Our industry is working to reduce the size of tailings ponds and the time needed to restore them.
The Issue: Finding Solutions for Reducing the Oil Sands Footprint
Oil sands are developed through two methods: open-pit mining and deep underground (in situ) production. In open-pit mining, companies use hot water to separate very heavy oil (bitumen) from the sticky sand. This water is then sent to a tailings pond – often a discontinued mine pit. The tailings are a mixture of water, clay, sand and residual bitumen. Tailings ponds allow the water to be recycled in the mining operation. While just 20 per cent of oil sands are produced through mining, the tailings ponds created are large and impact the landscape.
For oil sands mines, planning to restore areas is done before the first shovel of earth is moved. Returning a tailings pond to a sustainable landscape takes many years, because the fine silts in the ponds settle to the bottom very slowly. Once settling occurs, we remove the water and send it to another area of the mining operation. When the pond is properly drained, we contour it, replace topsoil and plant vegetation, trees and shrubs. We then assess the soil and vegetation on an ongoing basis to ensure we’re achieving the goals of the original plan. When the provincial government determines the area has met their criteria for reclamation (land that is restored to a sustainable landscape), they will certify it and the land will be officially returned to the Province. Although no tailings ponds have been reclaimed to date, Suncor Energy Inc. is working to have its first pond reclaimed in 2010.
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What We’re Doing: Finding Innovative Ways to Restore Tailings Ponds
Our industry is committed to reducing the size of tailings ponds, as well as the time needed to return them to sustainable landscapes. We believe research into and development of new technology will help us achieve this goal.
Technology and Innovation
Companies are developing new techniques to help restore tailings ponds. For example, Shell Canada Limited’s Albian Sands project uses thickeners in the tailings that allow water to be recaptured from the tailings, before they are released into the pond. This reduces the size of the pond and the amount of water the company uses in production.
Another innovative practice is at Canadian Natural Resources Limited’s Horizon project. Carbon dioxide (CO2) is captured from the facility and mixed with silts in the tailings, which causes a reaction that forms a solid, and allows the silts to settle more quickly. This process has multiple benefits: the CO2 is permanently trapped in the silts, and most of the water can be recycled while it’s still hot, so less energy is needed to reheat it. This results in reduced greenhouse gas emissions and smaller tailings ponds.
A number of universities and agencies are also researching new methods to speed up the separation of water and silts, faster recycling of water and new ways to return the land back to a sustainable landscape.
Tailings Technology: Reclamation Speeds Up
Suncor Energy Inc. reports on October 23, 2009 that it has submitted a regulatory application for changes to the company’s oil sands mining and extraction operations that target significant improvement in the speed of reclamation of oil sands tailings at the company’s existing oil sands operations near Fort McMurray.
Innovation Story: Shrinking the Tailings Pond
Canadian Natural Resources Limited (Canadian Natural) is using new methods resulting in less space for fluid tailings, accelerating the process of reclamation and reducing greenhouse gas emissions.
Canadian Natural is commercializing promising new ways to manage the tailings pond at its Horizon Oil Sands facility, 70 kilometers north of Fort McMurray. These new methods will require less space for fluid tailings, accelerate the process of reclamation and reduce greenhouse gas emissions.
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