BHP has significantly increased the rigour of its assessment and management of tailings storage facilities since the failure of the Fundão dam at Samarco in 2015.
Following that event, BHP completed Dam Risk Reviews for active, inactive and closed tailings storage facilities across our business. These reviews included a thorough evaluation of risks, and identified no significant deficiencies to the stability or management of our tailings storage facilities.
The risk reviews also highlighted new opportunities to improve the design, construction and operation of our facilities. In total, more than 400 actions were assigned to BHP Assets. These actions are 93 per cent complete, with the remaining actions considered low priority such as administrative actions and long-lead items regarding closure and climate change impacts. None of these actions is overdue.
Dam Safety Reviews were then completed following the guidelines recommended by the Canadian Dam Association (CDA) – widely regarded as the most rigorous in the industry.
Monitoring and alarm systems at all sites were reviewed, and supplemented where new opportunities to improve were identified. All significant tailings storage facilities have emergency response plans in place.
As part of our ongoing process of continuous improvement, external Dam Safety Inspections are conducted annually and risk-based Dam Safety Reviews every three to seven years, in line with CDA guidelines.
BHP’s tailings storage facilities are located at seven operated sites in Australia and Chile, with a further seven closed sites throughout North America, and four non-operated joint ventures in North America and South America.
We have a number of facility designs within our portfolio, and we have an assurance process in place that seeks to identify and manage the risks associated with each.
In total, there are 115 tailings storage facilities across these sites (including non-operated joint ventures) of which 20 are active. In total, 47 of these storage facilities have been constructed using the upstream method, of which 13 are active.
Those 13 operational upstream tailings storage facilities are located at the following operated sites: one at Mt Whaleback (Western Australia), two at Olympic Dam (South Australia), two at Goonyella and one at Blackwater (Queensland), and seven at Nickel West (Western Australia).
We have 26 upstream facilities at our closed sites in North America, and a further eight inactive upstream facilities at our operated sites.
The number of tailings storage facilities is calculated based on the definition used by the Responsible Dam Engineers at our sites. We keep this definition under review.
BHP will continue to accelerate its work with the industry to advance the science and technology required to improve the safety of tailings storage facilities. This includes existing workstreams such as early warning technologies, better models and monitoring of possible modes of failure, tailings dewatering options, and dry tailings storage viability at scale.
BHP will meet with a number of global bodies this month to expedite this work. BHP welcomes a common, international and independent body to oversee integrity of construction and operation of all tailings storage facilities across the industry.
In addition, BHP supports calls for greater transparency in tailings management disclosure and will work with the industry to make sure the disclosure is consistently applied and informs better tailings dam stewardship.