Before a shovel ever hits the ground, oil sands operators begin planning for how they will successfully reclaim the landscape to the standards of regulators and for the benefit of nearby communities.
This means managing tailings, which are the water, sand, silt, clay and other materials that remain when bitumen is separated from ore.
For more than 50 years, industry has been developing expertise in tailings management, and now those learnings have been reviewed and curated in the Deep Deposit Design Guide for Oil Sands Tailings, a best practice guide from COSIA. Deep deposits are tailings deposits more than two metres deep, which are stabilized, capped and reclaimed to a boreal landscape.
“Deep deposits can be an efficient way to manage tailings and may lead to faster closure,” said Paul Cavanagh, senior principal for dam safety, Imperial, and a member of COSIA’s Deep Deposit Working Group, which authored the guide. “And, as the tailings are deposited over a confined area, it provides opportunities to apply new learnings as they develop.”
Beginning in 2015, the working group – including representatives from Canadian Natural, Imperial, Suncor, Syncrude and Teck – began contributing projects, research and any other information they could lay their hands on for discussion. Identifying best practices wasn’t easy, as similar approaches can yield varied results, depending on the unique features of each operation, such as tailings composition and landscape characteristics.
Deep deposit designs also need to be flexible as the expectations of stakeholders change over time. But with persistence and true collaboration, the guide was assembled. “Designing and implementing deep deposits is challenging. But now, anyone — particularly new practitioners — can start with the knowledge in the guide, rather than rediscovering lessons we learned 20 years ago,” Cavanagh says.
Putting community first
When new practitioners pick up the Guide, they’ll find that the first principle of deep deposit design isn’t an engineering rule; it’s engaging with Albertans.
“When you’re looking at what you want to achieve at a tailings facility, you need a comprehensive set of goals. That’s where the community can step forward to provide guidance and traditional knowledge,” Cavanagh explains. “The community has special areas of knowledge and understanding that help the mining operators to develop and implement a deep deposit.”
“The 'aha' moment for the working group and for me in particular was when we realized we're not acting in isolation or trying to find solutions on our own. We need communities and regulators to help us understand what we're proposing and how it's going to affect them,” he says.
Continuing collaboration
“There's a long history of collaboration in the tailings world,” says Lucas Barr, COSIA’s tailings director. “It’s an area that industry felt they didn't need to compete on; they needed to work together to solve the challenges related to tailings management. The COSIA team that worked on this project have been working together for well over a decade on a variety of tailings related issues.”
The working group is sharing the Deep Deposit Design Guide for Oil Sands Tailings with regulators and with industry at the International Oil Sands Tailings Conference in December 2022. But collaboration won’t stop there because in identifying best practices, the group also identified areas where more study is needed.
“The journey is not done. Releasing the technical information is an important milestone in the bigger effort to collaborate across the industry and with community and regulators to share in both the benefits and challenges of development,” Cavanagh notes.
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