504 F. H. Hatch — Tlie Iron Ore Supplies of the World. 



The Iron Ore Supplies of the World. 



By F. H. Hatch, M.Inst.C.E., Past-President Inst. Min. Met. 



The following article originally appeared in the special " Iron and Steel " 

 number of the Times Trade Supplement on July 21 last. It is here reprinted, 

 with some small additions, by the courtesy of the proprietors of that journal. 



TX7ITHIN the limits of a brief article such as this must necessarily 

 ' ' be, it is impossible to do more than indicate the chief sources 

 of iron-ore supply. The subject is a big one, and of great importance, 

 not only to the British ironmaster, but also to every inhabitant of 

 this country. I am therefore pleased to be able to state that the 

 Federation of Iron and Steel Manufacturers has not only asked 

 the Imperial Mineral Resources Bureau to prepare a summary of 

 the existing information as to the iron-ore supplies of the world, but 

 is also assisting to finance the inquiry. This will mean a more 

 complete survey than is possible to-day. 



Any attempt to estimate the world's iron-ore resources is com- 

 plicated both by the diversity of the products manufactured from the 

 raw material and by the numerous factors which go to connote a 

 commercial iron-ore. Among these the iron content, the presence 

 of beneficial or deleterious constituents, physical condition, 

 geographical position, and means of transportation are all con- 

 siderations of the first importance. 



First consider the iron-content. According to the estimate of the 

 American geologist, Clarke, the crust of the earth contains 4*4 per 

 cent of metallic iron, of which but a very minute fraction has been 

 sufficiently concentrated by geological agencies to form commercially 

 available iron-ores : for one ton of these that contains 60 per cent 

 of iron there are very many tons that contain 50 per cent ; while 

 for one ton that contains 40 per cent there are vastly more that 

 contain 30 per cent, and so on. The amount of reserves in an iron- 

 ore field can, therefore, be indefinitely increased by lowering the 

 grade of the material to be included. 



With regard to the presence of beneficial or of deleterious con- 

 stituents, what is prejudicial in one case is beneficial in another. 

 The requirements of the smelters are decisive on this head. If 

 haematite pig iron for the acid process of steel-making is required, 

 phosphorus is barred ; if, on the other hand, the iron is destined 

 for the basic process, phosphorus is a desideratum. Titanium 

 rules out vast bodies of ore containing a high percentage of iron, 

 because the presence of titanic acid in any notable proportion raises 

 the temperature of fusion and leads to greater fuel consumption and 

 a heavier blast. A small quantity of manganese, on the other hand, 

 is beneficial, since it helps to get rid of sulphur. A high silica- 

 content is an objection, because of the limestone that has to be added 

 to the charge to neutralize the acid constituent, thereby reducing 

 the output per furnace and increasing the cost per ton of pig ; but 

 a calcareous ore is sought after, since it is either self-fluxing or can. 



