26 July 2002
	Thabazimbi A BRIGHTER FUTURE FOR OLDEST MINE By Brendan Ryan

With all the attention being lavished on Sishen and Hope Downs it seems Kumba's oldest iron ore mine - Thabazimbi - has been forgotten, but that may be about to change. Kumba has operated Thabazimbi since 1932 and until 1958 it was the biggest producer of iron ore in SA. The mine has reserves of haematite ore of 21 Mt and a total haematite resource of 91 Mt, giving it an estimated life of another 8-10 years. Thabazimbi employs 950 people and produces 2,2 Mt of iron ore/year, which is supplied to Iscor's steel works through a long-term contract agreement at a price that equals the cost of production plus a management fee of 3% of that cost. Kumba management is looking at ways to revitalise Thabazimbi and, if it all works out, Thabazimbi could be transformed from a mine nearing the end of its days to one that could have another 40 years of life left. The key lies in the utilisation of banded ironstone deposits in the region, which were previously considered uneconomic to mine. Operations instead concentrated on the haematite iron reserves. Iron ore business general manager Matie Von Wielligh says: "Now the problem is how to release the iron in the banded ironstone ore from the waste material. Thabazimbi's staff has been working on this for the past 30 years but until recently hit one dead end after another. However, during the past two years their persistence has paid off through new insights and new technology, which have put us in a much better position where we are more confident we can now succeed. The remaining challenge now is to test the ability of Iscor to fit a banded ironstone ore feed into their product mix to produce iron from their blast furnaces. "Having a product with the right chemistry that meets Iscor's specifications is not necessarily a guarantee that the product will add value for their steelworks," Von Wielligh says. "Iron-ore smelting is a black art. Contracts with steelworks typically contain conditions along the lines that future supply is dependent on the successful introduction of the new material into the blast furnaces for six months or the first 30 000 t of iron production." The reason is the iron ore might have some physical properties that could destabilise the functioning of the blast furnaces or inhibit the flow of gases through the furnaces. The risk is that after four or six months Iscor could decide it does not want the new iron-ore product. Von Wielligh's challenge is to ascertain the physical properties of the new ore without incurring the heavy costs of mining enough ore to produce 30 000 t of iron, which would require construction of a multimillion rand treatment plant. "We need to do more technical work to minimise the risks before we decide to go for large-scale mining of the banded ironstone deposits at Thaba-zimbi."