Abstract

3-5% of the electricity generated globally each year is used to break the rocks which provide us with the copper to manufacture our computers, gold and diamonds for our jewellery, iron to make our cars and so forth. With the spotlight fixed for the foreseeable future upon the cost of electricity generation and subsequent environmental impacts any reduction in usage will be significant. Many attempts have been made to reduce the amount of energy used to break rocks, including optimisation, simulation and conventional heat based thermally induced stress. However, just as it is more efficient to cook your jacket potato in the microwave the same is true for mineral-containing rocks. Whilst this may sound bizarre, a rock’s response to microwave heating can be likened to the behaviour of a treacle tart, the sugary centre heating rapidly whilst the outside remains cool, in a rock certain minerals respond quickly, others not at all. It is this differential heating which allows the generation of thermal stress. The seminar will review the fundamental interaction of microwave energy with mineral phases, explain the process of stress generation and how microwave power density can be manipulated to control the degree of fracture produced within the sample. Discussion of the major issues regarding scale up and the latest work concerned with the use of multiple MW micro second microwave pulses on fracture generation will be presented. The seminar will finish with a discussion of the future requirements for the development of industrial scale systems.