The regulator said Appin colliery complied with its directions in the prohibition notice and as such the ban on workers entering the underground mine was no longer in effect.
“Appin colliery has completed an investigation into the circumstances of the incident, which included reviewing the reliability of the gas drainage plant and the mine’s stoppage trigger action response plan,” it said.
“The regulator will monitor the mine’s operations while continuing its own investigation into the incident.”
Saleable production from South32’s Illawarra Metallurgical Coal subsidiary decreased 50% or 1.9 million tonnes to 1.9Mt in the December 2017 half year as the Appin colliery recovered from the extended outage.
The company restarted a single longwall at the Appin colliery on October 13 and remains on track to produce 4.5Mt of coal at Illawarra Metallurgical Coal in FY18.