ORES OF IRON 
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to their high content of titanium, which can only be washed 
out by melting with large quantities of flux at an extrava- 
gant cost for fuel. The price of fuel is an important element 
in iron smelting as from 3 to 4 tons of coal are required to 
smelt one ton of iron. Electric smelting where there is ample 
water-power renders possible the working of deposits where 
cheap fuel is not available. 
Iron ores are of unusual variety. They include materials 
which have been formed as igneous rock; as veins formed 
by ascending water and volcanic vapour; as replacement 
deposits formed at all depths by rising and descending solu- 
tions; as bedded ores deposited chemically or organically 
in sea, lakes, and swamps. The bulk of commercial iron ore 
has been formed by reactions which take place on or near 
the surface. 
CLASSIFICATION OF Iron ORES 
L. Igneous Ores. Titaniferous Magnetites. 
II. Contact Ores, e.g. Elba and Western America. 
LIL. Primary Lodes, e.g. Siderites of Czecho-Slovakia. 
IV. Replacement Ores— 
Pyritic masses. Rio Tinto, etc. 
2. Oxide Ore-Bodies due to Descending Solutions — 
(@) In limestones... Cumberland. 
) Bilbao. 
Lake Superior. 
Gellivaara and Adirondacks. 
(e) Mid-Sweden. 
3. Ancient surface sheets. Kiruna. 
V. Bedded and Organic Ores— 
I. Aqueous precipitates. Minette of Lorraine; Clin- 
ton; British Mesozoic ores; Wabana, etc. 
Altered representatives—banded ironstones, ita- 
birite, etc. 
2. Carbonaceous. Blackband ores. 
3. Bog Iron ores. 
VI. Surface Ores— 
Efflorescent residual ores and alluvial. 
Laterites. 
Brown iron ores in residual clays. 
Black iron sands. 
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