Minerals: A homogenous, naturally occurring substance with definable internal structure is called mineral.
Types of Minerals
a. Ferrous (containing iron): Iron ore, manganese, nickel, cobalt, etc.
b. Non-ferrous: Copper, lead, tin, bauxite, etc.
c. Precious: Gold, silver, platinum, etc.
Non-metallic: Mica, salt, potash, sulphur, granite, limestone, marble, sandstone, etc.
Energy Minerals: Coal, petroleum and natural gas
Mode of occurrence of minerals:
In igneous and metamorphic rocks: The smaller occurrences are called veins and the larger occurrences are called lodes. They are usually formed when minerals in liquid/molten and gaseous forms are forced upwards through cavities towards the earth’s surface. Examples: tin, copper, zinc,
In sedimentary rocks: In these rocks, minerals occur in beds or layers. Coal, iron ore, gypsum, potash salt and sodium salt are the minerals found in sedimentary rocks.
By decomposition of surface rocks: Decomposition of surface rocks and removal of soluble constituents leaves a residual mass of weathered material which contains ores. Bauxite is formed in this way.
As alluvial deposits: These minerals are found in sands of valley floors and the base of hills. These deposits are called placer deposits. They generally contain those minerals which are not corroded by water. Examples; gold, silver, tin, platinum, etc.
In ocean water: Most of the minerals in ocean water are too widely diffused to be of economic importance. But common salt, magnesium and bromine are mainly derived from ocean waters.
Iron Ore:India is rich in good quality iron ores. Magnetite is the finest iron ore with a very high content of iron upto 70%. This iron ore is valuable for the electrical industry because of its excellent magnetic properties. Hematite ore is the most important industrial iron ore; in terms of usage. The iron content of hematite is 50-60%.
Major Iron Ore Belts in India
A. Orissa Jharkhand Belt: Badampahar mines in the Mayurbhanj and Kendujhar districts of Orissa have high grade hematite ore. Additionally, hematite iron ore is mined in Gua and Noamundi in Singhbhum district of Jharkhand.
B. Durg Bastar Chandrapur Betl: This belt lies in Chhattisgarh and Maharashtra. The Bailadila range of hills in the Bastar district of Chhattisgarh have very high grade hematite ore. This hilly range has 14 deposits of super high grade hematite ore. Iron from these mines is exported to Japan and South Korea via Vishakapatnam port.
C. Bellary Chitradurga Chikmaglur Tumkur Belt: This belt lies in Karnataka. The Kudremukh mines located in the Western Ghats are a 100 percent export unit. The ore from these mines is transported as slurry through a pipeline to a port near Mangalore.
D. Maharashtra Goa Belt: This belt inculdes the state of Goa and Ratnagiri district of Maharashtra. The ores in these mines are not of very high quality. They are exported through Marmagao port.
Manganese:Manganese is mainly used in the manufacturing of steel and ferro-manganese alloy. It is also used in making bleaching powder, insecticides and paints.
Copper:Copper is mainly used in electrical cables, electronics and chemical industries. The Balaghat mines in Madhya Pradesh produce 52% of India’s copper. Rajasthan is the next leading producer with about 48% share. Copper is also produced in the Singhbhum district of Jharkhand.
Aluminium:Aluminium is lightweight yet strong and hence is used in a variety of applications. Amarkantak plateau, Maikal hills and the plateau region of Bilaspur-Katni are the main areas of bauxite deposits. Orissa is the leading producer of bauxite in India with 45% share. Panchpatmali in Koraput district is the most important centre of bauxite deposit in Orissa.
Mica: Mica is a mineral which is made up of a series of plates or leaves. The mica sheets can be so thin that a thousand of them can be layered into a few centimetre thick mica sheet. Mica has excellent di-electric strength, low power loss factor, insulating properties and resistance to high voltage. Mica is widely used in electric and electronic industries.
Mica deposits are found in the northern edge of the Chota Nagpur plateau. Koderma-Gaya-Hazaribagh belt of Jharkhand is the leading producer of mica. Ajmer in Rajasthan and Nellore in Andhra Pradesh are the other important producers of mica.
Hazards of Mining
Mining is a hzaradous industry; both for the workers and for the residents. The Miners have to work under tough conditions where no natural light is available. There is always a risk of collapse of mine roof, inundation with water and fire. The areas around mines face the problem of too much dust from the mines. Slurry from mines damages the roads and the farmland. Houses and clothes become dirty more often than in other areas. Miners are at great risk of getting afflicted with pulmonary disorders. Cases of respiratory tract diseases are very high in mining areas.
Conservation of Minerals
It takes millions of years for the formation of minerals. Compared to the present rate of consumption, the replenishment rate of minerals is very slow. Hence, mineral resources are finite and non-renewable. Due to this, it is important that we conserve the mineral resources.
Conventional Energy Resources: Firewood, cattle dung cake, coal, petroleum, natural gas and electricity (both hydel and thermal)
Non-conventional Energy Resources: Solar, wind, tidal, geothermal, biogas and atomic energy.
