supervision-1
Abstract
Kriging is a powerful spatial interpolation technique, especially for irregularly spaced data point, and is widely used through the earth and environmental sciences. In this thesis, a set of gold samples at Hangaliya region (El Shagara area) Eastern Desert, Egypt were collected in order to examine the best variogram model for Kriging the gold deposits. The data were first treated statistically, and then four variograms models were implemented over the data to compare and select the most appropriate one for geostatistical modelling using one or more of the different
Kriging techniques. The aim is to get reliable results and thus, better understanding of the spatial distribution of the Au % at the study area.
Gold mining is increasing with attracting attention in many countries of the world, although it has a major impact on the environment as large quantities of hazardous chemicals such as mercury or sodium cyanide are consumed to recover gold from its ores. This thesis addresses both environmental impacts and socio-economic issues concerned with the development or investigation operations of gold mining projects in general and at El Shagara area in particular. When properly designed and implemented an Environmental Impact Assessment (EIA) is a powerful tool for ensuring that environmental issues are given due consideration during project design, allowing the benefits of the project to be maximized, while reducing the environmental and social costs development.
Integrating the results of Kriging implementation to estimate the ore reserves at extraction zones and mapping the spatial distribution of the
Au % with the EIA statement would led to better management and control of both the production plans and environmental studies.
This investigation is a trail to introduce a methodology for no restricted time estimation of the deposits using Kriging techniques and flexible EIA matrix to assess a gold mining project at any time of its life cycle. Using the results of methodology implementation can support the decision making in plan, design, production and management of the project.
i
To my mother,
To my husband,
and
To my lovely son ii
Acknowledgement
All gratitude is to God who guided and helped me to being this work forward.
I would like to express my deep gratitude to my advisor Prof. Dr. Eng.,
M. R. El Tahlawi for his continuous encouragement, guidance, experience in the field of data mining and for providing insightful comments and helpful suggestions that helped me to improve the quality of the thesis.
Appreciation is also to Prof. Dr. M. Zaki Rashad for his continuous support in my academic endeavors and I thank him for sharing with me his expertise in data mining through numerous fruitful discussions and for teaching me valuable skills in conducting the thesis.
Special thanks to Dr. Sameh S. Ahmed for precious time reviewing my thesis and his, support, enthusiasm, continuous co-operation, thoughtful discussions, insightful ideas, great efforts and many critical comments he made in my thesis, the existence of this thesis is largely to him.
Last but not least, I am very grateful to my family especially my mother for their support, encouragement, and wide advice and she gave me all time and space to help me stay in good spirits and focus on my work.
I am very grateful to my dear husband for all his support, encouragement and sharing me joyful and sad moments so there are no words to describe the emotional and loving way he support me.
Amany Armia Anwer
2007
iii
List of Contents
Abstract …………………………………………………………………………....i
Acknowledgment …………………………………………………………………...iii
