Analyzing satellite data could have flagged structural issues ahead of a mining catastrophe that killed 270 people far enough in advance to take action to avoid the disaster, researchers recently concluded.
Images of a mine tailings dam owned by Vale SA that collapsed in 2019, killing at least 270 people near Brumadinho, Brazil, showed indications in advance of the disaster that problems were developing, researchers concluded. While mining companies use ground-based sensors to monitor dam stability, those devices do not provide a broader picture of the entire dam the way satellite imagery can, the researchers wrote.
The study used a satellite radar technique to measure millimeter-scale movements at the dam near Brumadinho, and the researchers said the results could prove useful to mitigate similar catastrophes in the future.
They wrote that tailings dams frequently shift during formation, but an accelerated movement is a precursor to a potential failure. Two of the study authors — Stephen Grebby, a professor at the University of Nottingham, and Andrew Sowter, chief technical officer at Terra Motion Ltd. — wrote in comments to S&P Global Market Intelligence that precursory movements at Brumadinho began about two months before the collapse.
"By studying the motion during this period, we found that the failure date could have been predicted to within a week of it happening, and this prediction would have been possible around 40 days prior to the collapse," Grebby and Sowter said. "This would have been adequate notice for appropriate action to have been taken to avert the disaster — whether that be implementing more detailed monitoring using different types of sensors or other mitigation measures."
The researchers said they used radar data from the Sentinel-1 satellite mission, which is free to use, and the data processing can be automated at a low-cost.
The technology does have some limitations. For instance, the terrain can obscure what the satellite can see, the researchers noted. Water on the surface of the tailings beach can also limit the measurements that can be analyzed.
The primary obstacles to using the tool are obtaining all of the needed measurements over the entire dam structure and interpreting what the detected motion means about the dam's stability, they wrote. The researchers said their work addressed both issues, and they are further developing the technique to provide an early warning system for potential dam failures.
