Mining

Topic: Primary Activities: Gathering, Pastoralism, Agriculture and Mining · NCERT: Class 12, Ch 4 "Primary Activities"

Meaning

Mining is the taking out of useful minerals from the earth's crust. A mineral is a natural, non-living substance with a fixed chemical make-up.

• Mining supplies the coal, metals, petroleum and battery metals that factories, transport and energy depend on.
• It also decides where many people live and work, and which countries earn most of their income from minerals.

Explanation

How mining grew over time

• Whole stages of human history are named after minerals:

• Copper Age, then Bronze Age (bronze is copper mixed with tin), then Iron Age.

• In ancient times, minerals had only a few uses: tools, utensils (pots) and weapons.

• Large-scale mining began with the Industrial Revolution (from the late 18th century).
• Factories, railways and steam engines needed huge amounts of coal and iron.

• Since then, mining has become more and more important.

• Rocks decide which minerals are found where:

• Metallic ores are found in igneous and metamorphic rocks.
• Coal, petroleum and salts are found in sedimentary rocks.

Factors that decide whether a mine makes a profit

Group	Factor	What it means
Physical	Size of deposit	A big deposit can be mined for many years. The cost of setting up the mine is spread over all those years.
	Grade of ore	How much metal the rock holds. High-grade ore gives more metal for each tonne dug.
	Mode of occurrence	Where and how the mineral lies: near the surface or deep down, in thick beds or thin veins. This decides the method and the cost.
Economic	Demand	High demand and high prices make mining worth doing.
	Technology	Better machines can reach deeper ores, or ores that are harder to treat.
	Capital	Money for infrastructure (roads, railways, power, water) and for machines.
	Labour and transport costs	Cheap workers and cheap transport to markets or ports lower the total cost.

• A deposit is "workable" only in economic terms:
• A low-grade deposit may be left alone today.
• If prices rise or technology improves, the same deposit can start making a profit.
• So the world's mineral map keeps changing, even though the rocks stay the same.

Methods of mining (NCERT Fig. 4.19)

The method depends on the mode of occurrence and the nature of the ore.

1. Surface or open-cast mining (for minerals close to the surface)

• Process:
• First, the overburden (the soil and rock lying over the mineral) is removed.

• Then the mineral is dug out of a wide, open pit with large shovels, dumpers and draglines.

• Advantages: it is the easiest and cheapest method. Safety precautions and equipment cost little, and output is large and quick.

• Problems:
• It scars the land with big pits and dumps of waste rock.
• It displaces people, because villages, farms and forests over the deposit must be cleared.
• The land then needs reclamation (bringing it back to use by filling pits, making slopes stable and planting trees).

2. Underground or shaft mining (for ore deep below the surface)

• Process:
• Vertical shafts (deep, straight holes) are sunk into the ground.
• Underground galleries (side tunnels) branch out from the shafts to reach the mineral.

• The ore is broken, carried to the shaft and lifted to the surface.

• Needs: lifts, drills, haulage vehicles (to move ore) and ventilation systems that pump fresh air in and push dangerous gases out.

• Risks: poisonous gases (such as methane and carbon monoxide), fires, explosions, floods (water bursting in) and caving in of the roof.

Feature	Open-cast	Underground (shaft)
Depth of mineral	Near the surface	Deep
Cost	Low	High
Output	Large, fast	Smaller, slower
Safety risk	Low	High (gas, fire, flood, roof collapse)
Main harm	Land scarring, people displaced	Accidents, subsidence, underground fires
India's coal share (2023-24)	~96.6% [7]	3.44% [7]

3. Other methods

• Placer mining: a placer is a deposit of heavy minerals (gold, tin, diamonds) that rivers have carried and dropped in sand and gravel. Miners wash the sand, and the heavy minerals sink and settle out.
• Dredging: a dredge (a floating machine) scoops minerals from river beds or shallow sea floors.
• Offshore drilling: wells are drilled into the sea floor from oil rigs to get petroleum and natural gas.
• Solution mining of lithium brines: a brine is very salty underground water. Lithium is taken from it without digging any rock.
• The brine is pumped up and spread in evaporation ponds. Dry, windy weather makes the water evaporate quickly [9].
• Lithium chloride is left behind. It is treated with sodium carbonate to make lithium carbonate, the main raw material of lithium-ion batteries [9].

The shift in where mining happens

• Developed countries are moving out of mining, processing and refining, mainly because of high labour costs.
• Developing countries with many workers are becoming more important in world mining.
• Mineral-dependent economies earn over 50% of their income from minerals alone. Several countries in Africa, and a few in South America and Asia, are like this.
• Why this is risky:
• Price volatility: world mineral prices rise and fall sharply, so national income goes up and down with them.
• Resource curse: a mineral-rich country may still grow slowly. Other sectors are ignored, and mineral money can feed corruption or conflict.

Where it occurs

India

• Open-cast coal mining is now the main method in India.
• Underground mining's share of coal output fell every year: 5.54% (2019-20) → 4.50% (2020-21) → 4.26% (2021-22) → 3.90% (2022-23) → 3.44% (2023-24) [7].
• Coal companies have found 179 pre-2009 and 162 post-2009 abandoned or discontinued mines. 147 of these are marked for closure. The rest are being joined to working mines and started again [8].

