The earth’s crust is made up of hard rocks which are in turn made up of solid substances called minerals. Minerals are formed when natural elements on the earth go through weathering processes such as evaporation of water, extreme heat and pressure.
Each mineral has its own unique physical and chemical properties, based on which, they are classified as metallic and non-metallic minerals.
Metallic minerals contain metal in raw form and are further divided into ferrous minerals and non-ferrous minerals. Ferrous minerals like iron ore, manganese and chromite contain iron. Non-ferrous minerals do not contain iron, but may contain some other metal, such as gold, silver, copper or lead.
Non-metallic minerals do not contain metals like limestone, mica, and gypsum.
Most minerals found in the earth’s crust are in the form of ores and they need to be extracted and purified before being put to various uses.
Minerals can be extracted by: Mining, Drilling and Quarrying. The process of extracting minerals from rocks buried under the earth’s surface is called mining.
The mining process is of two types: Open-cast mining and Shaft mining.
In the open-cast mining process, the minerals are taken out from the shallow depths by removing the surface layer. In the shaft mining process, deep bores (called shafts) are made to reach the mineral deposits that lie deep under the soil layer. In the drilling process, deep wells are bored into the earth’s surface to take out petroleum and natural gas.