Coking Coals : May have volatile matter content varying from 20% to 30% (South Wales coking coals are of 20/25% volatile matter) and yield dense, hard cokes which are used in foundry and metallurgical furnace practice
H. J. Porter (Chairman - Technical Committee), Dictionary of Fire Technology, The Institution of Fire Engineers, The Victory Press (Leicester) Ltd. 1979 UK. (Fr Tech - Brit) {81}