Applied Mining Geology (eBook)

Dr Abzalov is a geologist with 35 years of experience. He has obtained his PhD in Geology studying nickel sulphide deposits in Russia and Fennoscandia and then undertaken additional post-graduate studies of Applied Mathematics at Murdoch University, Australia and Geostatistics in Fontainebleau, France. He has worked in different roles in research, exploration and mining geology, including the positions of Geology Manager – Project for WMC Resources and Exploration Manager – New Opportunities (Eurasia) and Group Geostatistical Consultant for Rio Tinto. With diverse commodity and geographical experience, encompassing five continents, Dr. Abzalov has demonstrated skills in greenfields, brownfields and resource modelling. With an innovative approach of geostatistically assisted 3D structural modelling, he has lead WMC Resources to the successful resource growth at Olympic Dam and Cliffs deposits. He was also instrumental in the discovery of the uranium resources in Jordan.

About the Author 8
Acknowledgements 10
Contents 12
1 Introduction 22
References 23
Part I Mine Design, Mine Mapping and Sampling 24
2 Mining Methods 25
2.1 Open Pit Mines 26
2.2 Underground Mines 27
2.2.1 Underground Selective Mining Methods 29
2.2.1.1 Cut-and-Fill Method 29
2.2.1.2 Shrinkage Stoping 30
2.2.2 Underground Bulk Mining Methods 30
2.2.2.1 Block Caving 30
2.2.2.2 Sublevel Open Stoping 32
2.2.2.3 Sublevel Caving 33
2.2.2.4 Vertical Crater Retreat 34
2.2.3 Mining of the Gently Dipping Ore Bodies 34
2.2.3.1 Room-and-pillar Method 35
2.2.3.2 Longwall Mining 35
2.3 Unconventional Mining 35
2.3.1 In situ Leach (ISL) Technique 36
2.3.2 Dredging of the Mineral Sands 36
References 38
3 Mine Mapping 39
3.1 Mine Mapping Principles 39
3.2 Mapping Open Pit Mines 40
3.3 Mapping of Underground Mines 43
3.4 Mapping Using Digital Photogrammetry and Laser Technologies 50
3.4.1 Mapping Mining Faces Using Photogrammetry 50
3.4.2 Remote Mapping of the Mines Using Laser 53
3.5 Optimisation of the Mine Mapping Procedures 54
References 57
4 Drilling Techniques and Drill Holes Logging 58
4.1 Drilling Methods 58
4.2 Diamond Core Drilling 60
4.2.1 Core Quality and Representativeness 64
4.2.2 Orientated Core 68
4.2.3 Logging Diamond Core Holes 73
4.2.4 Sampling Diamond Core 77
4.3 Open Hole Percussion Drilling 78
4.3.1 Sampling Blastholes for Grade Control Purpose in the Open Pits 79
4.3.2 Use of `Jumbo' Drilling for Delineation of Underground Stopes 83
4.4 Reverse Circulation (RC) Percussion Drilling 84
4.4.1 Logging RC Holes 86
4.4.2 Sampling RC Holes 88
4.5 Sonic Drilling Technologies 88
4.5.1 Strength and Weakness of the Sonic Drilling 90
4.5.2 Logging and Sampling Sonic Drill Holes 92
4.6 Auger Drilling 93
4.7 Rotary Drilling Using Tricone Bit 95
References 95
5 Sampling of the Mine Workings 97
5.1 Sampling Rock Faces in the Underground Mines 97
5.1.1 Channel Sampling 98
5.1.2 Rock Chip Sampling 98
5.2 Sampling of the Broken Ore 100
5.3 Trenching and Winzing 102
References 103
6 Geotechnical Logging and Mapping 104
6.1 Geotechnical Logging of the Drill Core 104
6.1.1 Drilling Parameters and Core Recovery 105
6.1.2 Rock Weathering 105
6.1.3 Rock Strength 106
6.1.4 Rock Quality Designation Index (RQD) 106
6.1.5 Natural Breaks 107
6.2 Geotechnical Mapping 108
6.3 Geotechnical Applications of Rock Mass Classification Schemes 109
