Just how long has the principal that the minerals do not belong to the miners been held and if it's true why hasn't it been acted upon before half of WA has been exported to China.
http://en.wikipedia.org/wiki/Australian_mining_law
History of mining law
The first Australian mining laws were enacted in 1851.[1] Before that, ownership of minerals and petroleum passed to those who were granted title to land by the colonial governors according to common law concepts, except the right to "Royal Mines" (the precious metals of gold and silver) which remained vested in the Crown by virtue of Royal prerogative. From 1855, colonial parliaments legislated for ownership of minerals to be retained by the Crown in future grants of freehold title. Thus, the situation developed where throughout Australia, the Crown in right of the State owns nearly all the minerals.
More at the link...