Nova Scotia

Conveyor system to blame for recent Donkin coal mine fire, says N.S. Labour Department

Nova Scotia safety inspectors say an overheated ball bearing likely smoldered all day before igniting a fire-resistant conveyor belt in the underground mine in April.

Provincial inspectors say overheated ball bearing ignited conveyor belt

Smoke is seen billowing from the Donkin coal mine in Cape Breton April 30, 2023.
Nova Scotia's Department of Labour says an investigation has found an underground fire at the coal mine in Donkin, N.S., in April was caused by an overheated ball bearing in the conveyor system. (Daniel Dillon/Facebook)

A fire at the underground coal mine in Donkin, N.S., last month was caused by an overheated ball bearing in the mine's conveyor system, according to the Nova Scotia Department of Labour.

Senior executive director of safety for the department, Gary O'Toole, said no one was in the mine at the time and the conveyor was shut down, but it appears the problem started at the end of the previous shift.

"That overheated ball bearing came in contact with a stopped conveyor for an extended period of time, smoldered likely throughout the day resulting in more smoke nearer the end of the day, around suppertime, and that's when it became noticeable," he told reporters on Wednesday.

The fire occurred on April 30 and was quickly extinguished after an automatic sprinkler system kicked in and a crew arrived, O'Toole said.

The department issued a stop-work order, but lifted it last week.

The mine is back in operation and the department is confident it is safe, O'Toole said.

A man in blue shirt and sweater looks off camera.
Gary O'Toole, senior executive director of safety with the Department of Labour, says mine operator Kameron Coal will not face any warnings, orders or penalties as a result of the fire. (Rob Short/CBC)

"At the time of the fire, the conveyor system was not operating and was empty of any coal product," he said.

"The coal seam itself was not involved in the fire and we can confirm that there were no previous compliance actions since the mine reopened back in September that were directly linked to the cause of the fire or to the emergency response on April 30."

O'Toole said the conveyor belts are fire-resistant and take coal from the underground mine to the surface.

He said mine operator Kameron Coal will not face any warnings, orders or penalties as a result of the fire, but the company will now be inspecting the conveyor system more closely after every shift.

"Carbon monoxide monitoring will also be adjusted to a lower level than what's required, which will increase safety for workers and further increase the ability to detect potential fires even earlier," O'Toole said.

He emphasized that the Donkin mine is the most regulated and most inspected workplace in the province and the department has stepped up its unannounced inspections.

The most recent surprise inspection was conducted on Tuesday and no compliance measures were needed, O'Toole said.



Tom Ayers


Tom Ayers has been a reporter and editor for 37 years. He has spent the last 19 covering Cape Breton and Nova Scotia stories. You can reach him at

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