In view of the characteristics of the coal seam gas storage and the conditions of the fully mechanized caving face, the numerical simulation and field measurement methods are used to study the distribution of the gas concentration in space under the condition of the U+I ventilation mode, and the relationship between the gas emission, the coal production and the periodic weighting is analyzed. The results of the numerical simulation show that the U+I ventilation mode can effectively reduce the gas concentration in the upper corner and the return airway. With the working face advancing, the gas enrichment zone is constantly expanded in the goaf back. And the gas concentration rises in the back of the return air side. Therefore, it is suitable to bury the pipe in the return air side of the goaf back. The results of field measurements show that the gas concentration distributes gently from the inlet side to the middle of mining faces, increasing faster in the range of 50 meters near the return air side. The absolute outflows of the gas and coal productions are in an approximate linear relationship, and the gas emission sees periodic changes after first weighting. A comparison study shows that the results of the distribution of the gas concentration obtained from the numerical simulation and the field measurements agree very well. At the same time it is feasible to bury the pipe in the return air side of the goaf back to drain the high concentration gas, and it can significantly reduce the gas emission.

fully mechanized coal face  /  gas emission  /  fluent numerical simulation