The Australian Manufacturing Workers Union (AMWU) says job cuts at Anglo Coal's Dawson Mine in central Queensland are devastating for the local community.
The AMWU says 40 full-time maintenance positions will be made redundant at the Moura mine, south-west of Gladstone.
The company axed about 35 positions last week from its Grasstree mine at Middlemount, north-west of Rockhampton.
AMWU state organiser Phil Golby says companies are increasingly looking to a transient workforce.
"With the downturn in the coal and all other industries around the country, it seems to be a common theme is what we do is get rid of job security," he said.
"We get rid of jobs and basically replace them eventually with people on contract, working for contract companies and it basically drives down workers' conditions and wages across Australia." Mr Golby says he plans to meet workers next week.
"It's another kick in the guts," he said.
"Moura and a lot of the mining communities have been struggling to keep a community together with the advent of fly-in, fly-out workers.
"Eventually it means there'll be more drive-in, drive-out workers or fly-in, fly-out in the central regions."