This paper presents an overview of the design and development, application to date and potential of a real-time return gas monitoring system. Initially developed as an ACARP/Industry funded project, whose prime aim was to create a 'turn-key', prototype, stand alone, real-time, Return Gas Monitoring System (RGMS) capable of providing quantitative assessments of gassiness levels on a shift by shift basis, enabling unusual gas emission patterns to be readily flagged. aeoaAS designed and commissioned the RaMs and 'live-trialled' it at Tahmoor Colliery and Oartbrook Mine. The system has a number of features new to Australian underground coal mines and is comprised of three distinct components:- Hardware computer. high accuracy CH4 and CO2 gas ana1ysers, air velocity meter, belt weigher, PLC, modems and 2. Real time software -SCADA based control. trending and data logging software. 3. Offline software -GeoGAS's RGMS data post-processing software implemented to perform the calculations and data reduction, facilitate analysis, and present results. The system, currently monitoring longwall return conditions at Dartbrook Mine, has been in continuous use since February, 1995. Areas of potential application include :- Provision of an additional safety barrier in quantifying gassiness levels. Rationalisation of drilling & drainage operations. Post-analysis of real events. Support of operators and staff.