What is coal?
Coal is a fossil fuel. It is a combustible, sedimentary, organic rock, which is composed mainly of carbon, hydrogen and oxygen. It is formed from vegetation, which has been consolidated between other rock strata and altered by the combined effects of pressure and heat over millions of years to form coal seams.
Source: World Coal Institute


What is the characteristic of Indonesian's coal?
Indonesian coal in production generally have medium calorific values (5 000-6 300 kcal/kg with relatively high percentages of volatile matter; they benefit from low ash and sulphur contents, making them some of the cleanest coals in the world.
Source: Energy Information Centre