Miners at various sites have showed signs of ‘black lung’, and they are making their anger known.

Miners at Anglo American’s Grasstree coal mine walked off site last week over the safety concerns, and were followed soon after by a walk-off of workers from a Glencore mine site as well.

It came after ‘black lung’ was detected in three Queensland coal miners.

Miners at Glencore’s Oaky Creek complex have threatened to halt work over safety concerns too, local media is reporting.

“It's appalling that companies and regulatory bodies have let health standards deteriorate, putting the lives of workers at serious risk,” CFMEU district president Stephen Smyth said.

“This is a disease that takes hold gradually and we're extremely concerned that recent diagnoses are just the tip of the iceberg.

“Of great concern is that Australian health and regulatory frameworks are no longer equipped to deal with the disease.”

Glencore says workers at Oaky Creek North did walk off site over 'black lung' concerns, but they eventually returned to work.

Some have alleged that the workers were made to re-enter the underground complex on the threat of losing their jobs.

“After what we've learnt this week about the re-emergence of Black Lung, forcing workers back down underground against their wishes shows a stunning disregard for Australian employees health and safety,” CFMEU district president Steve Smyth said.

“Can you imagine the conversation these blokes are having with their families before they are forced back into the mine?

“There are going to be two sides to this - those mining companies that take ownership and want to be part of the solution, and those who don't. We're already seeing who is lining up where.”

A Glencore spokesperson has told reporters that safety remains a major issue for the company.

“None of the reported cases of pneumoconiosis involve Glencore’s underground coal operations in Queensland,” the spokesperson told reporters.

“Nor have any of our employees who stopped work over this issue been threatened with the risk of losing their jobs.”

”The health and safety of our workforce remains our top priority.”

“After spending time listening to our employees yesterday, we have undertaken to provide the following across the Oaky Creek complex, including chest X-rays for all employees who request them.

He said this would be combined with “a further review of all chest X-rays taken within the last six months; all chest X-rays to be viewed and read by a qualified radiologist who is a member of the Royal Australian and New Zealand College of Radiologists and has the necessary competencies; a refresher training in dust and the correct use of PPE; and education and training in relation to dust diseases (including pneumoconiosis).”