The Australian Council of Trade Unions has thrown its support behind the Construction, Forestry, Mining and Energy Union's bitter battle with BMA in the Bowen Basin.
ABC News reports ACTU president Ged Kearney said while the battle should not have taken so long, she was hopeful for a positive resolution for workers.
Kearney told ABC News she was disappointed in the way BMA had handled the battle and he hoped there would be a "decent outcome" from the dispute.
"It's unfortunate that BHP cannot simply see that an important way to show that you value your workers is to provide them with a decent living and decent conditions," she said.
Last week the CFMEU released a statement saying it had obtained a document that outlined a BMA plan to rehire a de-unionised workforce at the closed Norwich Park mine.
It called on the company to "come clean" on its plans for the mine and its workers.
BHP Billiton immediately denied the accusation and said there was no current plan to reopen Norwich Park.
It said the reasons for the mine's closure had already been made public and had not changed.
The company said the CFMEU's announcement was the "latest attempt to mislead BMA's employees" and had to be viewed in light of other battles it was waging in the Bowen Basin.