PERTH (miningweekly.com) – Coal miner Peabody on Wednesday said that longwall production at the North Goonyella operation would not resume until a number of modifications have been made at the operation, in order to avoid another fire at the operation.

The US major last year reported a fire at the North Goonyella operation.

The miner in early September evacuated personnel at the mine during a planned longwall move from the 9 North panel to the 10 North panel, owing to high gas levels.

Peabody detected elevated carbon monoxide from within the mine, which indicated the oxidation of coal. Over a number of weeks, the company worked with industry experts, and in consultation with the Queensland Mines Inspectorate (QMI), to take steps to treat the oxidation from the mine surface. 

Actions were ultimately unsuccessful, resulting in a fire in late September. 

Peabody said on Wednesday that its review of the incident concluded that areas of the mine demonstrated both elevated methane levels and elevated carbon monoxide levels following completion of coal production in the 9 North panel. 

During the longwall move sequence, a change in gas management focus to reduce elevated methane levels in the 9 North panel, including changes to the mine's ventilation system to increase airflow, inadvertently intensified the oxidation of coal that was likely causing elevated carbon monoxide levels. 

Despite sustained efforts to manage the oxidation from the mine surface, including use of nitrogen to create an inert environment within the 9 North panel, the oxidation accelerated into a spontaneous combustion event that eventually resulted in the fire.

“While this was a highly unusual combination of events, Peabody is making changes in systems, processes and training, where warranted, to put into place the improvements needed to successfully move forward from this incident. For example, we have already begun installing remote control ventilation systems at mine entrances,” said Peabody president for its Australian operations, George Schuller.

He added that longwall production at North Goonyella would not recommence until all necessary modifications were undertaken. 

Peabody's base case that targets limited continuous-miner volumes in 2019, with longwall production beginning to ramp up in early 2020, remains unchanged with approximately two-million tonnes of sales from North Goonyella in 2020. 

Peabody continues to progress the execution of the multi-phased reventilation and re-entry of the mine in consultation with the QMI.