Longwall Mining

Describes longwall mining and compares it with other underground mining methods. Describes major changes in the geologic, technological, and operating characteristics of longwall mining over the past decade. Shows how changes lead to dramatic improvements in longwall mining productivity. References for technology and historical development. Charts and tables.

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.

This Bureau of Mines report presents two phases of a research program to evaluate a single-entry system for longwall development. Organizations participating in the program, which began in July 1971, include the Bureau of Mines, the Mining Enforcement and Safety Administration, and the University of Utah, working under a cooperative agreement with Kaiser Steel Corp. at its Sunnyside mine in Utah. Part 1 of this report desribes the present longwall mining practice, including a brief history, and discusses the advantages and disadvantages of a single-entry development system and its introduction in the United States. Part 2 of the report presents the research program, test design, instrumentation for ground and support evaluation, and the test results from the No. 2 mine. Subsequent reports will describe the research conducted in the No. 1 mine.

The method of mining under specific mining conditions was for the first time implemented in India with success. Similar conditions may arise in other coalfields, and the detailed study would surely guide the operators to overcome any problems likely to arise during actual mining operations.

This book is offered as a contribution to the spread of knowledge and understanding in the field of strata mechanics in coal mining. It is written for professionals in the coal mining industry and students of mining engineering and includes some of the author's own philosophy of coal mine stability.