We report permeability data of a cylindrical sample of high volatile bituminous coal (25mm in diameter) with a clearly visible cleat system, to CH4 and CO2, performed under (near) fixed volume versus fixed stress conditions. To isolate the effect of sorption on permeability evolution, helium (non-sorbing gas) was used as a control fluid. All flow-through tests reported here were conducted under conditions of single-phase flow at 40℃, employing Terzaghi effective stresses of 14-35MPa. This experimental...