Evans / Pomeroy The Strength, Fracture and Workability of Coal

A Monograph on Basic Work on Coal Winning Carried Out by the Mining Research Establishment, National Coal Board
1. Auflage 2013
ISBN: 978-1-4832-2136-6
Verlag: Elsevier Science & Techn.
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 288 Seiten, Web PDF

The Strength, Fracture and Workability of Coal deals with the strength of coal and the way in which various aspects of strength enter into the processes of mechanical winning. This book aims to provide rationalization of the design of coal winning machines for use in British mines and an increase of efficiency in existing machines. This book is composed of 14 chapters, and begins with a description of a stratified structure comprising a number of components of coal. This topic is followed by detailed measurements on a bituminous and an anthracite coal using static and dynamic techniques. The subsequent chapters are devoted to the definition and determination of coal's mechanical properties, such as compressive, tensile, and routine strength, particle size distribution, breakage, friction, and wedge penetration. The concluding chapters cover the mechanics of certain possible modes of interaction of coal and tool. These chapters also examine the theoretical aspects of the cutting and ploughing of coal. This book will prove useful to coal mining engineers, designers, and researchers.

Autoren/Hrsg.

Evans, Ivor

Pomeroy, C. D.

Inhaltsverzeichnis

1;Front Cover;1
2;The Strength, Fracture and Workability of Coal;4
3;Copyright Page;5
4;Table of Contents;8
5;Dedication;6
6;Foreword;10
7;CHAPTER 1. The Nature of Coal and the Elements of Long-wall Mining;12
7.1;STRUCTURE AND PETROLOGY OF COAL;13
7.2;STRUCTURE OF COAL IN THE SEAM;14
7.3;COAL CLASSIFICATION SYSTEM;16
7.4;METHODS OF COAL-WINNING;22
7.5;RESEARCH WORK IN RELATION TO PRACTICAL PROBLEMS;25
7.6;REFERENCES;26
8;CHAPTER 2. The Static and Dynamic Elastic Moduli of Coal;27
8.1;STATIC COMPRESSION TESTS;28
8.2;STATIC BENDING TESTS;34
8.3;DYNAMIC MEASUREMENTS;36
8.4;COMPARISON OF STATIC AND DYNAMIC MODULI;41
8.5;REFERENCES;46
9;CHAPTER 3. The Compressive Strength of Coal;47
9.1;INTRODUCTION;47
9.2;DEFINITION OF STRENGTH;47
9.3;SYSTEMS OF STRESS;49
9.4;EARLY WORK ON COMPRESSIVE STRENGTH;50
9.5;EFFECT OF TESTING PROCEDURE;52
9.6;WORK AT THE MINING RESEARCH ESTABLISHMENT;53
9.7;CONSIDERATION OF RESULTS;57
9.8;STRENGTH OF RECTANGULAR BLOCKS;60
9.9;RESULTS OF EXPERIMENTS ON RECTANGULAR BLOCKS;63
9.10;APPLICABILITY OF WEAKEST-LINK THEORY TO RECTANGULAR BLOCKS;64
9.11;PHYSICAL IMPLICATIONS OF WEAKEST-LINK THEORY;65
