I don't know which mine or company you guys work for or have first hand exp with, but majority of workers do need some minimum skills, eg tech skills set.
Cleaners are the minority. Cooks do need to have some skills, even the kitchen hands.
It pays well but at an expense obviously hence the higher pay
But when you count the per hr rate, it's not a massive jump. The tax break helps in some cases, with the free accommodation. But if you don't make good use of the extra cash, you've just wasted the effort and sacrifice