Orange earthquake: gold miners fled to underground refuge chambers when 4.5-magnitude quake hit central west NSW

More than 150 workers at the Cadia goldmine in western New South Wales were evacuated after a nearby 4.5-magnitude earthquake on Tuesday evening, according to an internal company memo.

The mine has paused all underground operations pending a safety assessment.

The quake’s epicentre was just 3km from the Newmont Cadia goldmine tailings dam, which partially collapsed in 2018. Effects of the quake were felt hundreds of kilometres away.

The quake hit at 8.19pm on Tuesday at a depth of 5km about 30km south-west of Orange in central west NSW.

An internal Newmont announcement sent to Cadia goldmine staff, seen by Guardian Australia, said 153 people who were working underground “are accounted for, and were progressively returned safely to the surface, and have been debriefed”.

“Personnel underground moved quickly and appropriately to refuge chambers,” the announcement said.

“Mine rescue teams worked through a structured re-entry and rescue plan.”

The announcement said the earthquake occurred to the east of the underground mine and was felt across the central west.

“Safety and the wellbeing of our people remain the top priority,” the announcement said.

“We are working on a structured process to develop a mine recovery plan.”

The announcement acknowledged the event “may be unsettling for people. Please look out for one another, speak to your leader” and said a support service was available if needed.

The Blayney shire mayor, Bruce Reynolds, who lives about 12km from the epicentre, told Australian Associated Press his biggest concern when the quake occurred was the underground workers at the Cadia mine.

The quake “was like an explosion under the house,” Reynolds said.

John Clemens, the owner of the Forest Reefs Tavern about a 20-minute drive from the mine site, said they had just closed for the evening when they felt the quake.

“We’d just closed the tavern and were counting the takings and the place just shook like a truck was coming through it,” he said.

“It was crazy. Windows rattling, wine glasses rattling in the hotel.

“We had one once before out near the mine but that one last night was crazy.”

He said everyone at the tavern was alright and there had been no damage.

“The force coming from the mine side, the western side, it was like the pub leant one way and then came back the other,” he said.

The NSW premier, Chris Minns, said the government had no information to suggest the earthquake was linked to mining activity.

“We don’t believe it’s linked, or I’ve been given no information that it has been linked,” he said.

“I was briefed about it late last night, and there were evacuation protocols that were put in place for miners, but we’ll take a watching brief, and if we get any new or extra information we’ll obviously let the public know about it.”

A Newmont spokesperson said “safety procedures functioned effectively, and all underground personnel were accounted for and progressively returned above ground. There have been no reported injuries”.

“The safety and wellbeing of our people remains our highest priority. Underground operations have been paused while specialist teams undertake inspections and assessments,” they said.

“The company will provide an update on any material production impacts, if applicable.”

Geoscience Australia received more than 2,000 reports of tremors in the region, which a senior seismologist said were weak to light and felt as far as hundreds of kilometres south-east in Batemans Bay.

Dr Phil Cummins said only five quakes of a similar scale had been recorded within 50km of the quake site since 1977, with the previous one in a 4.3 magnitude in 2017. This was “a large earthquake for this area,” he said.

Cummins expected aftershocks would probably be much lighter and felt in a smaller area.

Additional reporting by Penry Buckley and Australian Associated Press