The opposition spokesman on regional development said it was no coincidence the US’s biggest coalminer had made a play to secure Macarthur’s Queensland mines a day after the federal government released details of a carbon tax that promised to hit gassy mines the hardest.

‘‘Coalmining companies like Peabody are ruthless,’’ Senator Joyce said.

‘‘As soon as their share price takes a hit on the stock exchange they will shut down any mines that are not making money.

‘‘Companies like this don’t muck around and Australia is encouraging them with ridiculous policies like this carbon tax.’’

Peabody’s joint bid with the world’s largest steelmaker, ArcelorMittal, is its second attempt at winning control of Macarthur within 14 months.

Peabody last year originally bid $13 a share, which was upped to $14 and later to $16, then reduced to $15 in an unusual move largely blamed on the federal government’s then-proposed Resources Super Profits Tax.

This time, Peabody is armed with the support of ArcelorMittal, a 14 per cent shareholder in Macarthur.

Queensland-focused Macarthur’s appeal is its status as the world’s largest exporter of pulverised coal, used in steelmaking, which is in tight supply amid high demand.

Pulverised coal has properties which make it a less expensive substitute for coking coal in blast furnaces.

A spokeswoman for Peabody Energy in Australia declined to comment last night on Senator Joyce’s comments until she contacted the company’s headquarters in the US.

She directed the Newcastle Herald to the company’s Australian website, which showed expansion plans under way, or in the feasibility stage, for all of the company’s Australian mining ventures.

Peabody’s major mining interest in the Hunter is Wambo Mine at Warkworth, near Singleton.

It also has the Wilpinjong mine near Mudgee.

The remainder of its major mining interests are in the Bowen Basin in Central Queensland and in south-east Queensland.