1. Minerals, ores and grade
- Mineral: natural substance with a definite chemical composition.
- Ore: rock from which a metal can be extracted profitably.
- Grade: share of metal in an ore; high grade → more metal, less waste.
- Ferrous (iron ore, manganese) and non-ferrous (copper, bauxite) metallic minerals.
- Metal in an ore = grade ÷ 100 × tonnes of ore.
| Ferrous | Non-ferrous |
|---|---|
| Iron ore | Copper |
| Manganese | Bauxite |
Key terms
- Ore
A mineral or rock from which a metal can be extracted profitably.
- Grade
The proportion of metal contained in an ore.
2. Iron ore: types and uses
- Magnetite: black, magnetic; richest (up to about 70% iron).
- Hematite: reddish; about 60–70% iron; most mined in India.
- Limonite: yellowish-brown, hydrated; lower grade (about 35–50%).
- Siderite: iron carbonate; many impurities; low grade.
- Uses: smelted with coke and limestone in a blast furnace → pig iron → steel for railways, bridges, ships, buildings, machinery, vehicles, tools, utensils.
- Grade values are approximate and vary between deposits.
| Ore | Colour | Grade |
|---|---|---|
| Magnetite | Black | Highest |
| Hematite | Reddish | High |
| Limonite | Yellow-brown | Medium |
| Siderite | Brownish (carbonate) | Low |
Key terms
- Hematite
A reddish iron ore with a high iron content; the ore most mined in India.
- Magnetite
A black, magnetic iron ore with the highest iron content.
3. Iron ore: distribution
- Leading states (as of the early 2020s): Odisha and Chhattisgarh; also Karnataka and Jharkhand.
- Odisha: Keonjhar (Joda, Barbil), Sundargarh (Bonai), Mayurbhanj (Gorumahisani, Badampahar, Sulaipat).
- Chhattisgarh: Bailadila range (Dantewada); Dalli-Rajhara (supplies Bhilai).
- Jharkhand: Noamundi, Gua (Singhbhum).
- Karnataka: Bellary–Hospet (Sandur).
- Mostly open-cast mining of thick surface deposits on hill tops.
- Steel plants are built near the mines because iron ore is heavy and bulky (Bhilai, Rourkela).
| State | Mining area |
|---|---|
| Odisha | Keonjhar |
| Chhattisgarh | Bailadila |
| Jharkhand | Noamundi |
| Karnataka | Bellary–Hospet |
Key terms
- Open-cast mining
Mining from an open pit after removing the overburden, used where the ore lies near the surface.
4. Manganese
- Uses: steel making (ferro-manganese hardens steel and removes impurities); dry-cell batteries; bleaching powder; insecticides; paints; glass and ceramics.
- Leading states (as of the early 2020s): Madhya Pradesh, Maharashtra, Odisha; also Karnataka.
- Areas: Balaghat and Chhindwara (Madhya Pradesh); Nagpur and Bhandara (Maharashtra); Keonjhar, Sundargarh, Koraput (Odisha); Sandur (Karnataka).
| State | Manganese area |
|---|---|
| Madhya Pradesh | Balaghat |
| Maharashtra | Nagpur |
| Odisha | Keonjhar |
Key terms
- Ferro-manganese
An alloy of iron and manganese used to harden steel and remove impurities.
5. Copper
- Properties: excellent conductor of electricity and heat; ductile; malleable; resists corrosion.
- Uses: electrical cables and wires, motors, transformers, generators, electronics, utensils, coins; alloys brass (copper + zinc) and bronze (copper + tin).
- Leading states (as of the early 2020s): Madhya Pradesh and Rajasthan; also Jharkhand.
- Areas: Malanjkhand (Balaghat, Madhya Pradesh); Khetri–Singhana (Jhunjhunu, Rajasthan), Alwar; Singhbhum belt — Ghatsila, Mosabani, Rakha (Jharkhand).
- Reserves are limited and low grade, so India imports much copper.
| State | Copper area |
|---|---|
| Madhya Pradesh | Malanjkhand |
| Rajasthan | Khetri |
| Jharkhand | Ghatsila, Mosabani |
Key terms
- Brass
An alloy of copper and zinc.
- Bronze
An alloy of copper and tin.
6. Bauxite
- Bauxite: ore of aluminium (hydrated aluminium oxide), found in laterite areas.
- Aluminium: light, strong, good conductor, does not rust; aircraft, vehicles, overhead cables, utensils, foil and cans, window frames. Bauxite also used for cement, abrasives, refractories.
- Process: bauxite → alumina (refinery, e.g. Damanjodi) → aluminium (smelter, e.g. Angul, Hirakud, Renukoot); smelting needs huge amounts of electricity. Rounded ratio about 5 : 2 : 1 by mass.
- Leading states (as of the early 2020s): Odisha and Gujarat; also Jharkhand, Chhattisgarh, Maharashtra, Madhya Pradesh.
- Areas: Koraput (Panchpatmali), Kalahandi (Odisha); Jamnagar, Kutch, Bhavnagar (Gujarat); Lohardaga (Jharkhand); Mainpat, Amarkantak (Chhattisgarh); Kolhapur, Ratnagiri (Maharashtra).
| State | Bauxite area |
|---|---|
| Odisha | Koraput |
| Gujarat | Jamnagar |
| Jharkhand | Lohardaga |
Key terms
- Alumina
Aluminium oxide, the white powder refined from bauxite and smelted into aluminium.
- Smelter
A plant where alumina is turned into aluminium by electrolysis.
Exam tips
Common mistakes
- Calling limonite the richest iron ore (it is magnetite).
- Placing Bailadila in Odisha or Khetri in Madhya Pradesh.
- Writing bronze as copper + zinc (that is brass).
- Saying bauxite is smelted directly (it is first refined to alumina).
How marks are usually awarded
- Uses: one mark per specific use (with the property where asked).
- Distribution: state plus a named mining area for each mark.
- Ore calculations: grade ÷ 100 × tonnes, with the unit.