Scott Nauss, the province’s senior director of inspection compliance, says there were no injuries in the incident, which comes after a series of roof collapses last year in working areas of the Donkin mine.
A spokesman for Kameron Coal said “an area of the roof” fell on Sunday.
Shannon Campbell said in an email the mine tunnel was first driven in 1984 and had not had any issues since then.
“The area and nature of this event is unrelated to the stress related issues experienced in the last half of 2018,” he wrote.
Kameron Coal’s operations in Cape Breton were suspended for just under a month in late December before the company was allowed to partially resume activities in one portion of the mine while it prepared a revised roof support plan.
The roof plan approved on May 7 allowed the company to mine in two sections of the Donkin mine totalling 730 metres of added rock face.
In late May, there was also a temporary closure of the mine after a small methane fire broke out and was rapidly extinguished along one rock face.
The last suspension of mining at Donkin due to a roof collapse occurred after Christmas, resulting in the province ordering the company to seek independent advice on a fresh roof plan.
It was the second collapse that month.
The December collapses came 11 weeks after a six-day closure in October, which was ordered after the company didn’t report two massive cave-ins within the required 24 hours.
Inspection documents say both reported collapses had spanned the entire six-metre width of a passage, as slabs of rock fell and left a ceiling gap up to almost four metres deep. The first rock fall ran over 18 metres along the underground roadway, while the second was about a third of the length of a football field.
The delay in reporting the falls resulted in a citation for contravention of the province’s underground mining regulations. There was no fine for that infraction.
The company was fined $2,000 for an accumulation of combustible coal dust and $2,000 for failing to implement the original roof plan in a way that “may have provided an indication that the roof strata were exhibiting signs of potential failure.”
As with the earlier collapses, no workers were injured.
Nauss said the extent of the roof fall in the latest incident hadn’t been determined yet, as inspectors were still examining the damage on Monday morning.
However, he said access to the mine was impeded.