Mount Polley spill may be far bigger than initially revealed

Mount Polley spill may be far bigger than initially revealed

Mount Polley spill may be far bigger than initially revealed
Aerial image after Mount Polley mine tailings spill (Cariboo Regional District)

Updated 7 PM, September 2

Volumes of water, tailings and other debris released into the environment by the August 4 breach of Imperial Metals’ tailings pond at Mount Polley Mine were at least 70% higher than initial estimates, the company revealed on its website yesterday.

Now, a report from BC Tapwater Alliance, using satellite imagery from NASA and the US Geological Survey to estimate the size of the containment facility, suggests even the company’s re-estimate may still be significantly underplaying the true scale of the disaster.

While the company boosted estimates from 14.5 million cubic metres of water and tailings to over 25 million cubic meters of combined debris spilled into Polley Lake, Hazeltine Creek and Quesnel Lake, that may be just the tip of the iceberg.

The BCTWA report pegs the total surface area of the breached tailings containment facility at 225 hectares – or 2.25 million square metres (see graphic below).

According to Wendy Stueck in the Globe and Mail, “The tailings dam was about 35 metres high when it was breached”, meaning that the total volume of water and tailings contained in the facility was closer to 80 million cubic metres – perhaps slightly less, taking into account the dam’s rounded edges.*

Local environmental consultant Richard Holmes tells me that, upon recent visual inspection, much of the actual tailings remain within the containment area – not all of them having washed out of the facility with the release of water. Nevertheless, even these revised estimates from Imperial Metals are likely still on the low side.

Graphic: Will Koop / BC Tapwater Alliance

Imperial increased production, tailings to fuel Red Chris

The BCTWA report also contains a series of satellite images of the pond itself (see below), which clearly illustrate the massive ramp up in ore production Mount Polley underwent in the lead-up to the disaster. Under pressure to provide cash flow for a major new mine in Northwest BC which Imperial Metals was developing, Red Chris, the company’s increased activity led to a corresponding rised in tailings, as reported by The Common Sense Canadian following the spill.

According to Tadzio Richards of Rivers Without Borders:

[quote]Imperial Metals ramped up daily production of ore from 18,000 tonnes per day in 2009 to more than 23,000 tonnes by 2014, with production escalating in the three months just prior to the breach.[/quote]

This occurred despite at least five warnings from Ministry of Environment officials, on top of concerns expressed by the facility’s original engineer, independent consultants and even a former tailings dam foreman, Gerald MacBurney, who quit over the lack of action from the company.

The selected satellite images below, drawn from the BWTA report – chart the massive influx of tailings into the pond corresponding with the period of increased gold and copper production at the mine.


Satellite images reveal a slight decrease in tailings levels over the summer, corresponding with the deliberate, emergency release of some tailings water after a dangerous incident on May 24 of this year. According to a provincial government backgrounder:

[quote]The ministry issued an advisory to Mount Polley Mining Corporation for exceedance of the height of effluent within the tailings impoundment. The effluent level returned to authorized levels commencing June 30, 2014.[/quote]

Yet, just over a month later, the dam would burst, as this satellite imagery from the USGS shows:

Mount Polley tailings dam -before and after

The BC government has yet to respond to Imperial Metals’ increased estimates of tailings debris.

*NOTE: Estimated height of tailings pond revised 


About Damien Gillis

Damien Gillis is a Vancouver-based documentary filmmaker with a focus on environmental and social justice issues - especially relating to water, energy, and saving Canada's wild salmon - working with many environmental organizations in BC and around the world. He is the co-founder, along with Rafe Mair, of The Common Sense Canadian, and a board member of both the BC Environmental Network and the Haig-Brown Institute.

10 thoughts on “Mount Polley spill may be far bigger than initially revealed

  1. But… but it’s because the soil was weak and eventually failed. Corporations always find a scapegoat for their actions. But what really surprises me is that they acknowledge negligence in some way. If the soil was weak, wouldn’t routine inspections indicate that? Either way you look at it, Imperial was negligent by not ensuring their tailings dam was adequate to contain the ramp up in production they were about to receive. So, whether this was related to the failure of the soil or the increase in production, that fact is they just did it anyway. This is gross negligence. Take a look at what Enbridge did in Michigan with that pipeline failure.

    The clear fact is that companies are negligent to the environment in favour of profit. And the government protects them (both sides of the border). We’ll take those royalties and keep increasing them, taking money away from the corporation to prevent damages like this. Then the government ends up giving the money back in cleanup efforts. At the end of the day, the corporation that caused the problem wins, no matter what. And I bet their CEO didn’t lose one cent over this.

    But I also read all the time about people complaining about the government cutting services because there is not enough money in the budget. Think about what would happen if there were no resource royalties given by these companies. The fact is, all governments, no matter who is running the show, will cater to corporations because they pay the bills. IMHO they don’t pay enough and so much lands on the tax payers. In the end the corporations win and the people and environment lose. And it happens all over the world.

    Our lifestyles have to change drastically if we care about putting this to an end. But for that to happen, well guess what, you wouldn’t be reading this right now because nothing would exist.

    90% of the people in this world do not care about anything but themselves, if you can change this mentality you may have a chance at changing the world. If there is no demand, who needs supply?

    But seriously, if you want to do something about it we have to change how we live. That gold they are mining, likely ends up in China so that Foxconn can build the motherboard for your brand new phone you just got to replace the one you’ve had for 6 months. And your environmentally friendly hybrid, it’s probably the worst of them all. They call them “rare earth metals” for a reason.


  2. Seize all assets of Imperial Metals…charge the executives, no bail, let them sit in jail until the court case…and, yes, as Kurt suggests, seize personal assets of the executives… they should have remembered what we were taught in the sandbox…always clean up your mess, don’t leave it for someone else!

  3. Imperial recklessly rolled the dice
    and lost

    time to cash in the chips boyz

    gross negligence…
    time to pierce liability-limitation (or rather liability-evasion)
    and the corporate web
    forensic audits
    propagate liability back to personal assets of the executive
    operate under bankruptcy-trustee or as a public corporation

    problem is the morons on the public payroll don’t inspire
    much confidence

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