Rock Reinforcement for Extreme Underground Mining Ground Conditions

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The proposed research program addresses fundamental and applied research needs in managing extreme ground conditions: a) mining induced seismicity, and b) large deformations and squeezing conditions. Rockbursts are violent events, triggered by mining induced seismicity, that result in the ejection of volumes of rock from the walls of underground excavations. They can be extremely hazardous and have been responsible for many accidents in underground excavations. Large deformations and squeezing ground conditions result in major operational problems often requiring major rehabilitation of existing support.****The formulation of this proposal is based on recent data driven work in Canadian mines that has identified the gaps in knowledge in managing ground control problems in extreme underground mining conditions. The first design measures that can be implemented to mitigate ground control problems at depth involves modifications to mine design layouts, excavation geometry and sequences of excavation. This can lead to better control over mining induced stresses but cannot alleviate all problems. The second measure, the focus of this proposal, is the development of new designs for improved rock reinforcement and surface support to contain and mitigate damage caused by these extreme ground control conditions and ensure the safety of mining personnel and the economic extraction of ore.****Conventional design approaches do not consider the complex loading mechanisms on ground support due to mining induced seismicity, and extreme stress and structure driven deformations. The introduction of new innovative ground support (yielding systems) has provided tangible benefits. Impact testing of reinforcement and support, although not able to capture the loading mechanisms or replicate mine induced seismicity, has provided useful tools for comparisons between different reinforcement elements. A major challenge is how to quantify the load transfer between the different elements to establish a “system capacity” that can be explicitly accounted for in the design of ground support. This research will rely on field and laboratory investigations of the performance of ground support systems. These will be complemented by 3D numerical modelling of support systems focusing on the load transfer mechanisms between the reinforcement and surface support elements.****The proposed research program will provide a unique training opportunity for a number of graduate students. They will all work closely with the Canadian mining industry and will have a unique opportunity to develop high in demand and well diversified technical skills.****The implementation of the proposed research at mine sites will contribute significantly to the safety of mine workers and has potential monetary implications in mitigating rehabilitation and production costs amounting to hundreds of millions of dollars.******