Full life cycle monitoring of TSF by satellite
Satellite imagery is a flexible and cost-effective means of monitoring tailings storage facility sites (TSF) over the full life cycle, writes Sonja Goosen (Managing Director) and Nicolaas Steenkamp (Earth Observation Manager) from Pinkmatter Solutions, South Africa.
Satellite imagery change detection and monitoring meets the six principles as set out by the Global Industry Standard on Tailings Monitoring (GISTM). The affected communities can be delineated, and a very visual presentation done on the potential impact of the TSF. By including the imagery along with the value-add change layers, on a dashboard, allows users to have an integrated knowledge base of all the factors, both direct and indirect, that is influenced by the TSF over the full life cycle.
Satellite imagery is used to generate digital elevation models of the selected area. This is used in planning of placement, the design and orientation of the TSF, regional hydrological studies and potential environmental impact footprint. Once the TSF enters into the construction phase, the satellite imagery products are used for monthly engineering and survey reports along with the quality assurance. The imagery and volume products are generally included in progress reports and the conformance to the design line and grade of the dam under construction.
During the operational phase, high resolution optical imagery is assisting the periodic site inspections and geotechnical evaluation of the wall conditions, including the general conditions, presence of erosion and cracking that could potentially result in failure of the dam wall. An important component is pond management, where stereo optical or SAR imagery is used to determine the remaining freeboard of the TSF, track the tailings deposition rate and the potential of over-topping of the facility.
The volume products can also be used to detect volume changes and deformation over time. Synthetic Aperture Radar (SAR) is used to detect millimetre vertical and horizontal displacement and the rate of displacement to create alerts of potential failure of dam walls, where it exceeds the normal settling rate.
The most common approach is to use the inverse velocity graphs to anticipate potential failure. The potential Tailing Spill Path (TSP) can also be generated as part of the risk management plan and emergency response in the event of a catastrophic failure. AI methods also allow dwellings to be automatically detected within the mining lease area and the TSP, using high resolution satellite images. Further applications include, support of the Environmental, Social and Corporate Governance (ESG) reporting and the Social and Labour Plan (SLP).
In the post-closure phase of the TSF, satellite data, both optical and SAR, are used to undertake continuous monitoring, including stability, environmental impact, and potential illegal mining. The volume products can also be utilised for calculating the potential of material available for reprocessing. The products can also be used to monitor the success of rehabilitation of the mine site.
This article was sponsored by Pinkmatter Solutions. If you are interested in sponsoring articles or advertising on the WhyAfrica website, in its newsletters or in the upcoming November digital magazine, please contact me on firstname.lastname@example.org.
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