Frankly I think BHP etc are entitled to make their money by selling our natural resource. They commit large capital expenditures with no guarantee of a satisfactory return (commodity prices can fall and make new projects lose large amounts of money). They took the risk, and if it pays off they're entitled to a reward.
If govts took the view that rewards that mining co's make ought to be seized, because, by some reasoning they are made at th expense of Australians, there would be no incentive to take the risk in the first place,depriving us of valuable jobs and tax revenue.