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Special fans supplied by Fläkt Woods are being used to ventilate a network of underground tunnels on a new ferrochrome mine, 600 metres underground in the Kemi district of Finland, for Outokumpu Stainless.
Fläkt Woods has supplied about 300 fans for the ventilation system of the Kemi mine. Two main fans, massive 2 metre diameter JM axial fans, supply the fresh air into the mine, while other JM axials located throughout the shafts act as exhaust air fans. Smaller Fläkt Woods fans are used in the roadway tunnels and as local fans of working locations.
"Fläkt Woods axial fans have been used in the mines and factories of Outokumpu for almost four decades now, which illustrates our long-term co-operation. Our operations are based on strong technical know-how, high-quality products and definite reliability, which are properties that guarantee satisfied customers", states Fläkt Woods’ Sales Manager Timo Saastamoinen.
The ferrochrome found deep underground is one of the components of stainless steel. Chrome ore has been mined in the open pit of Kemi for decades, but since 2003 preparations have been made to start operations underground in order to ensure full-scale utilisation of the chrome reserves. The open pit will be closed by the end of 2006.
Good air quality is essential at these depths as the mine’s Underground Director Juha Riikonen explains: "The need for ventilation is increased by explosion gases, exhaust gases from diesel-powered machinery, as well as dust that is generated by explosions and handling of blasted rock".
Ventilation system
The ventilation of the mine is realised by means of three ventilation shafts and underground fans. The fresh air is blown into the ore body through a hole drilled into the rock, using the two parallel axial fans. The exhaust air is sucked from the ends of the ore body through two exhaust air ducts.
All of the main fans are located on the ground surface, and they are controlled by frequency converters. The fresh air is directed to the
underground working locations by using local fans and ventilation ducts. The ventilation control is constructed so that it acts as a part of the whole mine automation system. The system programming is so sensitive it takes account of the time of year, schedule of explosions as well as reduced mine operations during nights and weekends.
"The basic requirement underlying fan selection was that the different parts of the mine needed to be supplied with necessary amount of air at a certain overall pressure. The outside use of the fans and the possibility to rotate them in the reverse direction in a fire situation were additional requirements. After considering these requirements and the total economic impact, we ended up choosing Fläkt Woods’ products", concludes Juha Riikonen.
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