Geological Methods in Mineral Exploration and Mining

by Roger Marjoribanks

Overview

This book is written as a practical field manual to effective. Each geolOgist has to develop his/her be used by geologists engaged in mineral explo­ own techniques and will ultimately be judged on ration. It is also hoped that it will serve as a text results, not the process by which these results and reference for students in Applied Geology were reached. In mineral exploration, the only courses of universities and colleges. The book 'right' way of doing anything is the way that aims to outline some of the practical skills that locates ore in the quickest and most cost-effective turn the graduate geologist into an explo­ manner. It is preferable, however, for an individ­ rationist:. It is intended as a practical 'how to' ual to develop his/her own method of operation book, rather than as a text on geological or ore after having tried, and become aware of, those deposit theory. procedures which experience has shown to work An explorationist is a professional who search­ well and which are generally accepted in indus­ try as good exploration practice. es for ore bodies in a scientific and structured way. Although an awkward and artificial term, The chapters of the book approximately fol­ this is the only available word to describe the low the steps which a typical exploration pro­ totality of the skills which are needed to locate gramme would go through. In Chapter 1, the and define economic mineralization.

Product Details

ISBN-13:	9783642435782
Publisher:	Springer Berlin Heidelberg
Publication date:	11/26/2014
Edition description:	Second Edition 2010
Pages:	238
Product dimensions:	6.10(w) x 9.25(h) x 0.02(d)