References 112
7 Dry Bulk Density (DBD) of Rocks 113
7.1 Types of the Rock Densities Used in the Mining Industry 114
7.2 Dry Bulk Density Measurement Techniques 114
7.2.1 Competent Non-porous Rocks 114
7.2.2 Porous and Weathered Rocks 116
7.2.3 Non-consolidated Sediments 120
7.3 Spatial Distribution of the Rock Density Measurements 120
References 126
8 Data Points Location (Surveying) 127
8.1 Surface Points Location 128
8.2 Down-Hole Survey 128
Reference 131
Part II Sampling Errors 132
9 Introduction to the Theory of Sampling 133
9.1 Types of Sampling Errors 133
9.2 Fundamental Sampling Error 135
9.2.1 Theoretical Background 135
9.2.2 Experimental Calibration of the Sampling Constants 137
9.2.2.1 Modified Sampling Tree Experiment (MSTE) 137
9.2.2.2 30-pieces Experiment 140
9.2.2.3 Heterogeneity Test 141
9.2.2.4 Calibration of the Sampling Constants Using Drill Hole Data 142
9.2.3 Sampling Nomogram 142
9.3 Grouping – Segregation Error 143
9.4 Errors Related to the Sampling Practices 145
9.5 Instrumental Errors 146
References 147
10 Quality Control and Assurance (QAQC) 148
10.1 Accuracy Control 148
10.1.1 Statistical Tests for Assessing Performance of the Standard Samples 149
10.1.1.1 Estimation Accuracy by Repeat Analyses of the Certified Standards, Single Laboratory 149
10.1.1.2 Estimation Accuracy by Repeat Analyses of the Certified Standards, Different Laboratories 150
10.1.1.3 Estimation Accuracy by a Single Assay of the Certified Standard 151
10.1.1.4 Within Laboratory Analytical Precision, Single Laboratory Case 151
10.1.1.5 Assessment of the Analytical Precision Using Round Robin Analysis of a Certified Standard Sample 152
10.1.1.6 Between Laboratories Precision 152
10.1.2 Statistical Tests for Assessing the Data Bias Using the Duplicate Samples 153
10.1.3 Diagnostic Diagram: Pattern Recognition Method 153
10.2 Precision Control 155
10.2.1 Matching Pairs of Data 155
10.2.2 Processing and Interpretation of Duplicate Samples 156
10.2.2.1 Method of Thompson – Howarth 156
10.2.2.2 Relative Precision Error 158
10.2.2.3 Geostatistical Approach of the Duplicate Samples Analysis 159
10.2.2.4 Partitioning of the Precision Error 160
10.2.2.5 Reduced Major Axis 160
10.2.2.6 Relative Difference Plot 161
10.3 Comparative Analysis of the Statistical Estimation Methods 163
10.4 Guidelines for Optimisation of the Sampling Programmes 167
10.4.1 Planning and Implementation of the Sampling Programmes 167
10.4.2 Frequency of Inserting QAQC Material to Assay Batches 168
10.4.3 Distribution of the Reference Materials 169
10.4.4 Distribution of the Duplicate Samples 169
References 171
11 Twin Holes 173
11.1 Method Overview 174
11.1.1 Objectives of the Twinned Holes Study 174
11.1.2 Statistical Treatment of the Results 175
11.1.3 Distance Between Twinned Holes 175
11.1.4 Drilling Quality and Quantity 175
11.1.5 Comparison of Studied Variables 177
11.1.6 Practice of Drilling Twinned Holes for Mining Geology Applications 178
11.2 Case Studies 179
11.2.1 Gold Deposits: Confirmation of High-Grade Intersections 180
11.2.2 Twin Holes Studies in Iron Ore Deposits 181
11.2.3 Mineral Sands Deposits: Validation of Historic Drilling 183
11.2.4 Bauxites: Use of Twin Holes as a Routine Control of Drilling Quality 183
References 186
12 Database 188
12.1 Construction of the Database 189
