comprise anthracite duff (as to approximately 65 to 85% of the total weight), petroleum coke (as to approximately 20% 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 ovoid-shaped briquettes with two parallel indented lines running longitudinally around the briquette;

have an average weight of 40g per briquette; and

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