Tailings dams rank among the largest engineered structures on earth and many have failed, with catastrophic results, spewing toxic materials into their surrounds.
New global safety and reporting standards were introduced in 2020, on the anniversary of the world’s biggest tailings dam collapse, at Vale’s Brumadinho dam, in Brazil, in which more than 250 people died and neighbouring communities were flooded with noxious waste.
The new Global Tailings Portal, set up after the disaster to track the integrity of the world’s tailings dams, now registers more than 1800 of the estimated 3,500 active tailings storage facilities worldwide.* Of these, more than 10 per cent are estimated to have had stability issues and one-third are at high risk of causing disaster to nearby communities if they crumble.
According to figures produced by researchers at World Mine Tailings Failures (WMTF), failure risk is on the rise as storage infrastructure ages: “Without major changes to law, regulation, and to industry practices, as well as without new technology that substantially reduces risk and increases loss control, our current prediction is for 19 very serious failures between 2018 and 2027.”
Tailings dams have a long history of ruptures and collapses. In this century alone, there have been around 60 tailings dam failures around the world, 11 involving gold mines. The devastating trend has seen insurance companies tighten requirements for coverage and engineers and miners searching for better construction, monitoring and maintenance regimes to minimise the risk.
But technology innovator Clean Mining, part of the Clean Earth Technologies group, is taking the solution one step further by eliminating the need for tailings dams altogether.
Cleaning Mining’s cyanide and mercury-free gold processing offers a clean, green and cost-effective retreatment option for tailings and an alternative to conventional tailings storage. It uses a benign reagent made from low-cost, plant-based organics, that has proven to be as effective and much safer for people and the environment.
Used in conjunction with a de-watering system, the process produces dry tailings that are safer and easier to store. Better still, the reagent itself can be recovered after processing and reused.
* The database was built by Norway-based environmental organisation GRID-Arendal as part of the Investor Mining and Tailings Safety Initiative, which is led by the Church of England Pensions Board and the Swedish National Pension Funds’ Council on Ethics, with support from the UN Environment Programme.