Eagle Gold Mine: Ground Displacement Monitoring Could Have Intervened

Introduction

On June 24, 2024, a catastrophic landslide occurred at the Eagle Gold Mine in Yukon, Canada. The failure, spanning approximately 1.3 kilometres along a heap leach pad, sent shockwaves through the mining industry and local community. While the immediate aftermath focused on emergency response and containment, the incident raises critical questions about risk assessment and monitoring practices at mining operations worldwide.

At Geofem, our team of remote sensing experts conducted a comprehensive analysis of satellite data capturing the two years leading up to this failure. Our findings reveal a troubling pattern of precursory deformation that, had it been properly monitored and interpreted, could have provided crucial early warning signs.

The Eagle Gold Mine: Background and Significance

The Eagle Gold Mine, located in the Yukon Territory of Canada, is one of the region's largest gold mining operations. The mine utilises heap leaching technology, a process where ore is crushed and stacked on specially designed pads, then treated with a cyanide solution to extract gold.

These heap leach pads are massive engineered structures, often containing millions of tons of crushed ore. Their stability depends on careful design, construction, and monitoring, as failures can lead to environmental contamination, operational disruptions, and potential safety hazards.

The June 24 Landslide: What Happened

The landslide at Eagle Gold Mine occurred suddenly but not without warning signs. A massive section of the heap leach pad failed, creating a 1.3-kilometre-long displacement zone. The failure involved the movement of hundreds of thousands of cubic meters of material, disrupting mining operations and raising concerns about potential environmental impacts.

Fortunately, no casualties were reported however, the economic and environmental consequences have been substantial.

Geofem's InSAR Analysis: Revealing the Warning Signs

Our team at Geofem analysed satellite radar images spanning from June 2022 to June 2024, with the final image captured just four days before the catastrophic failure. Using Interferometric Synthetic Aperture Radar (InSAR) technology, we were able to detect and measure surface deformations with millimetre-level precision over this two-year period.

Methodology

Our analysis employed advanced Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS) techniques to process the radar data. These complementary ground displacement monitoring approaches allowed us to identify both gradual deformations and more rapid changes in surface stability. By creating time-series deformation maps, we could track the evolution of surface movements across the entire mine site, with particular focus on the heap leach facilities.

Key Findings

Our analysis revealed several critical insights:

1. Precursory Deformation: Beginning approximately 8 months before the failure, our data shows clear evidence of accelerating deformation along what would eventually become the main failure zone. Initial movements were subtle—just 2-3 mm per year—but steadily increased to over 15 mm per year in the final weeks before collapse.

2. Spatial Pattern: The deformation pattern showed a distinctive horseshoe shape that closely matched the eventual failure geometry. This pattern is characteristic of deep-seated rotational failures in engineered slopes and could have served as a clear indicator of the failure mechanism.

3. Acceleration Phases: We identified three distinct acceleration phases in the deformation time series:

   • Phase 1 (October-December 2023): Initial slow movements averaging 2-5 mm/year

   • Phase 2 (January-April 2024): Moderate acceleration to 5-10 mm/year

   • Phase 3 (May-June 2024): Rapid acceleration exceeding 15 mm/year, with localized areas showing displacement rates up to 25 mm/year just days before failure

4. Temperature Correlation: Our analysis identified a correlation between increased deformation rates and spring thaw conditions, suggesting that water infiltration and changing pore pressures likely contributed to the ultimate failure mechanism.

"The patterns observed in our InSAR analysis show a textbook case of progressive failure that provided nearly 8 months of warning signals."

Interpreting the Data

The patterns observed in our InSAR analysis are consistent with a progressive failure mechanism where initial small-scale movements gradually evolved into a catastrophic event. The acceleration pattern follows what is known in geotechnical engineering as "tertiary creep"—a phase of accelerating deformation that typically precedes catastrophic failure.

Most significantly, the final InSAR image captured just four days before the event showed deformation rates that had reached a critical threshold typically associated with imminent failure. Had this data been available and properly interpreted in real-time, it could have provided approximately 8 months of warning time—potentially enough to implement mitigation measures or at minimum ensure complete evacuation of at-risk areas.

Ground Displacement Monitoring: Preventing Future

Failures

Building on our InSAR capabilities, Geofem has developed advanced landslide susceptibility mapping techniques that combine satellite-based deformation data with geotechnical models and machine learning algorithms.

By integrating these diverse datasets using machine learning algorithms, we create high-resolution susceptibility maps that classify terrain into risk categories ranging from "very low" to "very high" probability of failure.

