Chapter Ix. Minerals Used in the Production of

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