Rio Tinto Group told the Australian stock exchange that feasibility studies on Arizona's Resolution copper mine will cost $652 million, with Rio's share being $341 million. Rio Tinto owns 55% of the project and manages it. BHP Billiton owns the rest. The studies will be completed by 2012 with mining beginning by 2020.
[right: schematic of block cave mining technique at Resolution copper mine. Credit, Resolution Copper]
A proposed land exchange including private, state, and federal lands is critical to the mine moving forward.
Update (8-4-08): Mineweb.com has the most extensive article on this that I've seen. Details on the feasibility study, a fair amount of exploration history, geology, reserves, and the land exchange needed to make it all happen.