August 2016


Imperial Metals sets its sights on engineering firms

Mount Polley
Imperial Metals was given the go-ahead to resume normal operations at Mount Polley in late June, using its repaired and modified tailings facility (pictured) | Courtesy of Imperial Metals

Imperial Metals is suing Knight Piésold and Amec Foster Wheeler (formerly known as AMEC) for negligence and breach of contract over the August 2014 tailings dam failure at its Mount Polley mine in south-central B.C., which spilled 24 million cubic metres of water, tailings and "interstitial" water into nearby rivers and lakes. The company is requesting an undisclosed amount in damages.

In its filing to the Supreme Court of British Columbia, Imperial Metals claims “each of the defendants failed to undertake necessary, proper and reasonable investigation of the subsurface conditions underlying the tailings storage facility (TSF) prior to and during its phased construction and operation.”

Imperial Metals declined CIM Magazine’s request for comment.

Knight Piésold designed and supervised the dam from the late 1980s until 2011, when caretaking of the dam was transferred to Amec Foster Wheeler until its collapse in 2014.

The suit alleges the design and construction of the TSF did not have “an adequate factor of safety as required by applicable regulations and sound engineering practice.”

It claims that Knight Piésold failed to take into account the risks of the subsurface conditions and the effect it would have on the foundation when designing the TSF. The suit also alleges Knight Piésold “failed to design the TSF in compliance with the Dam Safety Guidelines and the HSR Code.”

Knight Piésold said in an email to CIM Magazine that “significant design changes” were made after the firm left the project, “such that the tailings storage facility at the time of the breach cannot be considered a Knight Piésold design.

“Knight Piésold is confident that our engineering services were appropriate and that the breach would not have occurred if the facility had continued to be developed and operated in accordance with our design,” the company said.

The lawsuit alleges Amec Foster Wheeler failed to identify and warn the company of the design flaws of the TSF created by Knight Piésold and concluded that the dam was safe in its 2006 AMEC Dam Safety Review.

Lauren Gallagher, a spokesperson for Amec Foster Wheeler, said the company could not comment on the matter, but that the company “continues to work with industry partners, professional organizations and regulators to ensure that the future of British Columbia mining prioritizes safety, accountability and environmental responsibility.”

The provincial government of British Columbia declined to charge Imperial Metals for the dam’s collapse in December 2015, and shortly after, a government-appointed panel found the dam failed because of its initial design.

The TSF had been shut down since the dam collapsed, but B.C.’s Ministry of Energy and Mines and Ministry of Environment gave the go-ahead for Mount Polley to return to normal operations in late June using its repaired and modified facility.

– Vince Morello

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