On April 14, a magnitude 4.5 earthquake struck Central New South Wales (NSW), around 35 kilometres from the town of Orange. It is the largest seismic event ever recorded in the region, with tremors reportedly felt as far away as Sydney, more than 250 kilometres to the east.
The earthquake shook homes in Orange for some 30 seconds, according to the Australian Broadcasting Corporation (ABC), but fortunately no major injuries were recorded. Geoscience Australia received almost 2,300 reports of tremors, the federal government’s earthquake monitoring agency told the Guardian.
The quake’s epicentre was near the Cadia Valley gold and copper mine, operated by Newmont Corporation. The initial earthquake struck at 8:19 p.m., with a magnitude 2.4 tremor recorded at 8:25 p.m. and a magnitude 2.2 shock at 8:50 p.m., all in the vicinity the Cadia mine site.
The 153 miners working underground at the time sheltered in emergency refuge chambers, with the last workers only returning to the surface at around 7 a.m., more than 10 hours after the earthquake.
The company reported no injuries. The site was evacuated and underground operations halted pending inspection. The company later stated that “while damage is present in certain underground areas, it is not significant.”
Mining.com.au wrote, “Newmont does not expect earthquake-affected Cadia to return to full capacity until at least the third quarter of 2026. At least five weeks of underground rehabilitation work will be carried out that will help the mine return to 80 percent operating capacity.”
Newmont is a multinational mining company producing a range of metals. Its Cadia gold mining operation is one of the biggest in Australia and, according to Mining Data Online, employed 1,343 workers directly and 1,028 contractors as of 2023.
Bruce Reynolds, mayor of Orange, told the Sydney Morning Herald, “a number of members in the community have anxiety and some concerns about a potential link between the earthquake activity and the mining activity.”
The University of Queensland Sustainable Minerals Institute explained that, while tectonic forces are the primary cause of earthquakes, human activity can also alter stress in the earth’s crust sufficiently to produce what scientists call “induced” earthquakes—seismic events that would not have occurred without human intervention. A related category, “triggered” earthquakes, describes events on existing fault lines that human activity has brought forward in time. Mining is among the human activities known to produce both.
A 2007 study, “Geomechanical modeling of the nucleation process of Australia’s 1989 M5.6 Newcastle earthquake,” found that decades of deep coal mining in the region likely contributed to the 1989 Newcastle earthquake. The Newcastle quake, one of the strongest in Australian history, killed 13 people, hospitalised more than 160 and damaged thousands of buildings.
On April 25, 2006, mining-induced seismic activity triggered a rock-fall at Beaconsfield Gold Mine in Tasmania, trapping three workers almost one kilometre underground. One of the trapped workers, Larry Knight, was killed in the collapse. Todd Russell and Brant Webb survived the rock-fall, but were trapped underground for 14 days before they were finally freed.
The earthquake at Cadia last month was not the first in the mine’s vicinity. In April 2017, a magnitude 4.3 earthquake—at that time the largest recorded in the region—forced miners into refuge chambers for seven hours before they could safely evacuate. Then owner Newcrest declared underground damage minimal, yet remediation work took nearly five months before operations returned to pre-earthquake levels.
The ABC reports that since the 1960s, around 22 earthquakes have been recorded within 10 kilometres of this location, most measuring between magnitude 2 and 3. While the current Cadia Valley Operations opened in 1998, the first underground mining in Cadia began in the 1860s.
Geophysics research fellow at the University of Melbourne, Dan Sandiford, told the ABC “For a case like the Cadia mine, where there’s been two earthquakes above magnitude 4, I think most seismologists would certainly suggest it’s very likely that the mining there is responsible for stress changes that would have led to seismic slip on faults potentially beneath or around the mine.”
Sandiford noted that determining conclusively whether the tremor was mining-related was difficult without close monitoring. Newmont operates its own seismic monitors at the mine, but that data is not publicly accessible.
Senior seismologist at Geoscience Australia Jonathan Bathgate stated, “It’s not our role to monitor mining activity—our role is really around that national scale earthquake hazard.”
In other words, it is left up to the mining companies themselves to monitor the impact of their operations on ground stability.
The closest seismic monitor to Cadia accessible to the agency is located more than 90 kilometres away in Oberon. There are only around 100 publicly accessible seismic monitors across the entirety of Australia. Bathgate said “We’d really love to have more data coming in so that we could locate earthquakes more accurately and to lower magnitudes.”
NSW Labor Minister for Natural Resources Courtney Houssos downplayed the concerns of residents and seismologists, telling the ABC the link between mining and earthquakes “is not supported by any current scientific evidence.”
To acknowledge the mining-earthquake link would raise the need for greater monitoring, stricter regulation, and restrictions to mining operations, none of which the pro-business Labor government has any intention of implementing.
Houssos’ dismissive comments recall the statement of Premier Chris Minns after last year’s explosion at Endeavor Mine in Cobar, which killed Patrick “Ambrose” McMullen and Holly Clarke. Minns blithely declared, “we can’t stop all accidents on work sites, and we can’t promise that. No responsible government can do that.”
Significantly, Minns made these comments to a meeting of delegates and officials from the Australian Workers Union (AWU), one of the two main unions covering mining workers. That the AWU bureaucracy, along with the leadership of the Mining and Energy Union (MEU), agrees with this position, that nothing can be done to prevent ongoing workplace deaths, is clearly expressed in the unions’ silent complicity in the reopening of Endeavor without any official explanation of what caused the blast.
In similar fashion, neither of the mining unions have issued a public statement about the Cadia earthquake, despite the clear threat it posed to the lives of the 153 workers who were trapped underground.
This is because the unions, like Labor, represent the interests of big business, whether by imposing sellout enterprise agreements that slash real wages, conditions and job security, covering over the environmental impacts of industry and suppressing any struggle by workers against unsafe conditions.
Nor can workers afford to place their lives in the hands of the official safety regulators, which, together with the unions, have presided for decades over the scourge of workplace fatalities and serious injuries. Their role is to cover up the responsibility of companies for these “accidents” and ultimately to conceal the real underlying cause of industrial deaths, the capitalist system, under which the health and lives of workers and the environment are subordinated to profit.