On 5 November 2015, a waste dam at an iron-ore mine in southeastern Brazil collapsed, unleashing a tide of slurry that killed 19 people, displaced hundreds more and polluted 650 kilometres of fertile valleys and estuaries before spewing into the ocean.
Two years later, fishing communities near the mouth of the still-contaminated Rio Doce on the Atlantic coast continue to struggle as a result of Brazil’s worst-ever environmental disaster.
“The social structure of this region has been turned upside down,” says Joca Thomé, a resident of the hard-hit coastal village of Regência and a leader of official efforts to monitor the damage to local biodiversity.
“Many families here lived from fishing, but because of the risk of contamination it is still prohibited,” Thomé told UN Environment. “Tourists stay away because the water quality is low and surfing is not recommended. A few still come, but only to look at what has happened to the river and the ocean.”
Although the number of dam failures has declined over many years, the number of serious failures has increased, despite advances in the engineering knowledge that can prevent them.
The Germano mine collapse is one of a catalogue of similar incidents highlighted in a new Rapid Response Assessment calling for international action to make the storage of mine waste more secure. The report was published jointly by UN Environment and GRID-Arendal, a UN Environment collaborating centre.
“Mine Tailings Storage: Safety Is No Accident” laments that, although the number of dam failures has declined over many years, the number of serious failures has increased, despite advances in the engineering knowledge that can prevent them.
The consequences, as at the Germano mine, can be a “tsunami-like wave of mine waste capable of destroying everything in its path” and inflicting long-term damage to the environment and the communities that depend on it.
While there is no publicly accessible inventory of tailings dams, one estimate has put their number at 3,500 worldwide. This is likely an underestimate since there may be more than 30,000 industrial mines across the world, although not all of these will have a tailings dam. The global volume of stored tailings is also unknown. However, recent disasters illustrate the potential scale of accidents.
The collapse of the dam at the Germano mine, which is owned by global mining giants Vale and BHP Billiton, released more than 33 million cubic metres of tailings, or waste left over from the processing of the ore. The mudflow destroyed forest along the river banks, wiped out fish and other wildlife and coated the river’s bed and banks with infertile sludge.
A dam failure at the Mount Polley copper and gold mine in British Columbia, Canada in 2014 released a similar volume of waste into a nearby lake, says the UN report. It lists a total of 40 such incidents in the past decade alone.
The report makes two central recommendations that can help the industry to eliminate tailing dam failures.
Firstly, it calls for a “safety-first” approach to tailings storage that should be reflected in both management actions and on-the-ground operations. Regulators, industry and communities should adopt a “zero-failure” objective in which “safety attributes should be evaluated separately from economic considerations, and cost should not be the determining factor,” the report said, echoing experts who examined the Mount Polley disaster.
The report also recommends establishing a UN Environment stakeholder forum to facilitate international strengthening of tailings dam regulation.
These approaches could include establishing a database of mine sites, identifying best practice and developing technical solutions to the main causes of failure. Regulations could be expanded to include, for instance, independent monitoring of waste dams and the enforcement of financial and criminal sanctions for non-compliance.
The assessment also discusses how mining firms can adopt cleaner processes, new technologies and re-use materials in order to reduce waste.
For Thomé, who works for Brazil’s Chico Mendes Institute of Biodiversity Conservation, the goal has to be eliminating such disasters, because the consequences for the victims – both material and psychological – are simply too severe.
“As well as monitoring the impact in the estuary and the ocean, I am trying to help the community and the fishermen to understand what has happened to them,” Thomé says. “They are getting compensation from the mining company to keep them going. But thousands of people have had their lives upended and they do not know what their future will be.”
Pollution is the theme of the 2017 UN Environment Assembly, which will gather in Nairobi from 4-6 December. A side event on pollution in the extractives industry will take place on Monday, 4 December from 6:00-7:30pm. For more information, please visit the Assembly website or email Oli Brown (oli.brown[at]unenvironment.org).