Practical methods for measuring the in situ gas contents of coal seams, modelling seam gas content trends, determining rates of methane emission from strata disturbed by mining and assessing the likelihood of unusual emissions are outlined. The constraints imposed by methane on coal production are highlighted and attention drawn to its attendant hazards. Successful planning for the control and exploitation of colliery methane cannot be achieved without a sound knowledge and understanding of the geology with which the mine interacts.