Stoping sequence optimisation at Eleonore Mine based on stress analysis through horizon scale numerical modelling

Abstract

The orebody at Eleonore Mine (Eleonore) consists of multiple lenses of narrow thickness. Owing to ground stability issues, the capacity of the support was increased and the mine sequence was changed successfully in 2016. In 2018, mine-scale geomechanical numerical analyses were conducted in the continuum code FLAC3D to better understand the conditions leading to these improvements and further optimise the sequence. Locations of falls of ground and damage, blast hole performance and a micro-seismic database were used to calibrate the model, and different future mining sequences were analysed. The models helped demonstrate that persistent shallow dipping joints subject to high horizontal stress put a lot of demand on bolts in the back of excavation; they are likely to be the main source of energy release as they are sheared peripheral to the top and bottom of the stopes. The narrow-mined width and good rock strength involve limited stope interaction, resulting in highly stressed remnant stopes and limited impact of the sequence.