Parasnis D.S. Mining Geophysics

Elsevier, 1966. — (Methods in Geochemistry and Geophysics). — 365 p.This book is intended as an introduction to the geophysical methods of ore prospecting and is written primarily for geologists and mining
engineers. However, that others may also find it useful. Considering that the day-to-day mathematical equipment of geologists and mining engineers does not, in general, go beyond elementary algebra and trigonometry, the author has avoided the use of higher mathematics in the main text. However, for the reader who is interested in knowing the basis of geophysical formulas, a few appendices on selected topics are included but even these do not require more than elementary knowledge of the calculus for their understanding.Several texts on applied geophysics exist at approximately the same introductory level as the present one, for example, Dobrin's Introduction to Geophysical Prospecting or Eve and Keys' Applied Geophysics in the Search for Minerals. Therefore, it should be of some interest to point out in what manner the present book differs from its predecessors.It appears in the first place that this is the first modern book devoted exclusively to mining geophysics and, as such, it treats several topics which are not treated, or at best mentioned only cursorily, in the older books of its class. Among these may be mentioned electromagnetic moving source-receiver methods, induced polarization, minimax estimates in gravity interpretation, mass estimates from gravity data, and airborne electromagnetic
work.The second point of difference is the relative emphasis on the various methods. In Dobrin's book, for example, the gravity and seismic methods occupy about 25 percent of the book each, while the self-potential, electromagnetic and electrical methods together receive only 7 percent of the book. While this proportion may meet the requirements of oil prospecting it is unsatisfactory from the point of view of ore prospecting in which the latter class of methods is, at least at present, of very much greater importance than the seismic method. The present book redresses the balance in favour of the geoelectrical methods without, however, sacrificing the gravity method which continues to enjoy the share appropriately due to it.At several places in this book reference is made to a previous monograph of mine Principles of Applied Geophysics, especially in regard to certain master curves and theoretical points of general interest. As both books cover a certain amount of common ground, and my previous monograph, being of recent date, is readily available, this course seemed to me a more sensible one than a mere repetition for the sake of completeness of the present volume. The space thus set free has been utilized in the discussion of case histories and of topics of specific interest to mining geophysics. However, either book has its well defined separate point of view and is selfsufficient as far as it goes.No attempt is made in this book to describe the details of calculating theoretical anomalies in interpreting geophysical data. Firstly, an adequate account of the technique of such computation can hardly be given within the scope of this book. Secondly, the fundamental problem of geophysical interpretation is not that of making subtle adjustments of the various parameters in order to seoure an agreement between theoretical and observed anomalies to some very high degree of accuracy, but that of understanding physical phenomena and of manipulating physical magnitudes in order to arrive at a working hypothesis concerning the structure of the subsurface, a hypothesis that is reasonable in the light of physical theories as well as geological knowledge.