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