The CFMEU says it will take Rio Tinto to court if a pay dispute over redundancy packages cannot be resolved.
Around 30 CFMEU members will continue rolling strikes after the union claimed last month that the mine’s redundancy package discriminated against its members.
The CFMEU says non-union members, who are on individual agreements, have been offered larger redundancy payouts.
"Depending on how long you've been at the mine, that market allowance could be up to many … thousands of dollars," CFMEU spokesperson Glenn Power said.
"It's very different for every individual or particular member but certainly there's a substantial amount of money that our members are going to go without."
While the Blair Athol coal mine in central Queensland is set to close next Friday, the union has warned Rio Tinto it will not ‘get away with this parting shot of discrimination.’
"This fight isn't going to finish on the ground, this fight's going to continue on in the courts.
"We'll fight Rio if it takes five, six, seven years to get justice," Power added.
However Rio Tinto have hit back, saying the packages had been negotiated in good faith.
"Rio Tinto is disappointed the CFMEU has chosen to encourage industrial action in the final weeks of operation at Blair Athol Mine," a spokesman told AAP.
"We believe that the Blair Athol Mine Workers Enterprise Agreement, including the redundancy payments, is fair and was bargained in good faith.
"Rio Tinto has plans in place to minimise disruptions using the remaining workforce and operations."
The dispute comes as the two year rolling battle between the CFMEU and BMA came to a close.