Have you ever stopped to think where we get the raw materials to make smartphones, cars or even aircraft? Most of them come from the ground. Here are 5 of the most important and widely-used.
1. Fossil Fuels
The three fossil fuels are coal, oil and natural gas. These were all formed in the distant past, millions of years ago. Coal was formed from peat, which produced on the floor of tropical forests from dead and decaying vegetation. Oil formed on the sea bed from dead and decaying remains of sea creatures, mainly plankton. Natural gas is formed with and at the same time as coal and oil. Oil is particularly useful as it gives us fuels as well as lots of other chemicals that we use to make things from, e.g. plastics.
2. Iron Ore
Chemically, the most common iron ore is the mineral haematite or iron oxide. To smelt iron ore, carbon is used as it is more reactive than iron and will remove the oxygen from the iron oxide, leaving the iron behind. Smelting is carried out on a large scale in blast furnaces. Iron ore deposits are usually mined directly from the surface using the open pit technique as you can see on the picture below. The largest iron ore mine in the world is Caraja mine in Brazil, but there are big ones in Australia and Africa too.
In the UK, the largest limestone quarries are in Derbyshire, right on the edge of the Peak District National Park. Limestone is mainly used as a building stone and as an aggregate for road foundations. Limestone mined in the south of the UK is also used for building, but in a different way — when it is roasted with clay and ground down into a fine powder, it is used to make cement.
In hot countries, clay can simply be dried into bricks and used for building. That would be no good in the UK as the climate is too wet, so we bake the clay in kilns to chemically change it into bricks and roof tiles that are waterproof. A type of clay called kaolin that is mined in Devon and Cornwall is used to make porcelain items, whilst other clays found around the country are used to make pots, cups, plates, ceramic tiles and more.
Bauxite is the ore from which we extract aluminium and, like iron ore, it usually occurs close enough to the surface to extract using surface mining methods like strip mining. This important metal is the basis for many light alloys, including those used to make aircraft. Before 1886, the only way to obtain aluminium was to displace it from its compounds using more expensive and more reactive metals so it was more expensive than gold. However, in 1886, an American and a French scientist independently devised a method of extracting it using electrolysis. The largest bauxite mine is Weipa in Australia.