A new video released today provides the clearest glimpse yet of what happened to Elliot Lake’s doomed shopping mall—and why.
Part surveillance footage, part digital reenactment, the two-minute video was prepared by NORR Ltd., the engineering firm hired by the Ontario Provincial Police to conduct a forensic investigation into last summer’s fatal roof collapse. The cave-in killed two women, injured 20 others, and triggered a controversial rescue effort.
“The mall was beset with a chronic leakage problem from the day it opened,” a narrator says, referring to the rooftop parking lot that covered the retail stores. “This went unabated due to the lack of a proper continuous waterproofing membrane at the parking level. Every owner addressed the leakage problem by attempting to seal and reseal cracks where leakage was observed. Water leaked onto the structural steel, carrying with it de-icing salt that accelerated corrosion rates to levels only found in marine environments. Corrosion progressed likely since the mall was built, until there was so little material left in one particular connection that it could no longer support the weight of the parking deck.”
By that Saturday afternoon—June 23, 2012—more than 85 per cent of the steel connection’s original weld capacity had been eaten away by corrosion. “Without support, the concrete panels collapsed into the upper mall adjacent to the food court,” the narrator continues. “The impact of the hollow-core panels killed two people.”