15. Dragonglow briquettes, manufactured by Tower Colliery Limited at Aberdare, Mid Glamorgan, South Wales, which—
(a)comprise tower duff (as to approximately 95% of the total weight) and a resin based binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving cold cure roll pressing;
(c)are unmarked pillow-shape briquettes;
(d)have an average weight of 100 grams per briquette; and
(e)have a sulphur content not exceeding 1% of the total weight.