The environmental safety of an underground mine depends strongly on its ventilation system. An efficient ventilation system provides fresh air, removes hazardous gases and dust, and maintains the temperature and humidity at appropriate levels. One of the most important factors in removing hazardous gases and dust is the dispersion behaviour in the mine network. This factor determines the longitudinal spreading and the average air residence time of gases or particulate matter throughout the mine. This paper describes tracer gas measurement in an underground mine and the utilisation and analysis of the dispersion characteristics using numerical simulations. The concentration-time curve obtained from the measurement is simulated to evaluate the effective diffusion coefficient that reflects the general dispersion characteristic of an entire mine. The evaluated values of effective diffusion coefficient are then compared to other data from several studies. The diffusivities obtained in this study were higher than other analytical and empirical results. More research is still required to identify the main factors causing such higher diffusivities. However, the results from the present work can be an important standpoint for future work. Numerical simulation conducted in this research was confirmed to be effective in detecting several leakage paths occurring in the mine ventilation network. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.