Monitoring Mining Activity with InSAR Technology
Douglas Park - New South Wales
Highlights
Effective Monitoring of Mining Activity Using InSAR Technology
Longwall mining is a common method for extracting coal from underground seams, but it poses significant environmental risks, particularly ground subsidence. This sinking of the land surface occurs due to the voids left by mining and can affect large areas long after operations have ended. The resulting ground deformation threatens natural ecosystems, infrastructure, and local communities, leading to issues like cracks in roads and changes in water flow. Therefore, effective monitoring is essential to mitigate these risks and protect both the environment and affected assets.
The Role of InSAR Technology in Monitoring Subsidence
What is InSAR?
Interferometric Synthetic Aperture Radar (InSAR) is an advanced remote sensing technology that uses satellite radar signals to accurately monitor ground movements. Unlike traditional methods that require on-site measurements, InSAR analyses radar images from different times to detect minute changes in the Earth's surface. By measuring phase changes in radar waves, it calculates ground displacement, providing high-resolution data over large areas, which is ideal for monitoring mining-induced subsidence.
Application in Douglas Park, New South Wales
Douglas Park, a mining region in New South Wales, Australia, served as an effective case study for using InSAR to monitor mining activity. Concerns about ground stability and its effects on infrastructure and the environment prompted a comprehensive study to assess InSAR's effectiveness in evaluating subsidence. Over twelve months, researchers analysed satellite data and compared it with traditional in-situ survey results. The findings highlighted InSAR's superiority in capturing detailed subsidence patterns across the large area impacted by mining.
Challenges of Traditional Surveying Methods
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Limited Coverage – Traditional surveys focus on specific points, making large-scale assessment difficult, especially in subsidence-prone areas like Douglas Park.
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Time-Intensive – Field measurements require significant time and resources, delaying critical insights in active mining regions.
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Safety Risks – Conducting surveys in unstable terrains poses hazards to personnel, highlighting the need for remote sensing alternatives.
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High Costs – Deploying survey teams and specialised equipment makes traditional methods expensive, particularly for long-term monitoring.
Benefits of using InSAR for Mining Monitoring
The Douglas Park study demonstrated several key advantages of InSAR over traditional monitoring methods:
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Wide Coverage – InSAR maps ground deformation across large areas, detecting subsidence patterns missed by point-based surveys, essential for monitoring mining impacts.
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High Precision – It detects movements as small as a few millimetres, ensuring accurate assessment of surface changes.
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Cost-Effective – By using satellite data, InSAR reduces the need for costly fieldwork, equipment, and personnel.
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Time-Efficient – Rapid data processing provides near-real-time insights, allowing proactive risk management.
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Non-Intrusive – As a remote sensing tool, InSAR minimises disruptions to communities and ecosystems, ideal for sensitive or hard-to-reach areas.
Comparing InSAR and Traditional Methods
In Douglas Park, researchers compared InSAR data with traditional in-situ surveys, yielding impressive results:
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Strong Agreement – InSAR closely matched conventional survey data, confirming its reliability.
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High Accuracy – Differences between InSAR and in-situ measurements remained within the ±15mm tolerance of traditional methods.
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Deeper Insights – InSAR’s ability to track temporal changes provided a more comprehensive understanding of ground movement dynamics.
These findings proved InSAR to be not just a viable alternative but a superior tool for monitoring mining-induced subsidence.
Broader Applications of InSAR in Mining
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Open-Pit Mining – InSAR detects early signs of slope instability, helping prevent wall failures and collapses.
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Tailings Storage Facilities – Continuous InSAR monitoring enhances dam stability assessments, reducing the risk of structural failures and environmental disasters.
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Infrastructure Protection – InSAR monitors ground movement near railways, pipelines, and buildings, aiding maintenance and risk mitigation.
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Environmental Monitoring – It tracks changes in landforms, water bodies, and vegetation, helping minimise mining's environmental impact.
Respecting Local Communities and the Environment
Mining often affects local communities and indigenous groups, with subsidence in areas like Douglas Park threatening livelihoods, cultural heritage, and ecosystems.
InSAR technology provides accurate, timely data, enabling stakeholders to:
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Make Informed Decisions – Authorities can regulate mining and enforce safety measures using InSAR insights.
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Protect Communities – Proactive monitoring minimises subsidence impacts on homes and cultural sites.
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Promote Sustainability – Continuous tracking of land and water resources supports environmentally responsible mining.
Prospects for InSAR in Mining
The Douglas Park study showcases InSAR’s transformative potential for mining. Future advancements may enable:
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Real-Time Monitoring – Faster processing for instant alerts on ground deformation.
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Data Integration – Combining InSAR with LiDAR, GNSS, and optical imagery for deeper insights.
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Greater Accessibility – Lower satellite data costs making InSAR viable for all mining operations.
Conclusion
InSAR is revolutionising mining impact monitoring by offering accurate, cost-effective, and wide-area insights into ground deformation. It overcomes traditional survey limitations, enhancing the protection of both natural landscapes and infrastructure. The Douglas Park study highlights its effectiveness in risk mitigation and sustainable mining. As the industry advances, InSAR will be key to ensuring safer, more resilient operations.
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Want to learn more? Contact Geofem today to discover how InSAR can support your geotechnical needs.
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