Repair and temporary dam at Mount Polley Mine near Williams Lake.

Mount Polley design, steep additions led to failure

Glacial layer in dam base not understood, plans to buttress slope put off until weight of water and tailings caused breach

The Mount Polley mine dam failed because of an overlooked glacial material layer in the foundation and a series of steep additions that eventually overcame it, an independent engineering review has concluded.

“Basically the weight of the dam was too much for the weak materials in the foundation to bear,” said U.S. consulting engineer Steven Vick, one of three experts called in to examine the failure that caused the dam to breach and fail in August 2014.

The report concludes that the concrete-like glacial till material in the base of the dam wasn’t understood in enough detail when the dam was designed and built in 1997. Later raising of the dam to hold more water and tailings weakened the base layer and led to the failure.

Vick said the additions to the dam were built at a steeper slope than the original dam, and plans to buttress the area were delayed until it was too late.

Energy and Mines Minister Bill Bennett said the report shows there were no warning signs, and no surface inspections could have detected the problem that was overlooked in the design and original construction.

Two more investigations of the mine failure are pending. Bennett said the Chief Inspector of Mines is likely to release his report by June, and the Conservation Officers’ Service will also report when its investigation is complete.

Bennett said the government is willing to see the Mount Polley mine reopen, but the other investigations must be complete first. The parent company Imperial Metals has applied to use an existing pit to store tailings and resume operations without using the original tailings pond again.

 

Just Posted

The Hub Organ Trio coming to Courtenay

The Georgia Straight Jazz Society features an amazing trio at the Avalanche… Continue reading

YANA a blessing for Michaela, Harley, and Baby Violet

Comox Valley association a pillar of the community

Deadline looming for North Island College scholarship applications

Students have until April 24 to apply for a record number of… Continue reading

AspieComic Micheal McCreary coming to the Comox Valley

Comox Valley Child Development Association hosting the fundraising event

BC Ferries to pilot selling beer and wine on select routes

Drinks from select B.C. breweries and VQA wineries to be sold on Swartz Bay to Tsawwassen route

Parliament Hill 4-20 organizers predict record crowd after legalization

A celebration? Yes, but organizers say concerns remain about the government’s decisions on legalization rollout

B.C. mountain biker sent home from hospital twice, despite broken vertebrae

Released in Maple Ridge to go home with three fractured vertebrae

Deck collapses in Langley during celebration, multiple people injured

Emergency responders rushed to the Langley home

Chaos at the ferry terminal for people heading from Vancouver to the Island

Easter crowds create backlog at Tsawwassen ferry terminal

B.C. RCMP receive application for Police Cat Services

RCMP announced the launch of the Police Cat Services unit as an April fools joke

Kirkland Signature veggie burgers recalled due to possible metal fragments

Recalled products came in 1.7 kg packages with a best before date of Apr. 23, 2019

Parents of 13 who tortured children get life after hearing victims

One of their daughters fled their home and pleaded for help to a 911 operator

Flooding, climate change force Quebecers to rethink relationship with water

Compensation for victims of recurring floods limit to 50% of a home’s value, or a maximum of $100,000

Storms blast South, where tornadoes threaten several states

9.7 million people in the Carolinas and Virginia at a moderate risk of severe weather

Most Read