Study on the new layout pattern about the gob‐side entry under dynamic pressure and its surrounding rock stability control

Abstract

Abstract Though the recovery rate of coal resources can be effectively improved by adopting the gob‐side entry longwall face, which is also easy to cause tension between mining and excavation. Therefore, a new type of roadway layout, narrow coal pillar entry retained (NCPER), was invented in the study. The NCPER is excavated together with the tailgate of next longwall face before the mining of prior longwall face, which is retained and reused during the mining of the next longwall face. The layout is based on the advantages and successful experience of the double roadways excavation, the gob‐side entry retained, and the roadway driven along gob‐side and heading for adjacent advancing coal face; moreover, the NCPER significantly shortens the preparation time of the longwall face while improving the recovery rate. Taking the production geological conditions of Yushuling Mine as the engineering background, the influence of factors such as roof‐cutting pressure relief and coal pillar width on the stability of the narrow coal pillar from the perspective of improving the stress environment of the roadway and strengthening the weak structure support of the surrounding rock was studied, and reasonable suggestions for selecting parameters of roof cutting and coal pillar width were given. Furthermore, the bidirectional grouting cable and its joist were used to strengthen the narrow coal pillar and the roadway roof, respectively, and a good effect of roadway control has been obtained. The invention and application of NCPER provided a new approach for the longwall face roadway layout and effectively eased the strained relationship between mining and excavating, which has a strong popularization and application value.

Keywords

• coal pillar width
• gob‐side entry
• narrow coal pillar entry retained
• roadway control
• roof cutting and pressure relief