Dams inspected for stability issues

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This article was published 16/06/2019 (1773 days ago), so information in it may no longer be current.

OTTAWA — Mining multinational Vale is inspecting its Thompson dams for stability issues, after a deadly collapse in Brazil.

An interim assessment suggested at least one dam in Manitoba was not up to safety standards, prompting local MP Niki Ashton to ask Ottawa to investigate.

“It is clear the severity of this issue has not been communicated to community members as it has been to shareholders,” Ashton said.

The Wall Street Journal reported last week on documents Vale issued to its shareholders, who demanded data following the January collapse of a dam that killed roughly 270 people in Brazil.

In that article, the company said it’s now probing a complex of six dams near Thompson, after outside inspectors flagged stability concerns in some of the dams’ foundations. The dams are used to hold hazardous mining byproducts, in order to prevent them from seeping into local waterways.

“A recent routine update to the stability analysis of one of the containment dams in Thompson, Manitoba calculated a lower factor of safety than that prescribed by the Canadian Dams Association,” Vale spokeswoman Angie Robson wrote on Monday.

But she noted that this came out of a drafted report that is still being reviewed.

“The results of the analysis do not match the actual performance of the dam in question,” Robson wrote, arguing all readings indicate the dam is operating fine. “There is no imminent threat of dam failure.”

Still, Ashton is urging the Liberals to look into the matter, saying she’s troubled it only came to light through an American newspaper.

“When you receive information like this from an American publication, that’s not OK,” she said. “I was shocked when they called me.”

In Monday’s question period, Ashton asked the government to act to avoid a repeat of the 2014 Mount Polley mine disaster, in which a tailings dam collapsed and contaminated nearby lakes.

Natural Resources Minister Amarjeet Sohi appeared unaware of the issue, but pledged he’d “absolutely follow up with” Ashton.

The Canadian Dam Association categorizes all six dams as a “very high” hazard, meaning that a collapse would kill up to 100 people and cause significant financial and environmental damage.

— with files from Kevin Rollason

dylan.robertson@freepress.mb.ca