A large amount of methane releasing from the residual coal and the surrounding pressure-relieved gas bearing strata may accumulate in the longwall gob of gas-bearing coal seam, which is increasingly exploited as a major source of coalbed methane (CBM) development in coal mining areas. Meanwhile, if the gob methane emits into the working space along with air-leakage flow, they may impair the safety and productivity of underground coal mines. Thus, gob gas drainage is of great significance to both the CBM development and the control of gob gas emission. Currently, there exist two major technologies for gob gas drainage gob gas ventholes (GGVs) drainage and underground drainage (such as high-level suction tunnels, high-located boreholes and buried pipes in the upper-corner). In practical engineering applications, the GGVs. have greater advantage over the traditional underground drainage in the extraction flux of gob gas and the control of gob gas emission, but the theoretical mechanism of GGVs has not yet been revealed in previous studies. Consequently, the characteristics of gob gas flow with GGVs drainage needs further research. In this paper, the numerical simulation of gas flow in gob gas reservoirs and the in-situ assessment of GGVs drainage are carried out to investigate the mechanism of the control of gob gas flow with GGVs drainage. Firstly, based on fluid mechanics in porous media the mathematical model of gob gas transport is developed. Then, the gas pressure distribution, gas flow patterns and methane concentration distribution in the gob under the conditions of no drainage measures, drainage with buried pipe in the upper corner and GGVs in different locations are discussed by conducting numerical simulation, respectively. In addition, the influence of distance between GGV and return airway on the gob methane flow and the strong control scope of GGVs are analyzed in detail. It is found that: 1) GGVs has the "flow-interception effect" on the gas in the deep zone of the gob and the "flow-reversal effect" on the gas in the gob close to the longwall face, which accounts for that GGVs drainage advantage over underground drainage. 2) GGVs can be applied to drain the gas in the deep zone of the gob massively and to control the gob gas migration effectively, so they are a top choice for the extraction of gob gas and the control of gob gas emission. Finally, both GGVs drainage and underground drainage are adopted to extract gob gas in east-102 working face in Weijiadi coal mine. The comparison of the extracted and emitted volume of gob gas with two different technologies shows that, GGV can drain the gob gas with greater flux and can better control the gob gas emission, which validated the prediction of numerical stimulation. (C) 2016 Elsevier B.V. All rights reserved.