As a prelude to studying the sorption desorption and permeability behaviour of coal cores in a triaxial stressing rig using sorb- able gases, the air permeability of typical cores was measured. Lump coal samples were obtained from three gas-troubled collieries in Queensland and New South Wales. These were cored in the laboratory and a simple laboratory permeameter employed which accepted 38 x 40 mm cores in a thick rubber sheath. Air pressure of 500 kPa was applied outside the sheath to provide suitable sealing between the rubber and the coal. Differential driving pressures up to 100 kPa were employed and the air flow measured by displacement of water columns in inverted graduated cylinders. Flow measurements accurate to + 2% could thereby be achieved._x000D_
Coal lumps were cored both parallel and perpen- dicular to the bedding plane, and were observed prior to measurement for any notable features, in particular for the presence of fissures._x000D_
Between samples an overall variation of from < 0.1 to > 100 milliDarcy was found in Appin, Westcliff and Leichhardt coals. Significant variation was observed both from section to section of a core and between regions of a