CANMORE – It was an airshaft that could not be found.
Through examining historic mine maps, geotechnical work that involved drilling thousands of holes in the ground and using 3D mapping – efforts on the part of Three Sisters Mountain Village identified mine works on its property prior to development. However, TSMV could not find a 56-metre deep airshaft created in 1938 as part of the No. 4 mine.
When a nearby pipe to a residential development burst in 2010, sending water through the ground and displacing the earth around it, the airshaft known as B14 dug to access the No. 4 coal seam was finally found.
It was underneath a municipally owned parcel of land used for a pathway in the subdivision area of Dyrgas Gate, and for those involved, it was an example of successful mitigation of old mine workings.
A newly adopted provincial undermining regulation for Canmore and its related guidelines for municipal infrastructure on undermined lands would see the airshaft mitigated to a higher standard if it were to come forward as part of a development proposal today.
“We have a fairly extensive record [identifying hazards from former coal mines] that has been developed over the long life of the mines and in the 40 years plus since the mines ceased operations,” said manager of engineering Andy Esarte.
“That helps you define the risk and there is a good technical body of knowledge about how to mitigate that risk. By raising the standard for municipal infrastructure and the study and mitigation of those lands, it will help address some of those issues.”
Esarte said the new guidelines, were they to be applied to the B14 airshaft, would not have approved the pathway mitigation approach taken, which in addition to placing it in an area without structures on top of it, saw a filter fabric overlaid in the general area.
“Going forward, we would not make that decision again, but mitigate it to a higher standard,” Esarte said, adding that would have included going down to the bedrock and putting mitigation measures in place there.
The recently updated undermining review regulation was one of three put in place by the province in 1997 under the Municipal Government Act in addition to other mitigation measures related to developing undermined lands.
For properties that were located on affected lands, undermining reports are required to be registered on title.
The other two regulations removed identifying and mitigating undermining from the development approval process for the Town of Canmore altogether and made the province liable.
The community and its elected leaders at the time were clear to both the developer and the province – which approved the resort and residential development project through the 1992 Natural Resources Conservation Board decision – that Canmore taxpayers would not accept liability in the event property was damaged due to former mine workings.
“These three regulations provided a framework of exemption and indemnifying the Town from liability and outlined how technical reviews should be undertaken on undermined lands prior to development,” Esarte said.
“These regulations also included a provincial requirement for a developer to maintain insurance to protect the province and property owners from losses.”
Esarte said the municipality approached the province to take responsibility for the 2010 sinkhole, as it was undermined land and the province was liable under the Town of Canmore’s understanding of the regulations to cover the cost of fixing the problem.
However, officials were surprised to learn the province interpreted the regulations to apply only to private property, and not to any land that was subsequently transferred from the developer to the municipality. Under the MGA, there are several types of lands a developer may be required to provide at subdivision, including roads, deep and shallow utilities, municipal reserve land for parks or trails, lands to build community housing and lands for schools.
“We were not protected for this particular type of loss,” Esarte said.
“The province, in this case provided a [$400,000] special grant to remediate the sinkhole.”
He said while the province paid for the work, the municipality cannot expect to receive funding in the future for similar circumstances.
“This raised a number of concerns for us,” he said.
“It appears the residents and the Town are assuming the full risk for undermining loss [for municipally owned land and infrastructure].”
While there are engineering standards to develop private property on undermined land, Esarte said the Town did not have a standard for accepting undermined land in the form of municipal property.
When the province announced it was reviewing regulations under the MGA, it subsequently agreed to look at the three related to undermining in Canmore.
However, only one regulation was updated and it was not the ones the Town of Canmore took issue with regarding which party is liable for problems that occur on municipal property.
The undermining review regulation was updated to clarify the engineering and approval process, insurance requirements and associated guidelines.
Originally, the regulation set out the developer is required to maintain insurance, but the type, amount and period of time was up to the minister of municipal affairs.
Now, the developer must have general liability insurance in place for two years after it transfers title of a property to a new owner and $5 million in insurance coverage for 10 years must be obtained by the engineers involved in the review process for an undermining assessment report.
That report can be an area mining impact overview report, a subdivision mining impact assessment report or a project undermining assessment report.
In addition, a, independent third-party reviewer checks that work to ensure the guidelines have been met. They must also carry the same insurance as the project’s engineers and all insurance certificates are required to be provided to the province annually.
QuantumPlace principal Chris Ollenberger, who has been at the helm of TSMV’s development efforts for almost 20 years, said the updated guidelines are a positive step forward for the community.
“These are really positive in terms of process and setting expectations,” Ollenberger said, adding the guidelines to evaluate proposed development on undermined lands had not been updated since they were created.
“The new guidelines, that is where the rubber hits the road and it is beneficial to the Town and Three sisters to have [clear direction] of when and what steps should be taken.”
But the risk to the municipality having to pay to fix any issues that arise in the future remains.
“If there are settlements of land that damages [municipal] structures or infrastructure, we are quite likely at risk of having to bear the cost of that damage,” Esarte said.
While the changes that ultimately came into effect as of April 1 were not the ones the municipality originally sought, Esarte said the new guidelines require a standard of mitigation for pathways and roads that is equal to those for privately owned property.
Additional insurance requirements for engineers, he added, provides extra protection against errors and omissions.
“The Town has no role in undermining,” Esarte said.
“Our role is largely focused around ensuring that the work is done properly because we are basically a buyer of municipal land and infrastructure. Like any other buyer, we need to do our due diligence before we receive those lands and infrastructure.”
Mayor John Borrowman said the work on the new guidelines is similar to the hazard identification and risk mitigation process adopted for steep mountain creeks after the 2013 flood.
“We cannot eliminate the risk entirely, but through engineering studies and development of infrastructure, we can reduce the risk ... to as low as reasonably possible,” Borrowman said.
