While the MRRT has been a national talking point for months, the design of the tax still needs to be worked out by the Policy Transition Group chaired by former BHP Billiton chairman Don Argus.

BDO tax manager Larras Moore, who previously held corporate tax roles with Xstrata Coal and Rio Tinto, has urged coal and iron ore companies to get involved in the Policy Transition Group’s forthcoming consultation process.

He said if mining companies voice their opinions they might get the changes they want.

Moore hopes the final design of the tax is clear and simple to remove any uncertainties.

His main bone to pick is the issue of the exact taxing point – which like many aspects of the MRRT remains unclear.

The speed of the tax design process also is important.

Moore said a major tax issue for coal and iron ore miners related to raising equity – sorting out the immediate risks to bring more investment back into the mining industry.

“You want certainty as quickly as humanly possible,” he said.

On the subject of whether the MRRT will bleed anywhere near the intended $10.5 billion of tax revenue from the coal and iron ore sectors within its first two years, Moore said anyone would be brave to put out a number of what the tax take might be.

“They are estimates based on assumptions of a lot of different variables,” he said.

Moore does not regard tax revenue targets as a sensible way of forming the tax.

“My view is let’s get a tax that is structured correctly, that the industry can bear the weight of it and not become internationally uncompetitive,” he said.

Deloitte resources tax partner Darren Lee said a lot of companies are taking a wait and see approach to the MRRT since the eventual election result.

“A lot of companies have already done the analysis on how the MRRT is going to impact them, a lot of them are waiting on the detail,” Lee said.

“How do you determine your mine gate price?”

Lee would also like to know how the transitional rules will operate.

Until the outstanding issues are resolved, mining companies will have difficulty in refining their models to determine the ultimate impact, Lee said.

He said companies should start revising the work they have done and be prepared to debate any issues that may arise as a result of the findings released by the Policy Transition Group.