Geomechcanical characteristics inferred from mine-scale rock mass behaviour

As with many other mining environments, the frequency of ground falls at Luossavaara-Kiirunavaara AB’s Kiirunavaara Mine has increased with the progression of mining depth. These instabilities, which are unevenly distributed throughout the rock mass, have failure modes primarily including spalling, strainbursting, structurally controlled failure, and combinations thereof. Although caused in part by the mine-wide stress redistribution and geomechanical features of the rock mass, the exact manner in which these factors control the spatial distribution and characteristics of the ground falls not well understood. The objective of this paper is to describe the development of a geomechanical basis for how and why the distribution and characteristics of the ground falls differ throughout the rock mass. Spatial and temporal characteristics of ground falls at the mine-scale were analysed using two main forms of data: 1) a database of ground fall events, and 2) laser imaging data. A methodology was developed specifically for the use of three-dimensional laser imaging data for mine-scale analysis of overbreak and falls of ground. In conjunction with geomechanical characterisation of the rock mass, these results can be used to assist with: identification of areas with higher risk of instabilities, production planning from an induced stress management perspective, location-based support system design in advance of drifting, evaluating the performance of drift development practice in different geomechanical conditions, and data collection and usage recommendations.ISBN för värdpublikation: 978-0-9924810-6-3