Major miners BHP Billiton, Rio Tinto and Xstrata will pay billions in mining tax, Treasurer Wayne Swan has declared, rejecting suggestions they will escape scot-free from the impost.
Mr Swan palmed off a question from his shadow, Joe Hockey, that instead of paying the minerals resource rent tax, the big three companies that negotiated in secret the details of the MRRT would have little or nothing to pay.
"We are absolutely satisfied that the revenue streams that we have forecast will be delivered," Mr Swan said.
The three had been expected to pay up to 90 per cent of the forecast $10.6 billion to be raised by the MRRT in its first three years of operation.
But there have been claims that because of the way the tax operates, they will have little or nothing to pay in its early years.
BHP confirmed yesterday that it expects to pay the tax, starting with an instalment later this year.
Rio Tinto is also expecting to start paying the tax in the upcoming financial year, though the full amount will not be known until late 2013 - likely after the next Federal election.
The debate over how much revenue would be raised by the tax came as figures from the nation's chief minerals forecaster suggested a slowdown in prices but a lift in total exports of coal and iron ore in coming years.
The Bureau of Resources and Energy Economics expects iron ore prices to average $US140 a tonne for the rest of this year, a 9 per cent fall on last year. Prices are then projected to ease gradually to reach $US109 (in 2012 values) by 2017.
Despite the drop, it expects iron ore exports to reach $77 billion by 2016-17 from about $60 billion today.
Thermal and metallurgical coal prices are tipped to ease but the value of exports are expected to climb or remain steady owing to increases in production.
There are growing concerns within the mining community that the May Budget will contain a reduction in the fuel tax credit aimed at miners.
The credit allows business operators such as miners and farmers to claim back the excise they pay on fuel as a legitimate business cost.