UPDATE 05/07 - Another two cases of black lung have been confirmed since the weekend.

The latest patients are a 56-year-old and a 39-year-old man, both coal mine workers, according to the Department of Natural Resources and Mines.

ORIGINAL - Two more Queensland coal miners have been diagnosed with black lung.

A 62-year-old underground coal miner has become the ninth case this year, just a day after the eighth diagnosis was made public.

Queensland’s Department of Natural Resources and Mines confirmed the latest cases of coal workers' pneumoconiosis (CWP), also known as black lung disease.

The eighth case in Queensland was a 55-year-old man who had worked across several Bowen Basin mines in the last 20 years.

Black lung disease comes from extended exposure to coal dust, but it was thought to have been eradicated over 30 years ago.

A paper published in the Medical Journal of Australia earlier this month called for a big upgrade to screening programs for at-risk workers.

The experts want at-risk workers checked every three years, and for a register to be set up with mandatory reporting of cases.

They also want the standard exposure limit to be lowered.

Currently, coal dust exposure limits vary between states, and there are even considerable variations in the monitoring protocols between different sites.

For example, Queensland’s allows 3 milligrams of coal dust per metre cubed, while the standard in New South Wales is 2.5mg.

“It is unacceptable that any new cases of CWP should be occurring in Australia in 2016, and our aim should be to eliminate CWP in Australia altogether,” the authors concluded.

CFMEU Queensland Mining and Energy division president Steve Smyth says the union expects many more diagnosed cases in coming months.

“We can’t put a figure on it because the regulatory system that is meant to detect problems has been asleep for decades, but it could be a big number,” Mr Smyth said.

“They haven’t had specialists, who are known as ‘B-readers’, checking miners X-rays and according to data reported by mining companies themselves, dust levels have been 5-10 times the legal limit. That has to change.”