Possibly you have ever seen combustible coal by itself either that is in stockpile or mine. This case is commonplace remembers coal is solid fuel where element of the former is plant containing carbon. Coal which pile up sufficiently long in stockpile or flammable mine by itself as result of oxidation process where oxygen steps into cavity's from coal heap, weather effect that is enough hot and accompanied rain and wind hence happened friction of oxygen with coal which pile up which has contained aqueous vapor because rain and temperature. From here happened happened hot friction and oxygen generating fire causing is combustible by itself.
For the reason management stockpile must be paid attention to avoid combustible coal by itself is between it :
1. Condition of stockpile must stay to hill (hill topography with high elevation).
2. Around Stockpile drainage there must be to avoid collected it water as result of rain.
3. From the angle of heap must be paid attention coal heap height; 5 m and coal heap must be compacted by means of weight to avoid existence of oxygen entering into coal heap cavity.