16. Dragonbrite briquettes, manufactured by Tower Colliery Limited, Aberdare, Mid Glamorgan, South Wales, which—
(a)comprise tower duff (as to approximately 95 per cent 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 pillow-shaped briquettes marked with the letter “T” on one side;
(d)have an average weight of 50 grammes per briquette; and
(e)have a sulphur content not exceeding 1 per cent of the total weight.