F. H. Hatch — The Iron Ore Sui^plies of the World. 511 



on Lake Erie. The bulk of it, however, is passed on by rail to 

 Pittsburg and other industrial centres of Pennsylvania and Ohio, 

 the total distance by water and rail to Pittsburg being about 

 1,200 miles, and thus greater than that of the iron mines of Spain 

 and Scandinavia from British or German furnaces. Cheap water 

 transportation on the Great Lakes has made this possible. The ore- 

 ships are loaded direct from the ore-trains at the rate of 10,000 tons 

 in half an hour, and discharged at the receiving dock in less than half 

 a day. In 1913 the rate for water transport and unloading averaged 

 less than '07 of a cent, or (at normal exchange) '035 of a penny per 

 ton-mile. Although navigation is closed for about five months in the 

 year, and a stock pile of 25 million tons has to be accumulated at 

 the loading end, over 60 million tons a year are conveyed in this 

 manner, and by the end of 1918 the Lake District had marketed no 

 less than 900 million tons of ore. 



A recent estimate of the available reserves at Lake Superior is 

 2,750 million tons of an average grade of 52 per cent iron {Mineral 

 Industry, 1918). 



The red or Clinton haematites are bedded oolitic ores of Silurian 

 age cropping out on the eastern flank of the coalfield from Maryland 

 through Virginia and Tennessee to Georgia and Alabama . They reach 

 their highest economic development in the Birmingham district 

 of Alabama, although they are also worked in Georgia and Tennessee, 

 and to a small extent in Virginia. Although the Clinton ores as a 

 whole are rather high in silica, this is to a considerable extent offset 

 by the presence of a good proportion of lime carbonate. Including 

 the Brown Ores worked in the Appalachian Valley and in Tennessee, 

 these south-eastern states had, up to 1918, produced 10 per cent of 

 the whole iron-ore output of the United States. The available 

 reserves are estimated at 1,750 million tons of 36 per cent grade 

 phosphoric ore. 



The north-eastern states (New York and New Jersey and 

 Pennsylvania), contribute 1 per cent of the total iron-ore output of 

 the United States. The ores are derived from magnetite mines in the 

 Adirondack region of New York, from Clinton ores in Pennsylvania, 

 and from Brown Ore in Northern New Jersey. In the main they are 

 phosphoric ore, and are used locally. The undeveloped reserves, 

 with an average grade of 35 per cent iron, are estimated at 

 2,500 million tons. 



The following table gives in parallel columns the most recent 

 estimates and those made for the Stockholm Geological Congress : — 



4,257-8 7,000 



