Banking service chronicle Published this article page no 4 For 11000 years human beings have been fashioning metal for their use. Ore metals are the source of most metals. First the ores are mined or quarried from beneath the earth or dredged from lakes and rivers then they are crushed and separated and finally they are refined and smelted to produce metal. By 5000 BCE copper was used to make beads and pins. By 3000 BCE tin was added to copper to produce bronze a harder metal. Iron even harder than bronze was widely produced by 500 BCE. The technology of how to master metals (copper bronze iron) developed independently in various parts of the world. By 3000 BCE most of the gold extracting techniques used today were already known in Egypt. The concept of carats indicates the amount of gold in gold! Nowadays copper and silver are often added to gold to make it harder. The gold content in this is known as carats. More than half of the gold mined with so much labour returns to the earth buried in bank vaults banking service chronicle monthly magazine buy
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