$11 billion initial investment
$17 billion in taxes and royalties
Additional export income of $2.5 billion a year
6000 direct and indirect new jobs, 1700 of which will be in Western Australia
Expansion of existing services and industries, and attraction of new ones
Underpinning the development of new technologies and skills, such as CO2 sequestration and subsea technology, creating regional capacity for future growth.
Which doesn't sound like a huge amount to me (though if anyone has $2.5 billion dollars spare I'm more than willing to take it off your hands).