Conservation news

Database offers new details on the dams that hold mining waste

  • A new database called the Global Tailings Portal pulls together information on 1,700 dams that store waste, or tailings, from mines around the world.
  • Around 100 publicly traded companies have shared information about their dams with GRID-Arendal, the Norwegian foundation that developed the database.
  • The portal’s creators say that much of the information, including the size, location, and risk factors associated with the included dams, hasn’t been publicly available before, even as catastrophic dam failures continue to occur.

On Jan. 25, 2019, the Brumadinho dam collapsed, releasing a slurry of water containing the waste products, or tailings, from the Córrego do Feijão iron ore mine in southeastern Brazil. The deluge that surged downstream killed 270 people, and for Vale, the company that ran the mine, it was the second such deadly accident in less than four years.

That catastrophe spurred a group of institutional investors to ask more than 700 mining companies to share information about how they store tailings at their mines. From the responses, GRID-Arendal, a Norway-based foundation, created the Global Tailings Portal, launched on the one-year anniversary of the Brumadinho collapse.

“This portal could save lives,” Elaine Baker, a geosciences professor with the University of Sydney in Australia and senior expert at GRID-Arendal, said in a statement.

The effects of climate change on the stability and lifespan of a tailings dam. Image by Kristina Thygesen/GRID-Arendal.

The database is aimed at investors, as well as communities, companies and regulators.

“With this information, the entire industry can work towards reducing dam failures in the future,” Baker added.

Estimates vary widely about the number of tailings dams that exist around the world. GRID-Arendal figures there are somewhere between 3,500 and 33,000 active and inactive dams, including a number of “orphaned” dams where it’s not clear who is responsible for ensuring they don’t threaten local communities and ecosystems. Baker also noted that the characteristics of dams and what they contain have changed over time, increasing the need for more transparency.

“Dams are getting bigger and bigger,” Baker said. “Mining companies have found most of the highest-grade ores and are now mining lower-grade ones, which create more waste.”

An iron ore railway bridge destroyed by mudflow, 3 kilometers (1.9 miles) downstream from the collapsed dam in Brumadinho. Image by Guilherme Venaglia via Wikimedia Commons (CC BY-SA 4.0).

A 2017 report by GRID-Arendal and the United Nations Environment Programme aimed to assess the risks from the ballooning number of tailings storage facilities. It laid out how climate change has altered the calculus on what types of structures can withstand expected weather patterns and how long the dams are expected to last.

But GRID-Arendal said that much of the data necessary for that report wasn’t readily available. That gap led the authors to recommend the development of a resource along the lines of the mine tailings portal.

Around 100 publicly listed companies of the 727 contacted after the Brumadinho disaster turned over information on their tailings dams. The portal now allows users to see where around 1,700 are located, which company owns them, and the severity of the consequences if they fail.

“Most of this information has never before been publicly available,” Kristina Thygesen, who leads GRID-Arendal’s geological resources program, said in the statement. The organization plans to continue to gather information from mining companies, including privately held ones.

A mining operation, illustrating a typical process in an open-pit mine, from excavation to waste disposal. Image by Kristina Thygesen/GRID-Arendal.

The team also plans to incorporate satellite monitoring of existing dams.

“This database brings a new level of transparency to the mining industry,” Thygesen said, “which will benefit regulators, institutional investors, scientific researchers, local communities, the media, and the industry itself.”

Banner image of the rupture of the Brumadinho dam in Brazil by IBAMA via Wikimedia Commons (CC BY-SA 2.0).

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