List of Contents …………………………………………………………………......iv
List of Figures ………………………………………………………………….…..viii
List of Tables ……………………………………………………………………......ix
Abbreviations ……………………………………………………………………....xi
Chapter 1: Introduction and Objectives …………………………………………..1
1.1 Introduction ………………………………..………………………………….1
1.2 Research Objectives ……………………….………………………………….2
1.3 Research Approach ………………………….………………………………..3
1.4 Thesis Organization ………………………….……………………………….5
Chapter 2: Literature Review ……………………………………………………...6
2.1 Introduction ………………………………….………………………………..6
2.2 Historical Development ……………………….……………………………...9
2.3 Development of Kriging Techniques in Mining.……………………………..11
2.4 Importance of Conduction EIA for Industrial Sites ………………………….15
Chapter 3: Kriging Techniques ……………..………………….…………………17
3.1 Introduction ……………………………….………………………………….17
3.2 Steps in Typical Geostatistics Study …………………………………………18
3.3 Variogams …………………………….……………………………………...18
3.3.1 Important Definitions …………………………………………………...21
3.3.2 Experimental Variogram ………………………………………………..21
3.3.3 Variogram Model……………………………………………………......22
3.3.3.1 Spherical Model..…………………………………………………..24
3.3.3.2 Exponential Model...……………………………………………….26
3.3.3.3 Gaussian Model..…………………………………………………...26
3.3.3.4 Power Model ………………………………………………………27
3.3.3.5 Nested Model ……………………………………………………...28
3.3.4 The Anisotropies ………………….…………………………………….28
3.3.5 Rules of Selection ………………….………………………………….. 29
3.3.5.1 Soft Data ………………………….……………………………… 29
3.3.5.2 Residuals ………………………….……………………………… 30
3.3.5.3 Model Validation ………………………………………………… 30
3.3.5.3.1 Calculation of Q
1
.................................................................. 31
3.3.5.3.2 Calculation of Q
2
……………………………………….…. 32
3.3.5.3.3 Variogram Testing ………………………………………….32
3.4 Principals of Kriging Techniques …………………………………………….32
3.3.1 Characteristics of Kriging ………………………………………………34
3.3.2 Types of Kriging ………………………………………………….…… 34
3.3.2.1 Simple Kriging (SK) ……………………………………………...34
3.3.2.2 Ordinary Kriging (Punctual Kriging)………………………………35
3.3.2.3 Universal Kriging (UK) ……………………………...……………35
3.3.2.4 Indicator Kriging (IK) …………………………..…………………35
3.3.2.5 Co-Kriging ………………………………………………………...35 iv
3.5 Theory of Ordinary Kriging ……………………………………………….....36
3.6 Some Applications of Kriging Techniques in Mining ……………………….39
3.7 Some Applications of Kriging and Environmental Studies ………………….41
3.7.1 Hydrology ……………………………………………….………………43
3.7.2 Environmental Monitoring and Epidemiology …………………………43
3.7.3 Soil Science and Agriculture ……………………………………………43
Chapter 4: Environmental Impact Assessment …………...……………………...45
4.1 Introduction …………………………………………………………………..45
4.2 What is Environment? ………………………………………………………..46
4.2.1 Physical and Chemical Environment …………………………………...46
4.2.2 Biological Environment ………………………………………………...46
4.2.3 Culture Environment ……………………………………………………46
4.2.4 Socio-Economic Environment ………………………………………….46
4.3 What is an EIA? ……………………………………………………………...47
4.4 Why an EIA? …………………………………………………………………48
4.4.1 EIA Provides a Formal Framework ………………………………….....48
4.5 Aims of EIA ………………………………………………………………….49
4.6 Characteristics of Impacts ……………………………………………………50
4.6.1 Effects and Impacts ……………………………………………………..51
4.6.2 Impacts Types …………………………………………………………..52
4.6.2.1 Direct Impact ………………………………………………………52
4.6.2.2 Indirect Impact …………………………………………………….52
4.6.2.3 Cumulative Impact ………………………………………………...52
4.7 The EIA Process ……………………………………………………………...53
4.7.1 Screening ………………………………………………………………..54
4.7.1.1 Methods of Screening ……………………………………………...57
4.7.2 Scoping ………………………………………………………………….57
4.7.2.1 Why Scoping? …………………………………………………......58
