Workers at Kirkland Lake Gold’s Fosterville gold mine (FGM) were evacuated after the site was rocked by a 2.5 magnitude seismic event last Tuesday morning.
FGM recorded the event as being 1km below the surface and said it was heard and felt by workers both above and below ground.
Eighty workers below ground recorded hearing loud bangs and rockfalls at around 8:25am, while buildings above ground could be heard to rattle.
No one was hurt and workers were able to contact family and friends after being brought to the surface.
FGM, the largest gold producer in Victoria, is located 20km North-East of Bendigo and neighbouring communities were able to hear the event occur.
General manager Lance Faulkner said that workers knew what to do in these events, adding that seismic events are common phenomena.
“Mine-induced seismic events are not uncommon, and they occur when there’s a redistribution of stress and that occurs as the mine advances,” Faulkner said.
In 2020, FGM installed a dedicated underground seismic monitoring system, allowing the teams to record when an event occurs.
The monitoring system also records the magnitude and location of seismic events, allowing FGM to adopt appropriate safety systems and procedures.
The seismic event that occurred on Tuesday morning was the largest since the technology was installed, with Faulkner adding “the next highest was at magnitude two level in the middle of last year.”
The information gathered from this event will allow FGM to further minimise the potential for mine induced seismic events.
“In this instance, we’ve been able to establish that the location of the event was over a kilometre below the surface and hundreds of metres away from our underground workings,” Faulkner said.