- What a mineral actually is, and the different ways minerals form inside the earth
- How to tell ferrous minerals apart from non-ferrous and non-metallic ones, with India’s major belts of each
- Why mining is dangerous for both miners and the environment, and how minerals can be conserved
- The difference between conventional and non-conventional energy sources, and where each comes from in India
- How coal forms, how petroleum and natural gas occur in rock traps, and where India’s biggest reserves lie
1What is a Mineral?
Almost everything around you, from the steel of a bus to the wire carrying electricity to your house, is made from something dug out of the earth. Geologists call this material a mineral. Even the toothpaste that cleans your teeth uses abrasive minerals like silica and limestone, and the sparkle in some toothpastes comes from mica.
A mineral is a “homogenous, naturally occurring substance with a definable internal structure,” as geologists define it: a natural material made of one uniform substance, with a definable internal structure.
A rock is different from a mineral: it is usually a mixture of several minerals in varying proportions. Some rocks, like limestone, are made of just one mineral, but most are a combination. Over 2,000 minerals have been identified, though only a handful are found abundantly in most rocks. A mineral’s colour, hardness and crystal shape depend on the exact physical and chemical conditions it formed under.
A geographer’s interest
- Minerals as part of the earth’s crust
- Where mineral resources are distributed
- Economic activities linked to minerals
A geologist’s interest
- How minerals actually form
- A mineral’s age
- Its physical and chemical composition
2How Minerals Occur
Minerals are usually found in ores. The type of formation or structure in which they are found decides how easily an ore can be mined, and this also decides the cost of extraction.
An ore is the term used for an accumulation of any mineral mixed with other elements. Mining an ore is only worthwhile (“commercially viable”) when the mineral content inside it is concentrated enough.
Minerals occur in five different ways depending on how and where they were formed:
Veins and lodes
In igneous and metamorphic rocks, minerals in liquid or gaseous form get forced upward through cracks and joints, then cool and solidify. Smaller deposits are called veins, larger ones lodes. Tin, copper, zinc and lead are found this way.
Beds and layers
In sedimentary rocks, minerals settle in horizontal layers (“strata”) through deposition and accumulation. Coal and some iron ore form this way under heat and pressure over long periods. Gypsum and salts form by evaporation in dry regions.
Decomposition of rocks
Surface rocks decompose, their soluble parts wash away, and a residual mass of weathered material is left behind, rich in the ore. Bauxite is formed exactly this way.
Placer deposits
Some minerals collect as alluvial deposits in the sand of valley floors and hill bases. These are called placer deposits and generally contain minerals that are not corroded by water. Gold, silver, tin and platinum are the most important such minerals.
Ocean waters and beds
Ocean water holds vast quantities of minerals, but most are too diffused to be worth mining. Common salt, magnesium and bromine do come from sea water, and the ocean beds are rich in manganese nodules.
Most of the minerals in India are nationalised, and their extraction is possible only after obtaining due permission from the government. But in most of the tribal areas of north-east India, minerals are owned by individuals or communities. Meghalaya has large deposits of coal, iron ore, limestone and dolomite. Coal mining at Jowai and Cherapunjee is done by family members in the form of a long, narrow tunnel, known as “rat hole” mining. The National Green Tribunal has declared this practice illegal and recommended it be stopped at once.
India’s mineral resources are rich and varied, but spread very unevenly. Peninsular rocks hold most of India’s coal, metallic minerals and mica. Sedimentary rocks on the peninsula’s western and eastern edges, plus Gujarat and Assam, hold most of its petroleum. Rajasthan has many non-ferrous minerals, while the alluvial plains of north India are almost empty of economic minerals.
The concentration of mineral in the ore, the ease of extraction and closeness to the market all affect whether a reserve is economically viable. To meet demand, a choice has to be made between a number of possible options; when this is done, a mineral “deposit” or “reserve” turns into a mine.
3Classifying Minerals
For general and commercial purposes, the chapter studies minerals under the groups below. Energy minerals (coal, petroleum, natural gas) are studied later, under Energy Resources.
4Ferrous Minerals
Ferrous minerals make up about three-fourths of the total value of India’s metallic mineral production. They form the base for metallurgical (metal-processing) industries; India exports large quantities after meeting its own demand.
