comprise anthracite duff (as to approximately 57% of the total weight), petroleum coke (as to approximately 17% of the total weight), bituminous coal (as to approximately 13% of the total weight) and molasses and phosphoric acid as 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 pillow-shaped briquettes with two parallel indented lines running latitudinally around the briquette;

have an average weight of 135 grams per briquette; and

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