The Economic Aspect of Geology

Chapter Ii. the Common Elements, Minerals, and

ROCKS OF THE EARTH AND THEIR ORIGINS 13

RELATIVE ABUNDANCE OF THE PRINCIPAL ELEMENTS OF THE LITHOSPHERE 13

RELATIVE ABUNDANCE OF THE PRINCIPAL MINERALS OF THE LITHOSPHERE 14

RELATIVE ABUNDANCE OF THE PRINCIPAL ROCKS OF THE LITHOSPHERE 16

WATER (HYDROSPHERE) 18

SOILS AND CLAYS 18

COMPARISON OF LISTS OF MOST ABUNDANT ROCKS AND MINERALS WITH COMMERCIAL ROCKS AND MINERALS 18

THE ORIGIN OF COMMON ROCKS AND MINERALS 18 Igneous processes 19 Igneous after-effects 19 Weathering of igneous rocks and veins 20 Sedimentary processes 22 Weathering of sedimentary rocks 23 Consolidation, cementation, and other sub-surface alterations of rocks 24 Cementation 24 Dynamic and contact metamorphism 25

THE METAMORPHIC CYCLE AS AN AID IN STUDYING MINERAL DEPOSITS 27

Chapter Iii. Some Salient Features of the Geology

AND CLASSIFICATION OF MINERAL DEPOSITS 29

VARIOUS METHODS OF CLASSIFICATION 29

NAMES 31

MINERAL DEPOSITS AS MAGMATIC SEGREGATIONS IN IGNEOUS ROCKS 34

MINERAL DEPOSITS WITHIN AND ADJACENT TO IGNEOUS ROCKS, WHICH WERE FORMED IMMEDIATELY AFTER THE COOLING AND CRYSTALLIZATION OF THE MAGMAS THROUGH THE AGENCY OF HOT MAGMATIC SOLUTIONS 36 Evidence of igneous source 37 Possible influence of meteoric waters in deposition of ores of this class 41 Zonal arrangement of minerals related to igneous rocks 42 The relation of contact metamorphism to ore bodies of the foregoing class 45

SECONDARY CONCENTRATION IN PLACE OF THE FOREGOING CLASSES OF MINERAL DEPOSITS THROUGH THE AGENCY OF SURFACE SOLUTIONS 46

RESIDUAL MINERAL DEPOSITS FORMED BY THE WEATHERING OF IGNEOUS ROCKS IN PLACE 50

MINERAL DEPOSITS FORMED DIRECTLY AS PLACERS AND SEDIMENTS 51 Mechanically deposited minerals 51 Chemically and organically deposited minerals 52

SEDIMENTARY MINERAL DEPOSITS WHICH HAVE REQUIRED FURTHER CONCENTRATION TO MAKE THEM COMMERCIALLY AVAILABLE 54

ANAMORPHISM OF MINERAL DEPOSITS 57

CONCLUSION 58

Chapter Iv. Mineral Resources--Some General

QUANTITATIVE CONSIDERATIONS 60

WORLD ANNUAL PRODUCTION OF MINERALS IN SHORT TONS 60

WORLD ANNUAL PRODUCTION OF MINERALS IN TERMS OF VALUE 62

SIGNIFICANCE OF GEOGRAPHIC DISTRIBUTION OF MINERAL PRODUCTION 63

THE INCREASING RATE OF PRODUCTION 63

CAPITAL VALUE OF WORLD MINERAL RESERVES 64

POLITICAL AND COMMERCIAL CONTROL OF MINERAL RESOURCES 65

RESERVES OF MINERAL RESOURCES 65

Chapter V. Water As a Mineral Resource 67

GENERAL GEOLOGIC RELATIONS 67

DISTRIBUTION OF UNDERGROUND WATER 68

MOVEMENT OF UNDERGROUND WATER 71

WELLS AND SPRINGS 72

COMPOSITION OF UNDERGROUND WATERS 73

RELATION OF GEOLOGY TO UNDERGROUND WATER SUPPLY 75

SURFACE WATER SUPPLIES 76

UNDERGROUND AND SURFACE WATERS IN RELATION TO EXCAVATION AND CONSTRUCTION 78

Chapter Vi. the Common Rocks and Soils As Mineral

RESOURCES 80

ECONOMIC FEATURES OF THE COMMON ROCKS 80 Granite 82 Basalt and related types 82 Limestone, marl, chalk 82 Marble 83 Sand, sandstone, quartzite (and quartz) 84 "Sand and gravel" 84 Clay, shale, slate 85 The feldspars 86 Hydraulic cement (including Portland, natural, and Puzzolan cements) 86

