The risk of explosions in coal mines is an important subject that requires a comprehensive understanding of explosion dynamics, mining operations, and mining safety. Recent spontaneous combustion events in New South Wales (NSW) and Queensland have resulted in mine evacuations due to a Trigger Action Response Plan (TARP) being activated at the evacuation level. A sound basis is required for defining the high-risk working zones, mine operational exclusion zones for both emergency activities and mine design considerations, and public exclusion zones during emergency situations. This paper presents a methodology for predicting and defining explosion risk around the coal mine portals developed using Computational Fluid Dynamics (CFD) and experimental results from an advanced blast simulator simulating blast waves exiting a portal entry and propagating over an outside mine site terrain. The methodology can be applied to generate exclusion zones that account for the effects of blast waves emanating from the mine openings. A worked example is provided at the end of the paper as a reference to engineers for the development of mine exclusion zones from blast wave effects.