ANTRACITE is a type of highest quality coal, having the characteristics of being hard and fragile, completely black, glossy and homogenous, with highly stabilized carbon content from 86 % up, low volatile matters, causing it to be non-inflammable, but when catching fire it generates very high heat and maintains combustion for a long period of time and contains very low sulfuric content.


BITUMINOUS COAL is a type of coal, having the nature that can gather itself to form a compact cake when heated, showing less carbon content than ANTRACITE, but containing more volatile matters, producing higher heating value, and catching fire more easily, giving less black coal ash and smoke, the black coal texture is glossy, containing low sulfuric content.


SUB BITUMINOUS COALS is a type of coal that comes in the state of being smooth surface, without being layers, showing brownish black or black, its texture is homogenous, containing low sulfuric content. This type of coal is used for generating electricity.



LIGNITE is the lowest level coal, having brown colour, its structure comes in the form of sheet type originated from plants, having high volatile matter content, high humidity, generating low heat value, and containing sulfuric content, with reasonable hardness, can be used as fuel.


PEAT, in many countries and in accordance with ASTM, PEAT, is not deemed to be fuel, but it is categorized into a group of decomposed plant scraps, which piled them up increasingly, mixed them up with soil, stone leavings and plant leaves, some parts of its texture have decomposed, they contain high oxygen and humidity contents. The PEAT is considered to be the initial product of the process in changing fossils to become coal.