Around 30 miners at Blair Athol will go on strike tomorrow.
Late last month the CFMEU announced that workers would carry out industrial action after it claimed that the mine's redundancy package discriminated against union members.
Now mining unions are trying to finalise a new enterprise agreement for their members at the mine, as they believe under current conditions unionised workers will receive less than those on individual agreements.
"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."
These unionised workers have now announced they will go on strike, according to CQ News.
Workers will carry out strikes on Tuesday night, and may hold further industrial action.
The initial strikes will last around 36 hours.