Stability control of narrow coal pillars in gob-side entry driving for the LTCC with unstable overlying strata: a case study

In underground coal mining systems, the subsidence of unstable overlying strata (UOS) has a key effect on the deformation of narrow coal pillars that are contiguous to the caved zone. This paper investigated the failure mechanism of coal pillars by combining the in situ testing and numerical modeling methods. Several striking findings can be drawn. (1) Six fracture patterns exist in the in situ pillar, and their distribution divides the coal...