IRON AND STEEL (THE FERRO-ALLOY GROUP) 154
GENERAL FEATURES 154
IRON ORES 158
ECONOMIC FEATURES 158
Technical and commercial factors determining use of iron
ore materials 158
Geographic distribution of iron ore production 160
World reserves and future production of iron ore 162
GEOLOGIC FEATURES 166
Sedimentary iron ores 166
Iron ores associated with igneous rocks 171
Iron ores due to weathering of igneous rocks 171
Iron ores due to weathering of sulphide ores 173
MANGANESE ORES 173
Economic features 173
Geologic features 176
CHROME (OR CHROMITE) ORES 178
Economic features 178
Geologic features 179
NICKEL ORES 180
Economic features 180
Geologic features 181
TUNGSTEN (WOLFRAM) ORES 182
Economic features 182
Geologic features 184
MOLYBDENUM ORES 185
Economic features 185
Geologic features 186
VANADIUM ORES 187
Economic features 187
Geologic features 188
ZIRCONIUM ORES 189
Economic features 189
Geologic features 189
TITANIUM ORES 190
Economic features 190
Geologic features 190
MAGNESITE 191
Economic features 191
Geologic features 192
FLUORSPAR 193
Economic features 193
Geologic features 194
SILICA 195
Economic features 195
Geologic features 196