DRDGold's Ergo gold recovery operation, in Gauteng
Ever since the Brumadinho tailings dam collapse, in Brazil, in 2019, which claimed the lives of 270 people and led to massive environmental damage, there has been a spotlight on how mining companies manage and monitor tailings storage facilities (TSFs).
Discussing the most common causes of tailings dam failures, University of the Witwatersrand School of Civil and Environmental Engineering senior lecturer Dr Luis Torres-Cruz said it was often not the geotechnical factors related to the physical structure of the TSF that caused failures, but the organisational and regulatory environment that TSFs were managed in.
Torres-Cruz, who participated in a webinar hosted by Creamer Media in partnership with gold producer DRDGold on February 24, said that, for example, mining officials were often pressured to deliver certain production figures, which may contrast with safety considerations.
“On most occasions, production will outweigh safety concerns,” says Torres-Cruz.
He adds that another problem is often regulatory compliance being seen as a tickbox exercise and regulatory compliance becoming an end in itself, instead of a means to an end, to ensure truly safe TSF management.
Moreover, Torres-Cruz said consultants were often pressured to produce favourable stability reports on TSFs, which also did not help to mitigate the risk of tailings dam collapse or failure.
Tailings deposition contractor Fraser Alexander, which has built 47 TSFs in the last 20 years, of which ten have been built in the last five years – including one of the largest TSFs in the world at 250 ha – says it manages tailings risk to a tee.
Fraser Alexander mineral processing COO Bongani Buthelezi said it stayed on top of research and development into the latest technologies to achieve minimal failure risk at its TSFs. For example, the company’s Technical and Operational Risk Assessment System (TORAS) was aligned with the Global Industry Standard on Tailings Management (GISTM).
International Council on Mining and Metals (ICMM) tailings lead Tabatha Chavez Matus explained that the GISTM had 77 requirements that ICMM’s 26 members across 60 countries have to adhere to.
The guidelines elevate accountability to the highest organisational levels, with clear independent oversight objectives. The GISTM was also established in response to the Brumadinho dam failure.
Meanwhile, Buthelezi explained that Fraser Alexander had made impressive strides in the digitalisation of tailings risk, which he said was reassuring for investors and the industry.
TORAS enables the company to determine and monitor operational risk for all deposition contracts, and manage it collectively with clients and the appointed Engineer of Record.
The TORAS application provides data and other relevant documentation to stakeholders through a single data access portal, increasing levels of transparency, reliability, visibility and automated operations.
On the tailings reclamation side, Fraser Alexander uses remotely operated mining units, which ensures a lower carbon footprint since it requires fewer secondary activities, and it ensures fewer people are required on site in harsh conditions.
As per the company’s 2020 Sustainability Report, it had no major or material environmental incidents in 2020, only 27 minor and ten moderate instances, which were mainly the result of hydrocarbon spillages linked to equipment failure, contained spillages and burst pipes. These did not, however, impact on surrounding water bodies or communities.
Buthelezi said innovation was central to Fraser Alexander’s business model and that real-time data collection through the Internet of Things and drones, for example, had made the mining industry, and TSFs in particular, a lot safer.
As another 100-year-old mining company that continued to innovate for cleaner and safer operations, DRDGold, with its Ergo and Far West Gold Recoveries tailings reclamation projects, spanning from the east to the west of Gauteng, claimed to produce the “greenest gold available” through its mining of tailings, its use of recycled water and in that it would soon commission a 60 MW solar and 160 MW battery storage plant to power its operations.
Responding to whether DRDGold would also treat some of its major shareholder Sibanye-Stillwater’s platinum tailings depositions, DRDGold COO Jaco Schoeman confirmed that “discussions are progressing” about this possibility.