The fatal accident occurred at an underground coal mine when the worker was overcome by an irrespirable atmosphere, the inspector said in a safety alert.

He had attempted to enter a part of the mine that was being inertised. Inertisation occurs when a sealed section is filled with inert gas to reduce the risk of gas explosions and fires.

To do so, he opened a hatch that had been closed, but was not clearly marked as inaccessible.

“Investigations are only in the preliminary stage, but this tragedy and a number of other incidents in recent times have identified inadequate controls being used for dealing with access to hazardous areas of a mine,” Clough said.

The other incidents involved an ERZ controller entering an area of a mine while it was being inertised with boiler gas; and a senior official and a ventilation officer investigating a fixed gas monitor alarm by walking towards increasing levels of gas while their personal gas monitors were emitting an alarm.

Issues that have been identified in these incident investigations include the provision of sufficient and accurate information to people who have to work near these hazardous areas and the need for people to be accompanied when carrying out certain tasks, Clough said.

“It is recommended that each coal mine conduct an audit of all such hazardous areas and ensure that these areas are secured to prevent inadvertent access signposted as to the nature of the hazard and as an area where entry is prohibited accurately depicted on plans and other relevant documents and that this information plus a familiarisation is provided to any person who has to work adjacent to these areas,” he said.