Mining giant Vale promises 'landmark' announcement Tuesday in Sudbury

Mining giant Vale is promising what it's calling a "landmark" announcement in Sudbury, Ont. on Tuesday.

In a written advisory sent to media on Friday, the company said it will be about environmental improvements to its operations in the northeastern Ontario city.

The company owns a smelter complex in the Copper Cliff area, which is home to a famous feature of the Sudbury skyline the 380 metre-tall superstack.

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The company has said that it's examining the future of the massive chimney, and whether two smaller stacks could replace it.

Vale has also said that it is working to reduce the air pollutants its operations produce. In June2016, the company said it would reduce the amount of sulphur dioxide by the end of 2017, and the levels of greenhouse gasses by 2020.