Ventilation air methane (VAM) is ultra-low concentration methane emitted from an underground coal mine. This is a consequence of the high ventilation air volumes (up to 600 m3/s) that are circulated through the mine to ensure that the methane remains below a safe operating concentration, typically less than 1 vol. % CH4. Currently, all underground coal mines in Australia vent VAM into the atmosphere, contributing to Australias national greenhouse gas inventory. In 2016, the Australian Government reported that fugitive emissions of methane from underground coal mines was approximately 19.0 million tonnes (CO2-equivalent) which was about 4.0 % of Australias national greenhouse gas emissions. The abatement of VAM therefore becomes important.The abatement of VAM in a fluidised-bed reactor where the process heat was recovered to produce power in a gas turbine and cooling via absorption chillers has been discussed in earlier work (Nadaraju et al., 2018). The process was simulated using Aspen+ process simulation package to determine the minimum methane concentration to operate the plant and concurrently maintain the oxidation of methane. However, a condensing recuperator and low temperature gas expansion was considered. This work describes an optimised process of heat recovery from the fluidised-bed VAM abatement reactor and the production of power and cooling. For a ventilation flow rate of 20 m3/s (equivalent to a single abatement unit), the minimum methane concentration for a direct gas turbine was 0.45 vol. % at a reactor temperature of 630 C and reactor pressure of 1.5 bar. An indirect gas turbine process operated with a minimum methane concentration was 0.4 vol. % at a reactor temperature of 630 C, compressor outlet pressure of 4.0 bar and turbine flow rate of 2.2 kg/s.The abatement process is modular and would require 15 units for the ventilation flow of 300 m3/s. At 0.45 vol. % a total of 5 700 kWR of cooling would be produced by the direct gas turbine and direct-fired chiller while 5 775 kWR would be produced by the direct gas turbine and indirect-fired absorption chiller. The indirect gas turbine and indirect-fired absorption chiller would produce 5 100 kWR of cooling. The cooling produced would offset the cooling requirement for a gassy coal mine with a high geothermal gradient. Furthermore, this translates into an operating cost saving of approximately A $ 0.5 M for the direct gas turbine processes and A $ 0.45 M for the indirect gas turbine process. CITATION:Nadaraju, F J, Maddocks, A R, Zanganeh, J and Moghtaderi, B, 2019. Ventilation air methane: a simulation of an optimised process of abatement with power and cooling, in Proceedings Australian Mine Ventilation Conference 2019, pp 6279 (The Australasian Institute of Mining and Metallurgy: Melbourne).