Peabody has also received approval from workers at its North Goonyella coking coal mine – which lies in the Bowen Basin near BMA’s operations – for a new labour agreement as it seeks to move to an owner-operated workforce model.

Peabody said the decision by workers at its Wambo and Wilpinjong mines in New South Wales to approve new labour agreements meant more than two-thirds of its high-value thermal coal exports from Australia were covered.

Peabody employees approved the new three-year Wambo enterprise agreement at the underground mine. Wambo employs 150 workers, producing high-quality thermal and PCI coal products. The mine's underground operations shipped 3.1 million tons in 2011.

The new four-year Wilpinjong agreement was reached with the mine's current contract operator, Thiess. Wilpinjong will be transitioning to Peabody owner-operator status beginning April 1, 2013.

Wilpinjong has a workforce of approximately 350 and produces thermal coal for both domestic and export markets. The mine shipped 9.8Mt of coal in 2011 and recently completed an expansion.

"These new agreements were approved by an average of 80 per cent, indicating a clear show of support from workers at our operations in Australia," Peabody president – Australia Eric Ford said.

"They follow the overwhelming approval of the new three-year North Goonyella enterprise agreement in Queensland last month, covering Peabody's highest-value hard coking coal production."

Meanwhile, BMA’s 4000 employees have overwhelmingly rejected a proposed enterprise agreement, paving the way for industrial action from this week at seven operations in the Bowen Basin.

The long-running stalemate was nowhere near resolution as the company pinned its hopes on a greater level of grassroots support for its EA offering but instead could only get a 17% acceptance.

It was up from an earlier poll that received only 7.8% approval.

Last month, Fair Work Australia ruled in favour of holding another postal ballot on a new EA.