1.Mine Safety Branch,China Coal Research Institute,Beijing ,China；2.State Key Laboratory of Coal Mining and Clean Utilization,Beijing ,China；3.Beijing Coal Mine Safety Engineering Technology Research Center,Beijing ,China

This paper is devoted to reveal the mechanism of gob gas exceeding the limit in the roadway for Inclined Type Y-ventilation and the effect of gas control through buried pipe gas extraction inventilation connecting roadways.A case study of No.5301 working face of Sihe Mine,Jincheng Coal Group is demonstrated in the paper. Based on the mining parameters and field measured gas emission parameters, a numerical model was built in UDF secondary development program to simulate the distribution of gas flow in gob.A prediction model was also built to estimate the gas concentration in upper corner and ventilation connecting roadway.The model was validated by field measured data, for which the difference between the simulated results and the measured data is less than 5%. The prediction model was applied to estimate gas concentration inventilation connecting roadways and upper corners when using buried pipe to drain gob gas in the second ventilation connecting roadway. The prediction results show that the gas volume fraction in the ventilation connecting roadway was reduced from 3.23% to 0.94% after applying the buried pipe to drain gob gas. The buried pipe gas extraction technology can effectively solve the problem of gob gas exceeding the limit inventilation connection roadways of Inclined Type Y-ventilation.