Research On Gas Field In Gob With Y-type Ventilation By Numerical Simulation

In Panyi eastern district1252(1) working face with Y-type ventilation as a prototype, studied gob porosity and range of "three zones" by similarity simulation experiment, combined statistics and prediction results of gas emission quantity, simulated and analyzed gob gas flow field, thereby, proposed high gas working face gas control measures.The results show that, without gas extraction, deep gob gas concentration up to90%, about60m away from working face the gob roadway gas concentration reachs1%, while200m away from working face the gas concentration is close to14%. Gob and gob roadway gas concentration have a different degree of reduction with different methods and layout parameters extraction. Gas extraction effect is relatively good with off cut buried pipe+gob buried pipe (spacing of20-30m)+high level boreholes+high pumping roadway extraction, it makes deep gob gas concentration down to15%, and makes gob roadway gas concentration down to0.5-0.8%. Therefore, this kind of extraction method can as the working face integrated gas control measure with Y-type ventilation.Gas control experiments show that, with end roadway buried pipe+gob buried pipe+high level borehole+high pumping roadway+surface borehole extraction, the working face gas extraction volume reaches97m/min, and its extraction rate reaches88%. High pumping roadway combined with cross-seam borehole extraction maximum volume of gas, and surface boreholes play a good role to compensate at high pumping roadway extraction insufficient, at the same time, high level boreholes play an important role in the early face mining. Therefore, extraction roadway or cross-seam borehole can be arranged between the coal seam and adjacent layer when the gas emission quantity of them is large, for insufficient of its extraction capacity at the early off cut and finishing cut line, can use surface borehole or wind roadway (end roadway) cross-seam borehole to compensate.