Hard Coal
European Commission - Eurostat

International Energy Agency (IEA)
Hard Coal refers to coal of gross calorific value greater than 23 865 kJ/kg (5 700 kcal/kg) on an ash-free but moist basis and with a mean random reflectance of vitrinite of at least 0.6. Hard coal comprises anthracite, coking coal and other bituminous coal (steam coal).

United Nations Economic Commission for Europe (UNECE)
Hard Coal refers to coal of gross calorific value greater than 23 865 kJ/kg (5 700 kcal/kg) on an ash-free but moist basis and with a mean random reflectance of vitrinite of at least 0.6. Hard coal comprises anthracite, coking coal and other bituminous coal (steam coal).

UNSD Energy Statistics Section
Coal that has a high degree of coalification with a gross calorific value above 23,865 KJ/kg (5,700 kcal/kg) on an ash-free but moist basis, and a mean random reflectance of vitrinite of at least 0.6. Slurries, middlings and other low-grade coal products, which cannot be classified according to the type of coal from which they are obtained, are included under hard coal.

There are two sub-categories of hard coal: (i) coking coal and (ii) other bituminous coal and anthracite (also known as steam coal).

(i) coking coal is a hard coal with a quality that allows the production of coke suiable to support a blast furnace charge.

(ii) steam coal is coal used for steam raising and space heating purposes and includes all anthracite coals and bituminous coals not classified as coking coal.