• Mine closure (closing and securing a mine once mining ends) restores the land by filling pits, making slopes stable, managing waste dumps and planting trees. Afforestation is the main part of this work [8].

• Jharia coalfield (Dhanbad, Jharkhand): coal seams have burned underground for decades, and the land above sinks (subsidence).

• The Jharia Master Plan (JMP) was approved on 12 August 2009 at ₹7,112.11 crore. It was to run for 10 years, after a 2-year preparation period [6].
• BCCL (Bharat Coking Coal Ltd) ran 27 fire projects. It used surface sealing, digging out burning coal, trenching, pumping in inert gas (a gas that does not burn) and flushing with a sand–bentonite mix [5].
• Surface fire sites fell from 77 to 27, and the fire area fell from 17.32 sq km to 1.80 sq km (2023) [5].

• The Revised Jharia Master Plan (2025) got ₹5,940.47 crore. It gives a ₹1 lakh livelihood grant and credit support of up to ₹3 lakh, for families with and without legal title to their land [6].

• Chasnala colliery (near Dhanbad, Jharkhand), 1975: water flooded the mine and drowned the miners underground. It is one of India's worst mining disasters.

World

• Katanga–Zambia copper belt (copper and cobalt), on the border of the Democratic Republic of the Congo (DRC) and Zambia in south-central Africa.
• Towns: Lubumbashi, Kolwezi (DRC, Katanga region); Ndola, Kitwe (Zambia, Copperbelt Province).
• Benguela Railway runs west to Lobito, Angola (Atlantic Ocean). TAZARA runs from Kapiri Mposhi (Zambia) east to Dar es Salaam, Tanzania (Indian Ocean).
• NCERT uses this belt as an example of minerals attracting population.
• The DRC mined about 76% of the world's cobalt in 2024 [2] and holds about 55% of world cobalt reserves (2024) [3].

• The USGS keeps a database of artisanal, small-scale and large-scale mines in this belt [4]. Artisanal mining (mining by hand with simple tools) is often unsafe and raises child-labour concerns.

• Salar de Atacama (a salt flat in the Atacama Desert, northern Chile):

• Brine is pumped from as deep as 30 m below the salt crust [9].
• Besides lithium chloride, the ponds yield potassium chloride, potassium sulphate, boric acid and magnesium chloride [9].

• It has the world's highest lithium concentration, about 6.3 million tonnes. This is the largest deposit on Earth that can be mined at a profit [9].

• Salar del Hombre Muerto and Salar de Olaroz (Andean salt flats, Argentina) also produce lithium from brine [10].

• Gulf of Mexico: offshore oil rig shown in NCERT Fig. 4.18.

Don't confuse with

• Open-cast vs shaft mining: open-cast removes the overburden and digs from an open pit (cheap, safe, fast). Shaft mining uses vertical shafts plus side galleries to reach deep ore (costly and risky).
• Physical vs economic factors: size, grade and mode of occurrence are physical. Demand, technology, capital, labour and transport are economic.
• Placer mining vs dredging: placer mining washes river sand and gravel so heavy minerals settle out. Dredging uses a floating machine to scoop minerals from river beds or shallow sea floors.
• Solution mining of brine vs other mining: lithium is taken from salty underground water through evaporation, and no rock is dug.

Prelims Hooks

• Open-cast = overburden removed first. It is the cheapest method, gives large and quick output, and has low safety costs.
• Trap: demand, technology, capital, labour and transport are economic factors. Only size, grade and mode of occurrence are physical.
• India's underground share of coal output: 3.44% (2023-24), down every year from 5.54% (2019-20) [7].
• Jharia (Dhanbad, Jharkhand) = coal fires and subsidence. Chasnala (1975) = mine flooding near Dhanbad.
• Katanga–Zambia belt: Lubumbashi, Kolwezi (DRC); Ndola, Kitwe (Zambia). Benguela Railway → Lobito (Angola, Atlantic); TAZARA → Dar es Salaam (Tanzania, Indian Ocean).
• DRC share of world cobalt output: ~76% (2024) [2]. Salar de Atacama (Chile) has the world's highest lithium concentration: brine → evaporation ponds → lithium carbonate [9].

Mains Points

• Changing geography of mining (GS-I):
• High labour costs push developed countries out of mining and refining.
• Mining moves to labour-rich developing countries in Africa, Latin America and Asia.

• Many become mineral-dependent economies (>50% of income from minerals) and face price swings and the resource curse.

• Open-cast vs underground trade-off (GS-III):

• India mines about 97% of its coal by open-cast because it is cheap and fast [7].
• The cost is scarred land, displaced tribal communities and lost forest.

• The policy response is mine closure plans, reclamation and afforestation [8]. Underground mining is being promoted again because it disturbs less land.

• Mine disasters and critical minerals (GS-III):

• At Jharia, underground fires cause subsidence and put towns in danger. Fire control (inert gas, sand–bentonite flushing) and a rehabilitation package with livelihood support form the response [5][6].
• Cobalt is concentrated in the DRC (~76% in 2024) and lithium in Andean brines [2][9]. This makes electric-vehicle supply chains risky and raises child-labour concerns. Countries respond by finding more suppliers and securing mineral assets abroad.

Related concepts

• Factors affecting mining activity
• Open-cast mining
• Underground mining
• Mineral-dependent economies
• Katanga-Zambia copper belt

Read more

• Mining: factors and methods