Investigating microwave assisted rock breakage for possible space mining applications

Abstract

An optimal combination of mechanical means and microwave energy to break rock material could prove beneficial for space applications in terms of large scale production drilling or rock removal processes. In the present paper, application of low power microwave pulses was used to induce thermal cracks in rock samples, before use of mechanical breakage methods. The present investigation is conducted with the scope of possible space bound and terrestrial applications. Experimental studies were carried out to assess the low power (∼150 W) microwave susceptibility of terrestrial basaltic rock samples (chosen for its close chemical similarity to lunar and Martian rocks). Point load tests were carried out on the microwaved rock samples in order to determine their strength before and after exposure to microwaves. The preliminary experimental results showed that the basalt rock samples used were quite susceptible to the exposure of low power microwaves. From the point load test results, a decreasing trend is observed in terms of strength of the rock samples with microwave exposure duration. Some rock samples even presented visible macro cracking and even splitting for the longest exposure duration used in this experimental program.