A global inquiry into mining waste storage systems of more than 700 resources companies, launched in April after the collapse of a dam in Brazil that killed hundreds, shows about a tenth of the structures have had stability issues.
The research, led by the Church of England (CoE) and fund managers, reveals that at least 166 of 1,635 dams holding mining waste — tailings — have had safety issues in the past.
The group noted it’s unclear how severe those issues had been, adding that miners said the problems had been addressed.
The results of the inquiry are only partial, as they only reflect disclosures from less than half of the 726 companies contacted following the collapse of Vale’s Brumadinho dam in January, which killed at least 250 people.
Less than half of the 726 miners contacted have responded, with most Chinese and Indian firms not providing information.
Most Chinese and Indian miners have yet to provide information, which leaves a significant gap in efforts to create a global picture of safety risks posed by tailing dams, the investors say.
Companies addressed included major industry names such as
BHP, Rio Tinto, Anglo American, Glencore and Vale itself, which were asked to
publicly disclose their dams’ size, construction methods and safety records.
All the major listed miners have already replied. Three of
them did so shortly after the inquiry was launched, unveiling they owned
tailings dams considered high or extreme-risk in the event of a catastrophic
failure. High-risk indicates dams that would have an immediate impact upon
failure, and could cause the deaths of at least 10 people, while extreme-risk
dams could cause the deaths of 100 or more people if they fail.
The facilities in question included four “extreme-risk” dams
at BHP’s Olympic Dam mine, Mount Whaleback mine, Pilbara mine and Leinster
mine. Two tailings dams at Rio Tinto’s Andoom and Torro mines in Queensland
have been deemed ‘high-risk’, along with two dams at Glencore’s Mount Isa
mining complex.
While those high-risk facilities made the headlines in
Australian media, the risk assessment for these dams related to the damage in
case of failure, not the likelihood that they will collapse.
Currently there are no set of universal rules defining
exactly what a tailings dam is, how to build one and how to care for it after
it is decommissioned.
There are about 3,500 tailings dams around the world. Unlike
the ones used to build reservoirs or hydroelectric projects, tailings dams are
not usually made from reinforced concrete or stone. They are mostly constructed
from the waste material left over from mining operations, which — depending on
the type of mine — can be toxic.
Only three countries in the world ban upstream dams — Chile,
Peru, and now Brazil. Chile, the world’s No.1 copper producer, also regulates
the minimum distance between dams and urban centres. But the nation still has
740 tailings deposits, only 101 of which are active, with the rest abandoned or
inactive, according to data from mining agency Sernageomin.
The results of the inquiry come as global investors are
increasingly focused on ensuring mining companies reduce their environmental
footprint, improve their governance and reduce the number of fatalities.
Other than CoE, the group carrying out the inquiry (representing more
than $13.5 trillion assets under management) includes Swedish Pension funds,
Dutch funds APG and Robeco, the UK’s LGPS Central fund, New Zealand Super, and BMO
Global Asset Management.