Understanding Coal
What is Coal?
Coal is a naturally occurring fossil fuel formed from ancient plant matter subjected to heat and pressure over millions of years. It remains one of India's most important energy resources and is extensively used across power generation, cement manufacturing, paper mills, ethanol plants, steel industries and industrial boilers.
The Four Types of Coal
🔥 Non-Coking Coal
Primarily used for power generation and industrial heating. This is the category most commonly traded by Nature Reserves. Grading is based on Gross Calorific Value (GCV).
⚙️ Coking Coal
Used in steel manufacturing and blast furnaces for its caking property. Grading is primarily based on ash content.
🏭 Semi-Coking Coal
Also called weakly-caking coal; used in sponge iron production and blending applications. Grading depends on combined ash and moisture content.
🪨 Lignite
A lower-rank, softer brown coal used mainly in power generation close to the mine mouth. Grading is based on Gross Calorific Value (GCV), similar to non-coking coal but at lower ranges.
Major Coal Producing States
Jharkhand
Odisha
Chhattisgarh
West Bengal
Madhya Pradesh
Telangana
Coal Grading Systems
Non-Coking Coal Grades
Graded according to Gross Calorific Value (GCV).
| Grade | GCV Range (kcal/kg) |
|---|---|
| G1 | Exceeding 7000 |
| G2 | 6700 – 7000 |
| G3 | 6400 – 6700 |
| G4 | 6100 – 6400 |
| G5 | 5800 – 6100 |
| G6 | 5500 – 5800 |
| G7 | 5200 – 5500 |
| G8 | 4900 – 5200 |
| G9 | 4600 – 4900 |
| G10 | 4300 – 4600 |
| G11 | 4000 – 4300 |
| G12 | 3700 – 4000 |
| G13 | 3400 – 3700 |
| G14 | 3100 – 3400 |
| G15 | 2800 – 3100 |
| G16 | 2500 – 2800 |
| G17 | 2200 – 2500 |
Coking Coal Grades
Graded primarily according to ash content.
| Grade | Ash Content |
|---|---|
| Steel Grade I | Ash content up to 15% |
| Steel Grade II | Ash content 15% – 18% |
| Washery Grade I | Ash content 18% – 21% |
| Washery Grade II | Ash content 21% – 24% |
| Washery Grade III | Ash content 24% – 28% |
| Washery Grade IV | Ash content 28% – 32% |
| Washery Grade V | Ash content 32% – 35% |
| Washery Grade VI | Ash content 35% – 37% |
Semi-Coking Coal Grades
Graded according to combined ash and moisture content.
| Grade | Ash + Moisture |
|---|---|
| Semi-Coking Grade I | Ash + Moisture up to 19% |
| Semi-Coking Grade II | Ash + Moisture 19% – 24% |
Lignite Grades
Graded according to Gross Calorific Value (GCV).
| Grade | GCV Range |
|---|---|
| Lignite Grade I | GCV exceeding 4000 kcal/kg |
| Lignite Grade II | GCV 3100 – 4000 kcal/kg |
| Lignite Grade III | GCV below 3100 kcal/kg |
Key Coal Quality Parameters
🔥 GCV
Higher GCV means more heat energy and better efficiency.
⚫ Ash
Represents non-combustible residue left after burning.
💧 Moisture
Excess moisture reduces effective heating value.
⚙️ Fixed Carbon
Determines fuel quality and combustion characteristics.
Industries Using Coal
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