Coke quality in the blast furnace is measured by its resistance to degradation. The roles of coke as a fuel and as a reducing agent are not limiting factors in terms of blast furnace performance. However, the role of the coke as a permeable medium is crucial in economic blast furnace operation. The degradation of the coke varies with the position in the blast furnace but in all cases involves the combination of reaction with CO2, H20 or 02 and the abrasion of coke lumps against each other and other components of the burden. In trying to relate coke quality to its ultimate use in the blast furnace, one of the primary attributes of the coke quality is the coke strength.