Mining Geophysics

Methods in Geochemistry and Geophysics, 3: Mining Geophysics focuses on the geophysical methods of ore prospecting, including radioactivity, collection of geophysical data, and field measurements. The manuscript first highlights the role of geophysics in ore prospecting and the general aspects of collection and presentation of geophysical data. Discussions focus on classification of geophysical methods, radioactivity, collection of preliminary information, field measurement, and isoanomaly curves. The text then surveys magnetic and self-potential methods, as well as the general magnetic properties of rocks, geomagnetic field, magnetometers, transverse magnetization, and measurement of self-potentials. The publication ponders on electromagnetic, electrical, and induced polarization methods. Topics include classification of electromagnetic methods; use of two frequencies in electromagnetic prospecting; moving source-receiver methods; electrode configurations in resistivity methods; and resistivity measurements in boreholes. The text also examines gravity, seismic, and airborne magnetic and electromagnetic methods. The manuscript is a valuable source of information for geologists and mining engineers.

Preface Chapter 1. The Role of Geophysics in Ore Prospecting Chapter 2. General Aspects of the Collection and Presentation of Geophysical Data Classification of Geophysical Methods Radioactivity Collection of Preliminary Information Trial Surveys Staking An Area Field Measurements Geophysical Maps Isoanomaly Curves Profile Drawing Interpretation Chapter 3. Magnetic Methods Introduction Recalling Some Fundamental Concepts Induced and Permanent Magnetism General Magnetic Properties of Rocks Susceptibilities of Rocks Permanent Magnetization (Remanence) of Rocks Measurement of Susceptibility and Remanence The Geomagnetic Field Magnetometers Field Work The Zero Level An Orebody As A Magnet Interpretation of Magn Depth,- Strike Length,- Dip and Pitch,- Depth-Extent,- Size and Magnetization A Simple Example of A Magnetic Survey (U-Dal, Central Sweden) Magnetic Survey in the E-O Orefield (Central Sweden) Transverse Magnetization A Simple Geometrical Construction For Determining the Position of An Ore Sheet Magnetic Effects of Broad Zones The Greenstone Area of Loos (Sweden) Vector Measurements Example of Vector Measurements Borehole Measurements Note On Reverse Magnetic Anomalies Chapter 4. The Self-Potential Method Introduction Origin of Self-Potentials Measurement of Self-Potentials Electrodes,- Cable,- Voltmeter Field Procedure Example of SP Surveys The Kimheden Orebody,- The Gransjö Orefield, Central Sweden,- The Copper Deposits of Chalkidiki, Northern Greece,-The Shales of Gautosjö, Northern SwedenChapter 5. Electromagnetic Methods Introduction Geometry of the Electromagnetic Field The Tilt-Angle Method Amplitude and Phase The Phase Angle and the Vector Diagram Real and Imaginary Components Measurement of the Real and Imaginary Components Classification of Electromagnetic Methods Fixed-Source Methods,- Moving Source-Receiver Methods Fixed-Source Methods Tilt-Angle,- Bieler-Watson,- Two-Frame Method,-The Compensator Or Sundberg Method,- The Turam Method Loop Layouts Moving Source-Receiver Methods Coils Horizontal and Coplanar,- Coils Vertical and Coplanar,- Coils Vertical and Coaxial,- Topographic Corrections Examples of Moving Source-Receiver Surveys The Svansele Orebody (Northern Sweden),- The R-Sjö Sulphide Occurrence (Sweden) Use of Two Frequencies in Electromagnetic Prospecting Depth Penetration of Electromagnetic Methods Afmag Chapter 6. Electrical Methods Introduction Resistivity Resistivity of Rocks and Mineral Apparatus Commutation of Current Classification of Electric Methods Equipotential Method Earth-Resistivity Methods Apparent Resistivity Electrode Configurations in Resistivity Methods Electric/Drilling Electric Mapping Mapping By Linear Current Electrodes (Theory) Field Examples of Line-Electrode Mapping The Mise-À-La-Masse Method Potential-Drop Ratio and A.C. Potential Methods Resistivity Measurements in Boreholes Chapter 7. Induced Polarization Methods Introduction Origin of Induced Polarization Electrode Polarization,- Membrane Polarization, The Condenser Model Effect of Alternating Current Time-Domain and Frequency-Domain IP Methods Measures of the IP Effect Time-Domain Measures,-Frequency-Domain Measures Polarizability of Minerals and Rocks Two Examples of IP Surveys Kankberg Orebody, Northern Sweden,- Broken Hill Area, Australia Concluding Remarks Concerning The IP Method Chapter 8.