Optimization of roadway layout in ultra-close coal seams: A case study.

Abstract

Most coal mines in China are currently mining close coal seams. Roadways in close coal seams, especially ultra-close coal seams, confronted difficulties in maintaining, including large deformation of the roadway, roof caving, rib spalling and floor heaving. This is mainly caused by the complicated stress and geological conditions, shattered roof, improper layout and support. To explore the issues mentioned above, the theoretical analysis was used to build a mechanical model and study the stress distribution under coal pillars, and FLAC3D modelling was adopted to build numerical models with different staggered distances. The optimal roadway layout was brought forward combining the result of numerical simulation and coal recovery rate. The field practice was carried out in the tailgate of panel 25301 to investigate the effect of the layout scheme. The results of field monitoring show that the roadway's stability is well maintained in the mining process.