Senator BIRMINGHAM (South Australia) (14:32): Mr President, I ask a supplementary question. I refer the minister to the published NGERS data, which indicates that the different operating entities of BHP Billiton reported more than 9.5 million tonnes of direct emissions in 2010-11, a figure which could only have gone up had the Olympic Dam expansion proceeded. Even after the application of so-called free permits, wouldn't BHP Billiton face a carbon tax liability of tens, if not hundreds, of millions of dollars each and every year?