Martin Blake, a former head of sustainability at Royal Mail Group, reportedly said the huge diesel bills racked up by mining companies every year could be substantially lowered with just a few easy adjustments.

Blake said mining companies had made little effort to improve their energy efficiencies but they had a lot to gain. He estimated that businesses could save up to 40% off their energy overheads.

"The most staggering energy bill that I've seen was in the mining industry for a remote mining site and it was a billion dollars a year in diesel," Blake told the The Australian.

"Our review has identified that at least 10 per cent of that is waste. So on my arithmetic it means that they are wasting $100 million a year, although I suspect that it is probably more than that."

Treasurer Wayne Swan had slammed rumours of a cut to the diesel fuel rebate in May’s federal budget as “malicious” but stopped short of ruling out any further taxes on the mining industry.

The comments were in response to a request by Atlas Iron chairman David Flanagan to rule out any future cut to the rebate.

It was widely expected that the government would cut the diesel fuel rebate in the budget and miners had lobbied hard in the lead-up.