By Theo Gerritsen
In Australia and across the world, external tailings management programs are being established to mitigate the risk of tailings dam failures.
These programs are typically developed by a mine owner, often at a corporate level, and are implemented to identify and manage risks throughout the life of the tailings storage facility (TSF). Most of these initiatives start by adopting standards and best practices; those initiatives that are more developed have adopted Engineers of Record (EOR).
Employing an EOR for a TSF is common practice in Canada, the United States and (to a lesser extent) in South America. In Australia the practice is becoming increasingly common.
In the Canadian Dam Association’s Dam Safety Guidelines, the EOR is “a qualified and competent engineer who is responsible for the design and performance of a mining dam.” The EOR is (ideally) involved in construction of the dam and is responsible for its integrity throughout its lifespan.
Having an EOR is advantageous. The EOR, and the team of people supporting the EOR, is contracted over an extended time period, to minimize the risks of losing knowledge associated with change of personnel and consultants. This provides continuity for the owner and other stakeholders. The EOR could be visualized as a long, continuous chain of knowledge that starts with the building of the dam and ends with its closure. Continuity is not only important for safety, but can also save the mine owner construction and operational costs by preserving institutional knowledge. Most importantly, the EOR provides consistency for the engineering, operation and management of the dam because the risks of a tailings dam upset – in terms of costs, the environment, and reputation – is simply too high.
“Mine owners know the importance of maintaining assets and understand the commercial, reputational and operational costs of any failure. The industry is serious about improving outcomes,” said Theo Gerritsen, principal geotechnical engineer in Stantec’s Global Tailings Group.
He added: “There is a noticeable push industry-wide and particularly in Australia to engage EORs to further develop and improve mine waste and tailings practices.”
Responsibility is key
Previously a consulting engineer would sign off on, say, one single dam raise design but would not carry responsibility for the overall integrity of the TSF. The EOR carries the responsibility for oversight of the design, construction, quality assurance and quality control. With this, the EOR becomes an integral part of risk management for dams.
“The EOR has an ongoing responsibility to make sure that every aspect of the dam is looked after properly,” said Gerritsen. Typical responsibilities include review of surveillance records, review and modification of the Operation, Maintenance and Safety (OMS) manual, dam design, design review, emergency support to the owner, dam safety audits as part of annual inspections, construction support and construction quality assurance (CQA).
Stantec was recently awarded EOR projects for two sites in Australia involving responsibility for three TSF facilities. In response to the demand from mining companies for more EORs, Stantec has expanded its team of tailings dam engineers in Australia – all of whom are backed by Stantec’s deep international expertise in mine waste and tailings management.
Gerritsen said one of the aspects of the EOR currently being discussed both within Stantec and within Australian industry bodies, is the scope of the EOR’s role. For example, how many tailings dams is it reasonable to ask one engineer to service? Further, it is important to define, in detail, what the scope of the EOR is. For example, what (technical) aspects are included and which are not? Where does the responsibility and accountability of the EOR stop and under what authority does the EOR operate? There is a gentle balance to be found where corporate support for the longer-term considerations made by the EOR may surpass short-term considerations from the site. Dams vary considerably in their size and complexity and issues such as definition of the EOR scope, support, authority, reporting lines, involvement in construction, CQA and succession planning are in various phases of development and discussion.
It is worth noting a recent initiative. The Queensland Tailings Group, a newly established industry body, is looking at questions like these. The group will be formally launched at the Mine Waste and Tailings 2018 conference, July 23-24, 2018, in Brisbane.
This content was originally published in mining.com.
About the author
Theo Gerritsen, principal geotechnical engineer in Stantec’s Global Tailings Group, has 20 years’ experience including designing mine waste and tailings storage facilities. He has a Master of Engineering degree from Delft University of Technology in the Netherlands. Gerritsen is based in Brisbane and supports projects in Asia Pacific and South America. Gerritsen is a founding member of the aforementioned Queensland Tailings Group.