Idemitsu did not reveal the price tag and said getting the regulatory approvals to close the deal might take several months.

“The transaction includes the agreement to supply thermal coal from the mine to Chugoku on a long-term basis,” Idemitsu said.

In the Gunnedah Basin, construction of the mine’s new coal handling and preparation plant to lift production capacity to 7 million tonnes per annum is due for completion in the June quarter of 2015.