Central to our approach is the recognition that maintaining TSF integrity is an ongoing process of continuous assessment that needs to be maintained for the life (including into closure) of each TSF. Operation, surveillance, maintenance, effective monitoring and review practices must operate in line with TSF design requirements and be quality assured and controlled to ensure the TSF is functioning as intended.
Effective governance of our TSFs requires all of the above elements – from change management to document management to appropriately qualified personnel with clear accountabilities – to be encompassed.
We have three key first line roles that we mandate across our operated assets:
- Dam Owner – the single point of accountability for maintaining effective governance and integrity of the TSF throughout its life-cycle
- Responsible Dam Engineer – a suitably qualified BHP individual accountable for maintaining overall engineering stewardship of the facility including planning, operation, surveillance and maintenance
- Engineer of Record – an individual external to BHP who is a suitably qualified professional engineer retained by the Dam Owner for the purpose of maintaining dam design, certifying dam integrity and supporting the Dam Owner and the Responsible Dam Engineer on any other matters of a technical nature
As explained below, some TSFs also have independent Tailings Review or Stewardship Boards to strengthen the control environment for TSF risks. BHP assesses the dam classification, risk, and operational circumstances in determining whether to empanel a Tailings Review or Stewardship Board. Not all facilities will have a Tailings Review or Stewardship Board; we have them in place (or are in the process of establishing them) for all our operated assets with ‘very high’ or ‘extreme’ classified tailings facilities.
Given TSFs are dynamic structures, effective monitoring, surveillance and review is central to ongoing dam integrity and governance. These processes span six dimensions with the specific details commensurate with the significance of the facility:
1. Monitoring systems: operating in real time or periodically
2. Routine surveillance: undertaken by operators
3. Dam inspections: more detailed inspections undertaken periodically by the Responsible Dam Engineer
4. Dam Safety Inspections: annual inspections undertaken by the external Engineer of Record reviewing aspects across both dam integrity and governance
5. Dam Safety Reviews: conducted by an external third party as described below
6. Tailings Review or Stewardship Boards: a panel of qualified independent individuals established, commensurate with dam significance, under specific terms of reference to review aspects such as the current status of the dam; any proposed design changes and outcomes of any inspections or Dam Safety Reviews
Dam Safety Reviews
Dam Safety Reviews are central to our approach to TSF integrity and continuous improvement. We undertake Dam Safety Reviews consistent with the guidance provided by the Canadian Dam Association (CDA) in its 2016 Technical Bulletin Dam Safety Reviews. As per this guidance, review frequency is informed by the dam classification under CDA.
Dam Safety Reviews are detailed processes that include a review of dam integrity and dam governance. They include a review of the dam break assessment and dam consequence classification. The review is led by an external Qualified Professional Engineer, who has the appropriate level of education, training and experience, with support and input from other technical specialists from fields that may include, for example, hydrology, geochemistry, seismicity, geotechnical and mechanical. At the conclusion of the review, the Qualified Professional Engineer is required to sign an assurance statement that includes a comment as to the integrity of the facility as a result of the review.