A panel of four geotechnical specialists has published its findings into the immediate causes of the failure of the Fundao tailings dam at the iron ore operations of Samarco Mineracao in Minas Gerais, Brazil, on 5 November.
Vale, BHP Billiton Brasil and Samarco jointly commissioned Cleary Gottlieb Steen & Hamilton LLP to investigate the immediate cause of the failure.
To assist with the investigation, Cleary Gottlieb retained the Panel to advise on the technical aspects of the failure and to conduct testing and analysis.
BHP Billiton's chief commercial officer, Dean Dalla Valle, said the dam failure had a devastating impact.
"In November 2015, BHP Billiton committed to making the findings of this investigation public, and we are determined to learn from this tragedy" Dalla Valle said.
"This important technical study will improve our understanding of what happened at Samarco. We have shared these findings so that the sector can learn from the dam failure and develop and implement further standards that can help prevent a similar event like this happening again."
Dalla Valle said, separate to the external investigation, BHP Billiton had also conducted its own reviews of other significant dams at its operations and of its non-operated minerals joint venture arrangements.
"In the wake of this event, we have separately undertaken a comprehensive review of our significant dams, which has confirmed that those dams are stable. We will take a number of actions to further enhance risk management at these facilities.
"We have looked comprehensively at tailings dam management and benchmarked to global leading practice. We have assessed our portfolio of dams against these global standards and are implementing actions to enhance the management of our dams.
"We also conducted a review into our non-operated minerals joint venture arrangements and have identified a number of opportunities for improvement. This is consistent with our commitment to continuously improve risk management and our determination to learn from, and share the lessons from, this tragedy."
The panel's findings released today are the outcome of a 10 month investigation and scientific analysis involving experienced geotechnical engineers and seismologists, led by Dr Norbert Morgenstern, a University Professor of Civil Engineering and an authority in the field of Geotechnical Engineering.
A full overview of the panel's findings, explanatory materials, detailed modeling, input data, a video and technical diagrams can be found at: Fundaoinvestigation.com