Future Fumes?: Will Sudbury super stack be needed by Vale after retrofit project? (Canadian Mining Journal – February/March 2015)


At more than 388m high and just over 36m wide at base, Vale’s “Super Stack” in Sudbury is unquestionably the city’s most outstanding feature.

In fact, it’s also one of Northern Ontario’s more outstanding features because it’s literally the tallest structure in the north and can be seen for miles from every direction as it towers over the city.

Even Sudbury’s world-renown “Big Nickel” pales by comparison when it comes to size and impressive landmarks. Built from almost 16,500m3 of concrete and strengthened with nearly 956 tonnes of 38mm and 13mm re-bar, the stack is a solid monument that has withstood the harshest of conditions that Mother Nature could throw at it.

Extreme cold and blowing snow, fierce winds and driving rain, heat and lightning, and even ground-shaking tremours, have barely made a mark on the stack. And, the fact that it’s also lined from top to bottom with 6.4mm nickel stainless steel and that its walls are 1.1m thick at the base and 267mm at the top, have all added to make the stack almost indestructible.

It was clearly built to last and since it started rising on the horizon in 1970, and subsequently going into service on August 21, 1972, the stack has performed as planned by safely carrying sulphur dioxide from INCO’s (now Vale’s) Copper Cliff smelter high into the atmosphere and away from the city.

However, long before any SO(2) reaches the atmosphere, a complex steel flue system almost 1.1km long has been designed to handle the 725 deg (F) gases.

Travelling at more than 88 km/h through 88 nickel-stainless steel diaphragm-type expansion joints, the gases are carefully monitored by 13 environmental control stations strategically placed along the flue system to collect and determine the dust burden, temperature, and volume of the gas flow.

Clearly the super stack has been designed with the environment in mind, but Vale is moving forward to make things in Sudbury even cleaner by embarking on a $1-billion AER (Atmosphere Emissions Reduction) Project to dramatically reduce emissions even further.

Eighty-five per cent further is what Vale is projecting as the company plans to capture sulphur-bearing gases from the smelter’s converter aisle at Copper Cliff and significantly reduce dust and metal emissions.

As mentioned earlier, the process of handling the gases is complex and involves a long and heavy system comprised of rectangular and circular sections, some as large as 7m in diameter, and flues, that combine to weigh 3,300 tons.

Trestles, bents and towers on which the flues are supported involve another 2,300 tons of steel, so once again, it’s not only a complex set-up, but a heavy one too.

For the rest of this article, click here: http://www.canadianminingjournal.com/news/will-sudbury-super-stack-be-needed-by-vale-after-retrofit-project/1003515398/