Abstract
Enhancement of the efficiency of mine-to-mill processes is one of the main focuses of sustainable development of mineral resources. However, relatively low energy efficiency in rock fragmentation processes, including excavation/comminution, is a major hurdle in achieving such a goal. Microwave pre-treatment technique has yielded promising results as compared to other pre-weakening solutions such as high-temperature torch, high-voltage electric pulse or high-pressure hydraulic fracturing. So far, the importance of the energy used in creating microwave-induced fractures is mostly overlooked. Current research, collaboratively carried out at The University of British Columbia and McGill University, aims to connect energy consumption and strength reduction by using both experimental and numerical methods. Towards this end, samples of rock and ore were treated under various microwave cavity settings with different distances with respect to the microwave waveguide. Calorimetric measurements were conducted to determine the microwave heating efficiency and its subsequent rock weakening effects. A Finite Element numerical tool was developed to simulate the microwave-treatment process taking place within the cavity. Additionally, a Discrete Element Modelling tool was built to evaluate the behaviour of rocks undergoing microwave treatment. This presentation offers an overview of the results of the numerical and experimental analyses and the designs needed to optimize the efficiency of microwave-fracturing in order to achieve energy viability in pre-conditioning of rocks/ores with microwave.