Page 64 - Vol 28 Issue 29 2019

mining tailings management

Investors push for positive global

change in tailings management

By Luis Alberto Torres-Cruz

Tailings dam

n interesting development emerged as South Africa, Japan, Italy, Canada – So why do tailings dams fail? And what
from the Brazil dam disaster: and, most recently, Brazil. In January can we do to try and avoid such failures?
Ainvestors work with mining 2019 a tailings dam at the Córrego do This is what we explored in a recent
companies and regulators to improve Feijao iron mine in Brumadinho, Brazil paper in Science Magazine. We pointed
tailings management systems. collapsed. According to the World Mine out, for instance, how the processes in
Tailings are a sand-like byproduct of Tailings Failure database, this resulted in a tailings dam can take up to decades
mining that results from crushing the the release of 12 million cubic meters of to manifest themselves. This means
ore before mineral extraction. Often, tailings. It also killed 240 people and, by that although the ultimate collapse of a
tailings are disposed of in dams built May 2019, 32 were still listed as missing. tailings dam can be sudden, the build-up
with tailings themselves, or with other Its high death toll sets the Brumadinho of conditions that lead to failure is often
mine waste products. The technical failure apart from many others. The World the result of protracted deviations from
knowledge exists to safely build these Mine Tailings Failure database, which good engineering practice.
structures. But tailings dams failures, with covers over a century of mine tailings The flip side of this is that the efforts
tragic consequences, are occurring at an incidents, contains only four failures with currently underway to improve the safety
unacceptably high rate. death tolls exceeding 250: Mexico in record of tailings dams will also take time
There have been significantly destructive 1937, Bulgaria in 1966, Italy in 1985, and – probably years – to manifest themselves.
tailings failures in countries as varied China in 2008. One of the most interesting developments

64 | AFRICAN POWER Mining & Oil Review Vol 28, Issue 29, 2019 Celebrating 10 years of excellence