I honestly have no idea what the conditions are around visas

For the Working Holiday Visa

Basic requirements

To be eligible, applicants need to meet the following requirements:

hold a passport issued by an eligible country or region be aged 18-30 (inclusive) at the time of applying not be accompanied by dependent children at any time during their stay in Australia meet health, character and financial requirements not have previously entered Australia on a Work and Holiday (462) visa not have prevsiouly entered Australia on a Working Holiday (417) visa (unless applying for a second visa, see 'Second Working Holiday visa' below) be outside Australia when they apply and when their visa is granted (unless applying for a second visa, see 'Second Working Holiday visa' below) apply within 12 months of intended travel to Australia.

I have no idea what the visa requirements for USAns are but they"re unlikely to be any more onerous. And all the mining jobs are going to be in the arse end of nowhere so you'll also be eligible for a second working holiday visa.