SAR satellite data can play a key role in preventing mining failures and save lives

Mines can be dangerous environments. From fires, floods and landslides to explosions and collapse, workers in the mining industry face multiple risks. To protect against these, synthetic aperture radar (SAR) satellites can provide constant monitoring and surveillance to detect changes and instabilities in the terrain over time. Regular monitoring can improve the safety of mining operations, support the planning and management of processes and resources, and minimise negative impacts on the environment. SAR satellite technologies also improve the frequency and coverage of ground deformation monitoring with low incremental costs.

Devastating mining failures

In 2020, poor conditions at the Wai Khar opencast jade mine in Myanmar caused a landslide that killed more than 170 people. Heavy monsoon rainfall was initially assumed to be the sole cause. However, according to a study of satellite and remote-sensing data analysis published in the ISPRS Journal of Photogrammetry and Remote Sensing, mismanagement and poor design contributed to the tragedy.

In Myanmar, SAR imagery, alongside other aerial and satellite data and video footage from the ground, allowed researchers to build a comprehensive mapping to identify possible failure causes. They found that seepage failure may have been a critical factor in the incident. The failure occurred under normal to drier conditions, which means that the sliding planes were already in a critical state and were bound to fail.

The walls of the mine were dangerously steep considering the weak nature of the rock surrounding the pit, and images captured between 2013 – 2020 indicated periodic landslides had occurred in this area. Accelerated deformation was found, which highlighted the need for proper deformation management monitoring at mining sites.

As is the case for many rural and remote mining sites around the world, it was difficult to carry out field surveys at the Wai Khar jade mine. Accessibility issues, due to geography or safety, can lead to land displacement being unmonitored and the risk of physical asset damage being unmanaged. To overcome this challenge, SAR satellite data can be used to regularly monitor and survey large areas from above, providing frequent revisit rates at high resolution. Mining disasters can still happen even with sufficient safety practices, but the data can be instrumental in finding a cause and ensuring similar failures do not happen in the future.

Accurate analysis using satellite data

SAR satellites emit radar microwaves aimed at observation targets and receive radio waves that are bounced back from these targets. By analysing the phase of radar microwaves, it is possible to develop a detailed displacement and deformation information of the ground surface. Unlike other surveying techniques, such as ground or drone surveys and conventional optical satellites, SAR satellites can acquire highly accurate ground information in any climatological condition day or night.

Conventional monitoring techniques that use robotic total station have been around for a long time and are proven to be highly precise. However, they are known to have high implementation costs and provide limited area coverage. SAR satellite technologies through interferometric SAR (InSAR) provide comprehensive monitoring coverage over a wide area at a millimetre level and at low cost. SAR is particularly advantageous in mining areas and tailing dams that have been abandoned, providing the only economical choice in ensuring safety regulations and site management practices.

By monitoring the risk of land displacement and ground deformation that can lead to physical damage, failures can be avoided and the lifetime costs of the mine can be minimised. Regular monitoring can lead to the discovery of less stable ground and slopes, and non-uniformity displacement patterns between nearby locations and sudden displacement changes before it is too late and human lives are put at risk. By using SAR satellite technology services, mining operators will benefit from a more comprehensive awareness of their site and the surrounding areas. If warning signs are found, further monitoring and structural and strengthening improvements can be carried out to minimise risk.

Enhancing safety through data-driven decisions

Having access to high-quality, in-depth and accurate SAR satellite data should be a priority for all mining operators. Satellite data can explain the phenomena around mining sites and be used to reduce the risks of a devastating incident, or provide answers in the aftermath. It is a cost-effective method for ground deformation monitoring for mining sites that cover a wide area. If any issues or risks are highlighted, operators have time to take preventative measures, such as deploying more sensors in a specific area of concern.

Satellite data can provide a wider perspective, which is much harder to achieve from surveying on the ground. Frequent observations can give operators the vital information they need to make data-driven decisions and improve the overall safety and operations of their mining sites.

Read the article online at: https://www.globalminingreview.com/special-reports/05012022/sar-satellite-data-can-play-a-key-role-in-preventing-mining-failures-and-save-lives/