Geostatistics for Natural Resources Characterization Part 1 NATO ASI Series Advanced Science Institutes Series A series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A Life Sciences Plenum Publishing Corporation B Physics London and New York C Mathematical D. Reidel Publishing Company and Physical Sciences Dordrecht, Boston and Lancaster D Behavioural and Social Sciences Martinus Nijhoff Publishers E Engineering and The Hague, Boston and Lancaster Materials Sciences F Computer and Systems Sciences Springer-Verlag G Ecological Sciences Berlin, Heidelberg, New York and Tokyo Series C: Mathematical and Physical Sciences Vol. 122 - Part 1 Geostatistics for Natural Resources Characterization Part 1 edited by G. Verly Department of Applied Earth Sciences, Stanford University, Stanford, U.S.A. M. David Departement de Chimie Mineral, Ecole Poly technique, Montreal, Canada A. G. Journel Department of Applied Earth Sciences, Stanford University, Stanford, U.S.A. and A. Marechal S.N. Elf Aquitaine (Production), Pau, France D. Reidel Publishing Company Dordrecht / Boston / Lancaster Published in cooperation with NATO Scientific Affairs Division Proceedings of the NATO Advanced Study Institute on Geostatistics for Natural Resources Characterization Stanford Sierra Lodge, South Lake Tahoe, California, U.S.A. September 6 - 17,1983 Library of Congress Cataloging in Publication Data NATO Advanced Study In stitute on Geostatistics for Natural Resources Characterization (2nd: 1983: South Lake Tahoe, Calif.) Geostatistics for natural resources characterization. (NATO ASI series. Series C, Mathematical and physical sciences; vol. 122) "Proceedings of the NATO Advanced Study In stitute on Geostatistics for Natural Resources Characterization, Stanford Sierra Lodge, South Lake Tahoe, California, U.S.A., September 6-17,1983"-T.p. verso. "Published in cooperation with NATO Scientific Affairs Division." I ncludes bibliographical references and index. 1. Mine valuation-Statistical methods-Congresses. 2. Geology-Statistical methods Congresses. I. Verly, G. (Georges) II. North Atlantic Treaty Organization. Scientific Affairs Division. III. Title. IV . Series: NATO ASI Series. Series C, Mathematical and physical sciences; Vol. 122. TN272.N38 1983 553'.0724 84-2155 ISBN -13:978-94-0 10 -8157 -3 e-ISBN-I3:978-94-009-3699-7 DOl: 10.1007/978-94-009-3699-7 Published by D. Reidel Publishing Company PO. Box 17,3300 AA Dordrecht, Holland Sold and distributed in the U.S.A. and Canada by Kluwer Academic Publishers, 190 Old Derby Street, Hingham, MA 02043, U.S.A In all other countries, sold and distributed by Kluwer Academic Publishers Group, PO. Box 322, 3300 AH Dordrecht, Holland D. Reidel Publishing Company is a member of the Kluwer Academic Publishers Group AI! Rights Reserved © 1984 by D. Reidel Publishing Company, Dordrecht, Holland. Softcover reprint of the hardcover 1st edition 1984 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner. TABLE OF CONTENTS FOREWORD xiii ACKNOWLEDGEMENTS xiv LIST OF PARTICIPANTS xv PART I - VARIOGRAM LECTURES - IMPROVING THE ESTIMATION AND MODELLING OF THE VARIOGRAM M. Armstrong 1 2 - TOWARDS RESISTANT GEOSTATISTICS N. Cress;e 21 CONTRI BUTIONS 3 - STATISTICAL INFERENCE OF THE SEMIVARIOGRAM AND THE QUADRATIC MODEL M. Al faro 45 4 - USE OF THE JACKKNIFE METHOD TO ESTIMATE AUTOCORRELATION FUNCTIONS (OR YARIOGRAMS) C.F. Chung 55 5 - COMPUTING VARIOGRAMS IN FOLDED STRATA-CONTROLLED DEPOSITS M. Dagbert, M. David, D. Croze1, A. Desbarats 71 6 - THE YARIOGRAM AND KRIGING: ROBUST AND RESISTANT ESTIMATORS P.A. Dowd 91 vi TABLE OF CONTENTS 7 - THE VARIOGRAM AND ITS ESTIMATION 107 H. Omre 8 - INFERENCE FOR SPATIAL AUTOCORRELATION FUNCTIONS P. SwHzer 127 PART II - PRECISION Of GLOBAL ESTIMATION LECTURE 9 - PRECISION Of ESTIMATION OF RECOVERABLE RESERVES: THE NOTION OF CONDITIONAL ESTIMATION VARIANCE R. froidevaux 141 CONTRIBUTIONS 10 - ESTIMATION VARIANCE OF GLOBAL RECOVERABLE RESERVE ESTIMATES B.E.Buxton 165 11 - COMBINING LOCAL KRIGING VARIANCES FOR SHORT-TERM MINE PLANNING Y.C. Kim, E.Y. Baafi 185 12 - APPLICATION OF A GEOSTATISTICAL METHOD TO QUANTITATIVELY DEFINE VARIOUS CATEGORIES Of RESOURCES R. L. Sabourin 201 PART III - KRIGING LECTURE 13 - CONDITIONAL BIAS IN KRIGING AND A SUGGESTED CORRECTION M. David, D. Marcotte. M. Soulie 217 CONTRI BUTIONS 14 - POSITIVE KRIGING R.J. Barnes. T.B. Johnson 231 15 - CORRECTING CONDITIONAL BIAS K. Guertin 245 16 - mAD AND