I base this on the petroleum/oil industry already being taxed at this level for the same thing and I don't see them going broke or shutting shop.
This just highlights the level of the debate around the place on the taxation regime for mining companies. I've even heard Fed govt ministers make this point and it is disingenuous at the least and dishonest at the worst.
Offshore oil and gas projects (like Gorgon et al) operate outside the jurisdiction of the States and therefore don't pay State royalties at all. Woodside for example pays peppercorn rates to the Shire of Roebourne for its monstrosity sitting on the Burrup and that's it - everything else goes to Canberra.
To compare the Federal taxation of an industry that doesn't pay State royalties to one that does is a complete bum steer. I wouldn't mind if the payment of royalties were backed off when these projects hardly make any money but no - they decide in their wisdom to only limit your upside while leaving you on your own with the downside. And on top of that to have no grandfathering provisions makes this a perfect example of sovereign risk that will flow through to other industries.
Now every Australian company knows it's OK to make a bit of money but if perchance you start making what we the govt think is "too much" then we'll cut you off at the knees. A great message for the investment community!