Environment and Climate Change Canada raised a litany of concerns with Teck Resources's proposed Frontier Oilsands mine during the last week of hearings.

Environment Canada was among several federal government departments that presented on Monday during the public hearing for the mega oilsands project.

Frontier is a $20.6-billion mega mine that's undergoing public hearings in Fort McMurray before a joint review panel established by the Alberta Energy Regulator and the Canadian Environmental Assessment Agency.

Frontier, which was first proposed as a four-phase project in 2011, would be built in two phases of 170,000 barrels-per-day (bpd) and 90,000 bpd with a planned mine life of 41 years.

The mine's lease area, 110 kilometres north of Fort McMurray, covers 292 square kilometres.

Environment Canada joined the region's First Nations in raising concerns about the impact of the mine on the health of the Ronald Lake Bison herd. The herd's current range overlaps with the Frontier lease area.

Map showing the location of the Ronald Lake Bison Range in relation to the Teck Resources Oilsands Frontier mine. (CBC News Graphics)

Susanne Forbrich, a regional director and the team lead for Environment Canada at the hearing, told the panel there is concern the mine would cause significant habitat loss for the wood bison herd.

Forbrich warned a loss of habitat would result in the depletion of the herd and facilitate disease transmission, as seen in other herds in Alberta.

"It is Environment and Climate Change Canada's view that the project represents a high risk to the Ronald Lake herd," Forbrich told the panel. "And that some of Teck's mitigation measures are potentially uncertain or ineffective."

Current bird deterrents don't work: Environment Canada

Forbrich also raised concerns that the mine would kill migratory birds that breed in Wood Buffalo National Park.

Frontier represents a "high mortality risk" particularly for whooping cranes — one of North America's rarest birds — and other migratory species, said Forbrich.

Environment Canada fears the mine would create more tailings ponds, which the cranes could mistake for a lake despite bird deterrent efforts, she said.

"This conclusion is based on evidence that whooping cranes land near the proposed mine, that whooping cranes have landed at existing oilsands mines and at tailings ponds despite the availability of bird deterrent systems," Forbrich told the panel.

Environment Canada submitted a list of recommendations for bison, whooping cranes and other wildlife the proposed mine would impact.

When it comes to bison it's calling for Teck to fund independent studies to understand the impact of the mine on the bison.

For whooping cranes, it called for the reduction of the size of tailings ponds and for the use of mitigation measures such as drones to patrol the area, and to fund studies into cumulative effects of the oilsands on migratory birds.

In documents filed with the joint panel Teck said it disagrees the Frontier Mine would pose a significant risk to the bison or migratory birds. But the mining company has agreed to fund studies to monitor bison and bird health and the effect of its mitigation measures.

Teck, First Nations and other groups are scheduled to cross examine Environment Canada and other federal agencies on Tuesday and over the next three days — the last week of the public hearings before closing statements.

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