Dismantling of Sudbury's Superstack could start this summer, says Vale

If all goes to plan, mining giant Vale will start dismantling the iconic Superstack in the northern Ontario city of Sudbury this summer.

Built in 1972, the 381-metre chimney located at the Copper Cliff smelter is the tallest in the Western Hemisphere.

The Superstack was built to spread sulphur dioxide emissions, diluting them over a wide geographic area. 

But in 2018, after years in delays complying with new government environmental regulations, Vale completed its $1-billion Clean Atmospheric Emissions Reduction (AER) project which reduced those emissions by 85 per cent. The company built two smaller stacks to replace Superstack, which was no longer needed.

The Superstack has been inactive since 2020, and Vale has been working on plans to safely dismantle the structure since then.

"In order to eliminate the risk of deterioration or anything else, we need to take it down," said Paul Guenette, the project lead for Vale's Superstack dismantling.

Because the Superstack sits atop a working processing facility, and near homes in Sudbury's Copper Cliff neighbourhood, Guenette said an implosion was out of the question.

The company looked at a lot of different ideas to take down the massive concrete structure.

"I had my own where we kind of dug a hole underneath to make it sink," Guenette said.

They landed on a plan to dismantle it from the top down.

Crews have finished building two elevators on the outside of the stack to lift people and equipment up and down.

"We'll be setting up a platform at the very top, which is what they're doing today for the next couple of weeks," Guenette said.

"After that, probably later on this summer, we're going to see this proprietary piece of equipment that's going to be hoisted up from the inside. It's going to sit on the concrete at the very top, and it's gonna essentially cut pieces of the concrete and make it fall on the inside."

Guenette said the work will be done without interrupting work at the smelter below. 

As the machine dismantles one level of the Superstack, crews will lower it until it eventually reaches the bottom, which could take five years. 

He said the machine will be operated remotely, although six workers will be at the top to clean up and make sure all debris falls inside the Superstack, where there's no risk of harm.

While some people consider the Superstack to be an eyesore, it's also a recognizable part of Sudbury's skyline. 

Guenette said he has mixed feelings about dismantling the landmark. 

"It will be sad," he said.  "However, I understand why we're doing it and it's actually for the benefit of everybody."