Observation and Analysis of Roof Lowering Wave observed at Mechanized Longwall Face

Abstract

Roof lowering wave phenomenon was first observed by O. Jacobi, German researcher at longwall faces where mechanized powered supports were introduced in West Germany. Since Kushiro Colliery, Taiheiyo Coal Mining Co Ltd.,was going to introduce fully mechanized longwall mining system to their Numajiri area, it was essential to scrutinize this phenomenon, because if wave should have happened at the face, full collapse of the supports, particullarly at the rear leg position by reciprocating roof lowering is likely to occur.
The author therefore carried out series of measurement at single prop and powered support faces, and introduced the results of measurement for basic design of the UU shaped frame type 12-leg powered supports.