You usually get a job via a labour hire company - not a lot of mining companies directly employ staff and you have to keep your eye out for any direct employment jobs. THere are a few websites around that deal with mining employment though, so have a google for 'mine jobs' and you should get some hits.

Some jobs will offer FIFO (fly in fly out) where they will fly you in and out of the mine, but whether that is worth it or not depends on his shifts - some companies will do several weeks on, 2 weeks off etc, but the mine where my DH works is 4 days on, 4 days off, so that isn't helpful at all for interstate workers. The money will vary greatly too. I know that coal mining pays more than some other mines. One thing to remember is that mining towns are expensive to live in - if he has to pay rent anywhere to live then that will eat into his income and therefore the income he has available for you. But if he gets a job where the accommodation is on site, then that will be a lot cheaper. I know the entry level income for truck drivers at DH's work is only $45K and the top level operators only get about $80k. Dh earns more driving the fuel truck around. But truck drivers at other mines can earn as much as $120K.