4.7.2.2 How is it Done? ……………………………………………………58
4.7.3 Analysis of Impacts ……………………………………………………..59
4.7.4 Monitoring ……………………………………………………………....59
4.7.5 Mitigation ……………………………………………………………….60
4.7.6 Reviewing ……………………………………………………………….61
4.7.6.1 Why reviewing? …………….……………………………………..61
4.7.6.2 What is it and how is it?…….……………………………………...62
4.7.7 Auditing ………………………………………………………………...62
4.7.7.1 Why Auditing? ………………………………………………….....62
4.7.8 Decision Making ………………………………………………………..63
4.7.8.1 Balanced decision making …………………………………………63
4.7.8.2 Public participation in all stages …………………………………..64
4.8 EIA Methodologies …………………………………………………………..64
4.8.1 Checklist ………………………………………………………………..65
4.8.1.1 Simple checklist ……………………………………………….......65
4.8.1.2 Descriptive checklist ………………………………………………65
4.8.1.3 Scaling checklist …………………………………………………...65
4.8.1.4 Scaling-Weighting checklist ………………………………………66
4.8.1.5 Questionnaire checklist ……………………………………………66
4.8.2 Networks ………………………………………………………………..67
4.8.2.1 Sorensen network ………………………………………………….67 v
4.8.3 Matrices …………………………………………………………………68
4.8.3.1 Simple interaction matrix ………………………………………….68
4.8.3.2 Quantified and graded matrix ……………………………………...69
4.8.4 Overlays ………………………………………………………………...70
4.9 Public Participation in the EIA Process ……………………………………...71
4.9.1 Identification of Public ………………………………………………….72
4.9.2 Transparency ……………………………………………………………73
4.9.3 Practical …………………………………………………………………75
4.9.4 Certainty ………………………………………………………………...76
4.10 The Role of Geostatistics in EIA Studies …………………………………...77
Chapter 5: Kriging Implementation at El Shagara Area
…...…………………...79
5.1 Introduction …………………………………………………………………..79
5.2 Description of the study area …………………………………………………79
5.3 Geology of the study area …………………………………………………….83
5.3.1 Quartz veins ……………………………………………………………. 83
5.3.2 Dykes ……………………………………………………………………83
5.3.3 Geology of El Shagara locality …………………………………………83
5.3.3.1 The first level ……………………………………………………...84
5.3.3.2 The second level …………………………………………………..84
5.3.3.3 The third level ……………………………………………………..84
5.3.3.4 The fourth level ……………………………………………………85
5.3.3.5 The fifth level ……………………………………………………..85
5.4 Data of El Shagara Area ……………………………………………………..86
5.5 Geostatistical Evaluation by Variogram and Kriging ……………………….86
5.5.1 Calculation for level 1 ………………………………………………….87
5.5.1.1 Spherical …………………………………………………………..88
5.5.1.2 Exponential ………………………………………………………..89
5.5.1.3 Gaussian …………………………………………………………...89
5.5.1.4 Linear ……………………………………………………………...90
5.5.2 Calculation for level 3 ………………………………………………….91
5.5.2.1 Spherical …………………………………………………………..92
5.5.2.2 Exponential ………………………………………………………..92
5.5.2.3 Gaussian …………………………………………………………...93
5.5.2.4 Linear ……………………………………………………………...93
5.5.3 Calculation for level 4 ………………………………………………….94
5.5.3.1 Spherical …………………………………………………………..96
5.5.3.2 Exponential ………………………………………………………..96
5.5.3.3 Gaussian …………………………………………………………...97
5.5.3.4 Linear ……………………………………………………………...97
5.5.4 Calculation for level 5 ………………………………………………….98
5.5.4.1 Spherical …………………………………………………………100
5.5.4.2 Exponential ………………………………………………………100
5.5.4.3 Gaussian ………………………………………………………….101
5.5.4.4 Linear …………………………………………………………….101
5.6 Calculations of ore reserves, grades and kriged values …………………….102
5.6.1 Calculation for kriged values ………………………………………….102
5.6.1.1 Kriged values at level 1 …………………………………………..102
5.6.2 Calculation of ore reserves …………………………………………….127
5.6.3 Calculation of Histogram of Blocks for Gold Assay ………………….128 vi
5.6.3.1 Histograms of Gold Grades in Block1 …………………………...128
5.6.3.2 Histograms of Gold Grades in Block 2 …………………………..129
