In the past 13 years since the publication of Longwall Mining, 2nd edition in 2006, although there have been no major changes in longwall mining technology and operations, many incremental developments in the whole system as well as various subsystems of the existing longwall mining operational technologies as detailed in the 2nd edition have been added to this edition.
Major developments are automation, and health and safety technology, as well as equipment reliability, thereby greatly increasing productivity and cutting cost. In particular, the longwall system can now run automatically cut by cut forever without operators' intervention provided that the geology allows it. Other health and safety features such as LASC, personal proximity detection, color lighting, automatic shield water sprays and remote shearer control are fully operational. There are more than 7000 sensors installed in current longwall mining systems. The big data obtained and fast communication technology have been fully utilized to improve and solve operational problems in real time. Those features are fully documented in the new edition. In pursuit of high productivity and cutting cost, life cycle management that increases equipment reliability has been implemented by OEM. Automation improvement such as tail-end automatic chain tensioner greatly extends AFC chain's service life. Other incremental improvements including dust and methane controls, entry development, panel design and face move are addressed. Additional operational issues such as extension of panel width and compatibility test are also discussed. Since the last plow longwall mine was closed in 2018, the chapter on plow longwalling has been dropped and in its place Automation of Longwall Components and System is added. Also, a new chapter Longwall Top Coal Caving Mining (LTCC) is added due to its successful application in Australia since 2005.
Longwall Mining, 3rd edition will be of interest to professionals and academics in the field of mining engineering specifically, serving both as a reference work and an (under)graduate textbook, but will also interest civil, geomechanical and geological engineers and rock mechanics professionals, as well as coal operators, mining consultants, researchers, equipment manufacturers, and government regulators.
1 US longwall mining
1.1 Introduction
1.2 Requirements and constraints for high production longwalls
1.3 Panel layout
1.4 Mining technique
1.5 Features and trends of US longwall mining
1.6 Summary of US longwall development trends
1.7 Management and human factors in high production longwalls
2 Longwall mine design
2.1 Introduction
2.2 General consideration of panel layout
2.3 Ground control consideration
3 Strata mechanics
3.1 Introduction
3.2 Overburden movement
3.3 Abutment pressures, gob caving, and gateroad convergence
4 Panel development
4.1 Introduction
4.2 Distribution and comparison of gateroad development systems
4.3 Methods and equipment used for gateroad development
4.4 Rapid development
4.5 Survey of types of pillar systems in gateroad development
4.6 Design of chain pillars and barrier pillars
4.7 Roof support
4.8 Factors affecting the development rate
4.9 Determination of required daily panel development footage
4.10 Examples of gateroad development systems
4.11 Calculation of coal recovery rate in a longwall panel
5 Shield support – general
5.1 Introduction
5.2 Two-leg shields
5.3 Elements of shield supports
5.4 Electrohydraulic control system
5.5 Performance of shield supports
6 Shield support – design/selection
6.1 Introduction
6.2 Elements of shield design
6.3 Preliminary determination of the overall dimensions of shield components
6.4 Determination of external loadings
6.5 Resultant load on the canopy and floor
6.6 Determination of floor and roof bearing capacity
6.7 Torsional strength of shield subject to bias loading
6.8 Static structural analysis of shield support
6.9 Testing of full-sized prototype shields and electronic and hydraulic units
7 Coal extraction by the shearer
7.1 Introduction
7.2 Layout of longwall face equipment using the shearer
7.3 Monorail system
7.4 Double-ended ranging drum shearer
7.5 Cutting drums and performance of the shearer
7.6 Installed power of the shearer
7.7 Haulage of the shearer
7.8 Cutting methods of the shearer
7.9 Coal loading of the shearer
8 Coal transportation
8.1 Introduction
8.2 Layout of coal transportation system
8.3 Major components of the armored chain conveyor
