Understanding tailings dam safety is important because people and ecosystems die when mine tailings dams fail. In 2019, a tailings dam collapsed in Brumadinho, Brazil killing 272 people and dumping 9.7 million cubic meters of mine waste over the surrounding areas.

Last week, Scientific Reports published an article on the safety of mine waste (aka tailings) storage facilities. The article shows how drastically the amount of mine waste companies produce is growing. The current volume is an already staggering 44.5 billion cubic meters, equivalent to filling the island of Manhattan 750 meters high with waste. Companies project creating an additional 2.5 billion cubic meters of tailings per year between 2019 and 2023, a 26% increase.

The article looks at data from 107 publicly traded mining companies on 1,742 tailings storage facilities worldwide. These data became available when the Investor Mine and Tailings Safety Initiative, which was created after the horrific Brumadinho failure, requested specific information on tailings dams from 726 mining companies. The investors made those disclosures searchable and publicly available through the Global Tailings Portal.

The authors find that tailings dams present safety concerns across the board. One in ten tailings facilities reported “notable stability concerns or failure to be confirmed or certified as stable at some point in their history.” Certain types of tailings storage facilities, specifically upstream and hybrid dams, present more risk. The likelihood of a “stability issue in active upstream facilities is twice that of active  downstream facilities and six times as many that of active dry-stack facilities.” Countries like Brazil, Chile and Peru have banned upstream dams based on the dangers they pose. However, despite the fact that upstream dams pose a greater risk, mining companies continue to use these types of dams, and are even proposing new upstream facilities around the world, from Michigan to Australia.

Even though there are safer technologies available, mining companies are not using them. The authors point out that the “removal of water from tailings is an important innovation with the potential to improve geotechnical and geochemical stability.” In 2015, the independent panel commissioned to review the tailings dam failure at the Mt. Polley mine in British Columbia, Canada found, “[t]here are no overriding technical impediments to more widespread adoption of filtered tailings technology.” However, of the 1,742 tailings facilities in the data set, only 13 facilities constructed over the last decade used a dewatering technology to build what are called “dry-stack” facilities. Additionally,  a single international mining company operates, or is the majority shareholder in, 72% of all the reported dry-stack facilities, also referred to as filtered tailings.

The analysis also finds that companies have not formally evaluated the effects of a potential catastrophic failure at 29% of the facilities. If mining companies themselves are unaware of the potential damage their facilities could cause, how are workers and downstream communities supposed to understand the potential risks?

The trends identified in this article serve as an important reminder that the mining industry needs to do better when it comes to safer tailings management. The industry must stop using practices and technologies that pose the greatest risk, like upstream dams, and needs to implement the technologies that have been shown to be safer, like filtered tailings. It must ensure that affected communities and workers have access to information about their own safety and the right to say “no” to a project they deem too dangerous.

The mining industry has not and will not make these changes by itself. Regulators, international agencies and investors need to hold mining companies accountable and ensure they move towards safety. Measures like banning upstream dams, requiring community consent and mandating the use of safer technologies need to come from governments, and international agencies and standard setters. In June of 2020, over 150 frontline communities, technical experts and civil society organizations released Safety First: Guidelines for Responsible Mine Tailings Management calling for mining companies to prioritize safety over profits. We need to better understand the risks posed by current tailings storage facilities. No one knows how many tailings dams exist across the globe because there is no comprehensive registry. The 1,742 tailings storage facilities in the Global Tailings Portal only represent a fraction of the active and closed facilities owned by publicly traded companies. These numbers do not take into account facilities owned by state run or private companies, to say nothing of the possibly tens of thousands of abandoned tailings dams who have no owner at all. While the data analyzed for this article show us important trends, we’re still a long way off from really understanding the danger posed by tailings.

Safety First says the “safest tailing facility is the one that is not built.”  As mining companies push towards more waste and larger tailings dams, we must look for ways to reduce the need for new mines. There is significant untapped potential to reuse and recycle minerals from batteries and other technology that has reached the end of its useful life, substitutions for other more abundant minerals, and ways to reduce overall demand by changing the transportation and energy mix