On Wednesday, October 24, Steve Thivierge, superintendent of engineering and geology for the Niobec Mine, spoke before the Thetford Mines Branch. About 40 people were present.
Located near Chicoutimi (City of Saquenay), the Niobec mining and metallurgical complex has been producing niobium (sometimes called columbium) concentrate for the past 31 years. Thivierge explained that since 1994, Niobec has a new converter on the mine site that transforms the concentrate to ferroniobium, which is then sold to 60 clients around the world.
The ore body containing niobium is a carbonatite buried beneath 230 feet of limestone. The proven reserves can sustain the current rate of niobium production for another 10 years; there are, however, possible resources for another 20 to 25 years.
The participants learned that about 1.7 million tonnes of ore per year are extracted by open stope mining from several levels at depths of 300 to 1,450 feet.
Thivierge also explained that the concentrate, containing about 58% Nb2O5, is produced by grinding and flotation of the pyrochlore ore. The concentrate is converted to ferroniobium through a complex aluminothermal reaction at 2,200ºC. After cooling, the ferroniobium is crushed and bagged or packaged in various metal containers according to clients’ specifications. Niobec produces 10 per cent of the world supply of ferroniobium; two Brazilian companies produce the other 90 per cent.
Ferroniobium mainly serves as a steel alloy for gas and oil pipelines, in automobile and aeronautical construction, as well as in buildings and bridges. Adding eight to ten ounces of niobium per tonne of steel can increase steel strength, ductility and corrosion resistance by up to 25 per cent.