8.4 Selection of armored flexible chain conveyor
8.5 Coal transfer system
8.6 Operation and maintenance of the armored flexible chain conveyor
9 Automation of longwall components and systems
9.1 Definition
9.2 Automation of three face machines
9.3 Automation of longwall system
9.4 The first modern longwall mining system standard
9.5 Real-time mining condition analysis and problem solving
9.6 Automated health and safety technologies since the mid-1990s
9.7 Discussion
9.8 Summary 335
10 Application issues of longwall mining
10.1 Factors to be considered in increasing panel width
10.2 Longwall compatibility test
10.3 Life cycle management, expert solutions, and equipment re-use services
10.4 Basic performance requirements for shields
10.5 Control of adverse roof conditions
10.6 Two-leg shields vs. four-leg shields and chock shields
10.7 How to accurately measure the shield hydraulic leg pressure
10.8 Pre-driven recovery room and mining through open entries
10.9 Longwall mining under hard-to-cave roof
10.10 Cutting through a fault
10.11 Pillar design for gas/oil wells
10.12 Cyclic failure of strong roof strata and seismic events
10.13 Faster or slower longwall advancing rate
10.14 Bottom coal, hard face, soft floor, and AFC creeping – causes, problems, and solutions
10.15 Stability of gateroad T-junctions subject to high horizontal stresses
11 Ventilation and methane, dust, and noise controls
11.1 Introduction
11.2 Longwall specific ventilation
11.3 Methane control
11.4 Dust control
11.5 Noise control
12 Longwall face move
12.1 Introduction
12.2 Pre-move preparation
12.3 Move preparation
12.4 Move
12.5 Installation of the new face at the set-up room
13 Longwall power distribution and system control
13.1 Introduction
13.2 Electrical power distribution
13.3 Longwall system control
14 Surface subsidence
14.1 Introduction
14.2 Characteristics of surface movement
14.3 Effects of geological and mining factors
14.4 Subsidence prediction, assessment, and mitigation
14.5 Surface and groundwater effects
15 Longwall top coal caving mining
15.1 Introduction
15.2 Panel and equipment layouts
15.3 Face equipment
15.4 LTCC mining technique
15.5 Automation of LTCC
15.6 Health and safety issues
15.7 Theory of withdrawn body in LTCC
Biography
Dr. Syd S. Peng is Charles E. Lawall Chair of Mining Engineering emeritus, Department of Mining Engineering, West Virginia University, Morgantown, WV, U.S.A. Dr. Peng received his undergraduate diploma in mining engineering in Taiwan. He came to the U.S. in 1965 for advanced study and received his Ph.D. in mining engineering from Stanford University in 1970.
From 1970 to 1974, he worked for the U.S. Bureau of Mines, Twin Cities Research Center in charge of rock physics research. He joined West Virginia University in 1974. In 1978 he was appointed as chairman of the Mining Engineering Department, a position he held until September 2006. In 1985, he established the Longwall Mining and Ground Control Research Center and assumed its directorship. In 1998, he was appointed director of Coal and Energy Research Bureau. He has performed research and investigated problems in more than 300 coal and industrial mines in all coal producing states in the U.S. and 16 foreign countries.
He has authored and co-authored 4 textbooks and 353 journal and proceedings articles in the areas of longwall mining, ground control and respirable dust. He initiated the annual international conference on ground control in mining since 1981 and served as editor/senior editor of the Conference proceedings. It is now recognized all over the world as an annual forum for exchange of information on ground control. He is frequently invited to lecture or chair conference sessions in the U.S. and all major coal producing countries.
He is a member of the National Academy of Engineering and was the recipient of numerous awards, including Rock Mechanics Award 1987, SME; Education Excellent Award 1988, Pittsburgh Coal Mining Institute of America (PCMIA); The Institution Overseas Medal 1992, The Institution of Mining Engineers (IMM), United Kingdom, and the Howard N. Eavenson Award 1998, SME; The 20th Conference Statute, Int’l Conference on Ground Control in Mining (ICGCM), 2001; The Donald S. Kingery Award 2001, PCMIA; The Erskine Ramsey Medal, AIME, 2002; Medal for Excellence for 2004, the Institutes of Materials, Minerals and Mining, United Kingdom; The 2004, 2005 and 2006 R&D 100 Awards; The 2005 Old Timers Club Faculty Award; and the West Virginia Coal Hall of Fame, 2007.
