Mineral belts of India

Topic: Mineral Resources of India: Distribution and Conservation · NCERT: Class 12, Ch 5 "Mineral and Energy Resources"

Meaning

A mineral belt is a large region where many mineral deposits occur together because they lie in the same old rocks. India has three main belts: the North-Eastern Plateau, the South-Western Plateau and the North-Western region. There is also a fourth, the Himalayan belt.

• The belts show why India's minerals are spread so unevenly. They also explain where heavy industries such as steel plants were built.

Explanation

Why minerals collect in belts

• Three things decide where minerals occur:
• Geological structure: the type of rock, and whether it has been folded (bent) or faulted (cracked and shifted).
• Geological processes: heat, pressure, weathering (rock breaking down) and sediment (sand and mud) laid down in water.

• Time: how long these processes have worked.

• Most valuable minerals are pre-Palaeozoic, meaning older than about 540 million years.

• They lie in the metamorphic rocks (rocks changed by heat and pressure) and igneous rocks (rocks formed from cooled magma) of the Peninsular plateau.

• These hard rocks have been worn down for a very long time, so the ores now lie near the surface.

• Each type of rock holds different minerals:

• Old crystalline rocks of the Peninsula hold metallic minerals and mica: iron ore, manganese, bauxite and copper.
• Gondwana basins hold coal. Gondwana rocks are sedimentary rocks laid down about 250–300 million years ago in long, sunken river troughs. Plants buried in these troughs slowly turned into coal.
• Young sedimentary basins, on land and offshore, hold petroleum and natural gas.
• The northern alluvial plains have almost no economic minerals. Himalayan rivers covered them with thick, young layers of silt and sand, which bury any old ore-bearing rock deep underground.

The four belts at a glance

Belt	States	Rock base	Key minerals	Weakness
North-Eastern Plateau	Jharkhand (Chhotanagpur), Odisha, West Bengal, parts of Chhattisgarh	Archaean–Dharwar rocks and Gondwana coal basins	Iron ore, coal, manganese, bauxite, mica, copper, uranium	Most diverse belt; no major weakness
South-Western Plateau	Karnataka, Goa, Tamil Nadu uplands, Kerala	Dharwar and crystalline rocks	High-grade iron ore, manganese, bauxite, limestone; monazite in Kerala	No coal except Neyveli lignite; fewer kinds of minerals
North-Western	Rajasthan (Aravallis), part of Gujarat	Dharwar rocks	Copper, zinc, marble, granite, sandstone, gypsum, Fuller's earth, limestone, dolomite, salt; petroleum in Gujarat	Few ferrous (iron-related) minerals
Himalayan	J&K, Himachal, Uttarakhand, North-East	Young folded rocks	Copper, lead, zinc, cobalt, tungsten; Assam oil; lithium (J&K)	Hard terrain, poor access

• Dharwar rocks are some of the oldest metamorphic rocks in India, about 2.5–1.8 billion years old. They are named after Dharwad in Karnataka and are rich in metallic ores.

Why the North-Eastern belt is the "storehouse of minerals"

• It has more kinds of minerals, in larger amounts, than any other region of India.
• Its minerals made it India's steel belt:
• Iron ore lies close to coking coal, which is coal that turns into hard coke when heated. Coke is the fuel in a blast furnace and also removes oxygen from the iron ore.
• Limestone, dolomite and manganese, which are also needed to make steel, are found nearby.

• Raw materials travel only short distances, so steel is cheap to make here.

• The eastern states hold most of the key minerals. Odisha, Jharkhand, Chhattisgarh, West Bengal and northern Andhra Pradesh together have about 80% of India's iron ore and about 100% of its coking coal [2].

When a deposit becomes a mine

• A deposit is a place where a mineral occurs naturally. A mine is a deposit that is actually being worked.
• A deposit is mined only if three conditions are met:
• Grade: the ore contains enough metal.
• Ease of extraction: the depth, thickness and surrounding rock allow cheap mining.

• Nearness to market: transport costs do not eat up the profit.

• This is why India has many known deposits that are not mined, especially in the Himalayan belt.

Where it occurs

• The Mangaluru–Kanpur line: an imaginary line drawn from Mangaluru (Karnataka coast) to Kanpur (Uttar Pradesh). Most major minerals lie east of it: coal, iron ore, manganese, bauxite and mica.
• North-Eastern Plateau belt:
• Iron ore: Noamundi and Gua (West Singhbhum, Jharkhand); Gurumahisani, Badampahar and Kiriburu–Bonai (Odisha); Bailadila (Chhattisgarh).
• Coal: Jharia, Bokaro and Karanpura (Damodar valley); Raniganj (West Bengal); Talcher (Mahanadi valley); Korba (Chhattisgarh).
• Manganese: Keonjhar and Sundargarh (Odisha). Bauxite: Kalahandi and Koraput (Odisha), and the Chhattisgarh plateau.
• Mica: Koderma–Hazaribagh (Jharkhand). Copper: the Singhbhum copper belt (Jharkhand). Uranium: Jaduguda (Jharkhand).
• Steel plants: Jamshedpur and Bokaro (Jharkhand), Durgapur (West Bengal), Rourkela (Odisha) and Bhilai (Chhattisgarh).
• Coal resources on 1 April 2021 (GSI): Jharkhand 86,216.82 million tonnes, Odisha 84,878.05 million tonnes and Chhattisgarh 73,423.54 million tonnes [5]. India's total coal resource was 361,411.46 million tonnes on 1 April 2022 (GSI) [6].
• Iron ore output, 2018-19: Odisha 113,119 thousand tonnes, Chhattisgarh 34,893 thousand tonnes, Jharkhand 23,433 thousand tonnes [7].

