If ‘steel mining’ only reminds you of the title for a school project, be prepared for a paradigm shift. From its humble origins as iron ore in dusty rock, steel mining has facilitated almost everything we equate with industrial, secular and domestic progress and plays a pivotal role in the innumerable inventions of modern civilisation and technology.
Steel mining’s Illustrious past
“Early man first worked iron ore in Southern Africa 14000 years ago, as indicated by the carbon-14 dating of certain ancient workings at Bomvu Ridge, the site of the Swaziland Iron Ore Mining Company. This specular iron ore was not used for smelting to iron but purely for cosmetic purposes. Slags found at Broederstroom in the Transvaal have been dated as from the 4th century A.D.
Fairly extensive pre-European iron ore mining was carried out in the vicinity of the Thabazimbi Iron Ore Mine. It is estimated that at least 400 tons were taken from there… and it was left to the Europeans, who had the necessary technology, to initiate the development and full exploitation of the iron ore reserves of the country.” – March 1988 Journal of the South African Institute of Mining and Metallurgy. Noble history indeed.
Today’s steel mining process
After mining, the ore is extracted from finely ground rock using magnetic rollers, where it heads for the blast furnaces after processing into coarse-grained clumps. A mixture of iron ore and coal is then heated in the blast furnace to produce molten iron, or pig iron, from which steel is made. In a basic oxygen furnace, molten iron ore is mixed with varying quantities of steel scrap and alloys to produce different grades of steel. In an electric arc furnace, recycled steel scrap is melted directly into new steel.
From the furnaces, molten steel passes through continuous casters and is formed into slabs- which are rolled for making flat products, blooms- which are shaped into girders and billets, which are formed into bars and rods.
Each of today’s main types of steel; cast iron, wrought iron and iron alloys have a unique application and niche, but of them all, steel exceeds all others.
Taking a well-deserved bow, we call an encore to steel mining, not just because it only requires 25% of the energy required for extracting the likes of aluminium, or that it is environmentally friendly as it can be recycled, but for its vital role from antiquity till today and for the ultimate show stealer, steel production is 20 times higher as compared to production of all non-ferrous metals put together. Long live steel!