Mine ventilation measurements using with SF6 as tracer gas were carried out at Kushiro Coal Mine operated by Taiheiyo-tanko Co., Ltd. in 1997, in order to investigate the flows in the inclined airway and its network flows from the inlet portals to the main fan. The photo-acoustic gas monitor of SF6 with high sensitivity of 10 ppb resolution of gas concentration was used to measure gas concentration-time curves. Two injection methods were applied to measure airflow in the inclined shaft by stepwise gas injection, and the ventilation network flows by pulsed injection of the tracer gas from the inlet portals. The effective gas diffusion coefficient in the single mine airway has been investigated by the measurement and numerical simulation results, and it was evaluated as 20 m
Furthermore, the revised equation and numerical method for gas concentration-time curves in mine network ventilation flows has been presented which was extended from the Taylor's equation to evaluate effective diffusion coefficient of a single flow channel, and it has been shown that the presented model can be used for matching with the measured results including gas diffusion characteristics of mine ventilation airflows.