Canada’s second-tallest freestanding structure will be slowly dismantled and taken to the ground over a five-year process scheduled to start in August.
The Vale Superstack, a chimney that rises 381 metres, or about 1,250 feet, above the mining town of Sudbury, Ontario, operated from 1972 to 2020. The smokestack became redundant after Vale invested $1 billion to install an advanced air filtration system at its Copper Cliff complex, which enabled the mining operation to lower sulfur dioxide emissions to 30% below provincial standards.
The quest to reduce pollutants from industrial facilities close to residential areas has prompted mining companies in other Canadian cities to find ways to lessen the impact of their operations. In the Quebec city of Rouyn-Noranda, Glencore has attempted a variety of approaches to deal with pollutants from its copper mining facility.
Mining companies in the United States are also grappling with how or when to demolish smelting facilities marked by chimneys that rise high into the sky. In late 2018, crews demolished the Magma Mine's copper smelter stack, which had stood for 94 years in Superior, Arizona, about an hour's drive from Phoenix.
The Vale Superstack is considered a landmark in Sudbury, a city of roughly 180,000 residents, a seven-hour drive north of Toronto. The smokestack is Sudbury's best-known man-made feature aside from the giant nickel that has offered tribute to the local mining industry since 1951.
The Vale Superstack is much taller than the recently topped-out One Bloor West skyscraper that rises 308.6 metres in downtown Toronto. Only Toronto’s CN Tower reaches higher, at 553.3 metres. The Superstack, however, is taller than the CN Tower's observation deck.
Vale has begun the demolition process by first removing the steel lining inside the structure as it prepares for what it calls “one of the tallest structural demolitions ever attempted.”
Vale said a concrete dismantling machine will be sent via elevator to a platform perched at the top of the smokestack. The mechanism will gradually cut away at the 9.5-inch-thick walls at the top. The company said it plans to employ conventional demolition techniques after the tower is reduced to 60 feet.
The rubble of the entire structure, including walls near the base that measure 40 inches thick, will be stored elsewhere on the property, Vale said.
The Inco Superstack, as the Vale structure previously was known, is the second-tallest chimney in the world behind one in Kazakhstan.
The demolition of the Superstack and two shorter nearby smokestacks would leave Sudbury with fewer supertall structures on its skyline. Once demolition is completed, Sudbury's tallest building would be the 12-floor Tom Davies Square that rises 54 metres, followed by Rockview Towers at 51 metres and Bonik Tower at 49 metres.