Abstract: Abstract The longwall mining under the room pillars is affected by both the active mining induced stresss and upper pillars’ concentrated stress, leading to instability accidents of road way due to the severe roof pressure. Based on the issues of possible instability accidents of road way in the No.22202 working face in the Daliuta Coal Mine, the methods of numerical simulation were applied to the mechanism of mining induced stress evolution and instability accidents. The result shows that with working face under the coal pillars, the advanced distance of bearing pressures’ peak point will significantly reduce, resulting in the superposition of roof stress and the bearing peak stress. Roof weighting and the superimposed stress contribute to instability accidents of road way. In the 20 m range of the front and back of the edge of the coal pillars, instability of roof movement and stress causes no apparent regularity of instability accidents. With the working face away from the edge of the mining gob after 60 m, the instability accidents will happen periodically because of the obviously periodical roof pressure.

Key words: room mining pillar, longwall mining, stress evolution, instability of road way, numerical simulation