4.1 Iron ore
Iron ore is the basic mineral and the backbone of industrial development. India has abundant, good-quality iron ore reserves.
| Magnetite | Hematite | |
|---|---|---|
| Iron content | Up to 70%, the finest iron ore | 50-60%, slightly lower than magnetite |
| Special property | Excellent magnetic qualities, valuable in the electrical industry | Most important industrially by quantity used |
Those four states, Odisha, Chhattisgarh, Karnataka and Jharkhand, together produced almost the whole of India’s iron ore in 2018-19. The major iron ore belts in India are:
| Belt | States / districts | Key facts |
|---|---|---|
| Odisha-Jharkhand belt | Badampahar mines (Mayurbhanj & Kendujhar, Odisha); Gua & Noamundi (Singhbhum district, Jharkhand) | High-grade hematite |
| Durg-Bastar-Chandrapur belt | Bailadila range (Bastar district, Chhattisgarh) + Maharashtra | 14 deposits of super-high-grade hematite; exported via Vishakhapatnam port to Japan & South Korea |
| Ballari-Chitradurga-Chikkamagaluru-Tumakuru belt | Kudremukh mines, Western Ghats, Karnataka | 100% export unit; among the world’s largest deposits; ore piped as slurry to a port near Mangaluru |
| Maharashtra-Goa belt | Goa + Ratnagiri district, Maharashtra | Lower-grade ore, but efficiently mined; exported via Marmagao port |
4.2 Manganese
Manganese is mainly used to manufacture steel and ferro-manganese alloy: nearly 10 kg of manganese is needed to make just one tonne of steel. It is also used in bleaching powder, insecticides and paints.
5Non-Ferrous Minerals
India’s reserves and production of non-ferrous minerals (copper, bauxite, lead, zinc, gold) are, in the book’s own words, “not very satisfactory,” yet these minerals are vital for metallurgical, engineering and electrical industries.
5.1 Copper
Copper is malleable, ductile and a good conductor, so it is mainly used in electrical cables, electronics and chemical industries. The leading producers are the Balaghat mines (Madhya Pradesh), the Khetri mines (Rajasthan) and the Singhbhum district (Jharkhand).
5.2 Bauxite
Several ores contain aluminium, but it is from bauxite, a clay-like substance, that alumina and then aluminium are actually extracted. Bauxite deposits form when rocks rich in aluminium silicates decompose (recall mode 3 from Section 2). Aluminium itself is valuable because it combines the strength of a metal like iron with extreme lightness, good conductivity and great malleability.
India’s bauxite is mainly found in the Amarkantak plateau, the Maikal hills and the Bilaspur-Katni plateau region.
Odisha was India’s largest bauxite-producing state in 2018-19; the Panchpatmali deposits in Koraput district are the state’s most important bauxite deposits.
When aluminium was newly discovered, Emperor Napoleon III wore aluminium buttons and hooks, and served food to his more illustrious guests in aluminium utensils, while the less honourable ones were served in gold and silver utensils. Thirty years after this, aluminium bowls were most common with the beggars in Paris.
6Non-Metallic and Rock Minerals
6.1 Mica
Mica is made of thin plates or leaves that split apart easily, so thin that a thousand stacked sheets are only a few centimetres high. It can be clear, black, green, red, yellow or brown, and its excellent insulating properties and resistance to high voltage make it one of the most indispensable minerals used in the electric and electronic industries.
Mica deposits lie along the northern Chota Nagpur plateau, with the Koderma-Gaya-Hazaribagh belt of Jharkhand as leading producer. Rajasthan’s main area is around Ajmer, and the Nellore mica belt of Andhra Pradesh is also important.
6.2 Limestone
Limestone is found with rocks made of calcium carbonate or calcium-and-magnesium carbonate, mostly in sedimentary formations. It is the basic raw material for the cement industry, and essential for smelting iron ore in a blast furnace.
The book’s Fig. 5.7 gives the state-wise share of limestone production in 2018-19: Rajasthan 22%, Andhra Pradesh 13%, Madhya Pradesh 13%, Chhattisgarh 11%, Karnataka 10%, Telangana 7%, Gujarat 6%, Tamil Nadu 5%, Maharashtra 4% and others 9%.
