comprise anthracite (as to approximately 60 to 80% of the total weight), petroleum coke (as to approximately 10 to 30% of the total weight) and a molasses and phosphoric acid binder (as to the remaining weight);

were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 300°C;

are unmarked pillow-shaped briquettes;

have average weights per briquette of either 55 or 80 grams; and

have a sulphur content not exceeding 2% of the total weight.