The Southern African Institute of Mining and Metallurgy, 2010. — 273 p. — ISBN 978-1-920410-06-3.Fundamentals.
Introduction.
First level of fundamentals.
Second level of fundamentals.
Beam behaviour.
Friction.
State of stress in the coal mining environment.
Mechanical properties of rock.
Geotechnical classification.
Introduction.
Rock mass classification.
Physical risk and performance rating.
Shafts and inclines.
Coal roof classification.
Roof and sidewall stability.
Introduction.
Pre-mining states of stress.
Effects of creating a roadway on the stress environment.
Failure modes of the roof.
Effects of discontinuities.
Controllable parameters.
Different support systems.
System selection.
Position of bolts.
Length of bolts.
Installation of a normal resin anchor.
Cable anchors.
Joint support.
Support of a very weak roof.
Supporting the competent layer.
Inspecting and making safe.
Ribside support.
Breaker line supports.
Probabilistic design methods.
Pillar design.
Introduction.
Basic mining methods.
History of pillar design.
Design of squat pillars.
Comparison of different strength formulae.
Correction for parallelogram shaped pillars.
Correction for continuous miners.
Barrier pillar strength.
Effects of discontinuities on strength.
Collapses since 1966.
Prevention of pillar failure.
Role of the overburden.
Holistic approach to pillar system design.
Pillar extraction.
Introduction.
Rock mechanics principles relevant to pillar extraction.
The extraction safety factor.
Pillar and system stiffness.
Direction of stooping.
The role of snooks in stooping.
Sizing of snooks using fundamental procedures.
Direction of splitting.
Sequence offender extraction.
Support during stooping.
Determining pillar sizes for stooping.
Rate of extraction.
Influence of the face advance on the stress regime.
Partial pillar extraction.
Evaluating old pillars for extraction.
General remarks.
Longwalling.
Introduction.
Stress history of a longwall panel.
Inter panel pillar design and longwall development.
Mining inter panel pillars.
Panel orientation and face shape.
Face breaks.
Face moves.
Negotiating dykes.
Face length.
Goafing.
Multiple seam longwalling.
Multiple seam mining.
Introduction.
Factors influencing interaction.
Bord-and-pillar mining.
High extraction over bord-and-pillar workings.
Longwalling underneath longwalling.
Longwalling underneath stooping.
Mining over goaf.
Simultaneous mining.
Design flowchart.
Shallow workings.
Introduction.
Underground mining from a highwall.
Sinkhole formation.
Determination of mineable depth.
Bord and pillar mining at shallow depth.
High extraction mining at shallow depth.
Practical considerations.
Numerical modelling.
Introduction.
The ‘nino’ principle.
Choice of model.
Two-dimensional analysis.
Two-dimensional discrete element modelling.
Three-dimensional analysis of layouts.
Detailed modelling in three dimensions.
Estimating input parameters.
Input for lamodel models.
General hints for creating grids.
General remarks.
Recommended reading.
Subsidence.
Introduction.
Mechanism of subsidence.
Related elements of subsidence.
Long term after effects of subsidence.
Sinkholes resulting from shallow workings.
The effects of subsidence on structures.
The effects of subsidence on agriculture.
Handling of subsidence in general.
Monitoring.
Introduction.
Roof monitoring.
Pillar monitoring.
Stress monitoring.
Subsidence monitoring.
Estimating the depth of subsidence without instruments.
Estimating the height of the goaf in a borehole.
General discussion.
Appendix A: Fundamentals.
Introduction.
Co-ordinate systems.
Stress, strain and Poisson’s ration.
Elasticity.
Hooke’s law in 1 dimension.
Hooke’s law in 2 dimensions.
Hooke’s law in 3 dimensions.
Stress transformations.
Friction.
Rock strength and failure criteria.
Beams and plates.
State of stress in the rock mass.
Plasticity.
Continuum mechanics.
Discontinuum mechanics.
Further reading.
Appendix B: Roof support.
Introduction.
The stress effects of creating a roadway.
Typical south african roof composition.
Increased jointing.
Thinning sandstone roof.
Competent layer underlain by thin layer of laminated material.
Thick laminated roof.
Suspension of thick weak roof.
The total stress state around a coal mine roadway (horizontal stress).
High horizontal stress.
Selection of components.
Characteristics of resin.
Probablistic design methods.
Appendix C: Pillar design.
Example 1: Mining underneath a hill, with increasing depth.
Example 2: Herring bone or rhomboidal pillar.
Example 3: Continuous miner adjustment.
Example 4: Design incorporating a weak floor.
Example 5: Design for auger mining layouts.
Example 6: Effect of gradient on pillar.
Notes on pillar and overburden stiffness and yield pillars.
Appendix D: Pillar extraction.
Introduction.
Estimating the effect of an intact overburden on inter-panel pillars.
Partial pillar extraction (ppe) and system stiffness.
Sizing of snooks.
Appendix E: Subsidence.
Subsidence prediction.
Subsidence monitoring.
Recommended reading.
Appendix F: Glossary of terms and definitions.
Appendix G: References.
Appendix H: Units and conversion factors.
The Southern African Institute of Mining and Metallurgy, 2010.
260 стр.
