Metals are inorganic materials characterized by a metallic bonding of the atoms, a crystalline structure and a metallic sheen.
They are generally very malleable, ductile, strong and tough. They have high densities and relatively low melting temperatures. Metals are good conductors of electricity and heat, and are easily attacked by corrosion and oxidation. Furthermore they are reflective and feel cool.
Mining is the work or business of taking minerals from the earth. A hole or tunnel is dug in the ground to take out metals, coal, salt, or other minerals.
Most substances obtained from the earth are gotten by mining. Mining provides iron for steel making, salt for food, coal for fuel, and gold, silver, and diamonds for jewellery. Mined materials also include stone for building, phosphate for fertilizer, and gravel for highways.
There are many methods of mining, dependent on where and how a coal or mineral deposit is found. Some substances are mined relatively cheap because they can be found at or near the earths surface. Some minerals are found as a compact mass, while others are widely scattered. Other mined materials are found far beneath the surface and removed by tunneling deep underground. Some mined substances are located beneath oceans, lakes, and rivers. Other minerals are concentrated in large bodies of water and are obtained by pumping.