Firewood and cattle dung cake: As per estimates, more than 70% of energy need in rural households is met by firewood and cattle dung cake. A decreasing forest area is making it difficult to use firewood. Dung cake can be put to better use in the form of manure and hence its use should also be discouraged.
Coal:India is highly dependent on coal for meeting its commercial energy requirements. Depending on the degree of compression during its formation, there are varieties of coal.
a.Lignite: It is a low grade brown coal. It is soft and has high moisture content. Neyveli in Tamil Nadu has the main reserves of lignite coal. This type of coal is used for electricity generation.
b.Bituminous coal: Coal which was formed because of increased temperature and was buried very deep is called bituminous coal. This is the most popular coal for commercial use. High grade bituminous coal is ideal for use in metallurgy.
c.Anthracite coal: This is the highest quality hard coal.
In India, coal occurs in rock series of two main geological ages. The Gondwana coal was formed over 200 million years ago. The tertiary deposits are about 55 million years old. The major sources of Gondwana coal are located in the Damodar valley (West Bengal-Jharkhan). In this belt; Jharia, Raniganj and Bokaro are important coalfields. Coal deposits are also present in the Godavari, Mahanadi, Son and Wardha valleys.
Tertiary coal is found in the north-eastern states of Meghalaya, Assam, Arunachal Pradesh and Nagaland.
Petroleum:After coal, the next major energy resource in India is petroleum. Petroleum is a major source of fuel for various uses. Petroleum also provides raw materials for various manufacturing industries; like plastic, textiles, pharmaceuticals, etc.
Most of the petroleum in India occurs in anticlines and fault traps in the rock formations of the tertiary age. The oil bearing layer is a porous limestone or sandstone through which oil may flow. The intervening non-porous layers prevent the oil from rising or sinking. Petroleum is also found in fault traps between porous and non-porous rocks. Gas usually occurs above the oil because it is lighter than oil.
Mumbai High produces about 63% of India’s petroleum, Gujarat produces 18% and Assam 13%. Ankeleshwar is the most important oil field in Gujarat. Assam is the oldest oil producing state of India. Important oil fields of Assam are Digboi, Naharkatiya and Moran-Hugrijan.
Natural Gas: Natural gas is found alongwith or without petroleum. It is used as fuel and also as industrial raw material. Large reserves of natural gas have been discovered in the Krishna-Godavari Basin. Gulf of Cambay, Mumbai High and Andaman Nicobar islands are also important areas with large reserves of natural gas.
The 1700 km long Hazira-Vijaipur-Jagdishpur pipeline links Mumbai High and Bassein with the fertiliser, power and industrial complexes in western and northern India. Natural gas is mainly used by the fertiliser and power industries. Now-a-days, use of CNG (Compressed Natural Gas) is increasing as vehicle fuel in the country.
Electricity: Electricity is generated mainly by two methods; by running water which drives hydro turbines and by burning other fuels like coal, petroleum and natural gas to drive turbines. Bhakra Nangal, Damodar Valley Corporation, Kopili Hydel Project, etc. are major hydroelectric producers in the country. At present, there are over 300 thermal power stations in India.
Non-conventional Sources of Energy
Nuclear Energy: Nuclear energy is obtained by altering the structure of atom. When the structure of an atom is altered, too much energy is released in the form of heat. This heat is utilised to generate electric power. Uranium and Thorium are used for generating atomic power. These minerals are available in Jharkhand and the Aravalli ranges of Rajasthan. The Monazite sand of Kerala is also rich in Thorium.
Solar Energy: Photovoltaic technology is used to convert solar energy into electricity. The largest solar plant of India is located at Madhapur near Bhuj. Solar energy holds great promises for the future. It can help in minimizing the dependence on firewood and animal dung cakes in rural areas. This will also help in conservation of fossil fuels.
Wind Power: India now ranks as a “Wind Super Power” in the world. The wind farm cluster in Tamil Nadu (from Nagarcoil to Madurai) is the largest cluster in India. Andhra Pradesh, Karnataka, Gujarat, Kerala, Maharashtra and Lakshadweep are also important centres of wind power production.
Biogas: Biogas can be produced from shrubs, farm waste, and animal and human waste. Biogas is more efficient than kerosene, dung cake and charcoal. Biogas plants can be set up at municipal, cooperative and individual levels. The gobar gas plants provide energy and also manure.
Tidal Energy: Floodgate dams are built across inlets. The water flows into the inlet during high tide and gets trapped when the gate is closed. Once the tide recedes, the gates are opened so that water can flow back to the sea. The flow of water is used to run the turbine to generate electricity. A 900 mw tidal energy power plant is set up by the National Hydropower Corporation in the Gulf of Kuchchh.
Geo Thermal Energy: We know that the inside of the earth is very hot. At some places, this heat is released on the surface through fissures. Groundwater in such areas becomes hot and rises up in the form of steam. This steam is used to drive turbines. Two experimental projects have been set up in India to harness geothermal energy. They are; the Parvati valley near Manikarn in Himachal Pradesh and the Puga Valley in Ladakh.