Cleaning up after Canada’s largest tailings pond leak

Uprooted trees, muddied water with a silvery sheen, fish belly-up on the surface. There was something essentially un-Canadian about the first galling photos to emerge out of Mount Polley, B.C., where a copper and gold mine’s tailings pond—a containment area where the waste produced through the mining process is treated and allowed to dry before being disposed—burst through its earthen walls last week. All told, 10 million cubic metres of water contaminated with arsenic and mercury and 4.5 million cubic metres of tiny silt silicates spilled into Hazeltine Creek and Quesnel Lake. All this, too, right before the beginning of what the Department of Fisheries has suggested might be the largest salmon run since it started keeping records in 1913: As many as 72 million sockeye, it says, could wind north through the Fraser River in the coming month.

So it’s little wonder that anger and disappointment have been the primary emotions. “Hazeltine Creek will never again be what it was. It’s outrageous, it’s awful, it’s catastrophic,” said Al Richmond, chairman of the Cariboo Regional District, where the leak occurred. “It’s devastating, and there’s a great deal of uncertainty and mistrust.”

The recovery, so far, has gone as expected. Imperial Metals, which owns the mine and its tailings pond, has claimed responsibility, paying for the potable water being shipped in. After an initial water ban and state of emergency, a B.C. report that found the water to be safe to drink resulted in a partial rescinding of the ban. In the ensuing days, a salmon expert told Maclean’s that the sockeye salmon run will not be affected by the leak because of how quickly the chemicals are diluting through the rapidly flowing water, and it turned out that the tailings were non-acidic—all good news in a bad-news climate. (Update: new information reveals there may indeed be a risk to the salmon.)

But the question of what comes next may be a far trickier proposition for what has been the largest such leak in Canadian history. What Imperial Metals will undertake is a long, arduous cleanup, the precise details of which have yet to be determined. It will take decades before it’s clear if it was successful—and, according to one expert, recent leaks in the United States have largely been handled by simply leaving the water and its tailings alone.

Tailings-pond leaks are rare, but they do happen: On average, three leaks occur every year worldwide. In B.C. alone, there are about 130 mines, each with at least one tailings pond, the default way of storing and disposing of mine waste “since the beginning of time,” said Scott Dunbar, the head of the University of British Columbia’s mining engineering program. “It’s a fact of life.” Reports say Canada’s previous case came last October, when a tailings pond that was in the reclamation process leaked at the Obed Mountain mine in Alberta, loosing 670,000 cubic metres of coal tailings into the Athabasca River.

That relative shortage of leaks means no one company specializes in their cleanup, and the fact that every region and leak is different means that a great deal of consulting needs to occur first, says Jack Caldwell, a mining and civil geotechnical consultant for B.C.’s Robertson GeoConsultants firm, who has been involved in “umpteen” tailings-pond designs and repairs over his four-decade career. First, Caldwell says, the breach must be closed. “Tailings are still flying out, and if it were to rain, more tailings would come out,” he said. Imperial has said this fix will be finished in three weeks’ time.

Then, the downstream tailings still floating on the surface of the water need to be picked up by one of three methods: a combination of front-end loader and trucks, a slurry pump, or using a water pump to blast the water and tailings toward another downstream embankment. Finally, the trickiest part of the process, is an effort so complex that one person involved in the industry posted on Caldwell’s mining blog that it’s like “putting smoke back into a cigar”—retrieving the tailings that are already at the bottom of the lake.

One option is dredging the lake, but Caldwell says that would actually loosen up all the tailings again, contaminating the water once more. “You’re probably going to cause more damage than benefit by doing that,” he said.

That means that the best course of action might actually be to leave the tailings in the lakebed, with the expectation that vegetation will grow over it. Caldwell, himself a proponent of this plan, says that’s what was done to handle decades’ worth of chemical runoff on the Palos Verdes shelf near Los Angeles and, in part, in Tennessee, where the Kingston Fossil Plant leaked more than four million cubic metres of coal ash in 2008, the largest such spill in America. After all, he says, “you’re never going to get everything clean.”

But if effectively doing nothing becomes the plan—Imperial has been given until Friday to file a report—it will further accentuate the perception of negligence on the part of Imperial by environmental groups. The damage—and it was devastating, especially at its epicentre—is also making it hard to move beyond the images to get to the facts and realities of the cleanup. “This is one of those horrible situations where you’re damned if you do, damned if you don’t,” says Caldwell. “I suppose, in this democracy, you’re just going to have to have a discussion to decide which is the lesser of the two evils.”

No one has denied that the spill is anything short of terrible, but, in the wake of the incident have come “crazy assertions” about the extent of the environmental impact before any reports have emerged, says Carl Walters, a professor emeritus at the University of British Columbia who has been studying sockeye salmon in the area for the last 40 years. He says he’s heard claims that the salmon would be confused by the scent of the contamination (they use scent, but only with organic compounds) and that for some of the claims about the spill’s effect on the lake to be true, “some of the water would have to flow uphill,” he says with a laugh. Walters expects that the contamination of the water—already somewhat low—will be carried out of the system within a month. “Unless they have another breach, it’s not really a big deal,” he said. “Anytime anything happens, the eco-babble comes out and, mostly, it sounds like science and, mostly, it has no scientific basis.”

That matter of knee-jerk environmental judgment—such as the David Suzuki Foundation’s recent call for a freeze on new permits for B.C. mines until every tailings pond is reviewed—also threatens to mask real issues. Take Jason McNamee, for instance: He’s a B.C. conservationist and a scientific adviser to the World Aquarium and Conservation for the Oceans Foundation, making him an unlikely dissident in the narrative that the Mount Polley leak is an unmitigated catastrophe.“The Mount Polley mine disaster is unacceptable,” he said, “but using the word disaster? Ah, I don’t know if that’s the correct terminology. It’s all about perspective; if we don’t take a longer-term perspective, how do we expect to make change?” He notes that volcanoes spew out ash that contains sulfuric acid and arsenic in “several orders of magnitudes more” than the Mount Polley spill did; the city of Victoria, too, unleashes around 130 million litres of untreated sewage every day into the Juan de Fuca Strait. “Some environmental groups like to rage at the system, but that doesn’t help. We need to be looking at solutions, and back that up with voting and other mechanisms of having your voice heard,” he said. “The miners are doing what miners do. They’re providing a necessary resource and making a profit. They’re not bad guys, and we don’t need to paint them as such.”

The long view is the wise one, especially since it will take a long time to assess the environmental impact. Caldwell says the cause of a tailings-pond failure in Bafokeng, South Africa, in 1972 is still something of a mystery, with the environment only finally recovering. And then, of course, there is cost. According to a Reuters report, analysts estimate that the cost of the cleanup could range from $50 million to $500 million, with BMO suggesting it will be in the $200-million range; over the weekend, Imperial Metals vice-president of corporate affairs, Steve Robertson, said any cost estimate at this point would be a mere guess. But Caldwell envisions the cost for the breach repairs and a likely facility replacement alone will be at least $200 million, a number that doesn’t even include legal costs and that tricky cleanup process; the 2008 Tennessee leak has recently exceeded one billion dollars in recovery costs. There are also questions about whether Imperial can endure that kind of financial hit without having to sell off assets, despite its commitment to cleaning up the spill: Mount Polley accounted for most of the company’s copper, gold and silver production in the second quarter.

In a situation where a decisive response is demanded by the local community, doing nothing, as some experts suggest, may yet be the best option. For the company, that presents a real risk. “Respect is earned, not given,” said Richmond, the Cariboo regional chairman. “It’s in Imperial Metals’ ballpark now.”