MARATHON, ONT. — A federal agency examining a proposal for a palladium and copper mine near Marathon said the proponent’s plan to deal with waste rock and other contaminants appears basically sound, if long-term monitoring and other refinements to the plan are applied.
“We are generally satisfied with the waste management plan,” Natural Resources Canada research scientist Michel Houle said Thursday during an ongoing virtual environmental hearing into the Generation Mining project.
Houle said if the proposal for the open-pit mine is approved, potential leachate material from acidified waste rock into adjacent waterways would have to be closely monitored.
The proponent should also be prepared to test for palladium residues in waste water, since new research shows that the precious metal can be harmful to fish and other aquatic life, even though there are no current environmental regulations about that, Houle said.
The 30-day hearing is being convened by a three-member panel of experts, who are to examine the evidence and prepare a report that will either recommend that the open-pit project proceed or be declined.
If the mine plan is approved by the federal and provincial governments, the operation would run for 13 years and create 375 jobs a short drive from Marathon.
In a separate presentation by Thunder Bay provincial hydrogeology expert Alisdair Brown, the company was found to have properly identified the risks associated with its proposed ore-waste (tailings) facility.
The facility is to release treated water into Hare Lake, which is known to be a good place for angling.
Brown said water from a rock storage area will eventually migrate to the Pic River over time after the mine closes, but said that would not cause any “measurable change” in the Pic’s water quality.
Waste particles from the mine site will remain there for at least 100 years, the company said. It will take 17-30 years for the pits to fill with water after they’re no longer being mined.
Brown also noted the new science about the environmental impacts of palladium, and recommended long-term monitoring of waterways around the mine site.
Ontario’s Ministry of Environment, Conservation and Parks said Generation Mining needs to increase sampling of local fish species.
De-watering of the mining pits will result in lower levels at adjacent waterways, but the level on the Pic River shouldn’t be impacted, the hearing heard.
Excess water captured at the mine site will be treated before being discharged into Hare Lake, the company said.
Generation Mining has maintained the mine will not cause any adverse environmental impacts as long as mitigation measures are implemented.
Jody Duncan, an aquatics biologist presenting for Biigtigong Nishnaabeg First Nation, said the community needs more information about the potential discharge into Hare Lake of reagent chemicals used to separate metals in the mining process.
Duncan said Generation Mining has yet to explain how it will treat reagents, or committed to measuring them in effluent or in areas downstream from Hare Lake.
Earlier this week, Duncan termed Generation Mining’s water management plan “unusual,” emphasizing that contaminated water must not flow towards the Pic River.
The company has pledged to ensure the Pic — a wide river and major Lake Superior tributary — isn’t negatively impacted.
On Thursday, researchers for Michipicoten First Nation told the hearing that the plan for the mine could increase the amount of phosphorous flowing into the big lake. They said that’s an often “glossed-over” concern because fish in Superior already show elevated levels of methylmercury.
Meanwhile, Vancouver hydrogeologist Kevin Morin ramped up his critique of the Generation Mining project, saying the company has so far failed to come up with a plan to deal with contaminants that dissolve in effluent.
Morin, who is representing citizen and environmental groups in the Thunder Bay district, said the impact of dissolved contamination has been “substantially under-estimated.”
Tests were conducted in lab settings using small samples when they should have been conducted at the mine site, using large piles of rock or crushed drill-core samples, Morin said.
According to Morin’s reading of the company’s documents, a plan to conduct larger tests after mining has started “will be too late.”
Water treatment plants need to be built and made operational before mining begins, so that large volumes of polluted water don’t have to be stored and risk seeping into waterways, Morin told the hearing.
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