• Odisha's shares (2020): about 51% of India's bauxite, 25% of its coal, 34% of its iron ore, 96% of its chromite and 44% of its manganese resources [3].

• South-Western Plateau belt:

• High-grade iron ore at Kudremukh, Ballari and Chikkamagaluru (Karnataka), and in Goa. Goa's ore is mostly exported through Mormugao port.
• Neyveli (Tamil Nadu) has lignite, a low-grade brown coal with a lot of moisture.

• Kerala's beach sands contain monazite, a mineral rich in thorium (a nuclear fuel). Kerala also has bauxite clay.

• North-Western belt:

• Copper at Khetri (Jhunjhunu, Rajasthan). Zinc and lead at Zawar (Udaipur, Rajasthan). Marble at Makrana (Nagaur, Rajasthan).
• Gypsum, and Fuller's earth (a fine clay used to clean and bleach oils). Limestone and dolomite feed cement plants.
• Petroleum in Gujarat's Cambay basin and at Ankleshwar.

• Salt: Gujarat makes it from sea water on its coast. Rajasthan gets it from salt lakes such as Sambhar.

• Himalayan belt:

• Copper, lead, zinc, cobalt and tungsten occur in both the eastern and western Himalaya.
• Oil in the Assam valley at Digboi, Naharkatiya and Moran.
• Lithium: GSI found an inferred resource of 5.9 million tonnes of lithium ore in the Salal–Haimana area of Reasi district, J&K. The survey work was done in 2020-21 and 2021-22, and the find was announced in 2023 [4].

Don't confuse with

• Gondwana coal basins vs the North-Western belt: Gondwana rocks are coal-bearing sedimentary rocks in the Damodar, Sone, Mahanadi and Godavari valleys. The North-Western belt lies in the much older Dharwar rocks of the Aravallis and has no Gondwana coal.
• Monazite vs uranium: Kerala's beach sands (South-Western belt) give monazite, which is rich in thorium. India's uranium mine at Jaduguda is in Jharkhand, in the North-Eastern belt.
• Lignite vs coking coal: Neyveli lignite is low-grade brown coal and the only coal in the South-Western belt. Coking coal, which steel-making needs, comes from the eastern states, which hold about 100% of it [2].
• Mineral deposit vs mine: a deposit is where a mineral occurs. It becomes a mine only when its grade, ease of extraction and nearness to market make mining profitable.

Prelims Hooks

• Storehouse of minerals: the North-Eastern Plateau belt (Chhotanagpur–Odisha–West Bengal–Chhattisgarh). Most major minerals lie east of the Mangaluru–Kanpur line.
• Odisha holds about 96% of India's chromite and about 51% of its bauxite resources (2020) [3].
• Coal resource ranking, 1 April 2021 (GSI): Jharkhand > Odisha > Chhattisgarh [5]. Odisha leads iron ore production (2018-19) [7].
• Place–mineral pairs: Khetri – copper (Rajasthan); Zawar – zinc and lead (Rajasthan); Makrana – marble (Rajasthan); Koderma – mica (Jharkhand); Jaduguda – uranium (Jharkhand); Kudremukh – iron ore (Karnataka); Bailadila – iron ore (Chhattisgarh).
• Trap: the South-Western belt has no coal except Neyveli lignite, and its Kerala sands give monazite (thorium), not uranium.
• Lithium: Salal–Haimana, Reasi district, J&K, 5.9 million tonnes at the G3 (inferred) stage. G3 is an early estimate based on limited drilling, not a proven reserve [4].

Mains Points

• Geology decides where the belts are, and the belts decide where industry grows.
• Old Peninsular rocks hold metals, Gondwana troughs hold coal, and the alluvial plains have almost nothing. So minerals gather in the Peninsula, east of the Mangaluru–Kanpur line (GS-I).

• Iron ore, coking coal, manganese and limestone lie together in the North-Eastern Plateau, which created India's steel belt. The eastern states' 80% share of iron ore and about 100% share of coking coal make them central to the "Purvodaya" plan [2] (GS-I and GS-III).

• Mineral-rich belts face a "resource curse".

• Odisha, Jharkhand and Chhattisgarh hold most of India's coal, iron ore and bauxite [3][5].

• Yet these states also suffer tribal displacement, forest loss and lower human development. Answers should suggest benefit-sharing with local people and sustainable mining (GS-III).

• The Himalayan belt is a new frontier, but a hard one.

• The Reasi lithium find [4] shows that critical minerals may lie in less-explored terrain.
• Steep slopes, weak and broken rock, poor roads, landslide risk, fragile ecology and the early G3 stage all mean more survey work is needed before any mining (GS-III).

Related concepts

• Distribution of minerals in India
• Mangaluru-Kanpur line
• North-Eastern Plateau mineral belt
• South-Western Plateau mineral belt
• North-Western mineral belt

Read more

• Distribution of minerals and the mineral belts