Minerals and fossil fuels

The first principle

A mineral deposit is a place where a geological process has concentrated an element far above its average level in the crust. Each process works only in certain rocks and settings, so minerals are not scattered at random: metals collect in the ancient igneous and metamorphic rocks of shields, fuels form in sedimentary basins where organic matter was buried, and bauxite forms where tropical weathering leaches everything else away. If you know a region's rock age and history, you can predict what lies beneath it, and that is the key to every question on mineral distribution.

The core

How minerals form and where

• Igneous and metamorphic processes. Hot fluids from cooling magma deposit metals in veins, and metamorphism concentrates ores further. India's Archaean and Dharwar rocks, over 2.5 billion years old, hold its iron ore, manganese, gold and copper.
• Sedimentary processes. Plant matter buried in swamps becomes coal, plankton in marine muds becomes oil and gas, and shells become limestone. India's Gondwana rocks (about 300 to 200 million years old) hold about 98 per cent of its coal, while younger Tertiary rocks hold its oil and the coals of the north east.
• Residual and placer deposits. Intense weathering leaves aluminium as bauxite and iron as laterite, and running water sorts heavy grains such as monazite, ilmenite and gold into river and beach sands.

India's mineral belts

The richest belt is the Chota Nagpur plateau and its extension into Odisha and Chhattisgarh, where Gondwana coal basins in the Damodar, Son, Mahanadi and Godavari valleys sit beside Dharwar iron ore (Singhbhum, Keonjhar, Bailadila), manganese, bauxite, mica and uranium. The Karnataka and Goa belt has iron ore and gold (Kolar, Hutti), the Aravalli belt in Rajasthan has zinc, lead and copper (Zawar, Khetri), and oil and gas come from Assam, the Cambay and Barmer basins and Mumbai High offshore. This clustering is why steel plants grew in a triangle around Jamshedpur, Bokaro, Rourkela and Bhilai.

Resource potential of the Deccan Trap

The Deccan Trap is a pile of basalt lava flows erupted through fissures about 66 million years ago, now covering about 5 lakh square kilometres of Maharashtra and neighbouring states.

• Soil. Weathered basalt gives regur, or black cotton soil, rich in clay that holds moisture through the dry season, which suits rainfed cotton, soybean and jowar, and sugarcane where irrigated.
• Stone. Hard, durable basalt is quarried as building stone and road and concrete aggregate.
• Water. Groundwater lies in weathered, vesicular and jointed basalt, a hard rock aquifer of low storage, which explains the recurring droughts of Marathwada; the Koyna and other dams use the Ghats for hydropower.
• Minerals. Laterite and bauxite cap high plateaus around Kolhapur and Belagavi, and zeolite crystals fill the gas cavities in the lava.
• Geothermal and tourism. Hot springs on the Konkan coast mark geothermal potential, and Ajanta and Ellora (carved in basalt), the Lonar crater lake, Mahabaleshwar and the Kaas plateau draw visitors.

Dimensions

Rich geology, small mining economy

India, a core of old Gondwanaland, produces about 95 minerals, yet mining and quarrying contribute only about 2 per cent of its Gross Domestic Product (GDP), while Australia, whose rocks once lay beside India's in Gondwanaland, earns a far larger share. The reasons are human, not geological. Exploration has been shallow, so deep seated ores of copper, nickel and rare elements are barely mapped. Many ore bodies lie under dense forest and Fifth Schedule tribal land, so forest clearance, land acquisition and the consent of gram sabhas take years. Leases were once given on a first come first served basis, which bred illegal mining and court ordered halts in Goa, Bellary and Odisha after 2011. Much ore is also exported raw, while India imports coking coal, lithium and rare earths.

Reforms

• Mines and Minerals (Development and Regulation) (MMDR) Amendment Act, 2015 (Ministry of Mines): made auction the only route for new leases and created District Mineral Foundations for mining affected people and the National Mineral Exploration Trust.
• MMDR Amendment, 2021: removed the distinction between captive and merchant mines and opened exploration to private agencies.
• MMDR Amendment, 2023: created exploration licences for deep seated and critical minerals and let the Centre auction critical minerals; in June 2023 the Ministry of Mines listed 30 critical minerals, including lithium, cobalt, nickel and rare earths.
• National Critical Mineral Mission (January 2025, Ministry of Mines): funds exploration at home, processing and the purchase of mines abroad, building on Khanij Bidesh India Limited (KABIL), which signed for lithium blocks in Argentina in 2024.

