Failure characteristics of roof in working face end based on
The roof of the goaf is treated by the complete caving method. The track roadway behind the goaf of the 3313 working face is reserved as the return air roadway. The roadway behind the goaf is supported by a 3 × 3 × 1.4-m flexible formwork wall and anchor cable. The roof is mainly gray-black mudstone and siltstone.