Table of Contents

1 Prospecting and the Exploration Process 1

1.1 Definition of Terms 1

1.2 Generating New Projects and Prospects 1

1.3 Some Ways of Generating New Exploration Ideas 3

1.4 A Check-List of Negative Assumptions 4

1.5 Stages in Prospect Exploration 5

1.5.1 Target Generation 5

1.5.2 Target Drilling 6

1.5.3 Resource Evaluation Drilling 6

1.5.4 Feasibility Study 6

1.6 Maximizing Success in Exploration Programmes 7

1.7 Different Types of Exploration Strategy 9

1.8 Exploration Feedbacks 9

1.9 Breaking Occam's Razor 10

References 11

2 Geological Mapping in Exploration 13

2.1 General Considerations 13

2.1.1 Why Make a Map? 13

2.1.2 The Nature of a Geological Map 14

2.1.3 Intelligent Mapping 15

2.1.4 Choosing the Best Technique 18

2.1.5 Choosing the Best Scale 20

2.1.6 Measuring and Recording Structures 22

2.1.7 Using Satellite Navigation (GPS) 23

2.2 Mapping Using Reflectance Imagery as a Map Base 25

2.2.1 General 25

2.2.2 Acquiring Air Photographs 26

2.2.3 Geological Interpretation 26

2.2.4 Determining Scale 27

2.2.5 Stereoscopic Image Pairs 29

2.2.6 Image Handling Techniques 31

2.2.7 Working with Enlarged Air Photographs 34

2.2.8 Data Transfer to Base Map 37

2.3 Mapping with a Plane Table 38

2.4 Mapping on a Pegged Grid 41

2.4.1 Requirements of the Grid 41

2.4.2 Making the Map 43

2.5 Mapping with Tape and Compass 47

References 49

3 Mine Mapping 51

3.1 General 51

3.2 Mapping in Open Cuts 51

3.3 Mapping Underground Openings 56

3.4 Safety in Mines 60

References 61

4 Trenching and Underground Development 63

4.1 Preamble 63

4.2 Pitting and Trenching 63

4.3 Underground Development 64

4.4 Safety and Logistics in Trenching 65

4.5 Geological Mapping 66

4.6 Geochemical Sampling 69

4.7 Examples of Successful Exploration Programmes 71

References 72

5 Drilling: A General Discussion the Importance of Drilling 75

5.1 Types of Drilling 75

5.2 Choosing the Right Technique 76

5.3 Targeting Holes 79

5.4 Drilling on Section 83

References 84

6 Rotary Percussion and Auger Drilling 85

6.1 Rotary Percussion Drilling 85

6.1.1 Reverse Circulation Drilling (RC) 85

6.1.2 Air Core Drilling 93

6.1.3 Rotary Air Blast (RAB) Drilling 93

6.2 Auger Drilling 96

References 97

7 Diamond Drilling 99

7.1 Preamble 99

7.2 Some Definitions 100

7.3 Before You Begin 102

7.4 Setting Up a Diamond Hole 102

7.5 Geological Observation 103

7.6 Recognizing and Interpreting Structures in Core 104

7.6.1 Statement of the Problem 104

7.6.2 Planar Structures 104

7.6.3 Faults 105

7.6.4 Linear Structures 107

7.6.5 Folds 109

7.6.6 The Scale Problem 110

7.6.7 Vergence 112

7.7 Measuring and Recording Structures in Core 113

7.8 Core Logging Systems 116

7.8.1 Prose Logging 116

7.8.2 Graphical Scale Logging 117

7.8.3 Analytical Spreadsheet Logging 119

7.9 Down-Hole Surveying 123

7.9.1 Procedure 123

7.9.2 Using Down-Hole Survey Data to Plot Sections and Plans 124

7.10 When Should Core Be Oriented? 127

7.11 Sampling and Assaying 127

7.12 Core Handling 130

7.13 Core Photography 135

References 136

8 Satellite Imagery 137

8.1 General Discussion 137

8.2 How Earth Observation Satellites Work 139

8.3 Display of Satellite Images 140

8.4 Geological Interpretation 140

8.5 Analysis of Reflectance Data 142

References 142

9 Geophysical and Geochemical Methods 143

9.1 General Discussion 143

9.2 Magnetic Surveys 146

9.3 Gravity Surveys 149

9.4 Radiometric Surveys 150

9.5 Electromagnetic (EM) Surveys 150

9.6 Electrical Surveys 151

9.7 Hybrid Electrical and Magnetic Surveys 152

9.8 Advances in Instrumentation and Data Modelling 153

9.9 Stream Sediment Sampling 155

9.10 Soil Sampling 157

9.11 Heavy Mineral Concentrate (HMC) Sampling 158

9.12 Rock Chip Sampling 160

9.13 Laterite Sampling 161

References 162

10 Geographical Information Systems and Exploration Databases 165

10.1 Definition 165

10.2 The Need for Digital Exploration Databases 165

10.3 GIS Storage of Map Data 168

10.3.1 Digitised Line Format 168

10.3.2 Polygon or Vector Format 170

10.3.3 Raster Format 170

10.4 Validation 170

10.5 Georeferencing 171

10.5.1 Geographical Coordinates 171

10.5.2 Cartesian Coordinates 171

10.5.3 Map Datums 172

10.5.4 Map Registering 173

10.6 Manipulation of GIS Data 173

10.7 Presentation of GIS Data 174

Appendix A Notes on the Use of Graphical Scale Logging 179

A.l Column 1 (Hole Depth) 180

A.2 Column 2 (Core Recovery) 180

A.3 Column 3 (Core Quality) 180

A.4 Column 4 (Sample No.) 180

A.5 Column 5 (Assay Results) 180

A.6 Column 6 (Mapping Logs) 180

A.7 Column 7 (Histogram Logs) 181

A.8 Column 8 (Geology Notes) 182

A.9 Column 9 (Summary Log) 182

A.10 Remarks Area 182

Appendix B Oriented Drill Core: Techniques and Procedures 183

B.1 Techniques for Orienting Drill Core 183

B.1.1 Non-mechanical Means 183

B.1.2 Mechanical Means 183

B.2 How to Handle Oriented Core 188

B.3 How to Measure Structures in Oriented Core 190

B.3.1 Before You Measure 190

B.3.2 How Many Measurements Are Needed? 191

B.3.3 Using a Core Frame 192

B.3.4 Using Internal Core Angles 195

B.3.5 Discussion on the Best Measuring Technique 201

B.3.6 Plotting Structure Measurements on Drill Section 202

Appendix C Calculating Strike and Dip from Multiple Diamond Drill Holes 205

C 1 The Three Point Problem 205

C.2 Solution Using Structure Contours 205

C.3 Solution Using a Stereonet 206

C.4 An Elegant Solution to Determining the Attitude of Planes in Non-oriented Core 208

Appendix D How to Use a Stereo Net to Convert Internal Core Angles to Geographic Coordinates 211

D.l The Solution for Planar Structures 211

D.2 The Solution for Linear Structures 213

Appendix E Practical Field Techniques 215

E.l Choosing the Right Compass 215

E.2 Understanding Your Compass 215

E.3 Measuring the Strike and Dip of Planes 217

E.4 Measuring the Trend and Plunge of Lineations 218

Appendix F Suggested Further Reading 223

Acronyms and Abbreviations 229

Index 233

Editorial Reviews

‘In my opinion the book is unique, well done and should be a handbook for mining geologists. It so reflects my personal opinions about mineral exploration that I am probably too prejudicial to be a "fair" reviewer. This book should be a reference in all geological libraries, for students in economic geology and for all economic geologists.'
Paul Eimonn, Commonwealth International Inc, Texas. Pre-publication reviewer for Chapman & Hall, 1996
‘With this book, Roger Marjoribanks has presented the extractive metals industry with a rare gift: a truly practical and approachable handbook that addresses the daily concerns of the exploration geologist... The open style of writing and Marjoribanks' effective hand-drawn illustrations make the book both approachable and readable... Perhaps of greatest value are the numerous practical tips for efficiently performing routing geological observations and measurements, which are based on the authors' extensive experience as a consulting geologist.
Four Appendices are provided, and these include some of the most useful information in the book (no, you can't stop reading at page 88 - the Appendices are a gold mine!).
I wholeheartedly recommend it to anyone embarking on a career in this field!'
Jeremy Richards, Economic Geology, 92 (1997)
‘First the recommendation: buy it. For any geologist who is involved in exploration, this book will save you time and money. All exploration managers should buy a copy each for the exploration geologists on their staff, and sit them down to read it.
Into his 128 pages, Marjoribanks packs a great amount of important practical knowledge.... Marjoribanks states that the book was written to be "a practical field manual to be used by geologists engaged in mineral exploration" and "a text and reference for students in Applied Geology courses of universities and colleges". He has succeeded in both aims... Chapter 2, "Geological Mapping in Exploration", contains some of the most important material in the book...Chapter 4, "Mineral Exploration Drilling", is a winner.
Finally, the reprise. For the practicing or aspiring geologist; seriously consider buying this book (or convince your manager to buy you one) because it is useful and practical, and will save you time and money.'
Chris Mawer, The Australian Geologist (TAG), 107, (June 1998)
‘This book will be an invaluable reference to newly graduated geologists in the process of converting academic, theoretical knowledge to practical use in mineral exploration.'
Australian Mineral Foundation Informative Book Review Series No. 3021, AMF Reviews 24:10 (October 1997)
‘This book deserves a warm welcome and wide readership.'
Minerals Industry International

From the Publisher