It was unclear last night whether the case was part of a workers' compensation matter, or whether it was a more serious contractual dispute.

Chandler Macleod is one of a number of labour hire firms to provide workers to Mount Arthur, which has been the focus of a long-running controversy across the coal industry over the use of so-called "permanent casual" employees.

Class actions alleging widespread underpayment of casual workers have spread into other sectors of the economy, causing unrest among employer groups and their representatives at the potential financial costs should the class actions succeed.

The situation at Mount Arthur has also caught the attention of One Nation Senator Malcolm Roberts, who took up the case of injured former Chandler Macleod "casual" Simon Turner. Senator Roberts has campaigned for more than a year against casual employment at Mount Arthur and more broadly in the NSW and Queensland coal industries.

Last night, in the latest stage of his efforts to have Canberra address the issue, he released a new video in which he sets out what he says is "exploitation, abuse and negligence" in the coal industry.

"It's horrific, it's unethical, immoral and unlawful, with deliberate breaches of laws," Senator Roberts says in a 22-minute piece that also features Mr Turner and mineworker Stuart Bonds, who intends to again challenge sitting Labor frontbencher Joel Fitzgibbon at the next federal election.

The court case listed for progress in the NSW Supreme Court yesterday is described as Ready Workforce (A division of Chandler Macleod) Pty Ltd v Mt Arthur Coal Pty Ltd.

Mt Arthur Coal Pty Ltd is one of a number of companies associated with the mine, which came into BHP's ownership when it merged with the Anglo-Dutch company Billiton in 2001.

No documents were publicly available for the hearing, which was described as a "return of subpoena". Despite a number of requests, both Chandler Macleod and BHP were both unable to say with any certainty what the case was about.

Some of the concerns raised in recent months by Senator Roberts over injured mineworkers are likely to gain further attention with the publication of a joint Sydney Morning Herald/Four Corners investigation alleging major problems with the NSW workers' compensation system.

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