DEVELOPMENTS IN GEOPHYSICAL EXPLORATION METHODS-4

Transcription

1 DEVELOPMENTS IN GEOPHYSICAL EXPLORATION METHODS-4

2 CONTENTS OF VOLUMES 1 TO 3 Volume 1 Edited by A. A. Fitch 1. Velocity Determination from Seismic Reflection Data. M. AL-CHALABI 2. Patterns of Sources and Detectors. S. D. BRASEL 3. Well Geophone Surveys and the Calibration of Acoustic Velocity Logs. P. KENNETT 4. Seismic Sources on Land. W. E. LERWILL 5. Marine Seismic Sources. R. LUGG 6. Gravity and Magnetic Surveys at Sea L. L. NETTLETON 7. Pulse Shaping Methods. D. G. STONE 8. Seismic Profiling for Coal on Land. A. ZIOLKOWSKI Index Volume 2 Edited by A. A. Fitch 1. Determination of Static Corrections. A. W. ROGERS 2. Vibroseis Processing. P. KIRK 3. The 11 Norm in Seismic Data Processing. H. L. TAYLOR 4. Predictive Deconvolution. E. A. ROBINSON 5. Exploration for Geothermal Energy. G. V. KELLER 6. Migration. P. HOOD Index Volume 3 Edited by A. A. Fitch 1. Underground Geophysics of Coal Seams. A. K. BOOER 2. Interrelationship of Resistivity and Velocity Logs. A. J. RUDMAN 3. Focused Resistivity Logs. A. Roy 4. Gamma-Ray Logging and Interpretation. P. G. KILLEEN 5. Acoustic Logging: The Complete Waveform and Its Interpretation. D. RADER 6. Electrical Anisotropy: Its EtTect- on Well Logs. J. H. MORAN and S. GIANZERO 7: Borehole Geophysics in Geothermal Exploration. W. S. KEYS 8. Measurement and Analysis of Gravity in Boreholes J. R. HEARST and R. C. CARLSON Index

3 DEVELOPMENTS IN GEOPHYSICAL EXPLORATION METHODS-4 Edited by A. A. FITCH Consultant, Formerly of Seismograph Service (England) Limited, Keston, Kent, UK APPLIED SCIENCE PUBLISHERS LTD LONDON and NEW YORK

4 APPLIED SCIENCE PUBLISHERS LTD Ripple Road, Barking, Essex, England Sole Distributor in the USA and Canada ELSEVIER SCIENCE PUBLISHING CO., INC. 52 Vanderbilt Avenue, New York, NY 10017, USA British Library Cataloguing in Publication Data Developments in geophysical exploration methods. ~4.~(The Developments series) 1. Prospecting~Geophysical methods I. Series 622'.15 TN269 ISBN-13: DOl: / e-isbn-13: WITH 8 TABLES AND 94 ILLUSTRATIONS APPLIED SCIENCE PUBLISHERS LTD 1983 Softcover reprint ofthe hardcover 1st edition 1983 The selection and presentation of material and the opinions expressed in this publication are the sole responsibility of the authors concerned. All rights reserved. No part of this pu blication rna y be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner, Applied Science Publishers Ltd, Ripple Road, Barking, Essex, England Photoset in Malta by Interprint Limited

5 PREFACE Geophysical prospecting is an applied science and the range of scientific principles to be applied is very wide. In this collection of original papers, the application of many different principles is described in the search for sulphides, other metallic ores and radioactive deposits. The papers are all concerned with surface observations and cover both the theory and the practice of the methods used. In all cases the advantages and disadvantages of the methods are described and their role in the detection of mineral deposits is discussed and placed in context. Electromagnetic methods are covered in detail, involving the use of both electric and magnetic field effects. Techniques are described involving observations both at a number of discrete frequencies and with continuously changing frequency. In spite of the diversity of method it is interesting to note the strong links between the papers; two chapters, for example, start from the same fundamental illustration, first published by Won, of the basic relationship between source frequency, ground conductivity and depth of penetration. The all-important economic aspects are not forgotten and the first chapter assesses the statistics of performance and describes their use in the shaping and management of an exploration programme. The editor takes this opportunity to thank the busy men who have set aside time to write these contributions. A. A. FITCH v

6 CONTENTS Preface. List of Contributors v IX 1. Estimation of Sulphide Content of a Potential Orebody from Surface Observations and its Role in Optimising Exploration Programmes. 1 E. GAUCHER 2. A Sweep-Frequency Electromagnetic Exploration Method 39 I. 1. WON 3. The Magnetic Induced Polarisation MethQd. 65 H. O. SEIGEL and A. W. HOWLAND-RoSE 4. Broadband Electromagnetic Methods W. MOTTER 5. Radon Mapping in the Search for Uranium. 155 W. M. TELFORD Index 195 vii

7 LIST OF CONTRIBUTORS E. GAUCHER Edwin Gaucher & Associates Inc., 2406 Quatre-Bourgeois, Suite 200, Sainte-Foy, Quebec, Canada GlV lw5 A. W. HOWLAND-RoSE Scintrex Pty Ltd, 6 Tramore Place, Killarney Heights, New South Wales 20987, Australia J. W. MOTTER Whitney & Whitney, Inc., PO Box 11647, Suite 135, 1755 E. Plumb LN, Reno, Nevada 89510, USA H. O. SEIGEL Scintrex Ltd, 222 Snidercrojt Road, Concord, Ontario, Canada L4K IB5 W. M. TELFORD Department of Mining and Metallurgical Engineering, McGill University, 3480 University Street, Montreal, Quebec, Canada H3A 2A7 ix

8 x LIST OF CONTRIBUTORS I. 1. WON Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, PO Box 5068, Raleigh, North Carolina, 27650, USA