FIVE earthquakes near one gold mine and another five near a separate proposed gold mine, but Geoscience Australia has avoided speculating on any links between mining and the tremors.
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The two most recent earthquakes occurred within two hours of each other on Sunday near the proposed Regis Resources’s McPhillamy’s Gold Mine site at Blayney.
The first struck at 9pm and measured 2.6 magnitude (ML), the other occurred at 10.54pm and was 2.1ML. Both occurred right on the earth’s surface.
A Geoscience Australia spokesman told Fairfax Media that the earthquakes were relatively small and were felt weakly up to 40 kilometres from the epicentre.
“Earthquakes of this size have very little associated shaking lasting only a few seconds,” she said.
“The earthquake [of this size] is often mistaken for thunder or an explosion.”
The spokeswoman said that Sunday’s quakes were not isolated incidents and that three others had occurred near the proposed Regis Resources mine in the past two years alone.
On January 17, 2016 two quakes occurred in the same region, both measured 1.8ML, while another occurred on January 15, 2016 and was 2.1ML.
The same number of quakes have occurred near Newcrest Mining’s Cadia Valley Operations (CVO) gold mine near Orange – the largest was 4.3ML on April 13, 2017, while the most recent was 3.8ML on July 22 this year.
Fairfax Media asked Geoscience Australia whether there was any link between mineral deposits and earthquakes, and also whether mine activity made an area more susceptible to quakes.
The spokesman declined to answer these questions.
During the most recent quake at CVO, underground crews were moved to safety chambers when they felt the ‘substantial’ earthquake which originated five kilometres from the heart of the mine’s operations.
It was the third earthquake near the mine this year.
CVO general manager Peter Sharpe said at the time that all staff were safe and well, and “Cadia geotechnical engineers [were] conducting inspections” before subterranean operations recommenced.
“All employees in the underground operations moved to refuge chambers and all are accounted for and safe,” he said.
Processing activities at CVO were uninterrupted.
Earthquakes of this size have very little associated shaking.
- Geoscience Australia spokesman
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