By Nicolaas SteenkampHealth related travel restrictions have added to the challenges of monitoring remote mining operations, but satellite imagery offers the solutions. After Covid-19 was declared a pandemic by the World Health Organisation (WHO), most countries have responded by imposing travel bans, travel restrictions and quarantine measures. Monitoring of remote mining operations have always been notoriously challenging to monitor. In most cases it would require mobilising skilled resources to visit the operations, conduct the legal observations such as environmental monitoring or safety inspections of excavations or material storage facilities or physical surveys. This also comes with a substantial price tag for travel, living-out allowances or danger pay. For the near future it would also appear that the viability of ad hoc site visits would be restricted. There is however a quick and easy to implement solution to conduct on-going operational surface monitoring without interruption. High resolution satellite imagery coupled with a change detection and visualisation platform being one of the top options. This allows management and responsible persons to monitor mining operations from a secure location or from home if need be. Pinkmatter Solutions have developed the FarEarth Change Monitor platform and have technical partnerships with the leading Earth observation satellite operators. The FarEarth Change Monitor is a web-based platform, capable of performing calculations on-the-fly. This means the platform can be accessed anywhere in the world with internet access and requires no specialist software to be installed and flexible subscription options. The platform is highly automated and intuitive to use. Satellite image acquisitions can be scheduled according to the customer’s requirements. Once the image is acquired, products such as elevation models are available on the change monitor platform within 48 hours. The subsequent images can be utilised for surface change monitoring, with the value of the interpretations and data increasing as the number of images in the series increases. Selected products can also be downloaded from a secure FTP site. High level observations and monitoring can be done by scrutinising high resolution optical images that have been cropped to focus on the mining operations or the general area of interest. These images are frequently printed in large format and pinned to offices walls and form the focus for planning or updating meetings. Optical images are collected in the red, green, blue (RGB) and near-infra red (NIR) spectrums. The imagery is used to track and visually represent surface changes, ranging from the areal extent of surface operations, surface water, surface disturbances and the addition or removal of surface infrastructure. FarEarth Change Monitor allows users to draw their own area of interest polygons, lines or points to measure objects at a specific time or to display changes over a time series. These measurement and shapes can then be shared with other users on the same platform and is a very popular application during management or board meetings.
The NIR spectrum also allows for environmental monitoring using the normalized difference vegetation index (NDVI), where the distribution of green vegetation can be monitored. Phenology curves and classes are displayed in easy to understand graphs by the FarEarth Change Monitor.It is also possible to perform volume calculations of excavations and material stockpiles or residue deposits, utilising photogrammetry. The volumes are displayed by the FarEarth Change Monitor for a single observation and over a time series, offering a quick and easy way to monitor the movement of materials and stockpiles. Two clicks are all it takes to draw a cross-section of either the topography or mining operation features. Interferometry synthetic aperture radar (InSAR) is used with great success to monitor surface subsidence, either due to natural processes, such as karst landscape formation in dolomitic areas or as a result of mining induced subsidence. It is also used in stability monitoring of tailing storage facilities and dam walls. SAR offers an alternative to generate volume products is areas prone to prolonged cloud cover, such as the equatorial regions. Artificial intelligence (AI) can also aid in risk identification and remediation. Functions range from fire detection platforms, like the FarEarth FireBox that alerts emergency response teams to active fires in near real time. It also offers the ability to manage environmental social and government (ESG) issues proactively through applications such as settlement expansion or encroachment monitoring on mining lease areas. The system can also assist in detecting unauthorised activity on-site during a period of temporary suspension of operations. Satellite imagery-based change detection and reporting platforms offers a safe and cost-effective alternative to remote site monitoring. Allowing companies, the ability to remain up to date on operational and site issues, without having a constant site presence.