(i) (a) Ferrous and non-ferrous minerals Ferrous minerals Non-ferrous mineralsThese minerals contain iron. They provide a strong base for the development of metallurgical industries.These minerals do not contain iron. They play a vital role in a number of metallurgical, engineering and electrical industries.Ferrous minerals constitute three fourth of total mineral production in India. India's reserves of non ferrous minerals is not very largeExample: Iron ore and manganese Example: Bauxite, lead and gold. (b) Conventional Source of Energy Non-Conventional Source of Energy These are generally exhaustible and polluting. These are usually inexhaustible and nonpolluting. Some Examples are: Firewood, Coal and Petroleum Some Examples are: Solar, Wind, Tidal and Atomic Energy