Methane drainage has become an integrated part of modern coalmine operation in areas where gas emissions cannot be practically handled using conventional ventilation techniques. The methods used for capturing coal seam gas are diverse and practised to large extent on the basis of experience. Boreholes are often drilled with limited knowledge of their performance. This paper describes the use of CFD techniques to model the migration behaviour of mine gas through permeable porous strata. CFD models were developed and incorporated the ability to simulate mixtures of methane and air around drainage boreholes. This allows sensitivity study of a wide range of drainage parameters, including suction pressure, strata with low/high permeability, and the role of mining-induced fractures. The CFD based approach can be used as a cost- effective alternative to the evaluation of a wide range of gas drainage design scenarios and the performance of individual drainage boreholes.