Ground control strategies for burst prone mines

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As Canadian mines continue to reach deeper deposits, more emphasis is being placed on ground control measures to deal with rock instability issues due to high in-situ stress leading to various forms of catastrophic rock failures such as strain burst, pillar burst, and fault-slip burst. The long-term objective of this research program is to contribute to the development of practical tools that would help mining operations take appropriate ground control measures to mitigate and control rockbursts. In the short term, this research program encompasses five research projects as follows. The first project (MSC 1) examines large-scale panel destress blasting, which is used when an ore pillar is highly stressed. The project aims to optimize the main design parameters namely 1) stand-off distance between the orebody contact and the panel, 2) blasted panel width and 3) panel extension beyond the ore pillar limits. Methodology is based on numerical modelling and analysis of field data. Project 2 (PhD 1, UG 1 to 3) seeks to investigate a range of Canadian mine hard rocks for their intrinsic properties. The goal is to better understand the influence of intrinsic rock properties such as grain size and mineral composition on the bursting behaviour of the rock. The work involves the use of scanning electron microscope, powder X-ray diffraction, particle flow code simulation (PFC) and laboratory testing. Project 3 (PhD 2, UG 4 and 5) will investigate borehole deformation and breakout in high stress environment. The goal is to develop a methodology to estimate mining-induced stress to help make informed decisions on ground control strategies. The project will test and develop two different approaches - one that is based on deformation measurement, and another based on forced breakout. The methodology involves CAD design and fabrication, numerical modelling, laboratory and field testing. The notion of notching boreholes under load to reduce the surrounding stress is explored in laboratory in Project 4 (MSC 2) and in the field in Project 5 (MSC 3). The aim is to find out if borehole notching could become a practical means for local energy dissipation through self fracturing of the boreholes. The work encompasses laboratory and field testing and numerical modelling. As a global mineral producer, Canada needs HQP with knowledge and skills in rock engineering, underground mining and rockburst control methods. This research program offers a unique opportunity for the training of 10 HQP namely 2 PhD, 3 MSC and 5 undergraduate (UG) students. The proposed work on borehole deformation and breakout (Project 3) has far more applications than presented in this proposal. It has potential applications in civil engineering tunnels and borewell stability projects. Therefore, a technological breakthrough could find much broader variety of end users.