state royalties and super tax

If the Super tax legislation is passed in 2012 by the federal government, what would prevent a state government with a non-labor government increasing the level of mining royalties to a level equivalent to the 40% supertax. (The current supertax proposal assumes that the mining companies will be re-imbursed for state mining royalties.) This would ensure 100% of the additional tax stayed in the particular state.

Is there anything in the current proposal to prevent states increasing their mining royalties? If not, how will the Super tax help the federal government with their budget shortfall?