51. Supertherm II briquettes, manufactured by Coal Products Limited at Immingham Briquetting Works, Immingham, North East Lincolnshire, which—N.I.
(a)comprise anthracite (as to approximately 36 to 51% of the total weight), petroleum coke (as to approximately 40 to 55% of the total weight) and an organic binder or a molasses and phosphoric acid binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing;
(c)are unmarked ovoids;
(d)have an average weight of 140g per briquette; and
(e)have a sulphur content not exceeding 2% of the total weight.