Rock Mechanics Approach for the Recovery of the Zone G Crown Pillar at the Raglan Katinniq Mine

2009

Richard Caumartin,

The Zone G crown pillar, located between the bottom of the open pit and the top of the underground workings, was recovered at the Raglan Katinniq Mine in Nunavut in the summer of 2008. This article describes the rock mechanics-based approach implemented to design the recovery of this valuable block of ore, whereby the ShapeMetriX3D photographic technique was first used to provide a comprehensive assessment of the various joint sets that comprised the pillar. The statistical distributions obtained for the dip, dip direction, spacing and persistence of these sets were then used in conjunction with the geometry of the large-scale faults present in the area to build and run a series of explicit rigid numerical models, each one with a slightly different jointing geometry, as randomly constructed from these statistical distributions. Incorporating in a properly formulated numerical model the variability of some of the input parameters has allowed the engineering team to assess in a rational and reliable manner the likelihood of success of the proposed mining method and sequence.

Keywords: Crown pillar, characterisation, Numerical modelling, Statistical variability