Dirty mines leave one positive legacy: NWT engineering
Clean-up work at the territory’s abandoned mines is leaving an engineering legacy already helping to keep the NWT cleaner.
That’s according to the project manager behind federal remediation of the Bullmoose-Ruth complex of former gold and tungsten mines, around 90 km east of Yellowknife.
A team has been working to clean up seven sites in the area since 2015. That work is now complete and Bullmoose-Ruth is being prepared for longer-term monitoring.
Ron Breadmore, the project manager for the clean-up, briefed reporters on the $22.5 million operation on Monday.
Nine mine openings – including a 200-ft open shaft and another “disaster waiting to happen” which could have potentially resulted in a 600-ft drop – were sealed, 28,000 metric tons of tailings and contaminated soil were cleaned up, and petroleum hydrocarbons were removed from the land and surrounding lakes.
Breadmore said the on-site contractor, Rowe’s Outcome Joint Venture, had made particularly innovative use of cold-weather working that could be adopted elsewhere in the North.
Workers at the site of the old Bullmoose mine devised a way to construct a landfill during winter. This is not usually attempted as ice between layers of soil and waste could lead to the landfill shifting or collapsing if it later thaws.
However, the Bullmoose remediation team found a means of creating the landfill in winter using only soils with a certain moisture content. The work took five weeks and, according to Breadmore, the landfill “survived its first winter no problem.”
Breadmore says this and other innovations allowed the project to complete much of its work on time or ahead of schedule, and saved Canada money in the process. (The federal government has, since 2005, spent around $810 million cleaning up contaminated NWT sites alone. Giant Mine, outside Yellowknife, is predicted to cost up to another billion by itself.)
In depth: Contaminated NWT: Counting the cost
“We share all of these [cold climate construction] approaches with industry,” said Breadmore, pointing to events like the Geoscience Forum held in Yellowknife each fall.
At this year’s forum, a Bullmoose-Ruth remediation project officer will present about how their team responded quickly to changing conditions and knowledge gathered on-site to do a better job, and how the team extensively engaged with affected communities.
As an example, Breadmore said, the team altered the course of its winter road to the contaminated mine sites after owners of nearby cabins and lodges expressed concern.
More: Federal government’s Bullmoose-Ruth remediation website
None of the past mine operators at Bullmoose-Ruth were required to make any security deposits guaranteeing care for the surrounding environment, as it was not standard practice at the time. (The Bullmoose mine was the last in the area to shut down, in the 1980s.)
In the 21st Century, significant securities to guard against the collapse of mine operators and huge clean-up bills are commonplace. Breadmore feels work at sites like Bullmoose-Ruth is helping private companies, and other mine sites, do a better job of looking after their sites as they go.
“It wasn’t always pleasant for the crews at minus-30, minus-40, but they pushed the winter envelope. Our work does open those doors … to professional engineers,” said Breadmore.
“They can see these approaches. Industry sees how we remediate sites and they do business differently these days, they do progressive remediation as they go.”
Breadmore used Con Mine, in Yellowknife, as an example. Earlier this month, in a presentation at a public hearing, Con owner Miramar said the former gold mine’s clean-up was a “rare example of a privately funded, successful mine closure in the North.”
“I used to be on that file in the day,” said Breadmore, describing taking his dog for a walk near the Con site recently. “It was just like walking through a wheat field in the Prairies, they’re doing such a good job.”
‘Alarmed’ by report
Not everyone has always held such a rosy view of clean-up work at the Bullmoose-Ruth sites.
In spring 2017, federal inspectors documented a range of problems in a report on the remediation work, demanding a series of immediate corrective measures for issues like hydrocarbon spills, operating an unauthorized quarry, and a lack of drip trays beneath equipment.
After the inspectors’ comments were published by the CBC, the North Slave Métis Alliance (NSMA) wrote to the project, saying: “NSMA is alarmed to learn that [the project team] has violated many of the Land Use Permit conditions that are meant to protect the environment … please keep NSMA informed promptly and directly, and not through the Public Registry or the media.”
Breadmore said the report had caught the project “at our worst” and noted inspectors were far less troubled on subsequent visits. He added feedback from the Yellowknives Dene First Nation following a recent visit “was really positive … they were really happy with what they saw.”
A March 2018 report had only “minor concerns” and, later in the same month, inspectors declared themselves “pleased with the progress and the condition of the site.”
With the clean-up now essentially complete, the seven Bullmoose-Ruth sites move into a longer-term monitoring and maintenance program at a projected cost to the federal government of $6.9 million (included within the $22.5 million overall price tag).
A monitoring plan created with communities will assess water quality, stability of engineered structures, sediment-erosion, revegetation, and health and wellbeing of local wildlife.
Meanwhile, several old items from the site have been donated to interests in and around Yellowknife. Old ore carts have been transferred to the Yellowknife Historical Society while a 1940s transport truck, belonging to a forefather of the NWT’s Robinson trucking dynasty, has been returned to the family, said Breadmore.