Prediction of Violent Rock Failure in Deep Underground by Rock Strain Energy

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Mineral resources constitute approximately 20% of the nation's exports. However, most of Canada's known mineral assets will be nearly exhausted within the next decade. To sustain the contribution of Canada's mineral resources to the national economic performance, the nation urgently needs additional high-quality resources to be developed; mining activities should take place beyond a 3,000-meter depth. Rock bursting, which is a violent and uncontrolled failure of rocks underground, is a major threat to this goal. Rock burst hazards are a significant mine safety issue and are a severe constraint on the economic viability of current and future Canadian mines.Therefore, it will have a direct and negative impact on the future of Canada's economy. This project will increase our knowledge of rock behaviors in deep underground environments. It will provide a more accurate and realistic prediction of bursting behaviors of rocks in the high-stress condition in the deep ground so that a more practical and cost-effective design of underground mining operation can be achieved. The proposed research involves examining the behavior of brittle rocks to investigate their failure behaviors under different stress conditions. By undertaking an extensive and advanced experimental study a database on behavior of different rocks will be generated. This unique and broad database will then be used to develop a strain burst proneness model. Based on the extensive experimental study, a damage model will be developed and implemented into a numerical model. The specific aims of the proposed program are to: a.Develop an experimental methodology to measure the failure behavior of brittle rocks subjected to monotonic and cyclic loading to replicate rock failure in deep ground mining. b.Develop a strain burst proneness model based on stored strain energy in rock to be used as a simple strain burst vulnerability assessment tool. This model will be validated by strain burst tests using a true-triaxial testing compression system. c.Develop a damage model based on pre-peak and post-peak responses and the failure behavior of rocks under high in-situ stress, taking into account anisotropy and scale effect. It will be implemented into a numerical model to simulate strain burst in deep ground. This project will provide new, fundamental knowledge concerning the damage process of hard rocks and how the rock nature and stress regimes influence the overall mechanical behavior of rocks leading to strain burst. This project will lead to fewer injuries and fatalities in underground mines. Furthermore, the project will allow the development of the new guidelines for governments, allowing better management policies to be developed so that future deep mining activities will be much safer. The 12 HQP (3 PhD, 4 MSc, and 5 Undergrad. Students) trained will address the substantial demand for experts in these topics to be recruited as geoengineering and mining professionals.