9.12;PATTERN OF BREAKAGE;67
9.13;COMPRESSIVE STRENGTH OF CUBES LOADED PARALLEL TO THE BEDDING PLANES;69
9.14;STRENGTH OF IRREGULAR LUMPS;74
9.15;COMPRESSIVE STRENGTH OF IRREGULAR LUMPS OF DEEP DUFFRYN COAL;75
9.16;COMPRESSIVE STRENGTH OF IRREGULAR LUMPS OF BARNSLEY HARDS;78
9.17;APPLICABILITY OF WEAKEST-LINK THEORY TO IRREGULAR LUMPS;80
9.18;COMPRESSIVE STRENGTH AND INDENTATION STRENGTH;80
9.19;MODE OF BREAKAGE OF IRREGULAR LUMPS;81
9.20;SUMMARY OF RESULTS RELATING TO UNIAXIAL COMPRESSION;83
9.21;REFERENCES;84
9.22;REFERENCES TO APPENDIX;88
10;CHAPTER 4. The Tensile Strength of Coal;89
10.1;METHODS OF TENSILE TESTING;89
10.2;RESULTS FROM BENDING TESTS;90
10.3;CONSIDERATION OF RESULTS FROM BENDING TESTS;92
10.4;METHOD OF DIAMETRICAL COMPRESSION;92
10.5;METHOD OF INDENTATION;96
10.6;DETAILED MEASUREMENTS OF THE TENSILE STRENGTH OF COAL BY MEANS OF THE DISC METHOD;96
10.7;STRENGTH-SIZE EFFECT;100
10.8;TENSILE STRENGTH OF REPRESENTATIVE COALS;101
10.9;CONSIDERATION OF RESULTS;102
10.10;REFERENCES;104
11;CHAPTER 5. The Strength of Coal under Complex Stresses;105
11.1;STRESS SYSTEMS LIKELY TO BE EXPERIENCED IN PRACTICE;106
11.2;TRIAXIAL COMPRESSIVE STRENGTH APPARATUS;107
11.3;PREPARATION OF SPECIMENS FOR TRIAXIAL COMPRESSION TESTS;108
11.4;TRIAXIAL COMPRESSIVE STRENGTH MEASUREMENTS;108
11.5;BIAXIAL COMPRESSIVE STRENGTH MEASUREMENTS;119
11.6;THE STRESSES IN A HOLLOW CYLINDER SUBJECTED TO EXTERNAL PRESSURE AND AXIAL LOADING;119
11.7;TENSILE STRENGTH MEASUREMENTS;126
11.8;STRENGTH THEORIES;130
11.9;DISCUSSION;131
11.10;REFERENCES;133
12;CHAPTER 6. Routine Strength Tests on Coal;134
12.1;SEAM TESTS;134
12.2;HISTORICAL BACKGROUND;135
12.3;M.R.E. PENETROMETER;136
12.4;TEST PROCEDURE;142
12.5;ADAPTATION FOR ROOF AND FLOOR TESTS;145
12.6;MEASUREMENTS WITH THE PENETROMETER;145
12.7;EXPANDING-BOLT SEAM TESTER;152
12.8;REFERENCES;166
13;CHAPTER 7. The Size Distribution of Run-of-mine Coal;168
13.1;DISTRIBUTION LAWS FOR SIZE AND WEIGHT OF BROKEN COAL;170
13.2;THEORETICAL ATTEMPTS AT DISTRIBUTION LAWS;171
13.3;AN ALTERNATIVE APPROACH TO THE PROBLEM;172
13.4;COMPARISON WITH EXPERIMENT;175
13.5;RELATION OF INCOMPLETE GAMMA FUNCTION TO ROSIN-RAMMLER DISTRIBUTION;177
13.6;SIZE DISTRIBUTION OF DUST;178
13.7;COMPARISON OF CURVES FOR RUN-OF-MINE COAL;180
13.8;MODE OF BREAKAGE BY MACHINES;181
13.9;REFERENCES;182
13.10;APPENDIX;182
14;CHAPTER 8. Numerical Methods of Studying Breakage: A Rational Index of Shatter;184
14.1;INTRODUCTION;184
14.2;NUMERICAL METHODS;185
14.3;VARIATION OF SELECTION FOR BREAKAGE WITH SIZE;188
14.4;INDEX OF SHATTER;190
