What are minerals and where are they found?
A mineral is a natural substance with a definite make-up, found in rocks. An ore is a rock with enough mineral in it to be mined.
- Veins and lodes: thin cracks in igneous and metamorphic rocks (tin, copper, zinc, lead).
- Beds or layers: in sedimentary rocks (coal, gypsum, potash, salt).
- Decomposed surface rock: bauxite.
- Placer deposits: in the sand of valleys and hill bottoms (gold, tin).
- Ocean water: common salt, magnesium, bromine.
Types of minerals
Ferrous (contain iron)
Iron ore: magnetite (best, up to 70% iron) and hematite (most used). Belts: Odisha–Jharkhand, Durg–Bastar–Chandrapur, Ballari–Chitradurga, Maharashtra–Goa. Manganese: used to make steel and ferro-manganese alloys.
Non-ferrous
Copper: carries electricity, used in wires (Balaghat, Khetri, Singhbhum). Bauxite: ore of aluminium, a light, strong metal (Amarkantak, Maikal hills, Odisha).
Non-metallic
Mica: splits into thin sheets; used in electric and electronic goods (Koderma–Gaya–Hazaribagh). Limestone: basic raw material of cement and for iron smelting.
Why conserve minerals?
They take millions of years to form and cannot be replaced. We should use them carefully, recycle metals, use scrap and find substitutes.
Conventional sources of energy
- Coal: most plentiful fossil fuel in India. Types: peat (low carbon), lignite (brown coal, Neyveli), bituminous (most used), anthracite (best). Gondwana coal (Damodar valley) is older; tertiary coal is in the north-east.
- Petroleum: fuel and raw material for many industries. Found in anticlines and fault traps. Mumbai High, Gujarat (Ankleshwar), Assam (Digboi).
- Natural gas: clean fuel; found with petroleum; Krishna–Godavari basin; used as CNG in vehicles.
- Electricity: hydel (fast-flowing water, renewable: Bhakra Nangal, Damodar) and thermal (burning coal, oil, gas: non-renewable).
Non-conventional sources of energy
- Nuclear: splitting uranium and thorium atoms gives huge heat (thorium in monazite sands of Kerala).
- Solar: sunlight to electricity by panels; India is sunny, so it has great scope (a big solar plant near Bhuj).
- Wind: Tamil Nadu (Nagercoil to Madurai), Gujarat, Rajasthan, Maharashtra, Karnataka.
- Biogas: cow dung and farm waste in a plant give gas for cooking and good manure (Gobar gas).
- Tidal: sea tides turn turbines; Gulf of Khambhat, Gulf of Kachchh, Sundarbans.
- Geothermal: heat from inside the Earth; Parvati valley (Manikaran) and Puga valley (Ladakh).
Conservation of energy
Energy runs everything: farms, factories, homes and transport. Our fossil fuels are limited and cause pollution. So we should: use public transport, switch off unused lights and fans, use energy-saving (star-rated) machines and LED bulbs, and use more non-conventional energy. "Energy saved is energy produced."
Try it
In the last 3D step, move the slider from 20% to 80% sun and wind. Predict first: will coal last twice as long or more? Then check. At home: count the bulbs and fans in your house and how many hours they run. Which could you switch off?
Key formulas and definitions
- Ore: rock with enough mineral to mine
- Ferrous: has iron (iron ore, manganese)
- Non-ferrous: no iron (copper, bauxite)
- Coal quality: peat < lignite < bituminous < anthracite
- Conventional: coal, oil, gas, hydel & thermal power · Non-conventional: solar, wind, nuclear, biogas, tidal, geothermal
Worked examples
1. Classify: iron ore, bauxite, mica, coal.
Iron ore: ferrous. Bauxite: non-ferrous. Mica: non-metallic. Coal: energy mineral.
2. Why is hydel power renewable but thermal power not?
Hydel uses flowing water, which is renewed by rain. Thermal burns coal or gas, which get used up.
3. A village has lots of cattle and no electricity line. Which energy suits it?
Biogas: cow dung gives cooking gas and the leftover slurry is good manure.
Common mistakes
- Saying bauxite is an iron ore. It is the ore of aluminium (non-ferrous).
- Calling hydel power non-renewable. Only thermal power is.
- Thinking nuclear energy comes from burning uranium. Atoms are split, not burnt.
- Mixing lignite (brown, low quality) with anthracite (best quality).