5.6.3.3 Histograms of Gold Grades in Block 3 …………………………..131
5.6.3.4 Histograms of Gold Grades in Block 5 …………………………..132
5.6.3.5 Histograms of Gold Grades in Block 7 …………………………..134
5.6.3.6 Histograms of Gold Grades in Block 9 …………………………..135
5.6.3.7 Histograms of Gold Grades in Block 10 …………………………137
Chapter 6: Application of EIA at El Shagara Area ……………...……………..140
6.1 Introduction …………………………………………………………………140
6.2 General Environmental Impact Assessment ………………………………..140
6.2.1 Screening ………………………………………………………………140
6.2.2 Scoping ………………………………………………………………...141
6.2.3 Impact Assessment ………………………………………………….....141
6.2.4 EIS Preparation ………………………………………………………..141
6.2.5 Post Project Analysis (PPA) ………………..…………………………142
6.3 Environmental Issues Related to Gold Extraction ………………………….143
6.3.1 Gold Extraction ………………………………………………………..143
6.3.1.1 Washing methods ………………………………………………...144
6.3.1.2 Amalgamating with Mercury method ……………………………144
6.3.1.3 Chlorinating Cyaniding and other Leaching Processes …………..144
6.3.1.4 Smelting method …………………………………………………144
6.3.2 Examples of Environmental Issues in Mining Gold Deposits ………...145
6.4 EIA for El Shagara Area ……………………………………………………147
6.4.1 Impacts during the Sampling Stage ……………………………………148
6.4.2 Impacts during the Extraction Stage …………………………………..149
6.4.3 Impacts during the Manufacturing Stage ……………………………...149
6.4.4 Impacts upon Mine Closure ……………………………..…………….149
6.4.5 Social Impacts …………………………………………………………150
6.5 The Role of Geostatistics and GIS in EIA Study …………………………..150
Chapter 7: Conclusions and Recommendations …..……………………………153
7.1 Conclusions ………………………………………………………………...153
7.2 Recommendations ………………………………………………………….155
List of References …………………………………………………………………156
Appendix A……………………………… ………………………………………..160 vii
List of Figures
Figure 1.1: A block diagram explains the thesis targets ……………………………..4
Figure 3.1: A variogram model demonstrating the variogram parameters ………….20
Figure 3.2: The variogram models …………………………………………………..25
Figure 4.1: Environmental Impact Assessment Process …………………………….55
Figure 5.1: Location map of the study area …………………………………………80
Figure 5.2 : Hangalyia Locality ……………………………………………………..82
Figure 5.3: The geometry of variorums models for level 1 …………………………8 7
Figure 5.4: The geometry of variogram models for level 3 …………………………91
Figure 5.5: The geometry of variogram models for level 4 …………………………95
Figure 5.6: The geometry of variogram models for level 5………………………….99
Figure 5.7: Distribution of gold assay samples for level 1 …………………………121
Figure 5.8: Distribution of gold assay samples for level 3 …………………………122
Figure 5.9: Distribution of gold assay samples for level 4 ....................................124
Figure 5.10: Distribution of gold assay samples for level 5 ……………………….125
Figure 5.11: Distribution of gold assay samples for all levels ……………………..126
Figure 5.12: The contour map of El Shagara area ………………………………….126
Figure 5.13: Histogram of block 1 …………………………………………………129
Figure 5.14: Histogram of block 2………………………………………………….130
Figure 5.15: Histogram of block 3 ...……………………………………………….132
Figure 5.16: Histogram of block 5………………………………………………….133
Figure 5.17: Histogram of block 7 ...……………………………………………….135
Figure 5.18: Histogram of block 9 ...……………………………………………….136
Figure 5.19: Histogram of block 10………………………………………………...138 viii
List of Tables
Table 5.1: The parameters of variogram model ………………..…………….......88
Table 5.2: Residuals of the spherical model ...........................................................88
Table 5.3: Residuals of the Exponential model ………..…………………………89
Table 5.4: Residuals of the Gaussian model ………..…………………………….89
