model assumptions based on previous studies resulted in overprediction of cave propagation and time-domain reflectometry (TDR) cable breakage, highlighting the need for site-specific calibration. Calibration was undertaken in 2 stages using monitoring datasets including TDR and Geo4Sight measurements. The first stage incorporated a detailed fault catalogue, improving the representation of structural controls on cave propagation and resulting in better agreement with interpreted cave geometry and extent of fractured zone. The second stage refined the mechanical response of the caved material by increasing the minimum Young’s modulus of broken rock within IMASS, reducing excessive deformation and improving agreement with observed propagation rates and TDR breakage. Results indicate that structural controls and the stiffness of the caved material are both key controls on model response in the C-Zone cave. The staged approach provides a transparent and practical framework for calibration, supporting the use of numerical models as effective tools for operational decision-making in block caving.

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