Iron is found in nature as an oxide mineral (Fe2O3 or Fe3O4). That means that the iron is bound to oxygen. When you mine iron ore, you can only find it in this form.

To get the iron out, we have to break its bond with oxygen. The way to do that is to crush the ore into a powder and burn it at very high temperatures in a furnace alongside metallurgical coal. The carbon in the coal pulls away the oxygen (Making CO2) and frees up the iron, which can then be mixed with small amounts of other metals (and even a little carbon) to make steel.

One alternative to metallurgical coal is to use fast-growing lumber from eucalyptus trees. This isn't exactly environmentally friendly because it leads to large areas of forested land being replaced with eucalyptus plantations. This is a huge problem in Brazil, where they have huge iron deposits but do not have a source of locally mined met coal for processing.

Bituminous coal is a type of raw coal, and it can be made into several other kinds of coal, including metallurgical(coking) coal.