Some mines will do their own training on site, so apart from a medical there probably isn't a lot that he really needs. I know the mine DH works at doesn't require any previous experience if you just want to be a machine operator because they will train you. If he is looking at more the maintenance side of things, then he will require some qualifications for that. You said yesterday he's sent his CV to the recruitment agencies? Then perhaps get him to give those places a follow up call and see what happens next and what he should do to increase his chances.