Investments in technology helped unlock the potential of the oil sands in the first place by improving reliability and environmental performance, driving down costs and expanding productivity. At Suncor, we continue to look to technology to achieve our vision of sustainable development.
An Improved Tailings Method: A Bridge Over Troubled Ponds?
It's hard to put a positive face on the tailings ponds that are currently part of every oil sands mining operation. They are big, unsightly—and difficult to reclaim. They have also become a highly visible symbol for critics of the oil sands industry.
But tailings ponds are no better liked within the industry. For decades, these settling ponds have been seen as a necessary, if unwelcome, part of the business. The fact is all forms of mining produce tailings—and operators must then determine how to safely and effectively dispose of this byproduct. With mining operations on the scale of the oil sands, the challenge is all the more daunting.
Over the years, Suncor has invested millions of dollars in researching and developing new technologies to accelerate the pace of tailings reclamation. There has already been considerable progress and we now believe we are on the cusp of taking another quantum leap forward.
Suncor is beginning to introduce new “dry tailings” methodology to our oil sands operations that could fundamentally alter the way we deal with mine tailings. Once successfully implemented on a commercial scale, this technology is expected to significantly reduce our current footprint of mine tailings. It may also mean we never have to build another new tailings pond.
Tailings 101. To appreciate the significance of these advances, it helps to understand how mine tailings form and the reclamation challenge this creates.
Oil sands tailings are a mixture of water, clay, sand and residual hydrocarbons produced during the extraction process. After, the tailings are pumped into large settling ponds—often a discontinued mine pit. Some of the sand is used to build containment dykes and the rest settles to the bottom of the pond. The fine clay mixture left over forms a stable suspension that, over time, will settle into a fluid-like deposit called mature fine tailings.The MFT is about 30 percent solid and 70 percent water. Left alone, that's about as solid as it will ever become.
To help transform the MFT into a soil-like deposit that can be reclaimed, Suncor pioneered the use of Consolidated Tailings (CT) technology in the 1990s. By adding gypsum and sand, we were able to accelerate the release of water from the MFT. The released water is then recycled in our operations.
This process works, but the pace is less than optimal—using CT technology, it still takes between 30 and 40 years to get from the point land is initially disturbed by mining to when surface reclamation is completed and the first trees can be planted.
Recent Innovations. Suncor has worked with university researchers and private consultants and has visited global experts to investigate alternative reclamation methods. One of the most promising advances is a drying technology that has been tested on our original tailings pond since 2005.
Using the drying method, we can pump MFT out of a pond and bring it to shore. We then add an inert, biodegradable chemical that causes the fine tailings that are dispersed in water to clump together. The majority of water is then released and can be recycled in other parts of our operations, the remaining de-watered solids are now dry and ready for reclamation.
With this drying method, we estimate it will take between 10 and 15 years from when land is initially disturbed to when it can be re-vegetated—shortening the current timetable by about two-thirds.
Another key advantage of the de-watering method is that it allows tailings reclamation to occur independent of mine operations. CT technology, by comparison, is dependent on a steady supply of sand from our plant operation, which limits the amount of MFT that can be treated at any one time.
This methodology is expected to eliminate the need for new tailings ponds. Instead of filling up mine pits with water to store excess MFT, we could start filling those pits as soon as the ore is mined with overburden (the soil and muskeg removed to get at the ore) and beached tailings (i.e. the fine tailings that have been treated and left on site to dry). Again, most of the water released during the drying process would be pumped away and re-used.
Suncor began operating its first drying unit in March 2009. At full capacity, this drying system can treat about 4,000 tonnes of MFT per day. Other units are expected to follow. Pending regulatory approval, we plan to be treating about 35,000 tonnes of MFT per day by 2012. At that point, we would be treating all the MFT we generate daily, plus an additional volume to deal with our backlog.
While the preliminary results from our drying unit look promising, we still need to demonstrate what can be achieved on a broad commercial scale. The next big challenge will be to come up with a combined mine and tailings plan that allows us to take advantage of this technology in the most efficient manner possible.
We are also continuing to investigate other tailings technologies. For example, in 2009 Suncor expects to build a pilot centrifuge drying system that could handle about 500 tonnes per day of MFT. This system involves feeding MFT into a portable mechanical device and applying centrifugal force 1,000 times more powerful than gravity. The solids in the MFT are forced out and hauled back to the pit while the liquids are captured and can be reused.
Potential Benefits. The potential environmental benefits of these new technologies are clear, including a significant reduction in Suncor's tailings footprint, much quicker reclamation of existing tailings ponds and the elimination of the need for any new tailings ponds even as production expands.
There are also economic incentives. Suncor has nine existing tailings ponds, covering a total of 31.8 square kilometres. Most are close to 45.7 metres in depth. Managing these ponds is an expensive, time-consuming business. While implementing this new technology will also be expensive, we are projecting significant operational savings that would largely be achieved by eliminating the need to build and maintain tailings ponds and allowing shorter hauls for moving overburden.
Suncor's tailings ponds account for about 30 percent of the 16,405 hectares of disturbed land Suncor is currently working to reclaim. So resolving the tailings challenge is critical to improving Suncor's overall reclamation performance. With the help of new technologies, we intend to do just that.
Other Promising Technologies
Suncor continues to invest in a range of new technologies aimed at improving our energy efficiency and environmental performance.
Gasification Technology. One promising approach is gasification technology to turn petroleum coke (a byproduct of the oil sands upgrading process) into synthesis gas. The synthesis gas could then be used to generate electricity and/or hydrogen, thereby reducing our reliance on natural gas. Suncor has invested in GreatPoint Energy, which is developing a gasification process that could enable Suncor to produce synthetic natural gas while also sequestering CO2.
Geothermal Energy. Suncor is also working with other oil sands operators to examine the possibility of tapping geothermal energy buried deep within the ground to produce the heat needed to extract bitumen from the oil sands. This could be another long-term alternative to natural gas.
Carbon Capture and Storage Technology. We are also involved in initiatives to advance carbon capture and storage technology. In addition to our participation in the Integrated CO2 Network (ICO2N), Suncor is a member of the international Carbon Capture Project, which is working on research and demonstration projects to help make large-scale carbon capture and storage a reality.
Solar-Powered Chemical Pumps. Suncor's natural gas division is making innovative use of solar-powered chemical pumps to replace traditional natural gas-driven equipment in our operations near Grande Prairie, Alberta. The older pumps emitted unburned natural gas into the atmosphere. Natural gas, which is primarily composed of methane, has a global warming potential 21 times greater than CO2. So containing the unburned natural gas is having a significant impact on reducing greenhouse gas emissions from this part of Suncor's operations.
Other Technologies. Other technologies which could have application in the oil sands include nuclear (using thermal heat to produce steam for in situ bitumen recovery), hydroflame (where a direct-contact steam generator sends steam and fluegas downhole for in situ recovery) and in situ combustion (where bitumen or coke are burned underground to provide heat for bitumen recovery.