"Millimetre-wave drilling is a process that can operate largely independent of depth," says Houde. "And millimetre-wave energy can also transmit through dirty, dusty environments."

The technology has grown out of nuclear fusion plasma experiments conducted by Paul Woskov, an engineer at MIT's Plasma Science and Fusion Centre. Millimetre-wave directed energy has been explored as a way of heating up plasma in nuclear fusion reactors since the 1970s, but a few years ago Woskov hit upon another use for the technology. He started using millimetre-wave beams generated by a device known as a gyrotron to melt through rock.