The Alberta Energy Regulator has approved an oilsands giant's plan to manage its vast tailings ponds.
The AER released its decision on Suncor Energy's Millennium mine on Wednesday.
The approval contains concerns about the length of time the company will take to remediate the ponds.
The regulator has added research, monitoring and reporting requirements to ensure efforts go ahead on schedule.
The approval quickly drew fire from some quarters.
The Pembina Institute called Suncor's plan unambitious and vague in explaining how the site will be returned to the landscape.
The regulator made the decision after rejecting an earlier proposal from the company on how it would manage its tailings ponds.
Watchdog group launches petition
SumOfUs, a global consumer watchdog group, has posted a petition demanding that Suncor adopt a more aggressive timeline to clean up the toxic tailings.
It says the petition has so far gathered 22,000 signatures.
The group complains the plan would allow the Calgary-based company to avoid cleaning up toxic tailings waste for 70 years.
"We are deeply concerned about the AER's decision. It is a bad deal for Albertans, Canadians and future generations," said Emma Pullman, campaign manager at SumOfUs.
The group says the plan proposes burying 60 per cent of tailings in "end pit lakes" and covering them with water.
"Suncor is pushing for a cheap, unproven technology, and there is a big chance it won't work," Pullman said in a release.
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