By Peter Ker, Philip Wen and Ruth Williams
DEBATE over the safety of ''fracking'' in Australia has reignited after a gas project in Britain was named as the likely cause of 50 seismic events earlier this year.
Seismic experts found it ''highly probable'' that fracking by Cuadrilla Resources was the cause of two tremors and 48 aftershocks near Blackpool in April and May.
Protesters vent their anger on a shale gas rig in England.Credit: AP
The findings - which indirectly affect Australian drilling company AJ Lucas - come after independent MP Tony Windsor this week told the Gillard government he would not support its mining tax unless more was done to investigate the safety of fracking in Australia.
Fracking is a controversial gas-extraction technique that uses high-pressure chemicals to fracture rocks deep underground. The process is used in coal seam gas and shale gas extraction, and if poorly executed can contaminate groundwater and trigger seismic activity.
Fracking is most advanced in the US, but is fast spreading to countries such as Australia and Britain, where Cuadrilla was hoping to develop a big gas source near Blackpool. But the company, which is 41 per cent owned by AJ Lucas, has been forced to launch an investigation after tremors measuring 2.3 and 1.5 on the Richter scale.
Geo-mechanical experts appointed by Cuadrilla confirmed the fracking was ''most likely'' to have caused the tremors, but added that ''rare'' geological factors in the region were also a factor. Environmental and geological authorities in Britain will now review the report. Their assent will be needed for fracking to resume.
In response to the report, AJ Lucas issued a statement to the ASX, in which it insisted it was a ''proven developer of unconventional hydrocarbon properties''. The company services the big coal and coal seam gas basins in Queensland and New South Wales, including the Hunter Valley, Bowen Basin and Surat Basin.
The Cuadrilla revelations are not the first time fracking has been linked to tremors, with regulators in the American state of Arkansas expressing concern that two shale wells - now owned by BHP Billiton - were responsible for causing earthquakes.
Mr Windsor said last night he was happy with the progress he had made in forcing the government to spend a further $400 million on studies into fracking and other mining tactics. He said the Cuadrilla report highlighted the need for more independent research.
The Lock the Gate Alliance, which has mounted a vocal campaign against coal seam gas in Australia, said concerns about seismic activity should have been considered before exploration permits were granted.