15 September 2022

Provisional InSAR data for the Jagersfontein Tailings Storage Facility failure

Posted by Dave Petley

Provisional InSAR data for the Jagersfontein Tailings Storage Facility failure

The fallout from the failure of the Jagersfontien Tailings Storage Facility (TSF) continues to develop, with increasing levels of interest in the owners, Jagersfontein Developments, and their political connections. Interestingly, In February 2021 the mayor of Kopanong Local Municipality Xolani Stalin-Tseletsele posted concerns about the facility on Facebook. He stated that: “If that dam breaks loose, the muddy water will ruin lives, cause deaths and damage the community”.  Prescient words indeed.

Meanwhile, once again this failure has sent a warning more widely about the danger posed by large tailings facilities.  I wonder if high energy costs are leading to a reduction in maintenance and monitoring of these facilities, with a resultant potential for failure.

Meanwhile, independent analyses of failure are being undertaken by the science community.  My friends at CGG Minerals and Mining, a data and analytics company with high levels of expertise in the use of InSAR analysis, have been quickly out of the blocks.  I’m posting the below with their permission, but you can see their original analysis on LinkedIn.

They have posted a high resolution satellite image of the aftermath of the failure, annotated with the key features:-

A high resolution satellite image of the aftermath of the Jagersfontein Tailings Storage Facility failure.

A high resolution satellite image of the aftermath of the Jagersfontein Tailings Storage Facility failure. Image processed by CGG Minerals and Mining, used with permission.

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The image highlights key features that I identified earlier this week, including the main breach with the three other locations of substantial erosion.  It is interesting that they have also identified damage to the dam crest on the west side of the TSF.  Of greater potential significance is a provisional InSAR analysis that they have undertaken for deformation between 1 and 13 August 2022:-

INSAR analysis of pre-failure deformation at the Jagersfontein Tailings Storage Facility.

InSAR analysis of pre-failure deformation at the Jagersfontein Tailings Storage Facility. Image processed by CGG Minerals and Mining, used with permission.

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CGG Minerals and Mining have provided their own interpretation of the data:-

CGG Minerals and Mining interpretation of their analysis of the Jagersfontein Tailings Storage Facility failure.

CGG Minerals and Mining interpretation of their analysis of the Jagersfontein Tailings Storage Facility failure. Copyright CGG Minerals and Mining, used with permission.

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The key element here is that deformation was observed in this image pair, and in others, in the walls at the southeast side of the TSF.  The element that I find most interesting is that a part of this section was showing movement away from the satellite, whist another section was showing movement towards it.  The junction between the two is close to the apparent failure point.

These types of analyses are very provisional at this stage, but may point to deformation of the TSF walls that led to failure.

As always, a forensic analysis of the events of Jagersfontein by an independent team of experts is needed urgently.  Mining Weekly has reported that “investigations are under way with the appointment of a task team to determine the cause of the incident and the extent of the damage”. At present there is little further detail that I can find.

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Acknowledgement

Many thanks to my friends at CGG Minerals and Mining for the analysis highlighted here and for their willingness for me to post their results.