Research On The Stability Of Small Pillar’s Stability Of Mining Face With Partial W-type Ventilation System

China is a big country with coal mining, many mining faces in china face with a stuation of higher density of gas and exceeding limit in upper corner, which pose a huge threat to safe and efficient mining. Owing to mining underground affected by many geological factors, roadway layout and choice in ventilation pattern is not optional. For this kind of problem especially coal mining in the working face with gas in special geological condition, several experts and scholars advise to use a working face with partial W-type ventilation system, which is a effective way to slove the problem. As reture airway is arranged in the location between rail tunnel and transportation tunnel which comparatively stand closely to rail tunnel, which create a small pillar on the top of working face in order to fulfill maximum mining ratio. On the other hand, spalling and roof falling easily appears in the small pillar because of many factor’s effect. Research on the stability of small pillar is very significant in ensuring stability of workspace and safe and efficient mining.This paper regard090606face of Duanwang mining which belong to Shanxi Jizhong energy group as engineering background and use a intergrated metiod of field test, theoretical analysis and numberical simulation to take a intensive study on the factors of small pillar’s stability and feature of in the stage of drilling and mining. Finally the paper use this method to grasp mechanism of deformation and failure and establish mechnical model in the stage of drilling and mining which offers a scientific and reasonable reference of pillar design.With research on the influence factors of small pillar’s stability, it demonstrate that there is a big difference in pillar’s pressure in the stage of drilling and mining. Both lateral support pressure on the two sides and advanced support pressure acts on small pillar during mining. On the basis of this theory, design formula of small pillar is established.According to the engineering background of090606working face, the paper applys theoretical analysis to get four kinds of different pillar design project, and study on mine pressure behavior and surrounding rock failure mechanism by using numberical simulation of FLAC3D, which proves the accuracy of pillar design formula ventilation and finally get a best solution of pillar’s size in the working face with W-type ventilation system.