comprise bituminous coal (as to approximately 10 to 15% of the total weight), petroleum coke (as to approximately 10 to 15% of the total weight), anthracite duff (as to approximately 70 to 80% of the total weight), and starch binder (as to the remaining weight);

were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 260°C;

are unmarked pillow-shaped briquettes;

have an average weight of 140 grams; and

have a sulphur content not exceeding 1.9% sulphur on a dry basis.