Teardown of Canada's second-tallest structure moving fast in Ontario

Ontario demolition crews are making quick work of what was, until very recently, the second-tallest structure in all of Canada.

The enormous Vale (formerly Inco) Superstack towering over Sudbury, Ont., reigned as the silver medallist of Canada's tallest structures behind the CN Tower until earlier this year, when demolition began to chip away at the 381-metre-tall smokestack.

The Superstack was built between 1970 and 1972, and briefly held the title of Canada's tallest structure from its completion until the opening of the CN Tower in 1976. 

Although it's spent much of its lifespan relegated to second place among Canada's tallest structures, the chimney retained the title of the world's tallest power plant from 1971 to 1987, when it was overtaken by Kazakhstan's Ekibastuz GRES-2 Power Station. The Superstack retained the title of tallest chimney in the Western Hemisphere at the time demolition began this past spring.

Teardown of the massive chimney got underway on June 1, and Vale Base Metals, which owns the structure within its broader Copper Cliff processing facility, has been sharing regular updates on its gradual disassembly.

The Superstack lost its status as Canada's second-tallest back in July, and Vale shared a new update on its deconstruction on Aug. 20, revealing that the chimney had lost almost 100 metres in height since work began, and now stands at 285 metres (936 feet).

The smokestack has been lowered by 30.5 metres (100 feet) in the four weeks since Vale last shared an update on the demolition, and has shed a total of 94.5 metres (310 feet) in height since work began a few months earlier.

At that height, the Superstack has fallen below the heights of Toronto's three tallest skyscrapers, dropping it to fifth place among the tallest structures in the country.

The Superstack's title of second-tallest now belongs to the 352-metre-tall Pinnacle SkyTower, with the 309-metre One Bloor West bumped up to Canada's third-tallest structure, and the 298-metre First Canadian Place falling to fourth place.

Amid the demolition work, Friday marks the 56th anniversary of the completion of pouring for the Superstack's concrete shell, which occurred just one day after a tornado ripped through Sudbury and gave the towering chimney its first true test.

According to a 1970 article in the now-defunct Inco Triangle, "There were 25 men aloft on the stack top when the Aug. 20 storm struck during the morning shift change."

"Undaunted by their hair-raising experience, all men either remained on the job or returned on their next shift as scheduled. Due to good general safety practices, including lashing down all loose equipment and material, no injuries or losses occurred."

It's a sad end for an industrial structure that was once world-famous for its sheer scale. 

Vale opted to demolish the massive chimney following the completion of a $1-billion modernization project in 2020 that rendered the Superstack obsolete overnight.

Designed to better disperse smelting gas from Vale's Copper Cliff Complex, the facility's recent retrofit eliminated the need for high-level dispersal. The company's plan to demolish the stack was first announced in 2024, initially aiming for dismantling to start in 2025 alongside the already-active removal of the complex's much shorter Copperstack.