Reference Document on Best Available Techniques for

20,6
MB Management of Tailings and Waste-Rock in Mining Activities

557
stron (July 2004)

1982
ID JRC-IPTS Instituto de Prospectiva Tecnológica (IPTS)

2004
rok

Mining Activities

EXECUTIVE SUMMARYI

PREFACE.XXI

SCOPE XLI

1 GENERAL INFORMATION. 1

1.1 Industry overview: metals 2

1.1.1 Aluminium 3

1.1.2 Base Metals (Cadmium, Copper, Lead, Nickel, Tin, Zinc) 4

1.1.3 Chromium. 9

1.1.4 Iron 10

1.1.5 Manganese . 11

1.1.6 Mercury. 12

1.1.7 Precious Metals (Gold, Silver). 13

1.1.8 Tungsten 17

1.2 Industry overview industrial minerals 17

1.2.1 Barytes . 18

1.2.2 Borates . 19

1.2.3 Feldspar. 20

1.2.4 Fluorspar 21

1.2.5 Kaolin 22

1.2.6 Limestone 22

1.2.7 Phosphate . 23

1.2.8 Strontium. 23

1.2.9 Talc . 23

1.3 Industry overview: potash 25

1.4 Industry overview: coal 26

1.5 European mine and mine waste production 28

1.6 Key environmental issues. 31

1.6.1 Site location . 32

1.6.2 Material characterisation including prediction of long-term behaviour . 33

1.6.3 Environmentally relevant parameters. 34

1.6.3.1 Typical emissions and management of water and reagent . 34

1.6.3.2 The environmental impact of emissions. 35

1.6.3.3 Acid rock drainage . 36

1.6.3.4 Accidental bursts or collapses 38

1.6.4 Site rehabilitation and after-care 40

2 COMMON PROCESSES AND TECHNIQUES 41

2.1 Mining techniques 41

2.1.1 Types of orebodies. 44

2.1.2 Underground mining methods 44

2.2 Mineralogy . 45

2.3 Mineral processing techniques . 46

2.3.1 Equipment 46

2.3.1.1 Comminution . 46

2.3.1.1.1 Crushing . 46

2.3.1.1.2 Grinding . 46

2.3.1.2 Screening 48

2.3.1.3 Classification 48

2.3.1.3.1 Settling cones and hydraulic classifiers 49

2.3.1.3.2 Hydrocyclones 49

2.3.1.3.3 Mechanical classifiers 50

2.3.1.4 Gravity concentration. 51

2.3.1.4.1 Dense medium separation 51

2.3.1.4.2 Jigging 52

2.3.1.4.3 Shaking tables 54

2.3.1.4.4 Spirals. 54

2.3.1.4.5 Cones 55

2.3.1.5 Flotation56

2.3.1.6 Magnetic separation58

2.3.1.7 Electrostatic separation.58

2.3.1.8 Sorting 59

2.3.1.9 Leaching .59

2.3.1.10 Dewatering60

2.3.2 Reagents .63

2.3.3 Effects on tailings characteristics .64

2.3.4 Techniques and processes.65

2.3.4.1 Alumina refining.65

2.3.4.2 Gold leaching with cyanide 66

2.4 Tailings and waste-rock management.69

2.4.1 Characteristics of materials in tailings and waste-rock management facilities.69

2.4.1.1 Shear strength .69

2.4.1.2 Other characteristics .70

2.4.2 Tailings dams70

2.4.2.1 Delivery systems for slurried tailings .73

2.4.2.2 Confining dams.73

2.4.2.3 Deposition in the impoundment80

2.4.2.4 Removal of free water 81

2.4.2.5 Seepage flow.83

2.4.2.6 Design flood .84

2.4.3 Thickened tailings 84

2.4.4 Tailings and waste-rock heaps85

2.4.5 Backfilling 85

2.4.6 Underwater tailings management .87

2.4.7 Failure modes of dams and heaps.87

2.5 Tailings characteristics and tailings behaviour .88

2.6 Closure, rehabilitation and after-care of facility .89

2.7 Acid Rock Drainage (ARD) .90

3 APPLIED PROCESSES AND TECHNIQUES.93

3.1 Metals 96

3.1.1 Aluminium96

3.1.1.1 Mineralogy and mining techniques.96

3.1.1.2 Mineral processing97

3.1.1.3 Tailings management98

3.1.1.3.1 Characteristics of tailings98

3.1.1.3.2 Applied management methods102

3.1.1.3.3 Safety of the TMF and accident prevention106

3.1.1.3.4 Closure and after-care.106

3.1.1.4 Current emission and consumption levels 107

3.1.1.4.1 Management of water and reagents 107

3.1.1.4.2 Emissions to air.108

3.1.1.4.3 Emissions to water 109

3.1.1.4.4 Soil contamination 109

3.1.1.4.5 Energy consumption .109

3.1.2 Base metals.109

3.1.2.1 Mineralogy and mining techniques.110

3.1.2.2 Mineral processing113

3.1.2.2.1 Comminution 115

3.1.2.2.2 Separation .118

3.1.2.3 Tailings management120

3.1.2.3.1 Characteristics of tailings121

3.1.2.3.2 Applied management methods127

3.1.2.3.3 Safety of the TMF and accident prevention143

3.1.2.3.4 Closure and after-care.149

3.1.2.4 Waste-rock management 152

3.1.2.4.1 Characteristics of waste-rock152

3.1.2.4.2 Applied management methods153

3.1.2.5 Current emissions and consumption levels.157

3.1.2.5.1 Management of water and reagents 157

3.1.2.5.2 Emissions to air 162

3.1.2.5.3 Emissions to water . 165

3.1.2.5.4 Soil contamination 167

3.1.2.5.5 Energy consumption. 168

3.1.3 Chromium 168

3.1.3.1 Mineralogy and mining techniques 168

3.1.3.2 Mineral processing . 168

3.1.3.3 Tailings management . 170

3.1.3.3.1 Characteristics of tailings . 170

3.1.3.3.2 Applied management methods . 170

3.1.3.3.3 Safety of the TMF and accident prevention . 171

3.1.3.4 Waste-rock management 171

3.1.3.4.1 Site closure and after-care 171

3.1.3.5 Current emissions and consumption levels 172

3.1.3.5.1 Management of water and reagents 172

3.1.3.5.2 Emissions to air 172

3.1.3.5.3 Emissions to water . 172

3.1.3.5.4 Soil contamination 173

3.1.3.5.5 Energy consumption. 173

3.1.4 Iron 173

3.1.4.1 Mineralogy and mining techniques 173

3.1.4.2 Mineral processing . 176

3.1.4.2.1 Comminution 176

3.1.4.2.2 Separation. 176

3.1.4.3 Tailings management . 177

3.1.4.3.1 Characteristics of tailings . 177

3.1.4.3.2 Applied management methods . 179

3.1.4.3.3 Development of new deposition methods 186