At the time of Independence we had very little information about mineral wealth of the country. Although the Geological Survey of India (GSI) was working since 1851 it took considerable interest in locating and harnessing the natural resources for meeting the growing demands of mineral/metal industries.
The organisation is not only carrying out survey and exploration work over land areas of the country but in the surrounding coastal areas and the Exclusive Economic Zones (EEz) and also in the icy continent of Antarctica. It has now about 2,900 scientists and technical professionals and around 13,400 supporting personnel.
The Indian Bureau of Mines (IBM) at Nagpur with 12 regional and 2 sub- regional offices is engaged in promotion, conservation and scientific development of mineral resources of the country.
India is richly endowed with different minerals. While the country has vast reserves of iron-ore, manganese, bauxite and lime-stone its position is critical in respect of non-ferrous metals like copper, zinc, lead, tin. Graphite, tungsten, sculpture, potash, rock phosphate and mercury etc. Table 17.1 gives an idea about the recoverable reserves of some of the important minerals of the country:
The total recoverable reserves of iron ore in India are about 12, 3 17 million tones of hematite and 5,395 million tones of magnetite categories. The total recoverable reserves of copper ore are 712.5 million tones equivalent to 9.4 million tones of metal content.
The all-India conditional resources of copper are 722 million tons (3.16 million tons of copper metal) and prospective resources are 0.6 million tons of copper ore. Out of total 114million tones of recoverable reserves of chromites, about 18% is metallurgical and 22% charge chrome grade.
The total recoverable reserves of bauxite in the country are placed at 2,584 million tons while the total in situ reserves are 3,075 million tones. Total gold metal ore reserves are estimated at 224 lakh tones, with 116.5 tones of metal. Total recoverable reserves (all grades) of lead and zinc ores are 231 million tones comprising metal content of 5.1 million tons of lead and 17 million tons of zinc metal.
The total recoverable reserves of manganese ore are 406 million tones out of which 104 million tones are proved, 135 million tones probable and 167 million tones of possible category. The total estimated conditional resources of nickel ore is 188.7 million tones located in Orissa (174.5 million tons) and Jharkhand (9 million tons).
The total recoverable reserves of tungsten ore have been estimated at 43.15 million tones or 132 thousand tones of WO3 content. The recoverable reserves of barites are 85 million tones. The Mangampet deposit occurring in Cuddapah district (Andhra Pradesh) is the single largest deposit in the world containing 61 million tones of recoverable reserves. The total in situ reserves of diamond are about 2.6 million carats and conditional resources of 1937 thousand carats.
Dolomite occurrences are widespread in almost all parts of the country. The total recoverable reserves of all grades of dolomite are 7.348 million tones 90 per cent of which is distributed in seven states of Madhya Pradesh, Chhattisgarh, Orissa, Gujarat, Karnataka, West Bengal, Uttar Pradesh and Maharashtra. The reserve of BF and SMS grade are large, but those of refractory grade at 425 million tones constitute only 5.8 per cent of the all India reserve.
India is the world’s leading producer of sheet mica and accounts for about 60% of global trade. The in situ reserves of mica in Andhra Pradesh are 42,626 tones; in Bihar 2,938 tones; in Jharkhand 1494 tones and in Rajasthan 2,007 tones. The recoverable reserves of gypsum are estimated at 383 million tones. Out of this, 2 million tones are of surgical plaster grade, 92 million tones of fertiliser/ pottery grade, 76 million tons of cement/paint grade, 13 million tones of soil reclamation grade and the rest is unclassified. The total recoverable reserves of limestone of all categories and grades are placed at 169,941 million tones and of conditional reserves at 3,713 million tones. The total recoverable reserves of magnetite are about 415 million tones of which 76 million tones are in the proved category.
The total recoverable reserves of kyanite and sillimanite are 8.1 million tones and 58.8 million tons respectively. Besides, conditional resources of 95 million tons of kyanite are also estimated. For sillimanite conditional resources of 5.9 million tones and prospective resources of 0.8 million tones have been estimated.
Other minerals occurring in significant quantities in India are betonies (Rajasthan, Gujarat, Jharkhand and Jammu and Kashmir), corundum (Karnataka, Andhra Pradesh. Rajasthan and Chhattisgarh), calcite (Andhra Pradesh, Rajasthan, Madhya Pradesh, Haryana, Tamil Nadu, Karnataka, Uttar Pradesh and Gujarat), fuller’s earth (Rajasthan, Jharkhand and Andhra Pradesh), feldspar (Rajasthan, Andhra Pradesh, Tamil Nadu, Maharashtra and West Bengal), garnet (Tamil Nadu, Kerala, Orissa, Andhra Pradesh and Rajasthan), Pyrites (Jharkhand, Rajasthan, and Andhra Pradesh), steatite (Raja Uttar Pradesh, Kerala. Maharashtra and Mai Pradesh-Chhattisgarh), wollastonite (Rajasthan J Gujarat), zircon (beach sand of Kerala, Andhra Pradesh and Orissa) and quartz and silica minerals arc will spread and occur in nearly all states. Besides, the country has vast resources of building and ornamental stones such as granite, marble and slate. Gral is mainly mined in Tamil Nadu. Karnataka, An Pradesh and Rajasthan: marble in Rajasthan) Gujarat: slate in Madhya Pradesh and Andhra Pradesh and sand stone in Rajasthan.