18 Jewel briquettes, manufactured by Eldon Colliery Limited at Newfield Works, Bishop Auckland, County Durham, which—
(a)comprise anthracite (as to approximately 30 to 50 per cent of the total weight) and Long Beach petroleum coke (as to approximately 50 to 70 per cent of the total weight) and a carbohydrate binder (as to the remaining weight);
(b)were manufactured from those constituents by a process involving roll-pressing and heat treatment at about 150°C;
(c)are unmarked pillow-shaped briquettes and have an average weight of 33 grammes; and
(d)have a sulphur content not exceeding 1.5 per cent of the total weight.