Álvarez, C, Ramirez, A & Galvez, F 2026, 'Numerical sensitivity models for Lift 2 design for Chuquicamata mine', 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. 1-12, https://doi.org/10.36487/ACG_repo/2645_95
(https://papers.acg.uwa.edu.au/p/2645_95_Alvarez/)
Abstract: The Chuquicamata underground mine started production in May 2019 with the undercutting of the central macroblock (MB) of Lift 1, located approximately 200 m below the open pit bottom. At present, several macroblocks are in production and have experienced different operational challenges related to drift stability and cave stagnation. Orebody heterogeneity remains an ongoing challenge and is being addressed through continuous drilling and laboratory testing programs. Chuquicamata mine has been proactive in integrating field observations with three-dimensional (3D) numerical modelling to anticipate and manage geotechnical risks.
The numerical modelling framework for Lift 1 is based on a hybrid methodology combining FLAC3D and gravity flow, which has been calibrated against observed events and is actively used to assess the predictive performance of macroblocks within Lift 1. Early designs for Lift 2, located approximately 400 m below Lift 1, are currently being evaluated using limited field data, including uncertainties in stress conditions at depth. Anticipating cave performance and drift stability is a key first step in assessing the business case for alternative production level layouts.
This study describes the application of the hybrid modelling methodology to assess the expected performance of a single macroblock in Lift 2. Sensitivity analyses are carried out considering a plausible range of in situ stress conditions and rock mass strength variations. The results provide a practical tool for evaluating cave performance, anticipating geotechnical risks, and supporting the business case for Lift 2.

Keywords: block caving, Lift 2, Chuquicamata mine, gravity flow, FLAC3D