Joint R & D projects on coal mine gas control

JCOAL and CSIRO commenced a co-operation project on mine gas control in 1997 based on the agreement between Australian and Japanese government. The aim of the project is to develop effective post-mining goaf drainage technology for highly gassy longwall mines. A suitable site in Australia has been identified at Dartbrook in Hunter Valley. Overall scope of the project include field experiments with gas drainage technologies such as long horizontal holes, cross measure holes and surface goaf holes, and other field experiments of tracer gas studies, goaf gas distribution, gas analysis and ventilation monitoring. The project also include computational fluid dynamics modeling of gas flow in goaf environments and 3D visualization of the workings and gas drainage holes.Dartbrook Colliery is one of the gassiest mines in Australia, with longwall goaf gas emissions in the order of 420 to 540 m3/min. The capacity of the post-drainage system designed should be large enough to capture a major proportion of these goaf gas emissions. The susceptibility of the coal seam to spontaneous combustion and large quantities of broken coal left in the goaf compound the gas problem at Dartbrook. The spontaneous combustion issue demands that oxygen ingress into the goaf should be minimised. Requirement for high goaf gas drainage capacity and the need to prevent oxygen ingress into the goaf are contradictory to one another and should be considered during design and implementation of goaf gas drainage system.This report presents the details and results of the joint R & D project.