"No government needs the agreement of the entity being taxed, to impose a tax."
Technically that's correct of course, but that's about it. The miner's do the employing, and pay the wages, so no Government will impose taxes without very carefully considering the bottom line cost.
In this contest, the Government is basically a plaything for BHP, so if they (the Government) are smart they will be very careful. They are not in the dominant position.