7Hazards of Mining, and Conserving Minerals
✓ What miners actually face
- Dust and noxious fumes inhaled by miners make them vulnerable to pulmonary (lung) diseases
- In coal mines, collapsing roofs, inundation (flooding) and fires are a constant threat
- Water sources near mines get contaminated
- Waste and slurry dumping degrades land, soil and rivers
✗ Why this needs strict rules
- Without stricter safety regulations, mining risks becoming a “killer industry”
- Environmental laws must actually be enforced, not just written down
The total volume of workable mineral deposits is a tiny fraction, only about 1% of the earth’s crust. Mineral deposits took millions of years to form and concentrate, but we are consuming them far faster than nature replaces them. This makes mineral resources finite and non-renewable: once used up, a rich deposit is gone. As mining goes deeper to keep up with demand, both cost rises and ore quality falls.
- Plan and use mineral resources sustainably rather than wastefully
- Keep developing better technology so low-grade ores can be used at a lower cost
- Recycle metals instead of mining fresh ore each time
- Use scrap metal and substitute materials wherever possible
8Energy Resources
Every activity, cooking, lighting, running vehicles, driving factory machines, needs energy. It comes from fuel minerals like coal, petroleum, natural gas and uranium, and from the electricity generated using them.
Conventional sources of energy are the traditional sources already in wide, established use: firewood, cattle dung cake, coal, petroleum, natural gas and electricity (both hydel and thermal).
Non-conventional sources of energy are newer sources, most of them renewable: solar, wind, tidal, geothermal, biogas and atomic energy.
Firewood and cattle-dung cake are the most common fuels in rural India. By one estimate, over 70% of rural households’ energy needs are met by just these two, but continuing to rely on them is becoming harder as forest area shrinks, and burning dung cake wastes manure that could go into farming instead.
9Conventional Sources of Energy
9.1 Coal
Coal is India’s most abundantly available fossil fuel and provides a major share of the country’s energy for power generation, industry and homes. It formed from plant material compressed over millions of years, so the exact form of coal depends on how much it was compressed, how deep it was buried, and for how long.
Metallurgical coal is a high-grade bituminous coal valued for smelting iron in blast furnaces. Lignite’s principal reserves are in Neyveli, Tamil Nadu, used to generate electricity.
Coal in India occurs in rocks of two main geological ages:
Gondwana coal
- A little over 200 million years old
- India’s major metallurgical coal
- Damodar Valley (West Bengal-Jharkhand): Jharia, Raniganj, Bokaro coalfields
- Also Godavari, Mahanadi, Son and Wardha valleys
Tertiary coal
- About 55 million years old
- Found in the north-eastern states
- Meghalaya, Assam, Arunachal Pradesh, Nagaland
Coal is bulky and loses weight as it burns down to ash, so heavy industries and thermal power stations are usually built on or near the coalfields themselves rather than transporting coal long distances.
9.2 Petroleum
Petroleum (mineral oil) is India’s next major energy source after coal. It fuels heat and lighting, lubricates machinery, and supplies raw material for many manufacturing industries; petroleum refineries act as a “nodal industry” for synthetic textiles, fertiliser and chemical industries.
Most of the petroleum occurrences in India are associated with anticlines (upward folds) and fault traps in rocks of the tertiary age. In folded regions, oil is trapped in the crest of the upfold inside a porous limestone or sandstone layer, prevented from rising or sinking by non-porous layers. Petroleum is also found in fault traps between porous and non-porous rocks. Gas, being lighter, usually occurs above the oil.
India’s major petroleum areas are Mumbai High, Gujarat and Assam. Ankeleshwar is Gujarat’s most important field. Assam is India’s oldest oil-producing state, with Digboi, Naharkatiya and Moran-Hugrijan as its key fields.
9.3 Natural gas
Natural gas is found along with petroleum and released when crude oil surfaces. It fuels homes and industry, generates electricity, is a raw material for chemical and fertiliser industries, and is used as transport fuel (CNG) and cooking fuel (PNG). Major reserves lie in Mumbai High and the west-coast fields, supplemented by the Cambay basin, with newer reserves in the Krishna-Godavari basin on the east coast.
9.4 Electricity
Electricity’s per-capita consumption is treated as an index of a country’s development, because it has such a wide range of uses. It is generated in two main ways, and once generated, electricity is exactly the same regardless of which way it was made.