Application to Mining Operations

When applied to the Eagle Gold Mine scenario retrospectively, our susceptibility modelling would have classified the failed heap leach area as "high risk" based on several factors:

1. The relatively steep angle of the heap leach pad foundations

2. The presence of previous minor instabilities detected through InSAR

3. The susceptibility of the area to seasonal water infiltration

4. The increasing load as the heap leach pad was expanded

Such classification would have triggered enhanced monitoring protocols and potentially proactive maintenance efforts against damage.

The Value of Proactive Monitoring: Lessons from Eagle Gold Mine

The Eagle Gold Mine landslide demonstrates both the consequences of inadequate monitoring and the potential benefits of advanced InSAR-based surveillance systems. Had our monitoring approach been implemented at Eagle Gold, several intervention points would have been possible:

"In geotechnical engineering, what we choose not to measure ultimately becomes what we cannot control."

Early Warning Timeline

Based on our analysis, an effective monitoring program would have generated alerts at these critical junctures:

• 8 months before failure: Initial detection of systematic deformation would trigger enhanced monitoring

• 5 months before failure: Recognition of acceleration patterns would prompt detailed geotechnical assessment

• 2 months before failure: Deformation rates exceeding threshold values would necessitate development of mitigation strategies

• 3 weeks before failure: Critical acceleration would trigger emergency protocols and possible operational adjustments

Each of these intervention points represents an opportunity to prevent the ultimate catastrophic failure or at minimum mitigate its impacts through controlled management.

Economic Benefits of Prevention

Beyond the obvious safety advantages, the economic case for implementing advanced monitoring is compelling:

1. Direct Cost Avoidance: The Eagle Gold Mine failure is estimated to result in tens of millions of dollars in direct clean-up costs, facility reconstruction, and operational downtime.

2. Regulatory Compliance: Mining operations demonstrating proactive monitoring typically face fewer regulatory hurdles and enjoy more streamlined permitting processes for expansions or modifications.

3. Insurance Benefits: Many insurers now offer premium reductions for mining operations that implement comprehensive monitoring programs, recognising the reduced risk profile.

4. Operational Optimisation: The same InSAR data used for safety monitoring can inform operational decisions about ore placement, equipment routing, and infrastructure development.

Our analysis suggests that implementing a comprehensive InSAR monitoring program typically costs less than 0.5% of the potential losses from a major failure event, representing an exceptional return on investment.

"The most expensive monitoring system is still orders of magnitude cheaper than the cost of a catastrophic failure."

Implementation Strategies: Making Monitoring Work

For mining operators interested in enhancing their geohazard management approach, we recommend a phased implementation of advanced monitoring:

Phase 1: Baseline Assessment

• Historical InSAR analysis to identify pre-existing deformation patterns

• Development of site-specific landslide susceptibility maps

• Identification of critical monitoring areas and threshold values

Phase 2: Monitoring System Implementation

• Establishment of regular InSAR acquisition schedule (typically bi-weekly)

• Integration of InSAR data with on-site instrumentation

• Development of automated alert systems for threshold exceedances

Phase 3: Response Protocol Development

• Creation of tiered response protocols based on deformation magnitudes and rates

• Staff training on interpretation and decision-making

• Integration with emergency response and business continuity plans

Phase 4: Continuous Improvement

• Regular review and refinement of threshold values based on observed behaviour

• Periodic validation of susceptibility maps with observed conditions

• Knowledge-sharing across similar operations to enhance industry practices

"Advanced InSAR monitoring doesn't just detect problems—it provides the time needed to solve them before they become disasters."

Conclusion: A Call for Industry Evolution

The Eagle Gold Mine landslide represents both a failure of existing monitoring practices and an opportunity for industry-wide improvement. The technologies needed to prevent such incidents are not futuristic concepts but commercially available solutions that can be implemented today.

At Geofem, we believe that comprehensive InSAR monitoring combined with advanced landslide susceptibility mapping should become standard practice for all major mining operations, particularly those involving large engineered slopes and heap leach facilities. The evidence from Eagle Gold Mine is clear: the warning signs were present and detectable through readily available technology.

As the mining industry continues to develop increasingly large and complex operations in challenging environments, the adoption of advanced monitoring approaches will be essential not just for risk management but for the industry's social license to operate. The June 24 failure at Eagle Gold Mine should serve as a catalyst for this evolution—a reminder that in geotechnical engineering, what we choose not to measure can ultimately lead to what we cannot control.

Through proper implementation of InSAR monitoring and susceptibility mapping, the next potential disaster can be transformed into a success story of prevention through technology. The tools are ready; the question is whether the industry is ready to embrace them.

For more information about Geofem's InSAR monitoring services and landslide susceptibility mapping capabilities, contact our team at info@geofem.com or visit www.geofem.com/contact.