Mining methods and roof caving mechanism in longwall mining through the abandoned gateroads of small mines

LI Yang; ZHU En-guang; ZHANG Kang-ning; QI Bei-di; SU Ji-min; CAO Peng; CAO Min; LI Cheng-kun; WANG Jia-xing; WANG Zheng

doi:10.13225/j.cnki.jccs.2016.1668

Abstract：Ground pressure behavior is different from that at ordinary panel face in longwall mining when the coal face goes through the abandoned gateroad of small mines.It is easy to induce the accident of face spalling,roof fall and crush shield support.In this paper,Cuijiazhai E13103 panel was used as a research site.By using mechanical analysis,numerical simulation and field measurement,the stress distribution for the panel in the disturbed area was determined with research on the damage range of the vertical,oblique and parallel abandoned gateroads of small mines.For the different types of abandoned gateroads,the mining technique was established for passing through the damaged area.Especially for the four parallel abandoned gateroads across the panel,the "swing-inclined face" mining method was employed in this paper.The mechanical model of roof caving was built by considering the stability of shieldground.The abutment pressure distribution of "swing-inclined face" was determined as well by using numerical simulation.By analyzing the relation between "roof-shield-abandoned gateroads-pillar-intact coal",the reasonable supporting capacity of shield was calculated when the face was in the damaged areas.It reveals the problems that the shield selection is not reasonable and it effectively guides the shield design and shield selection.Technical measures for safe mining were also proposed in longwall mining through the abandoned gateroad of small mines.