Fluid tailings are common to all surface mining operations and are comprised of the water, clay, sand and residual bitumen that is left over when the bitumen is separated from the sand. Tailings are stored in deposits that help separate the solids from the water, in order for the water to be reused. Reclamation of tailings ponds can be challenging as it can take decades for the fine particles like clay and silt to settle.
At our Kearl operation, our tailings management strategy is to minimize the fluid tailings we produce to ensure timely reclamation to support a diverse and self-sustaining ecosystem. We do this by treating tailings material right away through the use of thickener technology that intercepts the tailings produced by the extraction process and processes them into a paste. This process increases our ability to remove, and more efficiently recycle water, reduce our freshwater requirements, and reclaim our tailings faster.
In 2021, Imperial saw a step change in our “ready-to-reclaim” treated tailings volumes from approximately 65 per cent to more than 80 per cent of our inventory. This means that over 80 per cent of our treated tailings material is now in its final resting place and on the trajectory for full reclamation. We anticipate this value will fluctuate over time depending on the tailings materials being treated and the treatment method.
Tailings pond management approach
We develop detailed tailings management plans that incorporate industry best practices to help ensure tailings storage areas are designed for integrity and maintained accordingly. We also ensure ongoing monitoring and have comprehensive emergency response plans in place.
Imperial’s long-standing collaborative relationships with local Indigenous communities is core to responsible oil sands development and operations at our Kearl site. We regularly engage with communities through site tours, environmental stewardship discussions and tailings management plan reviews to develop solutions to tailings management together. We hold annual tailings forums working collaboratively with Indigenous groups to identify areas of interest and importance, which allows for focused discussion on priority issues. As a result, we have been recognized as industry leaders for our engagement and collaborative approach in this space.
Imperial is conducting a multi-pronged pilot study evaluating various treatment and deposition approaches with a goal of getting to “ready-to-reclaim” faster. With this pilot we are looking at the use of different chemicals, common in wastewater treatment, and evaluating how different tailings materials can be co-deposited. We have already seen tremendous success and are working to adopt new deposition methods at Kearl as a result.
As a member of COSIA, oil sands operators share tailings research with other oil sands operators to ensure we are collectively improving tailings management as an oil sands industry.