After being rocked by hundreds of job losses over the last week, the CFMEU has warned there could be more to come.
CFMEU president Stephen Smyth has accused major miners of flooding the market and said this was driving down coal prices and forcing others to rethink their positions.
The comments come after Vale and Sumitomo announced it would close Isaac Plains coal mine, 6 km east of Moranbah, affecting close to 300 jobs.
“Some of the major producers like AngloAmerican and BHP are actually flooding the market,” Smyth said.
“You could say the likes of Isaac Plains are being driven out of business by the bigger producers."
Smyth said the union would engage with both companies and its workers, but warned more jobs could disappear from QLD’s coal sector, Daily Mercury reported.
"There will be some tough times ahead. I think long term there's some further pain ahead," he said.
Queensland Resources Council chief executive Michael Roche said low prices meant miners were scrutinising their costs.
“The mines have had only one lever to pull and that's to deal with their own cost structures at the mine site and their own corporate overheads,” Roche said.
"No one is waiting around for a big upkick in coal prices.”
The Bureau of Resources and Energy Economics (BREE) said reduced demand and an oversupply would help to keep coal prices depressed.
BREE said some coal operations are unprofitable at the current level, and said cost-cutting in the form of mine closures or production slow downs would become common.
The government group said metallurgical coal would fetch US$123 a tonne in 2015 and thermal coal would settle at US$77 a tonne.