Visualisation of numerical model of goaf gas distribution
Improving control of mine gas
Controlling gas produced by mining can be a major problem, but CSIRO’s research is helping reduce gas-related delays at mines, while increasing safety for personnel.
2 February 2006 | Updated 14 October 2011
In longwall mining, a coal seam is divided into a series of parallel blocks, or panels, which average two kilometres in length and 250 m in width. A series of roadways is then developed to allow underground access for mining equipment and services.
As the longwall face mines the coal, the roof supports are moved forward, leaving the roof behind the supports unsupported. The roof collapses into this area, called the goaf.
Coal contains methane gas. When coal is mined this gas emits into the underground roadways. When methane gas concentration in the ventilation air reaches five per cent, it forms an explosive gas mixture, presenting a great danger to the people working underground.
Therefore, every mine has to develop effective gas control strategies to capture and control the gas, ensuring that gas concentration in the roadways is maintained below 1.25 per cent to prevent an explosion.
If a longwall mine cannot adequately control gas, the risk to worker safety increases and productivity decreases. In some cases, high gas levels can threaten the ongoing existence of a mining operation.
The gas research program at CSIRO has resulted in the development of a range of gas and spontaneous combustion (sponcom) control strategies.
CSIRO has undertaken research to characterise gas flow patterns in mines. This research has resulted in several design changes to the goaf gas management system.
CSIRO’s gas research has resulted in the development of a range of cutting-edge gas and spontaneous combustion control strategies.
After implementing these changes at a number of highly gassy mines in Australia, the goaf gas drainage system has improved by more than 50 per cent. At the mine, this has significantly:
A number of mines have already successfully used these gas management techniques to improve the efficiency of goaf gas drainage systems. Techniques developed by this research are also being applied to other related gas and sponcom issues.
CSIRO acknowledges funding and support for this gas research program from:
Japan Coal Energy Centre (JCOAL)
Australian Coal Association (ACA) members
Australian Coal Association Research Program (ACARP)
Learn more about CSIRO's research into Mining & Minerals