Another spill at Kearl mine reported in northern Alberta

The Imperial Oil logo at the company's annual meeting in Calgary on April 28, 2017. THE CANADIAN PRESS/Jeff McIntosh

There has been another spill at Imperial Oil's Kearl facility in northern Alberta, the Alberta Energy Regulator (AER) has confirmed.

"On Nov. 13, Imperial Oil reported to EDGE that there had been a release of water with Total Suspended Solids (TSS) more than their approved provincial regulatory limit from a sedimentation pond at their Kearl site," Teresa Broughton of AER wrote in an email to CTV News Edmonton. "Initial reports indicated approximately 670m3 of water was released into the Muskeg River."

According to the AER, the water was not processed water from a tailings pond but drainage from the surrounding landscape.

"The pond is a water treatment pond or a polishing pond that accepts water from muskeg drainage, overburden dewatering, overburden, and reclamation material storage areas or any areas not yet disturbed by mining and discharges to the environment.

"In this case, the pond collects and discharges run-off water into the Muskeg River in accordance with the AER-approved regulatory limit of 30 milligrams per litre."

Boughton said Imperial Oil has taken water samples upstream and downstream from the release, and the results showed the release into the river was 110 milligrams per litre over the approved limit.

Follow-up tests on Nov. 14 and 15 showed the levels of TTS downstream of the release were now within range of background conditions, Boughton added.

The spill happened because of a culvert failing, AER says.

A spokesperson for Imperial Oil says the company is now repairing the culvert and will continue to collect samples from the area.

"We continuously work to ensure our business operates in a safe and environmentally responsible manner. When this incident occurred, we took immediate steps to put mitigations in place and notified regulators and communities," Lisa Schmidt said in a written statement to CTV News. "We are sorry this happened and are applying the learnings from it to inform any additional preventative measures that are identified."

The AER is also reviewing water sample quality areas to determine any potential impacts to fish and their habitats.

Imperial Oil and the AER say they have contacted Indigenous communities in the area.

In May 2022, workers at the Kearl facility discovered what was first called "discoloured water" seeping from a tailings pond at the mine.

The substance was later confirmed to be groundwater mixed with tailings from the mine.

Imperial Oil failed to notify the neighbouring Athabasca Chipewyan First Nation until February, when 5.3-million litres of contaminated surface water overflowed from a containment pond.

Federal inspectors found the contaminated groundwater and surface water to be hazardous to wildlife.

With files from The Canadian Press