High stakes in Canada’s vast oil-sands fields
Trillions of dollars’ worth of oil are present, but the environmental costs are high, too – and growing.
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At Syncrude’s Mildred Lake plant, north of Fort McMurray, giant excavators have scarred the landscape. Like giant otherworldly beetles roaming the moon, 400-ton trucks haul the ore to the extraction plant. Two tons of loose rock and soil and two tons of ore have to be moved to produce a single barrel of oil. Surface mining also uses from 2 to 4-1/2 barrels of water per barrel of oil. The water is pumped from the nearby Athabasca River to produce steam, which helps separate sand and bitumen. Much of the water is recycled, but some is left to settle in highly toxic tailings ponds.Skip to next paragraph
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At the same time, Syncrude – a joint venture that includes Canadian Oil Sands Ltd., Imperial Oil (an ExxonMobil subsidiary), Petro-Canada, Nexen, ConocoPhillips, and others – is Canada’s largest single emitter of greenhouse gas, since it must burn 750 cubic feet of natural gas to generate the steam needed to produce a barrel of bitumen. That’s the equivalent of burning one barrel of oil for every eight barrels produced.
According to Steve Gaudet, Syncrude’s manager of environmental services, gradual progress is being made to reclaim land at mined sites by replacing topsoil and replanting shrubs and boreal forest trees. More than 20 percent of the Mildred Lake site has been reclaimed, he says, but desertlike areas remain.
In terms of water use, Mr. Gaudet says Syncrude uses 0.2 percent of the annual flow rate of the Athabasca River. “At the lowest flow rates, during the winter, we use 0.5 percent,” he notes. With the planned expansion, that figure will rise to 1 percent. (Some 60 percent of Alberta’s Bow River flow is exploited by cities like Calgary, as well as by agriculture and industry.)
Some aboriginal communities downstream are worried that contaminated water will seep back into the river and affect the drinking water and fish they depend on. This fall, the Alberta government is due to release a long-awaited report on the impact of oil-sands wastes on public health in the communities.
As surface mines of bitumen ore are gradually depleted, in situ (subsurface) extraction facilities like Surmont are springing up across the northern forest, connected to Alberta’s pipeline grid. They seem environmentally friendlier.
“Surmont is built on swampy muskeg,” Mr. Hansen of ConocoPhillips notes, “so clay had to be hauled in, and piles had to be driven into it to stabilize the plant.” In this particular area, the bitumen reservoir is 1,200 feet underground. “Drawing on a saline aquifer 650 feet down,” Hansen explains, “we inject steam through one well bore, and the steam gives the bitumen the consistency of cream. The bitumen then gravity-drains to a producer well. Once we stop injecting steam, it condenses to water and we recover emulsion, which is the combination of bitumen and water.” Most water is recycled, he says, and waste water is reinjected into the earth below the saline aquifer.