12.2 Data Entry 191
12.2.1 Electronic Data Transfer 191
12.2.2 Keyboard Data Entry 191
12.2.3 Special Values 192
12.3 Management of the Data Flow 193
12.4 Database Safety and Security 194
References 194
Part III Mineral Resources 195
13 Data Preparation 196
13.1 Data Compositing 196
13.1.1 Data Coding 196
13.1.2 Compositing Algorithms 197
13.1.3 Choice of the Optimal Compositing Intervals 197
13.1.4 Validating of the Composited Assays 199
13.2 High Grade Cut-Off 200
References 201
14 Geological Constraints of Mineralisation 202
14.1 Introduction to Wireframing 202
14.2 Characterisation of the Mineralisation Contacts 204
14.2.1 Contact Profile 204
14.2.2 Determining of the Cut-Off Value for Constraining Mineralisation 207
14.2.3 Contact Topography 208
14.2.4 Uncertainty of the Contacts 209
14.3 Geometry and Internal Structure of the Mineralised Domains 211
14.3.1 Unfolding 211
References 214
15 Exploratory Data Analysis 215
15.1 Objective of the EDA 215
15.2 Overview of the EDA Techniques 216
15.2.1 Spider Diagram 216
15.2.2 Data Declustering 216
15.2.3 Q-Q Plots 221
15.2.4 Box-and-Whisker Plot (Box Plot) 221
15.3 Grouping and Analysis of the Data 222
15.3.1 Data Types 222
15.3.2 Data Generations 224
15.3.3 Grouping Samples by Geological Characteristics 224
15.4 Statistical Analysis of the Resource Domains 225
References 227
16 Resource Estimation Methods 228
16.1 Polygonal Method 229
16.2 Estimation by Triangulation 230
16.3 Cross-Sectional Method 231
16.3.1 Extrapolation of the Cross-Sections 231
16.3.2 Interpolation Between Cross-Sections 233
16.4 Estimation by Panels 235
16.5 Inverse Distance Weighting Method 235
References 237
Part IV Applied Mining Geostatistics 238
17 Introduction to Geostatistics 239
17.1 Regionalised Variable and Random Function 240
17.2 Stationarity and Intrinsic Hypothesis 241
References 242
18 Variography 244
18.1 Quantitative Analysis of the Spatial Continuity 244
18.2 Intuitive Look at Variogram 245
18.3 Geostatistical Definition of Variogram 246
18.4 Directional, Omnidirectional and Average Variograms 247
18.5 Properties of the Variograms 247
18.5.1 Behaviour Near Origin 248
18.5.2 Anisotropy 249
18.6 Analysis of the Data Continuity Using a Variogram Map 250
18.7 Presence of Drift 252
18.8 Proportional Effect 252
18.9 Variogram Sill and the Sample Variance 253
18.10 Impact of the Different Support 254
18.11 Variogram Models 254
18.11.1 Common Variogram Models 254
18.11.2 Modelling Geometric Anisotropy 256
18.11.3 Nested Structures 257
18.11.4 Modelling Zonal Anisotropy 257
18.12 Troublesome Variograms 258
18.12.1 Hole Effect 259
18.12.2 Saw-Tooth Shaped and Erratic Variograms 259
18.13 Alternative Measures of a Spatial Continuity 260
18.13.1 Variograms of the Gaussian Transformed Values 261
18.13.2 Relative (Normalised) Variograms 262
18.13.3 Different Structural Tools 263
18.14 Indicator Variograms 264
18.15 Variograms in the Multivariate Environment 264
18.15.1 Multivariate Geostatistical Functions 265
18.15.2 Linear Model of Coregionalisation 265
References 266
19 Methods of the Linear Geostatistics (Kriging) 268
19.1 Geostatistical Resource Estimation 268
19.2 Kriging System 269
19.2.1 Ordinary Kriging 270
19.2.2 Simple Kriging 271
19.2.3 Simple Versus Ordinary Kriging 272
19.3 Properties of Kriging 272
19.3.1 Exactitude Property of Kriging 272