Table 5.5: Residuals of the linear model ………………………………………….90
Table 5.6: Residuals for the different models ……………………………………. 90
Table 5.7: The parameters of the variogram models ……………………………...92
Table 5.8: Residuals of the spherical model ………………………………………92
Table 5.9: Residuals of the Exponential model …………………………………...93
Table 5.10: Residuals of the Gaussian model ……………………………………..93
Table 5.11: Residuals of the linear model ………………………………………...94
Table 5.12: Residuals for the different models ……………………………………94
Table 5.13: The parameter of variogram models …………………………………,95
Table 5.14: Residuals of the spherical model ……………………………………..96
Table 5.15: Residuals of the Exponential model …………………………….........97
Table 5.16: Residuals of the Gaussian model ……………………………………..97
Table 5.17: Residuals of the linear model ………………………………………...98
Table 5.18: Residuals for the different models ……………………………………98
Table 5.19: The parameter of variogram models ………………………………….99
Table 5.20: Residuals of the spherical model ……………………………………..100
Table 5.21: Residuals of the Exponential model…………………………………..100
Table 5.22: Residuals of the Gaussian model ……………………………………..101
Table 5.23: Residuals of the linear model …………………………………………101
Table 5.24: Residuals for the different models ………………………………….. 102
Table 5.25: kriged values in level 1 ………………………………………………118
Table 5.26: kriged values in level 3 ………………………………………………118
Table 5.27: kriged values in level 4 ………………………………………………119
Table 5.28: kriged values in level 5 ………………………………………………119
Table 5.29: The coordinates for level 1 after calculation of kriged values ……… 120
Table 5.30: The coordinates for level 3 after calculation of kriged values ……….121
Table 5.31: The coordinates for level 4 after calculation of kriged values ……….123
Table 5.32: The coordinates for level 5 after calculation of kriged values ……….125
Table 5.33: Ore reserves in the different blocks …………………………………. 127
Table 5.34: The values of gold assay in block …………………………………… 128
Table 5.35: The histogram table of gold assay in block …………………………. 128
Table 5.36: The values of gold assay in block 2 …………………………………..129
Table 5.37: The histogram table of gold assay in block 2 ……………………….. 130
Table 5.38: The values of gold assay in block 3 …………………………………. 131
Table 5.39: The histogram table of gold assay in block 3 ………………………. .131
Table 5.40: The values of gold assay in block 5 …………………………………. 132
Table 5.41: The histogram table of gold assay in block 5 ………………………. .133
Table 5.42: The values of gold assay in block 7 …………………………………. 134
Table 5.43: The histogram table of gold assay in block 7 ……………………….. 134
Table 5.44: The values of gold assay in block 9 …………………………………. 135
Table 5.45: The histogram table of gold assay in block 9 ……………………….. 136 ix
Table 5.46: The values of gold assay in block1 ……………………………………137
Table 5.47: The histogram table of gold assay in block 10 ………………………...137
Table 5.48: El Shagara area calculations …………………………………………...139
Table 6.1: Possible errors in EIA process ……………………………………….....143
Table 6.2: Possible EIS Results with GIS-based Scoping Outcomes at El Shagara
Area ………………………………………………………………………………...150 x
Abbreviations
CEQ Council on Environmental Quality
EA Environmental Statement
EEAA Egyptian Environmental Affairs Agency
EIA
EIS
EMRA
Environmental Impact Assessment
Environmental Impact Statement
Egyptian Mineral Resources Authority
Exposure Point Concentration EPC
ES
GIS
IEE
IK
NEPA
OK
PPA ppm
SK
UK
Environmental Statement
Geographic Information System
Initial Environment Evaluation
Indicator Kriging
National Environmental Policy Act
Ordinary Kriging
Post Project Analysis parts per million
Simple Kriging
Universal Kriging
xi
