The pulverised coaldust streaming into the base of the furnace, alongside blasts of hot air from an array of metallic pipes called tuyeres, is a useful reminder that we cannot discuss iron and steel without discussing coal. For every tonne of molten pig iron you need just over a tonne of iron ore and just under a tonne of coal, most of it dumped in the top of the furnace but some sprayed into the sides in granulated form.fn1