In practice

Coal: why it is still unavoidable, and at what cost

Coal remains central because India has large reserves and little oil or gas. It generates about 70 per cent of electricity, steel needs coking coal, it is the largest single freight for Indian Railways, and royalties and the District Mineral Foundations fund Jharkhand, Odisha and Chhattisgarh. India produced over one billion tonnes in 2024 to 25, and solar and wind cannot yet supply power at night or during the evening peak without large storage.

The costs fall mainly on mining regions. Open cast mines strip forests and farmland, the Jharia coalfield has had underground fires for about a century, mine drainage acidifies streams and lowers water tables, coal dust and power plant emissions foul the air, and tribal communities are displaced. The balanced position, which India argued at the Glasgow climate summit in 2021, is a phase down rather than a phase out: cleaner supercritical plants, coal washing and flue gas desulphurisation now, coal gasification for chemicals, proper mine closure and reclamation, and a just transition for coal districts as renewables and storage grow towards net zero in 2070.

How oil forms and where it collects

Plankton settling in quiet, oxygen poor seas is buried in fine mud, which becomes a source rock. As burial deepens to roughly 2 to 4 kilometres and temperatures reach about 60 to 120 °C, organic matter cracks into oil, and at greater heat into gas. Being less dense than the water filling rock pores, oil migrates upward through porous sandstone or limestone until an impermeable seal of shale or salt stops it. A field needs all four: source rock, reservoir rock, a cap rock and a trap such as an anticline, a fault or a salt dome.

Offshore and onshore oil

Offshore oil is concentrated on continental shelves and passive margins, where the edges of rifted continents subsided slowly and collected kilometres of river sediment and marine organic matter. Large deltas (Mississippi, Niger), rift basins (the North Sea) and salt basins (the Gulf of Mexico and Brazil's pre salt fields beneath a thick salt layer) are the main settings, and Mumbai High sits on the shelf off western India. Onshore fields lie in interior basins and old deltas, such as Ghawar in Saudi Arabia, Assam and the Cambay basin. The two differ in cost and technology, since deepwater wells need floating platforms and subsea systems; in risk, as the Deepwater Horizon spill in the Gulf of Mexico in 2010 showed; and in their histories, since most early fields were onshore and the newest large finds are offshore.

Issues and way forward

Implications of the uneven distribution of oil

About half of the world's proven oil lies in the Middle East, and members of the Organization of the Petroleum Exporting Countries (OPEC) hold about four fifths of all proven reserves, while major consumers such as China, India, Japan and Europe import most of their needs.

• Geopolitical. Oil has shaped wars and interventions in the Gulf, gives OPEC and Russia leverage through output cuts, and makes chokepoints such as the Strait of Hormuz strategic.
• Economic. Producers earn huge rents, which Norway saved in a wealth fund while Venezuela and Nigeria suffered the resource curse of corruption and dependence on one export. Importers face price shocks, as in 1973 and 2022, that raise inflation and widen current account deficits.
• For India. India imports over 85 per cent of its crude, so it diversifies suppliers, buys discounted Russian oil, holds 5.33 million tonnes in strategic reserves at Visakhapatnam, Mangaluru and Padur, and pushes ethanol blending and electric vehicles.
• Refineries follow markets, not fields. Because crude is imported and products are many, refineries such as Jamnagar, the world's largest refining complex at one site, are built at ports or near consumers (see the note on factors in industrial location).

Common confusions

• Gondwana and Dharwar. Gondwana rocks are sedimentary and hold coal; Dharwar rocks are much older metamorphic rocks that hold iron ore and gold.
• Reserves and resources. Resources are all known deposits; reserves are the part that can be mined profitably with present technology, so reserves grow with price and technique.
• Source rock and reservoir rock. Oil forms in the source rock, usually shale, but is produced from the porous reservoir rock it has migrated into.

For the exam

• Keyword bank: Dharwar, Gondwana coal, Deccan Trap, regur, laterite and bauxite, placer, Chota Nagpur belt, auction regime, District Mineral Foundation, critical minerals, oil window, anticline and salt dome traps, passive margin, pre salt, resource curse, strategic petroleum reserve.
• Previous year questions: Practise the previous year questions on this topic →
• Use in an answer:
  • Introduction (data): India produces about 95 minerals, yet mining contributes only about 2 per cent of its GDP, a gap explained by policy and exploration rather than geology.
  • Introduction (judgement, quote or report): The Ministry of Mines' list of 30 critical minerals (2023) recognises that energy transition will depend on minerals as much as fossil fuels once did.
  • Conclusion: India must mine more, and mine better, by exploring deeper, auctioning transparently and sharing benefits with the people who live above the ore.
  • Conclusion: Coal and oil will remain bridges for some decades, but the bridge should lead to an economy powered by renewables and critical minerals.