Towards a better understanding of squeezing potential in hard rock mines

Abstract

A significant number of underground hard rock mines have to struggle to maintain and keep operational excavations in squeezing ground conditions. This can often result in considerable investment in rock reinforcement and support and in time‐consuming and possibly hazardous scaling and rehabilitation. The LaRonde Mine in Canada has reported squeezing conditions in geological conditions ranging from weak to hard rock. This paper reports on the development of a ‘Hard Rock Squeezing Index’ based on case studies reported from several mining operations and calibrated based on in situ observations from the LaRonde Mine. The Hard Rock Squeezing Index is based on the foliation spacing of the rock mass and the stress to intact rock strength ratio. This index further incorporates the influence of excavation orientation with regard to structure in order to provide an indicator of squeezing potential.