In the open-pit mining method of developing oil sands, companies use hot water to separate very heavy oil (bitumen) from the sand. This water is then sent to a tailings pond, which is often a discontinued mine pit.
Tailings are made up of natural materials that can include water, fine silts, leftover bitumen, salts, soluble organic compounds, and solvents added to bitumen during the separation process. These tailings ponds allow the water to be separated and then recycled for reuse in the mining operation, reducing the amount of fresh water used.
Eventually, after being recycled a number of times, the water that is left over – referred to as oil sands process-affected water (OSPW), has to be treated for future reuse and/or safe discharge into the receiving environment. OSPW treatment and management presents a challenge to the oil sands industry.
Why Is this Research Important?
Water management is a challenge for the sustainable development of the Athabasca oilsands in northern Alberta. Most of the water used by surface mining operations is recycled from settling basins (more than 80% of water requirements), with the remaining water taken from the Athabasca River. When the mined oilsands are separated using warm water, the fine clays are dispersed in the water, leading to large volumes of tailings.
Mining operators face two distinct challenges:
- Dealing with the legacy of accumulated volumes of settled sludge in tailings ponds (usually referred to as Mature Fine Tailings or “MFT”)
- Improving the extraction technology to minimize the future volume of tailings and to enable the sustained development of the resource
This research area will focus on the following:
- Tailings management, including minimizing segregated tailings
- Advanced treatment of OSPW and steam-assisted gravity drainage (SAGD) waste streams for reuse and/or safe discharge
- Background aquatic water quality and the toxicological impact of released OSPW after treatment
- Socio-economic evaluation and decision support for OSPW management
Over the first five years, our research will concentrate on the natural sciences and engineering issues listed above. Based on our findings, the socio-economic research would follow at a later time.
Dr Lukas Y. Wick
Group Leader – Bioavailability Group
Department of Environmental Microbiology
Helmholtz Centre for Environmental Research UFZ
Dr Mohamed Gamal El-Din
Professor, NSERC Senior Industrial Research Chair in Oil Sands Tailings Water Treatment
Department of Civil and Environmental Engineering
Markin/CNRL Natural Resources Engineering Facility
University of Alberta
Edmonton, Alberta, Canada