The World Chess Championship, Reykjavik, Iceland 1972. The Soviet Union’s Boris Spassky, defending champion, is defeated by Bobby Fischer of the United States. Dubbed the Match of the Century, it was hailed as one of the greatest single applications of human intellect.
There’s another match at play these days consuming significant brain power:
The oil sands industry versus mature fine tailings (MFT).
Fine tailings
MFT is made up of fine clay particles suspended in water. Left alone in an oil sands mining operations’ tailings pond, MFT would take centuries to solidify, a timeframe to test even the world’s most patient chess grandmaster.
Reclaiming tailings ponds is no game, but a serious application of intellect. Much of the effort has focused on techniques for dealing with MFT so ponds can be reclaimed more quickly than they are now.
Different approaches
Syncrude, for example, is working on three tailings technologies:
- water capping, which places freshwater over fine tailings to create viable lakes;
- composite tails, which mixes fine tailings with sand and gypsum to decrease settling time; and
- centrifuges that spin the water out of the tailings.
Meanwhile, Suncor’s TROTM tailings management process uses a polymer flocculent to bind MFT into a dry layer suitable for reclamation, a process similar to Shell’s Atmospheric Fines Drying technology.
Suncor is also accelerating pond reclamation using an approach that literally puts a lid on tailings. Coke capping involves using petroleum coke to create a solid surface on top of a tough-as-nails fabric laid on a frozen tailings pond. From a plane, this coke layer looks like a giant chessboard.
Coke, a byproduct of upgraded bitumen, is buoyant enough to stay floating on the surface of Suncor’s Pond 5, where the process was piloted in 2010. Despite its lightness, the material is strong enough to allow huge trucks to drive over the pond. Wicking drains in the coke cap, which act like straws, remove the water and potentially separate tailings and reclamation material.
The Pond 5 coke-capping project is one of the largest field trials of a tailings technology anywhere in the world. About 230 hectares are currently covered by a specially designed, space-age geo-fabric and enough coke to fill more than three football stadiums. All the water should be gone by 2019; then sand will be spread over the coke until tailings can support vegetation and further reclamation.
While coke capping is not the be all and end all, it is shaping up to be another viable method for handling Suncor’s legacy tailings inventories so ponds can be closed quicker.
Accelerating performance
The industry is expected to make serious progress on tackling its tailings challenge, through unprecedented collaboration. The creation of Canada’s Oil Sands Innovation Alliance (COSIA) and inclusion of tailings as a key environmental priority area is expected to help accelerate industry performance in the years ahead.
While coke capping is still in the early stages, it’s a good example of the type of innovative thinking required to solve the tailings riddle. Just because the current site looks like a giant chessboard doesn’t mean the industry can wait around for someone else to make the next move.
