Morales, D, Henríquez, JP & Castro, R 2024, 'Impact of undercut geometry on caving propagation', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 635-650.
(https://papers.acg.uwa.edu.au/p/2435_D-15/)
Abstract: Undercutting corresponds to the stage that begins the caving of the orebody, which consists of the basal cut of the ore column and the blasted material removal until the necessary air gap is achieved. One of the key factors for the success of this process is the design of the undercut geometry. The successful implementation of the undercut process requires careful management of various factors that ensure adequate caving propagation and an adequate ore flow to the drawpoints. This document presents an evaluation and analysis in terms of gravity flow using FlowSim BC®, analyzing the impact of undercut height, fragmentation, spacing between drawpoints and distance between production and undercut levels on the tonnage required to achieve the necessary air gap to ensure the caving propagation. From the simulation results, it was possible to determine the geometry of the blasted pile material and the tonnage necessary to reach the target air gap, where it is observed that a greater tonnage is required to be extracted to achieve the target air gap at a larger primary fragmentation size, greater spacing between extraction points, shorter distance between production and undercut levels, and greater undercut height. Finally, a sensitivity analysis was carried out in terms of bucket number and percentage of swell tonnage extracted until the target air gap was achieved. As a result, it is observed that a layout with greater spacing and a greater distance between levels requires greater swell tonnage removal of the undercut mineral to reach the air gap.