GEOLOGIC FEATURES OF THE COMMON ROCKS 88 Building stone 88 Crushed stone 90 Stone for metallurgical purposes 91 Clay 91 Limitations of geologic field in commercial investigation of common rocks 92

SOILS AS A MINERAL RESOURCE 94 Origin of soils 94 Composition of soils and plant growth 96 Use of geology in soil study 97

Chapter Vii. the Fertilizer Group of Minerals 99

GENERAL COMMENTS 99

NITRATES 101 Economic features 101 Geologic features 102

PHOSPHATES 104 Economic features 104 Geologic features 105

PYRITE 107 Economic features 107 Geologic features 108

SULPHUR 109 Economic features 109 Geologic features 110

POTASH 111 Economic features 111 Geologic features 112

Chapter Viii. the Energy Resources--Coal, Oil, Gas

(AND ASPHALT) 115

COAL 115

ECONOMIC FEATURES 115 World production and trade 115 Production in the United States 117 Coke 118 Classification of coals 119

GEOLOGIC FEATURES 123

PETROLEUM 127

ECONOMIC FEATURES 127 Production and reserves 128 Methods of estimating reserves 134 Classes of oils 136 Conservation of oil 137

GEOLOGIC FEATURES 140 Organic theory of origin 140 Effect of differential pressures and folding on oil genesis and migration 142 Inorganic theory of origin 143 Oil exploration 144

OIL SHALES 150

NATURAL GAS 151 Economic features 151 Geologic features 151

ASPHALT AND BITUMEN 151 Economic features 151 Geologic features 153

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

Chapter X. Copper, Lead and Zinc Minerals 197

COPPER ORES 197 Economic features 197 Geologic features 199 Copper deposits associated with igneous flows 200 Copper veins in igneous rocks 201 "Porphyry coppers" 203 Copper in limestone near igneous contacts 204 Copper deposits in schists 204 Sedimentary copper deposits 205 General comments 206

LEAD ORES 209 Economic features 209 Geologic features 211

ZINC ORES 213 Economic features 213 Geologic features 216

Chapter Xi. Gold, Silver, and Platinum Minerals 221

GOLD ORES 221 Economic features 221 Geologic features 226

SILVER ORES 231 Economic features 231 Geologic features 234

PLATINUM ORES 237 Economic features 237 Geologic features 239

Chapter Xii. Miscellaneous Metallic Minerals 241

ALUMINUM ORES 241 Economic features 241 Geologic features 243

ANTIMONY ORES 246 Economic features 246 Geologic features 248

ARSENIC ORES 249 Economic features 249 Geologic features 251

BISMUTH ORES 252 Economic features 252 Geologic features 252

CADMIUM ORES 253 Economic features 253 Geologic features 254

COBALT ORES 254 Economic features 254 Geologic features 255

MERCURY (QUICKSILVER) ORES 255 Economic features 255 Geologic features 258

TIN ORES 260 Economic features 260 Geologic features 261

URANIUM AND RADIUM ORES 263 Economic features 263 Geologic features 264

Chapter Xiii. Miscellaneous Non-Metallic Minerals 267

NATURAL ABRASIVES 267 Economic features 267 Geologic features 269

ASBESTOS 270 Economic features 270 Geologic features 271

BARITE (BARYTES) 272 Economic features 272 Geologic features 273

BORAX 274 Economic features 274 Geologic features 275

BROMINE 277 Economic features 277 Geologic features 278

FULLER'S EARTH 278 Economic features 278 Geologic features 279

GRAPHITE (PLUMBAGO) 279 Economic features 279 Geologic features 282

GYPSUM 283 Economic features 283 Geologic features 284

MICA 285 Economic features 285 Geologic features 287

MONAZITE (THORIUM AND CERIUM ORES) 288 Economic features 288 Geologic features 289

