The mine was already operating under a directive issued by the Mines Inspectorate on February 24, 2012 in relation to gas fume issues at the mine.

“The directive issued instructed the mine operator to take steps to reduce potential risks to workers associated with exposure to toxic and flammable gas at the mine,” a Department of Employment, Economic Development and Innovation spokesperson told ILN.

“The coal seam at the Collinsville mine is prone to gas emission because of intrusions and minerals such as iron pyrites found in the surrounding geology are prone to spontaneous combustion.

“The directive requires the mine operator to review its site safety and health management system in respect the development and implementation of a plan to further mitigate risk of gas-related incidents and heating of exposed coal seams.”

Five people were checked in with symptoms of exposure to hazardous gases and a further nine people working in the vicinity were taken to hospital as a precaution.

They have now been released as a full investigation into the source of hazardous gas continues.

Thiess is continuing to work with the government’s Safety in Mines Testing and Research Station and other technical experts to carry out additional testing.