Newmont Corporation has suspended underground operations at its Cadia mine in New South Wales, Australia, following a series of seismic events that struck the region over the weekend. The suspension comes after two distinct earthquakes, measuring 3.4 and 3.2 in magnitude, were recorded in the vicinity of the world-class gold and copper operation.
The decision to halt activity underscores the ongoing geotechnical challenges at the site, which remains a cornerstone of Newmont’s global portfolio. Cadia, located near Orange in the Central West region of NSW, is one of the largest underground gold mines in the world and currently accounts for approximately 11% of Newmont’s total Net Asset Value (NAV).
While no injuries or significant structural damage were immediately reported, the company has prioritized safety and ground stability assessments. The pause in production at such a high-output facility raises immediate questions regarding Newmont’s quarterly production targets and the broader stability of the Australian gold supply chain.
Seismic activity disrupts operations
The first earthquake, a magnitude 3.4 event, occurred in the early hours of the weekend, followed shortly by a magnitude 3.2 aftershock. While these magnitudes are considered small-to-moderate by global standards, their proximity to underground workings necessitates an immediate cessation of activities under Newmont’s strict safety protocols.
At Cadia, mining is primarily conducted through large-scale block caving: a method that involves undermining an ore body and allowing it to progressively collapse under its own weight. While highly efficient for massive deposits, block caving is inherently sensitive to seismic shifts, which can alter stress distributions within the rock mass and potentially compromise extraction levels or ventilation shafts.
Newmont’s technical teams are currently utilizing an extensive network of on-site seismic sensors and micro-seismic monitoring equipment to evaluate the impact on the mine’s lower levels. Underground personnel were safely evacuated to the surface following the initial tremor, and access to the underground workings will remain restricted until a thorough geotechnical review is completed.
A history of geotechnical challenges
This recent cluster of seismic events is not an isolated incident for the Cadia operation. The region has a documented history of seismicity that has previously forced operational adjustments. In April 2026, a more significant magnitude 4.5 earthquake struck the Orange district, leading to a multi-week suspension of work while engineers assessed the integrity of the tailings storage facilities and underground infrastructure.
Going further back, a 2017 seismic event led to a three-month shutdown of the Cadia East underground mine. These recurring events highlight the geological complexity of the Lachlan Fold Belt, where Cadia is situated. For Newmont, which acquired the asset through its multibillion-dollar merger with Newcrest Mining, managing this geotechnical risk is a permanent feature of the operational plan.
The frequency of these events in 2026 has prompted some analysts to call for enhanced regional monitoring. "When you have a tier-one asset like Cadia facing repeated downtime, it moves from a 'one-off event' to a systemic operational risk that needs to be priced into the NAV," noted one mining analyst following the news.
Financial and market significance
The halt at Cadia is significant not just for its volume: producing hundreds of thousands of ounces of gold and thousands of tonnes of copper annually: but for its impact on Newmont’s financial standing. As the mine represents roughly 11% of the company's NAV, any prolonged disruption could weigh on the company’s stock performance and regional production guidance.
Cadia is a low-cost producer, benefiting from significant copper by-product credits that drive down the All-In Sustaining Cost (AISC) per ounce of gold. This makes it a high-margin engine for Newmont’s Asia-Pacific mining operations. Investors are particularly sensitive to disruptions at Cadia because of its role in offsetting higher-cost operations in other parts of the Newmont portfolio.
Market watchers are now looking to the company’s next production update to see if the June cluster of earthquakes will necessitate a revision of 2026 guidance. While Newmont has a diverse global footprint, the "Big Three" Australian assets: Cadia, Boddington, and Tanami: are vital to its gold production leadership.
Operational response and safety-first culture
Newmont has consistently emphasized that safety takes precedence over production volumes. The current suspension is a reflection of this "Safety First" culture. The company’s response includes:
- Comprehensive Ground Support Inspection: Engineering teams are inspecting the integrity of bolts, mesh, and shotcrete used to stabilize the underground tunnels.
- Seismic Data Analysis: Reviewing the data from the weekend's tremors to see if they indicate a shift in the local fault lines.
- Tailings Facility Review: Though underground activity is the primary concern, the integrity of the tailings storage remains a priority for environmental and regulatory compliance.
The use of autonomous technology and remote monitoring has also allowed Newmont to keep a "digital eye" on the mine without putting personnel at risk. The integration of advanced technology in mining has significantly improved the speed at which companies can respond to such events, moving from manual inspections to data-driven stability assessments.
Looking ahead: 2026 Outlook for Cadia
The duration of the current halt remains uncertain. If the geotechnical assessment reveals no significant damage, operations could resume within days. However, if the quakes have caused localized rock bursts or damage to critical infrastructure, the suspension could stretch into weeks.
For the broader mining industry, the situation at Cadia serves as a reminder of the inherent risks of deep-level underground mining. As companies push deeper to access higher-grade ore bodies, the management of rock stress and seismic activity becomes increasingly central to operational success.
Newmont is expected to provide a formal update to the market once the initial assessments are finalized. For now, the focus remains on ensuring that when the drills start turning again, they do so in a stable and secure environment.
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? Newmont Halts Cadia Operations Following Twin Earthquakes ?
Newmont has suspended underground mining at its flagship Cadia mine in NSW after magnitude 3.4 and 3.2 tremors. With Cadia accounting for 11% of Newmont's NAV, the suspension highlights the geotechnical risks facing one of the world's premier gold and copper assets. Safety assessments are underway. #MiningNews #GoldMining #Newmont #Cadia #MiningSafety #ASX #GoldPrice
