Reading a coal specification

How much heat the coal gives off, in kilocalories per kilogram (kcal/kg). Typical traded thermal coals range from about 4,200 to 6,300 kcal/kg. More heat means a higher price.

Moisture adds weight but no energy. Ash is the rock left after burning. Both lower the value and raise handling costs for the buyer.

Sulphur causes air pollution and is limited by many power plants, so low-sulphur coal earns a premium. Volatile matter affects how easily the coal ignites and burns.

Independent inspectors take samples while the vessel is loaded. The laboratory results set the final price under the contract's adjustment formula.