ROCK PROPERTIES AND ROCK RESPONSE TO MINING (Under moderate to high stress conditions)

2002

Ted Anderson, Ken Judge, Blain Conlon, Russell Boyle,

Mining at depth under moderate to high stress conditions presents numerous challenges to operators and engineers, either in terms of ground control, environment and ventilation of openings, to guarantee the safety of underground workers and the continuity of the mining cycle. High stress conditions mean higher pressure at the work face and on mine structures such as pillars and abutments, an increase risk of violent failure, larger failure zones around excavations, higher loads on ground support, etc. This article will present an overview of work done by part of CANMET's Ground Control Program personnel over the last seven years, in conjunction with mine operators and other reseach partners, to document and monitor stress levels in mine structures, and to correlate properties determined in the laboratory and predictions made at the design stage with observations made at the wall of excavations or throughout boreholes within rock structures. Most of the cases presented show that observations made in the field correlate well with properties determined or extrapolated from the laboratory, or with predictions made at the design stage. These observations should then be considered as sound indicators of stress levels around excavations or inside rock structures, and used to monitor their degree of stability and to help keeping operations safe and productive.

Keywords: Rock mechanics, Stress level, Field and laboratory testing, Violent failure, Mine pillars, Failure zone, Field investigation, Borehole survey, Field monitoring, mine openings