"We will have to adapt and change as new practices and technologies emerge and as we continue to work hard to meet regulatory requirements.” - Stuart Nadeau, Imperial Oil
Long before start-up of the Kearl Oil Sands Project, Imperial Oil began working on its long-term reclamation and closure plans.
“Kearl is an incredibly complex undertaking,” says Stuart Nadeau, environmental and regulatory manager for the project. “We think we’ve got a comprehensive reclamation plan based on what we know today, but we will have to adapt and change as new practices and technologies emerge and as we continue to work hard to meet regulatory requirements.”
Nadeau says over the decades the mine will operate, there will be many advances in reclamation technologies — from restoring wetlands to shrinking tailings. “Every year, we advance things from a research standpoint. I have every reason to believe that will continue.”
In the meantime, part of the reclamation plan for Kearl is to build three small lakes connected to the existing Kearl Lake. These lakes will replace the aquatic habitat that will be removed when many of the small streams and tributaries are removed as the mine progresses. Construction of the first lake is already complete. While replacing the streams is not feasible, the new lakes will be deeper, allowing fish to survive the freeze over winter.
Kearl will channel water through a series of man-made wetlands and lakes to further filter and naturally treat the water before it’s discharged back to the natural watershed.
Tailings from the mining and extraction process will initially be stored in an external tailings area that’s surrounded by an extensive network of monitoring and collection wells to minimize seepage. As mined-out areas become available, the fine tailings will be directed to thickeners to concentrate the solids and recycle water back to the process. The concentrated tailings will then be co-deposited along with the sand from the extraction process into the mined-out areas of the pit, then covered with overburden and topsoil, facilitating the ongoing reclamation process.
In developing reclamation plans for Kearl, Imperial is working closely with neighbouring oil sands operations — Syncrude and Shell — to make sure drainage, reclamation and closure plans are integrated. “This was unheard of before. But people now realize that, to put things back together, we have to work together,” says Nadeau. “This requires a huge industry-wide effort, including sharing information and utilizing best practices.”
Stuart Nadeau, Imperial Oil's
environmental and regulatory
manager for Kearl oil sands project
Kearl is expected to operate from about 2012 to at least 2050, with only some of the land being mined at any one time. Many areas will not be affected for up to 25 years. The reclaimed landscape will be a mix of native plants and forest with lakes and wetlands. So far, there has been initial ditching, drainage and clearing of the site. Timber has been salvaged for sale and topsoil and peat have been stockpiled to use in reclamation.
Nadeau says there are two key words about Kearl’s reclamation plans. “First, it’s progressive — we want to get in and begin the environmental work earlier. Second, it’s adaptive, which means the plan will change as new technologies and learnings emerge, and as societal expectations about the desired end point of reclamation continue to shift.”