Queensland Rail did not achieve its coal-hauling obligations to the Dalrymple Bay Coal Terminal at Mackay, Rio Tinto Coal Australia claims, as the industry continues to battle the planned $3 billion float of QR's freight operations.

Rio Coal Australia managing director Bill Champion said congestions in the Goonyella coal chain were attributable to QR's underperformance.

"We've had a lot of problems with the productivities and the efficiencies that were promised to us by QR, and they've simply not been able to meet those performance expectations," he said.

Rio and other Queensland coal companies seek to throw down the planned QR float with their own $4.85 billion offer for the coal chain's rail track.

QR denied the accusations, announcing yesterday that it had consistently surpassed contractual targets with Rio, except for in February when the whole coal system was affected by storms and wet weather.

Mr Champion said it was difficult to determine how responsive the Bligh government was to the miners' bid because of the latter's focus on the planned resource super-profits tax.

He said implementation of the tax would severely affect the valuation of the planned QR float.

"If you don't have a growing industry, that IPO value is going to be diminished quite significantly," Rio's managing director said.

Only recently, QR chief executive Lance Hockridge said that he believed there would be solid interest in the float.

Mr Champion said Rio was planning to increase its Queensland coal production by as much as 50 per cent in the next four years, pending a review of the effect of the super-profits tax.