Coal is one source of energy with substantial reserves, Coal in Indonesia generally are low rank coal that have not been utilized optimally. As for the classification of coal are based on degree and quality of the coal itself, there are Peat with a 1.700-3.000 kcal/kg calorie value, Lignite with a 1.500-4.500 kcal/kg calorie value, Sub-Bituminous with a sub-bituminous calorie value, Bituminous …