Anglo American has withdrawn its workers from the Grasstree mine in the Bowen Basin, Queensland following a change in the underground environment.
The incident took place after gas measurements were taken on Monday November 18 during a sealing operation behind a newly sealed longwall area.
Media reports claimed the oxygen levels had trended towards the explosive range.
By Tuesday afternoon, Anglo American re-established normal underground conditions and workers re-entered the mine.
Anglo American withdrew its workers from the underground environment as a precautionary measure and notified the relevant authorities, according to an Anglo spokesperson.
The Queensland Mines Inspectorate (QMI) provided the company with “certain risk management information which was required as a condition of re-entry,” a QMI spokesperson said in a statement.
“The safety of our people is our first priority, and this was reflected in our decision to take early action to respond to environmental changes, based on effective use of our early automated gas monitoring processes,” the Anglo American spokesperson said.
The Grasstree mine is an underground longwall operation that is part of Anglo American’s Capcoal complex near Middlemount.
Anglo American completed a longwall move at Grasstree in the March quarter, following a planned move in the mine in the same period last year.