The economic cost of using labour hire workers as mining casuals could be more than $800 million a year, new research shows.
The construction union commissioned the McKell Institute to look at wage-cutting strategies in the mining industry.
The modelling found across the three coal regions with the highest proportion of mining jobs, the direct and indirect economic impacts of lower wages paid to labour hire workers is up to $825 million a year.
The report puts the growth in mining industry casualisation at more than 59 per cent between 2014 and 2018, exceeding all other industries.
Wages for employees in central Queensland and the state's Mackay-Isaac-Whitsunday region were $160,000 a year on average, compared to $114,000 for a contractor.
In the NSW Hunter Valley, excluding Newcastle, employees are on $133,000 while contractors earn an average of $90,000.
At BHP's Mount Arthur site, its in-house labour hire firm workers are being paid $106,000 compared to the rate in the union agreement of $159,200.
Labor leader Anthony Albanese used the findings to attack the coalition government for backing the mining industry but not its workers.
"For them, mining is about those who get the profits, not those who create them," he said during a speech in Mackay to launch the report.
"But the same government that likes to champion mining seems happy enough for mine workers to get ripped off."
The opposition is trying to patch up its relationship with coal workers after Queensland gave Labor a beating at last year's federal election.
"If we are to judge this government by its record, we would have to conclude that they value resources far more than they value the people who actually dig them up," Mr Albanese said.
"The scale on which miners are being ripped off through the casualisation of the workforce is nothing less than a crisis. And it is growing."
He said BHP has 13,000 workers across nine Queensland mines, but fewer than 3000 are under site enterprise agreements.
CFMEU mining president Tony Maher said, when other coal mining regions were factored in, the economic cost could be closer to $1 billion.
"Anyone with any exposure to the mining industry knows the toxic effect that labour hire has had," Mr Maher said.
"What this report does is lay out the total impact in stark dollar terms and it's brutal."