19.3.2 Negative Kriging Weights and Screening Effect 273
19.3.3 Smoothing Effect 275
19.3.4 Kriging Variance 278
19.3.5 Conditional Bias 279
19.3.5.1 Slope of the Z"026A30C Z* Regression 280
19.3.5.2 Correlation of the Z and Z* 282
19.3.5.3 Lagrange Multiplier 282
19.3.5.4 Weight of the Mean Value 283
19.4 Block Kriging 284
19.4.1 Blocks and Point Estimates 284
19.4.2 Kriging of the Small Blocks 285
References 291
20 Multivariate Geostatistics 292
20.1 Theoretical Background of Multivariate Geostatistics 293
20.1.1 Ordinary Co-kriging 293
20.1.2 Collocated Co-kriging 293
20.1.3 Properties of the Co-kriging 294
20.2 Kriging with External Drift 294
References 294
21 Multiple Indicator Kriging 296
21.1 Methodology of the Multiple Indicator Kriging 297
21.2 Practical Notes on the Indicators Post-Processing 298
References 299
22 Estimation of the Recoverable Resources 300
22.1 Change of Support Concept 301
22.1.1 Dispersion Variance 301
22.1.2 Volume Variance Relations 302
22.1.3 Conditions for Change-of-Support Models 303
22.2 Global Change of Support Methods 303
22.2.1 Affine Correction 303
22.2.1.1 Recovered Grade 304
22.2.1.2 Recovered Tonnage 304
22.2.1.3 Recovered Metal 304
22.2.2 Discrete Gaussian Change of Support 305
22.3 Local Change of Support Methods 306
22.3.1 Uniform Conditioning 306
22.3.2 Localised Uniform Conditioning 307
22.3.3 Application of the LUC Method to the Iron Ore Deposit 311
References 312
23 Model Review and Validation 314
23.1 Validating of the Global Estimates 314
23.2 Validating of the Local Estimates 315
23.2.1 Validating of the Local Mean 315
23.2.2 Validating by the Drill Hole Intersections 317
23.2.3 Cross Validation Technique 317
23.3 Validating of the Tonnage 317
References 318
24 Reconciliation with New Data 319
24.1 Validating Using the Infill Drilling Data 319
24.2 Reconciliation with the Mine Production Data 321
24.3 Ore Grade Control 322
24.3.1 Grade Control at the Open Pit Mine 322
24.3.2 Grade Control at the Underground Mines 323
References 324
Part V Estimating Uncertainty 325
25 Grade Uncertainty 326
25.1 Methods of Conditional Simulation 327
25.1.1 Turning Bands 327
25.1.2 Sequential Gaussian Simulation 328
25.1.3 Sequential Indicator Simulation 328
25.2 Application of the Conditional Simulation in the Corridor Sands Project 329
25.2.1 Project Background 329
25.2.2 Scope of the Conditional Simulation Study 331
25.2.3 Implementation of the SGS Technique 331
25.2.4 Results and Discussion 332
25.2.4.1 Recoverable Resources 332
25.2.4.2 Risk of Exceeding Plant Tolerance Thresholds 332
25.2.4.3 Comparison of the SGS and OK Results 333
References 335
26 Quantitative Geological Models 337
26.1 Geological Models 337
26.2 Indicator Assisted Domaining 338
26.2.1 Indicator Probability Model 339
26.2.2 Structural Interpretation 341
26.2.3 Boundary Conditions 341
26.3 Stochastic Modelling of the Geological Structures 341
26.3.1 Plurigaussian Conditional Simulation: Case Study 342
26.3.1.1 Methodology of Plurigaussian Simulation 342
26.3.1.2 Estimating of the Lithotypes Proportions 344
26.3.1.3 Applying of the `Lithotype Rule' 344
26.3.1.4 Plurigaussian Variograms 346
26.3.1.5 Results and Discussion 346
References 349
Part VI Classification 350
27 Principles of Classification 351
27.1 International Reporting Systems 351
27.2 Mineral Resources and Ore Reserves 351
