Its primary contractor, Downer EDI Mining, had sole responsibility for the composition of recent redundancies at Boggabri Coal Mine, Idemitsu chief operating officer Rod Bridges said.

“This is a very unfortunate situation and the redundancies made by Downer EDI Mining were unavoidable given the current circumstances surrounding the mine,” he said.

“As an organisation, Idemitsu Australia Resources always seeks to maximise the use of local skilled employees and is a long-standing member of the local community.”

Boggabri is at the centre of a storm over temporary visas, with Downer EDI dismissing a third of the workforce onsite while retaining temporary overseas workers.

It highlights the urgent need for legislation to address “rorts” within the 457 visa scheme, says Construction, Forestry, Mining and Energy Union national secretary Dave Noonan.

More than 100 local workers at Boggabri Coal were made redundant, while six diesel fitters on 457 visas kept their jobs.

Bridges said Idemitsu was making a concerted effort to allow standard operating shifts to resume at the mine.

“In May, preparation of construction commenced on the infrastructure to support the extension to Boggabri Coal Mine, including a rail loop, load-out facility, and coal-handling and preparation plant, which when complete, will enable the mine to operate at full capacity,” he said.

“Boggabri Coal Mine is committed to working with all stakeholders to ensure the mine continues to provide opportunities to support the needs of the community.”

Boggabri Coal Mine is expected to reach peak production in 2016 and will support an increased approved production limit of 7Mtpa.