Abstract
Excavation in hard rocks is an ongoing challenge in mining engineering. Different methods have been employed to overcome this challenge, one of the most significant of which is mechanical excavation. This method, however, suffers from several drawbacks including the low production rate and short life span of the cutting tools. In this research, microwave irradiation is investigated as a preconditioning method to reduce the strength of rocks prior to the excavation. This study improves the understanding of heat transfer regime and rock energy absorption during microwave heating of rocks by incorporating Maxwell’s equations and investigating the effect of electromagnetic wave distribution inside the microwave cavity. The experimental results show that by optimizing the placement of the sample inside the cavity, the energy absorption can be increased by more than 30 percent. Furthermore, a coupled thermo-electromagnetic numerical model is developed using the finite element method representing the heat transfer phenomenon during microwave irradiation in single-mode cavities. The results of the numerical model are validated against the experiments by the calorimetric measurements and thermal imaging. The developed model can be used to improve the efficiency of rock fragmentation using microwave irradiation.