CONDITIONAL QUANTILE ESTIMATORS A.G. Journel 261 TABLE OF CONTENTS vii 17 - KRIGING SEISMIC DATA IN PRESENCE Of fAULTS A. Marechal 271 18 - CO-KRIGING - NEW DEVELOPMENTS D. E. Myers 295 PART IV - INDICATOR KRIGING LECTURE 19 - THE PLACE or NON-PARAMETRIC GEOSTATISTICS A.G. Journel 307 CONTRIBUTIONS 20 - INDICATOR KRIGING AS APPLIED TO AN ALLUVIAL GOLD DEPOSIT B.M. Davis 337 21 - ESTIMATING LOCAL RECOVERABLE RESERVES VIA INDICATOR KRIGING I.C. Lemmer 349 22 - CONDITIONAL RECOVERY ESTIMATION THROUGH PROBABILITY KRIGING - THEORY AND PRACTICE J. Sullivan 365 PART V - RECOVERABLE RESERVES LECTURES 23 - RECOVERY ESTIMATION: A REVIEW OF MODELS AND METHODS A. Marechal 385 24 - THE SELECTIVITY OF THE DISTRIBUTIONS AND THE "SECOND PRINCIPLE OF GEOSTATISTICS" G. Matheron 421 CONTR I BUTI ONS 25 - LOCAL ESTIMATION Of THE RECOVERABLE RESERVES: COMPARING VARIOUS METHODS WITH THE REALITY ON A PORPHYRY COPPER DEPOSIT D. Guibal. A. Remacre 435 26 - ISOfACTORIAL MODELS AND CHANGE Of SUPPORT G. Matheron 449 viii TABLE OF CONTENTS 27 - GEOSTATISTICAL APPLICATION IN TABULAR STYLE LEAD-ZINC ORE AT PINE POINT CANADA G.F. Raymond 469 28 - LOCAL ESTIMATION OF THE BLOCK RECOVERY FUNCTIONS A. Soares 485 29 - THE BLOCK DISTRIBUTION GIVEN A POINT MULTIVARIATE NORMAL DISTRIBUTION G. Verly 495 PART VI - SPECTRAL ANALYSIS AND DATA ANALYSIS LECTURE 30 - THREE-DIMENSIONAL. FREQUENCY-DOMAIN SIMULATIONS OF GEOLOGICAL VARIABLES L. Borgman. M. Taheri. R. Hagan 517 CONTRI BUTlONS 31 - FACTORIAL KRIGING ANALYSIS: A SUBSTITUTE TO SPECTRAL ANALYSIS OF MAGNETIC DATA A. Galli. F. Gerdll-Neuillet. c. Dadou 543 32 - THE FACTORIAL KRIGING ANALYSIS Of REGIONALIZED DATA. ITS APPLICATION TO GEOCHEMICAL PROPECTING L. Sandjivy 559 33 - THE ANALYSIS OF SECOND-ORDER STATIONARY PROCESSES: TIME SERIES ANALYSIS. SPECTRAL ANALYSIS. HARMONIC ANALYSIS. AND GEOSTATISTICS A.R. Solow 573 FOREWORD Since October 1975 and the first NATO ASl "Geostat - Roma 1975", there has not been an advanced workshop on geostatistics where experts from throughout the world could meet, teach and debate without the pressure of an ordinary professional confer ence. This second NATO ASI "Geostat - Tahoe 1983" was intended as a high-level teaching activity yet opened to all new ideas and contributions to the discipline of geostatistics. It was expected that the institute would bridge the gap since "Geostat - Roma 1975" and establish the state of the art of the discipline as of 1983. "Geostat - Tahoe 1983" fulfilled all expectations. The institute, held in September 1983 at the Stanford Sierra Lodge near Lake Tahoe, California, was attended by all major players in the field, representing evenly the academy and the industry of 23 different countries. Twelve guest lecturers were backed by some 50 original contributions. Particularly important for the future was the active participation of graduate students, glvlng evi dence of the dynamism of a still very young discipline. Applications of geostatistics are no longer limited to the mining industry, and the original scope of the ASI had to be wid ened to witness the progress made in such fields as hydrology, soil sciences, pollution control and geotechnical engineering. Also important was the cross-fertilization from oiher statistical branches such as spectral analysis and robust statistics. The NATO ASI "Geostat - Tahoe 1983" will be remembered as a major milestone in the development of the discipline. I invite all of you who did not make it to the ASI to dive into these pro ceedings and share a bit of the excitement that pervaded this summer's end at Lake Tahoe. A.G. Journel Director of the ASI ACKNO\{LEDGEMENTS The Scientific Affairs Division of NATO is gratefully acknowledged for having sponsored this Advanced Study Institute. Additional support was, provided by Stanford University, Ecole Poly technique de Montreal, and Ecole des Mines de Paris. We thank the group of following companies which helped finance the Institute: BRGM, France CERCHAR, France COGEMA, France Elf Aquitaine (Production), France Schlumberger E.P.S., France TECMIN, France Shell, Netherlands We are especially grateful to the team of Stanford students who made possible the organization of the ASI. The overwhelming success of this Institute would not have been possible without the dedication of our lecturers and contributors. The Organizing Committee George Verly Michel David Andre Journel Alain Marechal Stanford, October 1983 xi