The company's gas management focus included changes to the mine's ventilation system to increase airflow to no avail.
"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 goaf, the oxidation accelerated into a spontaneous combustion event that eventually resulted in the fire," the company said.
Peabody president - Australian operations George Schuller said while this was a highly unusual combination of events, Peabody was making changes in systems, processes and training to put into place the improvements needed to move forward from this incident.
"For example, we have already begun installing remote control ventilation systems at mine entrances," he said.
Schuller said longwall production at North Goonyella would not restart until all necessary modifications were undertaken.
Peabody CEO Glenn Kellow said when the incident at North Goonyella occurred, Peabody committed to sharing learnings for the benefit of its operations, its stakeholders and others in the industry.
"We believe that the beginning of the planned reventilation and re-entry activities warrant a sharing of our initial learnings at this point," he said.
"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."
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 about 2 million short tons 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 Queensland Mines Inspectorate," the company said.
