One year ago, on November 5, 2015, a mining waste dam failed at the Samarco iron mine in rural Brazil, unleashing an enormous torrent of chemical-laden sludge into the Rio Doce. At least 19 people died and some 700 people were left homeless. Aquatic ecosystems were wiped out by the plume of pollution that reached the Atlantic Ocean. What remains is a polluted river that locals will have to contend with for decades to come.
Prosecutors assert that company executives knowingly dismissed the engineering flaw in order to continue production. On October 20, 2016, they charged 21 people, including senior BHP and Vale executives, with qualified homicide for their alleged roles in this disaster. The companies were also charged with 12 environmental crimes.
Sadly, disasters involving poorly managed mine waste storage are not unique to Brazil. In the past few years alone, there have been a number of high-profile mine tailings dam disasters that communities from Canada to Mexico are still dealing with. The year before Samarco, a mining waste dam at the Mount Polley mine burst in British Columbia, Canada, releasing 24 million cubic meters (about 848 cubic feet) of waste into the Fraser River watershed. There were no fatalities, but the scale of the spill was high enough to warrant international attention and prompted the provincial government to conduct an independent investigation into the disaster.
The Mount Polley Independent Expert Investigation and Review commissioned by British Columbia concluded that the industry must adopt a major change in mining norms: taking dams out of the equation eliminates water from the waste and the areas in which the waste is stored. Instead, mine tailings would be stored as dry, stackable waste. As the investigators wrote: “Simply put, dam failures are reduced by reducing the number of dams that can fail.”
And yet, a year after this call to reduce dams, the Samarco dam failed, causing even more destruction than Mount Polley.
A separate study conducted by independent mining experts found that without the changes recommended by the Mount Polley Investigation, the rate of major mine waste failures like Samarco will only grow, as companies process lower and lower grade ore, producing more and more waste.
We can’t wait for another Mount Polley or Samarco mine disaster to occur. Regulators must set strong rules to require dry mine waste storage — eliminating the need for gigantic, disaster-prone dams by dewatering mine waste. Banks and insurers must make responsible mine waste management a precondition of their investment. Downstream consumers of metals — such as jewelry, automotive, and electronics companies — must insist that mining companies follow best practices, even in regions where government oversight is weaker. And while mining companies cannot be the ones in charge of defining these practices or self-policing, they must publicly acknowledge the problem and commit to following best practices so no community or ecosystem is ever at risk from another disaster like the one that occurred at the Samarco mine.