It’s been seven months since the seven companies operating, building or planning to build oilsands mines signed an agreement to share their knowledge around tailings management in the hope of collectively reducing the footprint of blackened, dead lakes in northern Alberta. After taking a tour of the tailings recovery at the four operating mines (Suncor, Syncrude, Shell and Canadian Natural Resources Limited) this week, I can report that they’re farther advanced than I thought. Indeed, even with the expected doubling of oilsands production over the next decade, the number and size of tailings ponds will shrink. In fact it’s already doing so.
As Canadian Business reported last fall, Suncor has essentially remediated the first of its eight tailings lakes accumulated over 44 years of operation with the help of a technology called TRO that it pioneered in 2007. Essentially, when it mines oilsand, Suncor first extracts the bitumen (heavy oil) and the coarse tailings (sand)—the easy part—and leaves the troublesome and toxic mature fine tailings (MFT) to settle in a pond for three years. Then it dredges the MFT up, adds a polymer flocculant used in municipal wastewater treatment, and pours it onto a sloping beach or drying cell to dry. Within three weeks it’s “traffickable” solid ground.
Other operators, notably Shell, had made this same discovery around the time the Oil Sands Tailings Consortium was formed in December. Now, though Suncor is patenting it to prevent an outside party from doing so, they can all use it without paying a royalty.
But what I didn’t know until this week was the strides other companies had made, to the point that they too are on the verge of returning former ponds and tailings material to nature. Indeed, the newer mines like CNRL’s Horizon and future ones like Imperial Oil’s Kearl will have only one tailings pond over their lifetimes, continually cycling wastewater into it and material out of it. Meanwhile, the operators of legacy ponds, Suncor and Syncrude, will mop them up. Hence fewer ponds, smaller surface area.
Some highlights: Syncrude has been testing “water capped” tailings—leaving settled tailings at the bottom of man-made ponds—since 1989 and next year will create a full-size lake on this model in its original East Pit. Syncrude’s test ponds have shown that in as little as a year naturally occurring microbes break down the worst naphthenic acid residues in the tailings mud, such that rainbow trout can survive in them. Within a few more years you have aquatic plants. It’s a lake, basically.
Other MFT gets “dewatered” in a centrifuge and dumped to make dry landscape in former mine sites. Syncrude’s latest creation is a half-wet, half-dry fen, a much more complex habitat found commonly in the boreal forest. How successful it will be depends a lot on where the groundwater establishes itself.
Shell, meanwhile, had perfected the use of “thickeners” such that it need not leave the MFT to settle in a pond the way Suncor does. It goes straight to atmospheric drying. CNRL is using an end-to-end process whereby the fines get mixed back together with sand and carbon dioxide. Right now the CO2 is trucked in from a plant in Fort Saskatchewan but by 2015-16 it will be recaptured from CNRL’s plant, lowering its emissions by 10% to 12% and sequestering the CO2 in the remediated landscape. Two birds with one stone, in other words.
All these different solutions are applicable to mines at different stages of development using different extraction technologies, and there will likely be better options discovered in the future. It was nearly impossible to get our hosts, engineers all, to give a straight answer about the size and timeline of the cumulative tailings reduction. But in an impromptu dinner speech, Ron Myers, manager of facilities and environmental research for Imperial Oil, was willing to offer the opinion that “In 20 years, this industry will have a smaller footprint. Not just in tailings, but also in the landscape, the emissions, the fresh water use.” In conversation afterward, he said these goals will be achieved in absolute terms, even if oil production goes to three million or five million barrels a day. That’s a meaningful goal and a message the industry has to get across.