Sudbury Superstack's days are numbered: Vale plans to replace chimney in favour of short stacks.

• Position: MINING

Sudbury miner Vale announced it will take its landmark and controversial Superstack at its Copper Cliff operations out of service by the second quarter of 2020.

The 1,250-foot (381-metre) stack will be replaced by two smaller 450-foot (137-metre) stacks.

"We are proud to be reducing emissions to a point where the Superstack is no longer required," said Stuart Harshaw, vicepresident of Vale's Ontario Operations, in a Jan. 24 statement.

"Taking the Superstack out of service is a great symbol of how far Vale has come in terms of shrinking our environmental footprint and making Greater Sudbury a better place to work and live."

The company said the two smaller stacks will be more efficient, will require less energy to operate, and will reduce greenhouse gas emissions from the Copper Cliff smelter by approximately 40 per cent.

At the same time, Vale's Clean AER (Atmospheric Emissions Reduction) Project will reduce particulate emissions by 40 per cent and reduce sulphur dioxide emissions by 85 per cent.

The company said by changing to two smaller and more efficient stacks, natural gas consumption is estimated to drop by nearly half, from 94 million cubic metres per year to 48 million cubic metres per year.

Vale said the savings are equivalent to the average fuel consumption of approximately 17,500 homes or one-third of all the households in Sudbury.

Construction of the two new stacks begins early this year and will take two years to complete.

By the second quarter of 2020, the Superstack will be placed into care and maintenance mode as an extensive study is conducted to determine the best way to safely demolish its concrete shell.

Vale said there is no hurry for the shell to be...