CFMEU spokesman Steve Smyth was quoted by ABC as saying that the miner has terminated ten employees at the mine, south-west of Mackay.
Another 56 permanent workers are expected to be sacked by the company, added Smyth.
The union claims that the termination of the permanent employees is in breach of the company’s commitment given at the annual general meeting about the use of casual labour.
Rio Tinto, however, has denied the claims and stated that both contract and permanent jobs are to go, without giving any numbers.
Smyth added: "Our concerns are with the behaviour shown by the company this week and their disregard for their permanent employees, this could be the start of more to go.
"We’re not sure, they may shut down other pieces of equipment, but at this stage 56 unfortunately."
