Residents on the Tara residential estate on Queensland's Western Darling Downs have reported the presence of gas smelling like 'rotten eggs' and another 'sweet-smelling' gas and, as a result, teams from both state and federal governments have begun investigations of the area to determine if these are linked with nearby coal seam gas activities.
The gas smells were reported to the state government several weeks ago and residents have been complaining about symptoms like nose bleeds and chronic headaches in their children.
The Lock the Gate Alliance recently released video footage of gas bubbling up through the Condamine River and both the coal seam gas company, Origin, and the Queensland government have admitted it is methane but are claiming it is from 'natural sources'.
Lock the Gate Alliance president, Drew Hutton, said it is highly likely the 'rotten egg' gas is hydrogen sulphide, the 'sweet-smelling' gas in nitrous oxide and that both are coming from the same place as the methane – the de-watered coal seams from which coal seam gas companies are extracting both water and gas.
"When water is extracted from the coal seam, the resultant de-pressurisation releases methane and other gases, much of which will be collected by the gas well but some could find other pathways to the surface, depending on the level of inter-connectedness," Mr Hutton said.
"If the material overlaying the coal seam contained such potential pathways, then you would expect methane and other gases to travel to the surface where they would present a major health hazard."
Mr Hutton said the recent report by the Queensland Water Commission indicated that this area would be the first affected by large draw-downs in the water table. It also admitted there would be high levels of inter-connectivity from the coal seam aquifer.
The Lock the Gate Alliance is calling on the Queensland government to:
- demand all seismic and other data from Origin and QGC to establish if there is the potential for gas, migration from the coal seam in this area to the surface
- employ the services of an independent expert to assess this information, and
- close down all gas wells in the area with the capacity for lowering the water table and immediately commence a study on the potential of other gas fields for similar gas migrations if this area is found to have the potential for gas migration to the surface from the coal seam.