High-energy content or calorific value. Anthracite variety of coal has high calorific value.
Low sulphur content - Coals naturally contain sulphur. Burning coal is the primary human-caused source of sulphur dioxide. SO2 is an air pollutant, the main cause of acidic rain. So it is desired low sulphur content in coal.
Low ash content- Ash is a noncombustible residue after combustion of coal. It is an indicator for quality of coal. It is represented as the percentage of original weight.
Excellent weatherability - Weatherability defined as the ability to resist weathering process.
Good burning characteristics - Complete combustion without agitation.
Good grindability - sometimes it is needed to grind coal before burning. Good coal should not cause high abrasion on the machine.
High ash softening temperature - High Ash softening temperature lower the risk of slagging.
