The province will allow the Donkin Mine to reopen.
That reopening is contingent on its owner, Kameron Coal, meeting the terms of two work orders issued Tuesday.
The province issued a stop work order on July 15, after a “significant” roof fall in the mine corridor known as Tunnel 2. That came eight days after another, albeit smaller, roof fall in the same tunnel.
In September, the Department of Labour, Skills and Immigration contracted Andrew Corkum, a Dalhousie professor and geotechnical engineer, to study the mine. Corkum completed his report on the mine Monday, but while the resulting work orders are public, the report itself hasn’t yet been released. The Department of Labour says it is conducting a privacy review of the report in order to redact what are termed proprietary details that supposedly could put Kameron at a competitive disadvantage should those details be made public.
Corkum’s study of the mine consisted of a review of 45 documents and a site visit in late October to inspect Tunnels 2 and 3.
“Based on the review, the issue at the tunnels is primarily related to the presence of a mudstone rock in the roof in many locations,” Corkum said Wednesday. “And this clay-bearing type of rock has a tendency to degrade with the presence of water and is very sensitive to water weathering and so on. And so it’s particularly sensitive to the humidity inside of the tunnel. And that’s why there’s a tendency for problems to occur in the high humidity seasons. And there’s really little, if any, record of any problems in the low humidity seasons like the winter.”
For that reason, Corkum suggested a two-phase approach to reopening the mine.
Phase 1 will allow Kameron to reopen the mine in low-humidity winter conditions, which effectively means as soon as conditions of the work order are met. Specifically, the work order requires an update of the hazard assessment classification system and to add monitoring measures in Tunnels 2 and 3.
The work order references the findings in Corkum’s report, but again, the report is not public. The work order does say, however, that “the hazard assessment classification system should not rely on steel set performance unless the integrity of steel sets can be assured through testing.”
Phase 2 requires a more detailed review of the mine’s ground control plan by Feb. 2, which is a more or less arbitrary date thought to come before the higher humidity of spring and summer.
I asked Corkum directly if the Phase 2 directives are connected to a humidity threshold, and he said they were not.
“The humidity level isn’t defined,” explained Corkum. “But instead, I used recommendations based on seasons. It also is tied into the historical record of performance. So there has been really no record of any problems in the winter when humidity has been fairly standard.”
Specifically, the work order tied to Corkum’s Phase 2 recommendation requires a “third-party report by an experienced professional engineer specializing in mining and tunneling to determine the engineering basis for the ground support system in use in Tunnel 2 and Tunnel 3.” Corkum said there are several Canadian firms that specialize in such work.
Corkum said Donkin has a “complicated history”:
The original tunnels were drilled in the 1980s with a tunnel boring machine that was brand new technology. And in fact, at the time, they used cutting edge engineering’s finite element analysis and computer simulations that’s only now becoming commonplace. It seemed reasonable. But when you’ve flooded it multiple times and it has a clay bearing rock that is very sensitive to moisture, it substantially changes the entire situation in the way stability needed to be assessed.
Should government inspectors have identified problems in the mine before the July roof collapses? Scott Nauss, the Senior Executive Director of Safety with the Department of Labour, had this exchange with a reporter:
Nauss: I can say that this is the most heavily inspected workplace in all the province. And in order to operate, the mine operator has to submit plans to the government for approval prior to operation. And we have three dedicated staff that are dedicated to this mine. So a lot of effort went into reviewing the plans and conducting very frequent inspections of this mine. These recent rockfalls occurred on a travelway and a lot of our focus had been in the more riskier production areas where typically, you know, it tends to be the higher risk areas. So as Dr. Corkum mentioned, you know, this mine had been flooded a number of times and that has no doubt impacted the travel areas as well. And now that we’re aware, we’ve taken action to make sure that these areas will be safe.
Reporter: Do you think that anyone like the inspectors missed it, based on their experience like that, that should have recognized that?
Nauss: I wouldn’t say that inspectors missed it. It’s, you know, it’s a combination of the fact that this travelway had been flooded numerous times. And we did have some very high humidity this summer. And we don’t know the impacts of climate change on this mine as well. So, no, I wouldn’t say staff had missed this, but now that we’ve had some serious near misses, we’re taking appropriate action and ensuring that that mine operator puts in corrective measures to prevent a recurrence.
I asked Jill Balser, the Minister of Labour, about the risk of reopening the mine. Our exchange:
Bousquet: Minister, we’re all obviously not saying ‘Westray’ here, but that’s the context of moving forward [with Donkin]. I’m just wondering if you could speak to the risk assessment of, you know, how many jobs are we talking about versus whatever reduced risk is coming through Dr. Corkum’s recommendations. How are you weighing that?
Balser: Thank you for your question, because, of course, Westray is on the minds of Nova Scotians, and for those who were directly impacted by the catastrophe that happened. We think about that every day. And I know one of my first events to be able to attend as minister was the 30th anniversary. And I think that’s when for me, not growing up in a mining community, but growing up in a fishing community, could link that to the impact of what it means for people growing up in that community. And I think that that informs our direction as a department to make sure that workplace safety is the top of mind of everything that we do and understanding the complexity of this particular work environment. We needed to make sure that we had as much information as we possibly could, especially after the two rockfalls that happened, to be able to pause and say what is really going on here and to be able to now have the findings from Dr. Corkum, I think is going to inform how we work as a department and how the mine can work and operate even more safely going forward.
Bousquet: And you’re comfortable this is a risk worth taking?
Balser: We know the mining is inherently risky, but I think for the department, safety is always a priority. We have to make sure that we have done all the work that we possibly can to ensure the safety of the miners. And knowing that we took that time to pause, contracted Dr. Corkum to do his work, we now have findings that we may not have had otherwise and it will inform the work that we do going forward.