Microwave tunnels?

The March 15th Economist (as I work my way though the backlog created by the weeks in Calgary) had a piece on the using of microwaves in the mineral extraction process, and the work of Sam Kingman of Nottingham University, rather that using grinding to breakup chucks of rock before separation of minerals/metal. A quick google search turned up more references, such as this : Microwaves in Mining, Engineering & Mining Journal.

Brain Fart: Could this technique be used to make mining and tunneling cheaper/faster? I envision beaming the microwaves ahead of the gouging machine, adjusting for the take of material being dug in. That made me think of tunneling for Horta’s ala classic Star Trek's “Devil in the Dark”