Development of novel 100 kW microwave-assisted rock excavation system for large scale proof-of-concept

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The future of mining industry is believed to be continuous, automated, real-time monitoring and control, consistent product, efficient, conserve energy and reduce environmental footprint. Currently, most of mining process are in batch mode using drill and blast technique, albeit some soft-rock and coal mines started implementing continuous mining method using continuous miner, shearer and other rock cutting tools. In hard-rock mine, however, continuous mining method still faces many challenges and far from efficient due to low penetration rate of mechanical cutters, high wear of mechanical tools, unpractical size of equipment (if it is in underground mines) and high energy consumption of the tools. Started in 2008, our team has explored various possible method of continuous mining using explosive free rock breaking techniques. It was concluded that the most feasible technique to pre-condition (weaken) the rock using microwave irradiation coupled with mechanical rock cutting tool. This conclusion drew the attention of mining companies and resulted in securing an NSERC Collaborative Research and Development (CRD) grant in 2011 – 2016 (Phase II). Basic parameters affecting the irradiation of rocks samples and its influence on the reduction of rock strength has been demonstrated. This study investigated and proved the feasibility of using microwave-assisted rock breaking technology in excavation. Also, this previous NSERC CRD grant enabled the applicants to build a state-of-the-art 15 kW microwave-assisted rock breakage test rig, unique to McGill University in Canada and one of the few in the world. Currently, our rock-microwave research is entering Phase III. NSERC Collaborative Research and Development (CRD) grant supported by mining companies is underway. The objective of Phase III is large scale in-field tests for proof of concept of microwave assisted rock excavation tool. The equipment requested through NSERC RTI is a 100 kW rock-microwave system to upgrade our existing 15 kW rock-microwave system. Note that our existing 15 kW rock-microwave system was successfully used for lab-scale proof of concept; however, stronger microwave irradiation power of 100 kW is essential for large scale in-field tests, i.e. rocks are much larger and confined naturally in the mining bench or mining face as well as the stochastic nature of the heterogeneity of rock particles composition under real mining environment coupled with rock cutting tool equipment.