Samarco: BHP blames construction flaws

EXPERTS have blamed construction and design flaws for last year’s Samarco disaster in Brazil, when a dam operated by mining giant BHP Billiton collapsed and killed 19 people.

According to an influential report commissioned by BHP and published last night into the cause of the accident, problems at the dam made it more unstable, causing “liquefaction” in the dam wall.

BHP Billiton, and its partner Vale, have set aside up to $1.3bn (£1bn) to cover costs arising from the fatal accident that occurred at an iron ore mine in Brazil last year.

The US law firm commissioned to publish the report, Cleary Gottlieb Steen and Hamilton, hired a panel of experts to work out why the dam collapsed. The panel, chaired by geotechnical engineer Norbert Morgenstern, used eyewitness accounts, advanced lab testing and computer modelling.

The authors said the original design had to be changed, which used a type of sand designed to prevent a process known “liquefaction” – where soil loses its strength and stiffness when pressure is applied to it.

“As part of this modification, a change in the design concept was also adopted and saturated conditions were permitted to develop in the sand,” the report said.

An earthquake that took place just before the collapse, which has also been linked to the disaster, was not the sole cause, they said. “This likely accelerated the failure process that was already well-advanced.”

Melbourne-based BHP had previously set aside $1.3bn (£1bn) to cover its funding commitments under a “framework agreement” it struck with the Brazilian state earlier this year, but since then the country has changed government.

The FTSE 100 company and its partner Vale now face a much higher damages claim from Brazil’s Federal Public Prosecution Service, which insists that the existing deal to cover the costs of a fatal dam collapse at the Samarco mines in Brazil was insufficient.