Environment Canada, DFO want more details about mine clean-up plan

DENISE RIDEOUT

Environment Canada and the Department of Fisheries and Oceans say the owners of the Nanisivik zinc mine have to do more to reassure them that contaminants on nearby land and waters will be cleaned up after the mine closes this fall.

In reports released last week, the two federal government departments say the mining company is too vague on some of its plans to restore the mine site to an environmentally sound state.

Nanisivik will stop mining zinc on Sept. 30. The mine’s owner, CanZinco Ltd., is shutting down the 26-year-old mine because zinc prices are low and the once-rich ore reserves have run out.

In closing the mine, CanZinco had to submit a detailed plan to the Nunavut Water Board that outlines how it will clean up old equipment, buildings, waste rock, tailings and contaminated soil from the site.

Following a public hearing later this month, the water board will decide whether to grant CanZinco an “abandonment and reclamation” license, which will allow it to go ahead with the closure and clean-up.

As part of the licensing process, agencies that have a stake in the mine clean-up — such as Environment Canada and DFO — can make their own comments about the plan.

Last week, both departments submitted reports containing their concerns and questions to the water board.

Environment Canada, which is responsible for environmental protection and management, says CanZinco’s plan to monitor the mine site for five years following its closure isn’t sufficient.

“It is unlikely that five years will be long enough to establish that water quality has been stabilized, and that there is no mobilization of contaminants,” its report reads.

Environment Canada is recommending the company keep watch on the site for as long as 10 years.

As for the actual clean-up, Environment Canada questions a few of CanZinco’s approaches.

In particular, Environment Canada isn’t entirely convinced the company’s plan to cover the dump with 1.25 metres of shale will ensure that permafrost will form. CanZinco is relying on the permafrost to freeze any contaminants at the dump and preventing them from seeping into the ground.

Environment Canada also wants to know how CanZinco will deal with the 2,000 barrels of oil at the dump. “Closure of the landfill must ensure waste oil does not migrate out,” the report says.

As for the Department of Fisheries and Oceans, its concerns have more to do with contaminants seeping into waters around the Strathcona Sound during the clean-up phase.

Over years of mining, concentrations of metals in Twin Lakes Creek have increased, DFO’s report says. Between 1995 and 2000, for example, lead concentration increased in one area by 34 times.

“This evidence suggests that past operation at Nanisivik mine negatively affects water quality in Twin Creek, and ultimately results in metal loading in Strathcona Sound,” the report says.

DFO suggests CanZinco undertake sampling of marine sediments near the mouth of Twin Creek.

The department also wants the company to test the marine soil around the mine’s dock to find out the extent of contamination there. Zinc, lead, cadmium and hydrocarbons have likely built up, DFO says. It suggests that a better picture of the level of contamination is needed the guide clean-up of the area.

DFO and Environment Canada will present their reports to the Nunavut Water Board at a public hearing in Nanisivik on July 22.