The company’s review concluded that areas of the mine demonstrated both elevated methane levels and elevated elevated carbon monoxide (CO) levels following completion of coal production in the No. 9 North panel. During the longwall move sequence, a change in gas management focus to reduce elevated methane levels in the No. 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 CO levels.

Despite sustained efforts to manage the oxidation from the mine surface, including use of nitrogen to create an inert environment within the No. 9 North panel goaf (gob), the oxidation accelerated into a spontaneous combustion event that eventually resulted in the fire, the company said. “We believe that the beginning of the planned re-ventilation and re-entry activities warrant a sharing of our initial learnings at this point,” said Glenn Kellow, president and CEO, Peabody Energy. “We are taking multiple actions to integrate these learnings into our practices at North Goonyella and our other operations, where appropriate. The goal here is clear, to reduce the risk of such an event reoccurring at North Goonyella or any of our other mines in the future.”

During the incident, elevated CO detected from within the mine indicated oxidation of coal. Over a number of weeks, the company worked with industry experts and with the Queensland Mines Inspectorate (QMI) to take extensive steps to treat the oxidation from the mine surface, but actions were unsuccessful, and a fire occurred in late September.

Personnel were safely evacuated and there were no injuries. “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,” said George Schuller, president-Australian operations for Peabody Energy. “For example, we have already begun installing remote control ventilation systems at mine entrances.”

Longwall production at North Goonyella will not recommence until all necessary modifications are undertaken, according to the company. Peabody anticipates limited continuous miner volumes in 2019 with longwall production beginning to ramp up in early 2020 with approximately 2 million tons of sales from North Goonyella in 2020. Peabody said it continues to progress the execution of the multi-phased re-ventilation and re-entry of the mine in consultation with the QMI.