The Construction Forestry Mining and Energy Union have again accused BMA of trying to de-unionise its coal mine workforce.
Last month the miner was accused of formulating a secret plan to restart the Norwich Park coal mine with a de-unionised workforce.
At the time the CFMEU said it had obtained a document that indicated BMA had a five year plan to restart operations at Norwich Park with different employees.
CFMEU district president Stephen Smyth said BMA needed to "come clean" on its plan for the mine and its staff.
"Workers already held fears that BHP's decision to close Norwich Park may not have been purely for the operational reasons the company cited," he said.
"Having a document turn up apparently showing BHP has a five-year plan to employ new workers at a mine that is supposed to be closed does nothing to allay these fears."
BHP was unavailable for comment but told reporters there was no plan to reopen Norwich Park.
Now the CFMEU is again accusing BHP of trying the same tactics.
CFMEU district president Steve Smyth said the miner is planning to reopen Norwich Park by October, according to the ABC.
It will reportedly run the mine through another of its joint venture operations, BHP Billiton Mitsui Coal (BMC), and hire outside contractors.
Smyth said it is clear the miner is trying to work around the ongoing enterprise agreement negotiations.
Under "the current agreement we say if they were to restart [it] requires them to comply with the current agreement and re-employ the Norwich Park employees that were displaced and the agreement now is valid in the law court, so to even consider bringing in contractors just goes back to the heart of the issue," Smyth explained.
"We say they were out to de-unionise and offer less conditions and entitlements."
While Smyth declined to state where he received his information this time, he said "the information we've got is that BMC will be coming in to look after the mine and manage most of the key components of the dragline and wash plant and that BHP are looking at one of two major contractors to come in and run the operation.
"They've denied it until now but when you've got senior people ringing us and inquiring that has brought us to bring it to BHP's attention."
The CFMEU has previously accused BHP of 'doing a Dubai', referring to the Patrick lockout in the 1990s, where plans were made to replace workers with contractors trained in Dubai.
It went on to claim that the entire closure of the mine was simply to de-unionise the workforce, pointing to BMA statement that the mine would stay closed until it was "significantly reconfigured".
"At the end of the day, they don't want a permanent workforce at Norwich Park, they want to de-unionise the coal industry – this is a part of it," Smyth said.
"It's very apparent now that they want to run the mine with contractors, introduce whatever shift they see fit and have people living in single person's accommodation."
He went on to claim that the closure itself was a deception.
The miner has denied these claims and restated that is has no intention of reopening the mine any time soon.