Reference 354
28 Methodology of the Mineral Resource Classification 355
28.1 Geostatistical Classification Methods 355
28.2 Classification Related to the Mine Production Plans 356
28.2.1 Classification Criteria 356
28.2.2 Classification Procedures 358
28.2.3 Classification Using Auxiliary Geostatistical Functions 360
References 363
29 Conversion Resources to Reserves 364
29.1 Mining Factors 365
29.2 Metallurgical Factors 365
29.2.1 Metallurgical Systematics of the Ore Reserves 366
29.2.2 Representativity of the Bulk Samples 366
29.3 Project Economics 370
References 371
30 Balance Between Quantity and Quality of Samples 372
30.1 Introduction to a Problem 372
30.2 Geological Factor and Sampling Error 373
References 374
Part VII Mineral Deposit Types 376
31 Lode Gold Deposits 377
31.1 Geology of the Orogenic Gold Deposits 378
31.2 Sampling and Assaying of the Gold Deposits 381
31.2.1 Samples Preparation 381
31.2.2 Gold Assays 383
31.2.3 Samples Quality Control 385
31.3 Dry Bulk Density 385
31.4 Estimation of Resources and Reserves 386
31.4.1 Top Cut 386
31.4.2 Classification 387
References 387
32 Uranium Deposits (In-Situ Leach Projects) 389
32.1 Sandstone Hosted Uranium Deposits 390
32.2 Resource Definition Drilling 391
32.3 Geophysical Logging of the Drillholes 393
32.3.1 Gamma Logging 394
32.3.2 Prompt Fission Neutron (PFN) Analyser 394
32.3.3 Supplementary Geophysical Techniques 395
32.4 Drillhole Sample Assays 395
32.5 Data Quality and Mineral Resource Categories 395
32.6 Geological and Geotechnical Logging of the Drillholes 396
32.6.1 Lithology 396
32.6.2 Hydrogeology 396
32.6.3 Permeability 397
32.6.4 Porosity and Rock Density 397
32.7 Resource Estimation 397
32.7.1 Geological Model 397
32.7.2 Estimation of Uranium Grade 398
32.7.3 Geostatistical Resource Estimation 398
32.8 Viability of the Resources 399
32.9 Reconciliation of the Resources 401
References 401
33 Iron-Oxide Deposits 403
33.1 Geological Constraints of the Resource Models 403
33.2 Resource Estimation Drilling 406
33.3 Sampling and Assaying 407
33.4 Dry Bulk Density of the Rocks 407
33.5 Estimation Resources and Reserves 407
References 408
34 Bauxite Deposits 409
34.1 Geological Constraints of the Resource Models 410
34.1.1 Shape of the Bauxite Plateaus 410
34.1.2 Contacts 410
34.1.3 Vertical Profile of the Bauxite Seams 411
34.1.4 Domains 413
34.2 Drilling 415
34.3 Sampling and Logging Holes 417
34.4 Sample Preparation and Assaying 417
34.4.1 Sample Preparation 417
34.4.2 Analytical Techniques 418
34.4.3 Sample Quality Control 419
34.5 Dry Bulk Density of the Rocks 419
34.6 Estimation Bauxite Grade 420
34.7 Classification 420
34.7.1 Mineral Resources 420
34.7.2 Conversion to Ore Reserves 420
34.7.2.1 Mining Parameters 420
34.7.2.2 Metallurgical Factors 422
References 423
35 Mineral Sands 424
35.1 Geology of the Selected Deposits 425
35.1.1 Fort Dauphin 425
35.1.2 Corridor Sands 426
35.1.3 Richard's Bay 427
35.2 Drilling 428
35.3 Sample Processing and Assaying 429
35.4 Samples Quality Control Procedures 429
35.5 Dry Bulk Density of the Rocks 429
35.6 Estimation and Reporting Resources 429
References 430
Appendices 431
Appendix 1: List of the Exercises and Electronic Files with the Solutions 431
Appendix 2: Mathematical Background 431
Normal Distribution 431
Lognormal Distribution 432
References 433
Index 440