A BHP coal mine halted operations on Tuesday after the fourth earthquake in almost as many months left thousands without power in the Upper Hunter Region of NSW.
The regional mining town of Muswellbrook was hit by a magnitude 4.1 earthquake about 12.12pm on Tuesday with a revised depth of 3km, according to Geoscience Australia.
The epicentre was near BHP’s Mount Arthur mine site, southwest of Muswellbrook with operations paused temporarily as a result.
Know the news with the 7NEWS app: Download today
Geoscience Australia senior seismologist Dr Hadi Ghasemi told 7NEWS that “what we are observing in the Muswellbrook region is what we categorise as ‘earthquake swarm’.
“The mining activity … can basically disturb the current tectonic setting of that particular site.”
Power supplier Ausgrid reported more than 2,500 addresses had lost power after the quake including St James’ Primary School in Muswellbrook – however, services were restored about 2:30pm.
“No power. We will need an inspection. Please come and collect your children,” the school said on Tuesday.
Some 315 people reported they felt the quake from as far as Wollongong and Coffs Harbour, 300km away.
No injuries are believed to have been reported.