Stability assessment of long gateroad pillar in ultra-thick coal seam: an extensive field and numerical study

Abstract Sustainability of an underground longwall operation is highly dependent on stability the pillars during panels extractions to ensure continuous serviceability gateroads. In Chinese mining, gateroads are typically driven as a single roadway with “long gateroad pillar” which different common practice where consists number known chain pillars. Such unique has been proven be more economical maximum recovery while safety remains at its highest level. this study, based data obtained from Tongxin coal mine in China, mechanical long pillar was investigated. The focus two nearby top caving and their impacts behaviour retreat. To do so, initially area selected for field instrumentation collection. These included vertical stress measurement depth damage assessment within panel. Hence, convergence level quantified used numerical modelling assessing performance designed finite difference technique using FLAC 3D . Double-yield strain-softening ubiquitous-joint constitutive models were simulate goaf material strata, respectively. Finally, extensive sensitivity analysis conducted compare range wide narrow It concluded that 50 m ideal dimension future achieve productivity safety. Article highlights validated model study pillar”. Premature yielding 38 would lead severe geotechnical issues. Deep roof blasting edge or can improve conditions