Contents 1 Prospecting and the Exploration Process 1 11 Definition of Terms 1 1.2 New Prosp 1 13 enerating New Exploration Ideas. A Che egative Assumptions 4 1.5 Stages in Prospect Exploration. 5 1.5. larget Generation.。.。. 1.5.2 Target Drilling. 6 1.5.3 Resource Evaluation Drilling 6 1.5.4 Feasibility Study 6 16 Maximizing Succ ess in Exploration Programmes 7 17 s of Exploration Strategy 0 18 0 1.9 azor 10 References Geological Mapping in Exploration 3 2.1 。 3 21.1 Why Make a map? 13 2.1.2 The Nature of a Geological Map 2.13 Intelligent Mapping 214 Choosingthe Best Technique 215 Choosing the Best scale ng 2.2 Mapping Using Reflectance Imagery as a Map Base 。 2.2. General. 2.2.2 Acquiring Air Photographs. 22.3 Geological Interpretation 2.2.4 Determining Scale. 225 Stereoscopic Image pairs 3 236 age Handling Technig 2.2.7 Working with Enlarged d Ai r Photographs xi
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 xi
Contents 2.2.8 Data Transfer to Base Map 2.3 Mapping with a Plane Table 24 24 pping ona Pegged Grid ents of the 2.4.2 ing the Ma p 2.5 Mapping with Tape and Compass References. 49 3 Mine Mapping 3.1 General 5 3.2 Mapping in Open Cuts 33 Mapping Underground Openings 24 Safety in Mines 6 4 Trenching and Underground Development 6 Preambl 4.2 Pitting and Trenching 63 4.3 Underground Development 64 4.4 Safety and Logistics in Trenching 45 Geological Mapping 46 Geochemical sampling 47 Examples of Successful Exploration Programmes References 72 Drilling a general dis scussion the Importance of Drilling 3 T 52 Choosing the Right Technique 5.3 Targeting Holes,.,.,.,.,. 5.4 Drilling on Section.,.,.,.,., References 94 6 Rotary Percussion and Auger Drilling 。 6.1 Rotary Percussion Drilling 8 6.1.1 Reverse circulation drilling (RCy 6.12 Air Core drillins 93 6.1.3 ry Air Blast(RAB)Drilling Auger Drilling erences 。 09 7 Diamond Drilling 1. Preamble 99 7.2 Some Definitions 73 Before You Begin 102 74 Setting Up a Diamond Hole 102 7.5 Geol gical Observation 103 7.6 10g
xii Contents 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
Contents xii 7.6.1 Statement of the Problem,···,·····,··· 7.6.1 Planar Structures 104 7.6.3 Faults 105 764 Linear Structures 107 765 Folds 109 766 The Scale Problem 110 767 e 112 77 Measuring and Recording Structures in Core 7.8 Core Logging Systems 7.8. Prose Logging 6 7.8.2 Graphical Scale Logging. 1 7.8.3 Analytical Spreadsheet Logging 119 7.9 Down-Hole Surveying 123 701 Procedure 123 7.9.2 Using Down-Hole Survey Data to Plot Sections nd Plan 124 7.10 When Should Core Be Oriented? 127 Sampl 7.12 and Assaying· Core Handling 7.13 Core Photography 135 References 136 8 Satellite Imagery 。 137 81 General discussion 137 82 How Earth Observation Satellites Work 139 83 140 84 Display of Analysis of R 9 Geophysical and Geochemical Methods 143 9.1 9.2 Magnetic Surveys 。 93 Gravity surveys. 149 04 Radiometric surveys 150 9.5 Electromagnetic(EM)Surveys 150 9.6 9 Hybrid and Ma agnetic Su 152 Advance s in Instrumentation and g Stream Sediment Sampling. 9.10 Soil Sampling s55 9.11 Heavy Mineral Concentrate (HMC)Sampling. 158 9.12 Rock Chip Sampling 160 9.13 Laterite Sampling 161 References 162
Contents xiii 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
xiv Contents 10 Geographical Information Systems and Exploration Databases 165 10.1 Definition 102 165 10.3 prage of M ap Da Digitise e Format 10.32 Polygon or Vector Format. 10.3.3 Raster Format,.。.,. 170 10.4 170 10.5 Georeferencing 171 10.5.1 Geographical Coordinates 171 10.5.2 Cartesian Coordinates 10.5.3 Map Datums 17 10.5.4 Map Re 173 10.6 Manipu 173 10.7 Presentation of GIS Data 174 Appendix A Notes on the Use of Graphical Scale Logging. A.I Column 1(Hole Depth) 180 A2 Column 2 (Core Recovery) 180 A3 Column 3(Core Ouality) 180 AA Column 4(Sample No.) 180 Column5(Assay Results) 180 Columr apping L gs lumn A.8 Column 8 (Geology Notes). W88 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 R11 Non-mechanical means 183 B12 Mechanical Means How to Handle Oriented Core B.3 asure Structures in Oriented Core 8 B3. Before You Measure 0 B.3.2 How Many Measurements Are Needed?. 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 App endix c Calculating Strike 205 int Problem.······· 205
xiv Contents 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.1 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
Contents 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 dinate Structure The Solution for Linear Structures Appendix E Practical Field Techniques.··.····· 。 215 E.I Choosing the Right Compass. 215 B.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
Contents xv 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.1 The Solution for Planar Structures . . . . . . . . . . . . . . . . 211 D.2 The Solution for Linear Structures . . . . . . . . . . . . . . . . 213 Appendix E Practical Field Techniques . . . . . . . . . . . . . . . . . . . . . . . 215 E.1 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