Álvarez, C, Barra, C & Barindelli Pizzaro, G 2026, 'Calibration of caving behaviour in Macroblock S2S3 at 
Chuquicamata underground mine using 3D numerical modelling', 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. 1-14, https://doi.org/10.36487/ACG_repo/2645_94
(https://papers.acg.uwa.edu.au/p/2645_94_Alvarez/)
Abstract: The transition of the Chuquicamata mine in Chile to large-scale block caving has required a robust understanding of rock mass response and cave propagation mechanisms at depth. The mine was designed with multiple macroblocks, with operations starting in the central macroblock in 2019. Caving performance has been strongly influenced by orebody heterogeneity, leading to local challenges in the southern sector of the central macroblock. Caving in Macroblock S2S3 stalled, requiring mitigation measures that involved blasting the pillar between S2S3 and the adjacent central macroblock, which ultimately triggered cave propagation.
This study presents the calibration of caving behaviour for Macroblock S2S3 using 3D numerical modelling based on a hybrid approach combining FLAC3D and MassFlow (gravity flow) software. Key calibration parameters are related to post-peak rock mass behaviour. Geological and geotechnical inputs were kept unchanged, reflecting a robust site characterisation through a rock mass rating block model (GSI). A key outcome of the calibration is the reproduction of cave breakout, including its size and location, as identified by the monitoring system and captured by the numerical model. The calibration improved the reliability of numerical predictions and provided a sound basis for future analyses. Modelling results for predictive mining are presented as an application.

Keywords: block caving, Chuquicamata mine, preconditioning, gravity flow, FLAC3D