The earth contains many minerals that are vital to us today. Minerals are non-living substances such as rocks and metals found naturally in the Earth’s crust.
Some metals, such as gold, can be found at the surface, but others are buried deep in the ground and have to be mined. Copper was one of the first metals to be used by people, but it is brittle and breaks if it is hammered too much. Early metalworkers discovered that if they hammered copper, then heated it in the fire and then hammered it again, it was easier to work with. This was the discovery of a process called annealing.
Some metals have to be extracted from the rock, or ore, in which they are found. The process used is called smelting. The rock is heated to a high temperature so that the metal melts and runs out.
Metals found near the surface are mined by the opencast method but those found deeper down have to be drilled out of the ground. First, geologists determine where the metals are. They carry out surveys of the rock layers beneath the surface, and also measure the magnetism of the rocks and minerals. This is because the magnetic field is stronger in rocks that contain metals such as iron, nickel and cobalt.
INDUSTRY
The word “industry” describes an activity that produces the goods or services that people need or want. There are many different kinds of industry, including mining, farming, fishing, manufacturing and the provision of services for people to use.
Industries fall into three groups. Primary industries are those which extract or grow raw materials, such as mining, fishing, farming and forestry. Manufacturing industries, which turn the raw materials into products such as cars, matches, books and buildings, are known as secondary industries. Tertiary industries include transport, shops, health care, banking, education, leisure and tourism.
In many manufacturing industries around the world, for example, cars, plastics and electrical appliances, machines are used instead of people to make goods. Highly automated industries, as they are called, are using more and more specialized equipment such as electronic technology and industrial robots to increase productivity. This has been partly responsible for increasing unemployment in certain countries. During the last part of the 20th century, Japan and other East Asian countries have developed highly automated industries, including electronics, computers and cars.
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