Hydroelectricity
- Running water drives hydro turbines
- A renewable resource
- Examples: Bhakra Nangal, Damodar Valley Corporation, Kopili Hydel Project
Thermal power
- Burning coal, petroleum or natural gas drives turbines
- Uses non-renewable fossil fuels
10Non-Conventional Sources of Energy
Growing energy consumption has made the country increasingly dependent on fossil fuels; rising prices and the risk of future shortages threaten energy security, and fossil fuels cause serious environmental problems too. This makes renewable sources, solar, wind, tidal, biomass and waste-based energy, urgently necessary. India is rich in sunlight, water, wind and biomass, and has the largest programmes to develop them.
Nuclear (atomic) energy
Made by altering the structure of atoms, releasing heat that is used to generate electricity. Uranium and Thorium are found in Jharkhand and the Aravalli ranges of Rajasthan; the Monazite sands of Kerala are also rich in Thorium.
Solar energy
India is a tropical country with enormous potential for solar power. Photovoltaic technology converts sunlight directly into electricity, and solar energy is fast becoming popular in rural and remote areas. Some big solar power plants are being established in different parts of India; they will reduce rural households’ dependence on firewood and dung cakes.
Wind power
India’s largest wind-farm cluster runs from Nagarcoil to Madurai in Tamil Nadu. Andhra Pradesh, Karnataka, Gujarat, Kerala, Maharashtra and Lakshadweep also have important wind farms; Nagarcoil and Jaisalmer are especially well known for effective wind-energy use.
Biogas
Made from shrubs, farm waste, and animal and human waste. It has higher thermal efficiency than kerosene, dung cake or charcoal. Plants using cattle dung are called “Gobar gas plants” and give farmers a double benefit: energy, plus better-quality manure. Biogas plants are set up at municipal, cooperative and individual levels, and biogas is by far the most efficient use of cattle dung.
Tidal energy
Floodgate dams built across narrow inlets trap water at high tide; as the tide falls outside, the trapped water is released through a turbine. Ideal Indian sites: the Gulf of Khambhat, the Gulf of Kuchchh (Gujarat), and the Sunderban region of the Gangetic delta (West Bengal).
Geothermal energy
The earth grows hotter with depth; where this heating is unusually fast, groundwater absorbs the heat and turns to steam at the surface, which drives turbines. India has several hundred hot springs that could be used to generate electricity. Its two experimental projects are at Manikaran (Himachal Pradesh) and the Puga Valley (Ladakh).
11Conserving Energy Resources
Energy is a basic requirement for economic development: agriculture, industry, transport, trade and homes all need it, and India’s consumption has risen steadily since Independence. India is currently one of the least energy-efficient countries in the world, so a sustainable path is urgently needed, built on energy conservation plus greater use of renewable sources.
The book’s own suggestions for saving energy as an individual are: use public transport instead of private vehicles, switch off electricity when not in use, use power-saving devices, and use non-conventional energy sources. Remember the chapter’s closing line: “energy saved is energy produced.”
12Recap and Practice
- A mineral is a homogenous, naturally occurring substance with a definable internal structure; a rock is usually a mix of several minerals
- Minerals occur five ways: veins/lodes, beds/strata, residual decomposition, placer deposits, dissolved in ocean water
- Minerals studied: ferrous (iron ore, manganese), non-ferrous (copper, bauxite), non-metallic (mica) and rock minerals (limestone)
- Magnetite has up to 70% iron; Hematite has 50-60% but is used more industrially
- 97% of India’s iron ore (2018-19) came from Odisha, Chhattisgarh, Karnataka and Jharkhand
- Bauxite forms by decomposition; Odisha alone produced 65% of India’s bauxite (2018-19)
- Mineral resources are finite and non-renewable; only about 1% of the earth’s crust is workable deposit
- Energy is conventional (coal, petroleum, gas, hydel/thermal electricity) or non-conventional (solar, wind, tidal, geothermal, biogas, nuclear)
- Coal forms peat → lignite → bituminous → anthracite; India’s coal is Gondwana (~200 million years) or Tertiary (~55 million years) old
- Can I name the five ways minerals occur, with an example mineral for each?
- Can I name all four iron ore belts and one state/district in each?
- Can I list the four stages coal passes through, in order?
- Can I name all six non-conventional energy sources, and give an Indian location wherever the chapter names one?