A medium-rank hard coal with either a gross calorific value (moist, ash-free basis) not less than 24 MJ/kg and with a vitrinite mean random reflectance less than 2.0 per cent, or a gross calorific value (moist, ash-free basis) less than 24 MJ/kg provided that the vitrinite mean random reflectance is equal to or greater than 0.6 per cent.