Imperial and Alberta regulator knew for years about oilsands tailings seepage, documents show
CBC
Documents filed by Imperial Oil Ltd. show the company and Alberta's energy regulator knew the Kearl oilsands mine was seeping tailings into groundwater years before a pool of contaminated fluid was reported on the surface, alarming area First Nations and triggering three investigations.
"They knew there was seepage to groundwater," said Mandy Olsgard, an environmental toxicologist who has consulted for area First Nations.
"The [Alberta Energy Regulator] and Imperial decided not to notify the public and just manage it internally."
Imperial said in a statement that seepage was anticipated in Kearl's original design. Spokeswoman Lisa Schmidt said the company has kept both the regulator and area communities informed.
"We have been working to address the areas of shallow seepage from our operating lease area," she said.
"We recognize there are concerns regarding water quality, and we take this very seriously."
Alberta Energy Regulator spokeswoman Lauren Stewart said the agency is committed to strong oversight of the Kearl site.
"It is of upmost priority that downstream water continues to remain safe, and any potential impacts to the public are both mitigated and communicated transparently," she said in an email.
"During this period, there were no signs that indicated the system was not functioning according to its intended design."
Olsgard points to groundwater monitoring reports filed by Imperial to the regulator. The 2020 and 2021 documents acknowledge tailings were seeping from the ponds that were supposed to contain them.
The tailings were detected at monitoring wells within the mine's lease area, about 70 kilometres north of Fort McMurray.
Earlier studies suggest those results could have been influenced by natural variation or chemical processes in the soil.
The 2021 document says little room for doubt remained.
"[Process affected water] seepage, or potential early arrival of [such water], was reported at 11 monitoring locations in 2021, indicated by trends and/or [control objective] exceedances in multiple [key indicator parameters]," it says.