HALIFAX -- Nova Scotia's labour minister says the threat of closure is his best tool to penalize a coal mine that broke mining rules by not reporting two massive cave-ins within the required 24 hours.

Labi Kousoulis says issuing fines is far less potent than telling Kameron Coal, Canada's only underground colliery, it can't operate the Donkin mine in Cape Breton unless his officials approve a safe roof support plan.

"On two occasions at least, we've shut the mine down completely," he said in an interview.

"So, regardless of what administrative penalties we have in place, we still have the tool of the strongest penalty which is 'We're shutting you completely down,' which is much greater than a fine."

Kousoulis was reacting to inspection reports obtained by The Canadian Press that showed the colliery broke provincial regulations by not reporting a massive cave-in on Sept. 18 until inspectors visited 15 days after the rock crashed down.

According to the inspection reports obtained by The Canadian Press, mine management also didn't initially report a second, Oct. 1 cave-in until the Oct. 3 arrival of the inspectors. There had been two other cave-ins which aren't described in detail in the reports.

The 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 s. 32.1(f) of the province's underground mining regulations, which require a report within 24 hours of an unplanned roof fall that results in conditions that include a blockage of the mine roadway, a disruption of work for more than an hour, and/or an impairment of ventilation in the mine.

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 - referred to in Canadian mines as a ground control plan - in a way that "may have provided an indication that the roof strata were exhibiting signs of potential failure."

Six days following the revelation of the cave-ins, the Labour Department allowed the mine to resume operations after approving more roof support systems and more monitoring.

Almost 11 weeks later, while the mine was on a Christmas break, there was another cave-in on Dec. 18, then on Dec. 28 there was another collapse in the same general area.

As with the earlier collapses, no workers were injured. The mine's licence to operate was suspended after the Dec. 28 incident, with a requirement that the operators provide a revised plan for their roof support system.

Kameron Coal, a subsidiary of U.S.-based Cline Mining Corp., has declined to specifically comment on why it didn't report the cave-ins until the inspectors arrived, though the safety reports indicate they had been taking measures to shore up the roof in the areas of the collapse.

In an e-mailed statement sent last Thursday, Shannon Campbell, vice president of project development at the Donkin mine, said a revised roof support plan was sent to the Nova Scotia Department of Labour and Advanced Education on Jan. 16 and after further consultations a new procedure was submitted on Jan. 31.

The mine has been given approval to resume production on one panel in a limited area. Meanwhile, the department has contracted an independent third-party expert who is expected to make a site visit within the next two weeks.

"We are focused on safely completing the work at hand and look forward to progressing through the details of the new ground control plan with the provincial regulators. Kameron Coal is confident that the plan submitted is sufficient to further minimize the risk of roof falls," said Campbell in the statement.

However, Tammy Martin, the labour critic for the provincial NDP, said the level of fines given out, and the lack of a fine for not reporting within 24 hours, are "ridiculous."

"At the end of the day ... it is a matter of life and death. And I believe that these miners' lives are worth a lot more than $2,000. That's a slap on the wrist," said Martin, who is also the member of the legislature for Cape Breton Centre.

Harold Carroll, the executive director of the occupational, health and safety division, said in an interview the fines begin with $1,000 for contravening the health and safety regulations and can go up to $2,000.

Departmental guidelines state the decision to impose a fine is based on whether the infraction posed "a serious risk to health or life," meaning the worker was exposed to a hazard that could reasonably be expected to cause serious injury or death.

Carroll said that in its two years of operations, Kameron has received 63 orders telling them to comply with a mining rule, 63 warnings of failure to comply and 11 fines.

The senior civil servant said under the guidelines, his inspectors saw "the significant levels of combustible dust" accumulated along the floor in an entry area of a mine corridor to be the higher risk than the failure to report the cave-ins.

He also noted a $2,000 fine was given out for the roof falls by an inspector who believed the original roof plan, "if fully addressed, may have provided an indication the roof strata was exhibiting signs of potential failure."

"The lack of a notification is a concern and we addressed that concern. Did we feel it was high enough an issue to warrant a penalty? No," he said in an interview.

Kousoulis said "fines of $2,000, $20,000 and $200,000 a lot of time are a drop in the bucket for some companies."

"What we do in this mine (is), we shut it down if we're not happy and we don't feel it's safe for the workers to go back underground."

Still, Steve Hunt, a director of the United Steelworkers' western region and a union safety expert, said fine levels in Nova Scotia are in the low range, and a failure to notify regulators of cave-ins should draw a penalty.

Hunt, who testified at the inquiry into the 1992 Westray mine disaster in Plymouth, N.S., that killed 26 men, said "failure to report is a violation of the act," and added that Nova Scotia of all provinces should be aware of this given its history of disasters.

"Anywhere there's a possibility of injuring or killing of a worker, it's a high risk."

Other experts, including a former director of inspections of Kentucky's coal mines, have suggested the mine have weekly inspections, rather than bi-weekly.