Satellite imaging of remote mining operations can be 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 – a vital component of mining management amid Covid-19-related travel restrictions being put in place by a growing number of countries around the world.
The outbreak of Covid-19 has led to most countries imposing travel bans, travel restrictions and quarantine measures on its citizens, thereby making it increasingly difficult for personnel to monitor remote mining operations.
Conventionally, in most cases, monitoring of such mines requires 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.
However, this can be costly, taking into account the cost of 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, says Earth observation software company Pinkmatter Solutions.
The company notes that satellite imaging has the potential to bridge the gap of conducting ongoing operational surface monitoring without interruption, using high-resolution satellite imagery coupled with a change detection and visualisation platform. This enables management and responsible persons to monitor mining operations from a secure location or from home if need be.
In this regard, Pinkmatter Solutions has developed a Web-based platform – the FarEarth Change Monitor platform − which is capable of performing calculations on-the-fly.
The platform relies on data obtained through technical partnerships with Earth observation satellite operators. This means the platform can be accessed anywhere in the world with Internet access and requires no specialist software to be installed.
FarEarth Change Monitor is highly automated and intuitive to use, with satellite image acquisitions having the ability to be scheduled according to the customers' requirements.
Once the image is acquired, products such as elevation models are available on the FarEarth Change Monitor platform within 48 hours. The subsequent images can be used 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 File Transfer Protocol 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.
Optical images are collected in the colour spectrums of red, green, blue (RGB) and near-infra red (NIR).
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.
The NIR spectrum enables environmental monitoring using the normalised 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, using 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.
Interferometry synthetic aperture radar (InSAR) can also be used to monitor surface subsidence, either as a result of 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. InSAR offers an alternative to generate volume products in areas prone to prolonged cloud cover, such as the equatorial regions.
Artificial intelligence 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 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.