14.5;USE OF THE INDEX;191
14.6;APPENDIX;192
14.7;REFERENCES;194
15;CHAPTER 9. Friction between Coal and Metal Surfaces;195
15.1;EXPERIMENTAL DETAILS;196
15.2;PREPARATION OF COAL AND METAL SPECIMENS;197
15.3;DETAILS OF COALS AND METALS USED;197
15.4;RESULTS;198
15.5;THE EFFECT OF CHANGES IN NORMAL PRESSURE;200
15.6;THE EFFECT OF HARDNESS OF THE STEEL SURFACE;201
15.7;THE EFFECT OF LOADS LARGE ENOUGH TO CRUSH THE COAL;201
15.8;FRICTION BETWEEN COAL AND BRASS;202
15.9;DISCUSSION;203
15.10;WET SLIDING;206
15.11;CONCLUSIONS;208
15.12;REFERENCES;208
16;CHAPTER 10. Wedge Penetration into Coal;209
16.1;APPARATUS;209
16.2;TYPICAL EXPERIMENT;211
16.3;EXPERIMENTAL PROCEDURE;214
16.4;PENETRATION OF CWMTILLERY COAL;214
16.5;TREATMENT OF EXPERIMENTAL OBSERVATIONS;214
16.6;RELATION OF COMPRESSIVE STRENGTH TO PENETRATION RESISTANCE;216
16.7;EFFECT OF FRICTION BETWEEN COAL AND STEEL;217
16.8;RELATION OF RESULTS TO THOSE FOR EXTENDED MEDIUM;219
16.9;PENETRATION OF DUCTILE MATERIALS;219
16.10;PENETRATION OF A BRITTLE MATERIAL;220
16.11;REFERENCES;221
17;CHAPTER 11. The Breakage of Coal by Wedge Action;222
17.1;1. FACTORS INFLUENCING BREAKAGE;222
17.2;EXPERIMENTAL TECHNIQUE;223
17.3;DETAILS OF THE EXPERIMENTS;224
17.4;DEPTH OF CUT;225
17.5;COAL PROPERTIES;227
17.6;TOOL SIZE;234
17.7;MISCELLANEOUS FACTORS;235
17.8;IMPACT BREAKAGE;241
17.9;DISCUSSION;244
17.10;REFERENCES;246
18;CHAPTER 12. The Breakage of Coal by Wedge Action;247
18.1;2. FACTORS AFFECTING TOOL DESIGN;247
18.2;THE EFFECT OF FRONT RAKE AND BACK CLEARANCE ANGLE ON CUTTING;247
18.3;THE EFFECT ON CUTTING PERFORMANCE OF RIDGING AND POINTING PICKS;254
18.4;THE IDEAL PICK;258
18.5;SUMMARY;265
18.6;REFERENCES;266
19;CHAPTER 13. Theoretical Aspects of the Cutting and Ploughing of Coal;267
19.1;1. SHARP WEDGES AND BLADES;267
19.2;INTRODUCTION;267
19.3;CONSIDERATION OF COAL STRENGTH;268
19.4;CUTTING OF A BRITTLE MATERIAL;271
19.5;COMPARISON WITH EXPERIMENT;277
19.6;ABSOLUTE ACCURACY;279
19.7;EFFECT OF OBLIQUITY OF ATTACK BY A WEDGE;280
19.8;TRANSVERSE FORCE ACTING ON CUTTING TOOLS;282
19.9;ENERGY FOR BREAKAGE BY IMPULSIVE BLOW;285
19.10;THE EFFECT OF POINTED BLADES;287
19.11;REFERENCES;290
20;CHAPTER 14. Theoretical Aspects of the Cutting and Ploughing of Coal;291
20.1;2. EFFECTS OF BLUNTING OF WEDGES;291
20.2;INTERPRETATION OF RESULTS IN TERMS OF GRIFFITH'S THEORY;292
20.3;THEORY IN TERMS OF WEDGE ACTION;293
20.4;EXPERIMENTAL;296
20.5;ILLUSTRATIONS OF USE OF THEORY;298
20.6;NORMAL FORCE;300
20.7;REFERENCES;301
21;APPENDIX: Practical Applications of Theory;302
21.1;PROBLEMS;302
22;Name Index;304
23;Subject Index;306