LONGWALL MINING.

Abstract

This book emphasizes practical knowledge for longwall operations. It begins with various U. S. panel layouts and mining techniques, followed by the strata disturbance caused by longwall mining. Based on the theories of strata movements, the roof control methods are introduced. These include the elements, designs, and applications of powered supports. The methods of coal extraction are discussed separately, depending on whether the shearer or the plow is used. A chapter is devoted to face transportation of coal by armored flexible conveyor. Methane, dust, and surface subsidence, the safety, health, and environmental problems associated with the high production and complete extraction of coal in longwall mining, are discussed. Their significance and methods of control are treated separately. Face move is discussed and all the representative instruments are grouped. Refs.