Characteristic and Mechanism of Roof Fracture Ahead of the Face in an LTCC Panel When Passing an Abandoned Roadway: A Case Study from the Shenghua Coal Mine, China

Due to the abandonment of roadways after the use of conventional mining techniques, fracture behaviours of the roof of a longwall top coal caving (LTCC) working face significantly differ from general coal mining behaviours. This study examines conditions of the no. 3 LTCC working face of the Shenghua coal mine. By theoretical analyses, analogue simulation tests and numerical calculations, we examined the roof failure characteristics, forces...