PRECIOUS STONES 289 Economic features 289 Geologic features 291

SALT 294 Economic features 294 Geologic features 295

TALC AND SOAPSTONE 299 Economic features 299 Geologic features 299

Chapter Xiv. Exploration and Development 301

THE GENERAL RELATIONS OF THE GEOLOGIST TO EXPLORATION AND DEVELOPMENT 301

PARTLY EXPLORED VERSUS VIRGIN TERRITORIES 303

THE USE OF ALL AVAILABLE INFORMATION 304

COOPERATION IN EXPLORATION 305

ECONOMIC FACTORS IN EXPLORATION 306

GEOLOGIC FACTORS IN EXPLORATION 307

MINERAL PROVINCES AND EPOCHS 308

CLASSIFICATION OF MINERAL LANDS 309

OUTCROPS OF MINERAL DEPOSITS 311 Some illustrative cases 312 Topography and climate as aids in searching for mineral outcrops 314 Size and depth of ore bodies as determined from outcrops 315 The use of placers in tracing mineral outcrops 316 The use of magnetic surveys in tracing mineral ledges 317

THE USE OF ELECTRICAL CONDUCTIVITY AND OTHER QUALITIES OF ROCKS IN EXPLORATION 319

THE USE OF STRUCTURE AND METAMORPHISM IN EXPLORATION 319

DRILLING IN EXPLORATION 320

QUANTITATIVE ASPECTS OF GEOLOGIC EXPLORATION 321

ORIGIN OF MINERAL DEPOSITS AS A FACTOR IN EXPLORATION 322

LAKE SUPERIOR IRON ORE EXPLORATION AS AN ILLUSTRATION 323

DEVELOPMENT AND EXPLOITATION OF MINERAL DEPOSITS 326

Chapter Xv. Valuation and Taxation of Mineral

RESOURCES 328

POPULAR CONCEPTION OF MINERAL VALUATION 328

VALUATION AND TAXATION OF MINES 329 Intrinsic and extrinsic factors in valuation 329 Values of mineral deposits not often established by market transfers 331 The ad valorem method of valuation 331 Other methods of mineral valuation and taxation 335

GENERAL COMMENTS ON TAXATION OF MINERAL RESOURCES 338

Chapter Xvi. Laws Relating to Mineral Resources 342

I. LAWS RELATING TO OWNERSHIP AND CONTROL OF MINERAL RESOURCES 342 On alienated lands 343 On the public domain 344 Nationalization of mineral resources 345 Effect of ownership laws on exploration 347 Use of geology in relation to ownership laws 349

II. LAWS RELATING TO EXTRACTION OF MINERAL RESOURCES 355

III. LAWS RELATING TO DISTRIBUTION AND TRANSPORTATION OF MINERAL RESOURCES 355

IV. OTHER RELATIONS OF GEOLOGY TO LAW 356

Chapter Xvii. Conservation of Mineral Resources 359

THE PROBLEM 359

DIFFERENCES BETWEEN PRIVATE AND PUBLIC EFFORTS IN CONSERVATION 363

THE INTEREST RATE AS A GUIDE IN CONSERVATION 364

ANTI-CONSERVATIONAL EFFECTS OF WAR 365

CONSERVATION OF COAL 366

MEASURES INTRODUCED OR PROPOSED TO CONSERVE COAL 367 (A) Mining and preparation of coal 368 Progress in above methods 370 (B) Improvement of labor and living conditions at the mines 372 (C) Introduction or modification of laws to regulate or to remove certain restrictions on the coal industry 373 (D) Distribution and transportation of coal 376 (E) Utilization of coal 377 (F) Substitutes for coal as a source of power 378

DIVISION OF RESPONSIBILITY BETWEEN GOVERNMENT AND PRIVATE INTERESTS IN THE CONSERVATION OF COAL 379

CONSERVATION OF MINERALS OTHER THAN COAL 382

Chapter Xviii. International Aspects of Mineral

RESOURCES 383

WORLD MOVEMENT OF MINERALS 383 Movement of minerals under pre-war conditions of international trade 385 Changes during the war 385 Post-war condition of the mineral trade 387

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