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A coal comeback

coal

After closing due to a fire in 2018, the North Goonyella coking coal mine will reopen in early 2024.

North Goonyella owner Peabody Energy, a US-based coal company, will spend more than $760 million to bring the Bowen Basin mine back into operation.

North Goonyella is an underground metallurgical coal mine located in Queensland’s Bowen Basin region. The mine boasts over 70 million tonnes of coal reserves.

Peabody has also acquired a nearby coal deposit, which is expected to give North Goonyella a life of mine in excess of 25 years.

Sudden fire
In September 2018, rising methane levels within the North Goonyella underground mine halted operations. Mine officials and safety regulators worked for weeks to stabilise gas levels, but efforts were unsuccessful.

The coal seam spontaneously combusted, causing a fire that significantly damaged the mine and caused it to stay shuttered for five years.

Coal fires are known to trigger relatively easily and burn intensely, posing a significant challenge for emergency services.

In addition to the danger posed by the fire itself, burning coal releases a number of dangerous gases like carbon monoxide, nitrogen dioxide and sulphur dioxide, which poses a significant risk to workers.

Fortunately, North Goonyella workers were evacuated from the site in the early days of the incident, before the gas combusted.

In a 2014 interview with ABC Science, former director of the Minerals Industry Safety and Health Centre at the University of Queensland, Professor David Cliff, spoke about some of the challenges associated with coal fires.

“Unlike timber, coal when it gets hot has massive thermal mass which is very hard to extinguish,” he said.

Cliff said coal fires can be triggered both by external sources of heat, such as open flames, as well spontaneous combustion as the coal oxidises. The latter is what happened in the case of North Goonyella.

“Spontaneous combustion is a well understood phenomenon,” Cliff said. “Coal … is very reactive to oxygen and will generate carbon dioxide, and that creates heat.

“As the coal gets hotter it will eventually get to flame temperature and that coal will burn.”

In an underground environment, mine workers are in a constant battle to reduce gas levels and heat near coal seams to prevent spontaneous combustion.

Common controls in underground coal operations include ventilation, automatic fire warning devices, instruments to measure gas level, water sprays to reduce dust levels, and physical control measures to prevent potential ignition sources from coming into proximity of the coal seam.

Cliff said that with enough coal in one place, a fire can burn for years without relenting. Such is the case at the aptly named Burning Mountain in New South Wales, were a coal seam 30m below the surface has been burning for almost 6000 years, before recorded history began.

Despite how easily a coal fire can start, they are notoriously difficult to extinguish.

“The way to put a fire out is to cool it down and exclude the air, but the carbon dioxide and carbon monoxide fumes from such a large fire will be toxic at close range and the heat will be unimaginable so you can’t get the firemen too close,” Cliff said.

“You have to start with massive amounts of water from high-pressure water hoses from a safe distance, and once you can start to bring the temperatures down you can do other things to try to restrict the air access.”

In an underground environment such as North Goonyella, these challenges are compounded.

In a preliminary investigation into the incident, Resources Safety and Health Queensland (RSHQ) made a number of observations.

The regulator indicated that a review of the mine’s records suggested that the gas trends were not given sufficient consideration.

“Some key reports relating to the mine’s ventilation plan, gas alarm system and explosion risk zone controls do not appear to have been reviewed or countersigned by key personnel, as required under the mine’s safety and health management system,” the RSHQ said.

According to the regulator, there was evidence that some boreholes located deep within mined-out regions were insufficiently sealed, allowing ingress of oxygen into active parts of the mine with the potential to escalate conditions for spontaneous combustion.

“There is evidence to suggest that the gas drainage system was being operated to focus on management of methane instead of the potential spontaneous heating event that was occurring underground,” the RSHQ said.

“There is evidence to suggest the mine did not follow its own procedures relating to major ventilation changes.”

As part of recent redevelopment works, Peabody has targeted improved ventilation, conveyor systems, infrastructure and more to safeguard the mine against future gas and fire risks.

Reopening the gates
With the lessons of the 2018 fire taken in stride, Peabody said the North Goonyella will reopen safer and stronger than ever. In late 2023, Queensland Mines Rescue Service (QMRS) entered the damaged mining zone to assess the mine for safety compliance.

Following the investigation, QMRS will officially hand over to North Goonyella management.

The mine’s reopening is good news for the local economy, with North Goonyella mine expected to support hundreds of jobs.

“We’re trying to source as much of the labour, supplies, equipment and manufacturing as we can from the local area,” North Goonyella general manager Dan Proffitt told 7News Mackay.

“To us, this is the culmination of four years of hard work to get back to this position.”

Peabody president of Australian operations Jamie Frankcombe said that although there remains plenty of work ahead, he is pleased to see North Goonyella on track for first production in 2024.

“This is a really exciting turning point for Peabody and the team at North Goonyella as we … take a big step in our staged approach to restarting one of the best steelmaking coal mines in the world,” Frankcombe said.

“At Peabody safety is our core value and the safety of our workforce will be the top priority as they work towards bringing the mine up to full production.

“I want to thank all the hardworking teams that helped us reach this important milestone including our employees who have been there for Peabody for over five years since the incident, as well as RSHQ, the community and the industry for their support throughout the process.”

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