Giant Mine clean-up work, the bulk of which is set to begin next summer and continue over much of the next decade, is expected to need several million cubic metres of rock material.
Where that aggregate is sourced, however, is yet to be determined.
An annual progress update to city council by the Giant Mine Remediation Project team took place during Monday’s government priorities committee meeting in the midst of a citizen outcry over a proposed quarry near Vee Lake and Giant Mine.
That quarry, which many residents say will disrupt a popular recreational area near Ranney Hill, is expected to be a supplier for aggregate in time for when the remediation project needs it.
Council heard that the remediation team is expecting to have a Type A water licence awarded by the Mackenzie Valley Land and Water Board in July or August.
Land use permit is expected in May.
Remediation work would then begin in the summer of 2021.
City councillor Niels Konge asked Natalie Plato, deputy director of the remediation project, about the quantity of rock her project will require over its course.
Plato said the project team did some engagement work last December to help identify what rock material might be needed, and although the team aims to produce much of it onsite, there is a possibility that supply will need to be sourced off-site.
“For that work we might need to borrow supply and where we get that is still open to discussion,” she said of the remediation project. “If we produce it ourselves or purchase it off site – we are open to both.
“We are still in final design stages but we anticipate about three million cubic metres of coarse grain material (gravel, boulders, rip rap, anything that can be produced from a quarry) and about half a million cubic materials of fine grained materials (clay, silts, smaller sands).
“Of that, we anticipate from our project works we’ll be able to generate 2.5 million cubic metres of coarse grain ourselves. We think we will need to be able to produce it ourselves or outsource around (730,000) cubic metres of coarse grain material.”
She said the team is putting out “a request for information” for potential local suppliers this month to get feedback on what can be provided to the project and what the chemistries of supply will involve.
“The project agreed to put out a request for information this month which will look at what any of the suppliers could supply and what the material will look like because we certainly have geo-chemical requirements for any material on site,” she said. “It can’t be acid generating and depending on where it comes from, arsenic levels can’t be higher in this area. So we wouldn’t want to contribute to the loading of water we have to treat.”
That same evening, city council voted unanimously on two bylaws at third reading that will seek a leasehold for Commissioner’s Land near Vee Lake for a quarry that would be operated by Det’on Cho Corporation.
Representatives from the company said Monday night that if approved, its quarry will mainly function to provide aggregate for the remediation project. This is largely because the aggregate supply has been identified as close to the remediation site and of non-acid leaching properties.
The corporation has stated that based on a topographic survey and environmental assessment that the quarry would be able to “produce good quality materials with
an approximate quantity of five million cubic metres of aggregate,” according to city minutes from the Feb. 17 Government Priorities Committee meeting.
“When looking at opportunities, we do what is called a demand schedule so we looked at all opportunities and in this case our anchor contractor opportunity is Giant Mine which drives the bulk of the volume over the 10 years,” said Paul Gruner, CEO and president of Det’on Cho Corporation.
“If Giant Mine is not part of that does it have to be at that site? No. This is largely based on strategic positioning to supply for the Giant Mine site. Does that mean that we will pull aggregate from that for other uses? Yes.”