The Queensland Mines Inspectorate and mining unions are investigating a series alleged coal gas leaks at the Collinsville mine.
On Friday three workers were forced to evacuate from an area undergoing dragline operations after high gas levels were detected, A Department of Employment, Economic Development and Education spokesperson said.
Last month a female truck driver was also exposed to high gas levels, and reported symptoms of gas exposure.
A mines inspector and DEEDI representative have already visited the site to uncover the cause of the leaks, the Daily Mercury reports.
According to the DEEDI the Collinsville coal mine’s seam is historically known to be prone to emissions, however the CFMEU pointed the finger at management on the site.
"(The gas leaks) are from years and years of mismanagement," CFMEU industry safety and health officer Tim Whyte said.
"The mines need to have stringent controls in place… at the moment there are only temporary measures.
"Humans cannot smell or see the gases… exposure to the gasses can be fatal."
A directive was already in place which required the mine operator – Thiess – to review the coal mine’s safety system regarding mitigation of gas related accidents and the heating of exposed seams.
At the Hazelwood Power Station a two kilometre coal seam caught fire in 2006.
Similarly, Burning Mountain in the Hunter Valley is coal seam that is believed to have been burning slowly for the last 6000 years.
Thiess confirmed that no one was injured in the gas leak on Friday.
The coal mine is a joint venture between Xstrata, Itochu, and Sumitomo.