It has been just over four years since the Global Industry Standard on Tailings Management (GISTM) was launched, and much is being learnt as mining companies and professional experts continue to maintain compliance, SRK Consulting experts are reporting.
The experts – Franciska Lake, Partner and Principal Environmental Scientist; Philippa Burmeister, Partner and Principal Environmental Scientist; James Lake, Partner and Principal Environmental Scientist; James Dutchman, Associate Partner and Principal Engineering Geologist; Kavandren Moodley, Principal Environmental Scientist; Andries Fourie, Principal Technologist in Disaster and Risk Management; Lindsay Shand, Partner and Principal Environmental Geologist; and Mondli Mazibuko, Senior Civil and Tailings Engineer – saw the GISTM has brought a more integrated approach to the design, construction, operation and closure planning of tailings storage facilities (TSFs). This has meant that an even wider range of disciplines now need to engage collaboratively in projects that relate to TSFs – from environmental, social and governance (ESG) specialists to practitioners in mine closure, climate change, hydrology, geochemistry, water stewardship and disaster management.
Integration
There was initially the need to raise awareness about the high level of integration required between the ESG aspects and the traditional, technical aspects of tailings management. The importance of trust and understanding between the mine and project-affected people also needed to be emphasised. Building cooperative relationships between mines and their stakeholders remains a continuous challenge but has been a crucial ingredient in meeting GISTM standards.
There also still potential misalignments between local regulatory requirements and the GISTM. In building the environmental knowledge base that the GISTM requires, additional information is often needed beyond what local regulations or historical legislative conditions may have demanded. In many cases, mines have focused solely on their project development areas, paying limited attention to the broader risks of a tailings breach. Closing these gaps requires collaboration between regulators, the mine and other stakeholders.
People at risk
Significant work and innovation have been dedicated in recent years to helping mines effectively comply with the GISTM. One of the key lessons learned from this process is the critical importance of ongoing engagement and relationship building with project-affected people throughout the lifecycle of a TSF. This approach fosters an environment where meaningful dialogue can take place around decisions that impact project-affected people, including the risks and potential consequences of a TSF failure.
SRK has observed that mines can significantly enhance their engagement and communication efforts when they have a well-established and effective stakeholder engagement plan in place. In contrast, strained communication with project-affected people makes it more difficult to deliver critical messages, often delaying the implementation of GISTM requirements. This in turn heightens the risk for people in the inundation zone, who are often the most vulnerable.
The basis for identifying which people are particularly at risk is determining the inundation zone, which the GISTM requires to be accurately modelled. This forms a key component of the Emergency Preparedness and Response Plan (EPRP), which is also a GISTM requirement. Good communication channels need to be in place, she said, to allow not only for messaging from the mines on the risks associated with TSFs, but to clearly and effectively communicate during emergency situations.
Emergency capability
A further critical area of the GISTM relates to emergency preparedness and response, which requires mines to plan in detail for disaster scenarios arising from TSF failure. This process involves engaging other stakeholders in the required EPRP. One of the challenges that mines in countries like South Africa face is that capacity in the field of emergency response can be limited. The GISTM requires mines to consult with government and to obtain a commitment to be part of this planned response.
This means that mines must gauge the stakeholders’ capacity to contribute; given the lack of resources in certain areas, local mines have had to look elsewhere for partners in securing the necessary support in the case of an emergency. Instead, industry agencies like Mine Rescue Services South Africa have been able to provide that response capacity.
A further challenge is that in nations with high unemployment rates, mining operations often draw informal settlement of individuals seeking job opportunities. When the establishment of these settlements are not appropriately planned and managed, significant numbers of people establish homes and livelihoods near a TSF.
Monitoring and data
Another important challenge on many mine sites was the significant lack of meteorological monitoring. This meant that TSFs were being managed without sufficient accurate weather data, including the site-specific rainfall levels.
From a climate change perspective, one of the biggest gaps in meeting GISTM requirements is the monitoring of meteorological parameters. This is not just about having a functional weather station on site, but also about regularly analysing and acting on the weather data received. Water management is key to preventing TSF failures and this requires action associated with observed trends provided by meteorological monitoring.
The scientific instruments also need regular calibration if they are to remain reliable, and mines need to be actively engaging with the data stream. There is scope to use modelling in some contexts, but modelled meteorological datasets tend to have inherent limitations.
In the real world, however, there are situations where data levels are not optimal – and so SRK has developed an approach through which we can use modelled data in conjunction with the monitored data that is available. This can create datasets which are usable by some of the disciplines involved in TSF management and closure.
This lack of data also exacerbates the challenge of predicting future key weather conditions like rainfall, as projections tend to be a ‘best guess’. There is a need to improve the reliability of projections by comparing them regularly to current data collected from monitoring activities. Given this uncertainty, SRK collaborates with international peer reviewers and academics to improve confidence in forecasts.
Integration of data remains another central challenge, as the monitoring data really needs to be available to other disciplines. The GISTM requires climate change to be built into our TSF and water management designs, and for these designs to be continually updated and assessed as the climate changes.
Real-time technology
On the positive side, digital technology was facilitating a rapid move towards near real time monitoring of TSFs. This is an important source of information for better understanding the performance of each TSF and its risk profile; modern equipment and instrumentation is allowing monitoring systems to populate datasets that support the GISTM’s monitoring and surveillance requirements.
It is now possible to monitor the changing risk in near real time against the performance baseline. There has been a shift from manual, single-point data collection to high-frequency big data platforms – which provides an opportunity to examine micro-trends and the inter-relationships between the metrics that govern TSF safety and other conformance aspects.
Blue-chip mining companies are moving actively towards implementing real-time monitoring systems, which will help TSF owners, operators and engineers of record (EORs) to monitor and manage TSF risk more effectively.
The knowledge base has also emerged as a vital focus for closure aspects of GISTM compliance. SRK has noted that there are often gaps in mine closure knowledge bases, where assumptions must be relied upon instead of evidence. This of course undermines the confidence in the closure design itself.
The information deficit often applies to physical and chemical characteristics of the tailings material, the cover requirements and stability aspects. It is recommended that the necessary data be gathered and analysed regularly through the mine lifecycle, ensuring that the funds are more readily available. As mines reach closure phase, the financial conditions often become more constrained.
Flood risks
The introduction of the GISTM has brought a change in design criteria – particularly around water management. In South Africa, for example, closure plans consider a 1-in-100-year flood event, in line with local legislation; there is now a move toward a probable maximum flood consideration, which implies significantly more rainfall over a defined period.
From a technical engineering perspective, the more stringent demands of the GISTM are clearly raising the cost of TSF design, construction and management. Mines sometimes look to reduce upfront capital costs by cutting out certain aspects of work that is now becoming essential for GISTM compliance.
SRK has found that a more useful way of approaching this challenge is to generate a master plan for the life of the TSF. This creates the opportunity to mines to make provision for an annual investment in TSF safety, ensuring that the cost is manageable in terms of the expected result.
Long-term view
Mines are learning to take a longer term view of TSF compliance – from design and construction through to closure – and this is enabling a more cost-effective and multi-disciplinary workflow over time. This allows mines to strategically optimise their capital costs by having clear deliverables in place. In the past, mines have worked with consultants and contractors with a short-term view – whereas this probably needs to be considered as a medium-term to long-term view that encompasses the full range of disciplines required to meet the new global standard.
A key cross-cutting element in various aspects of the GISTM is clearly the management of surface and groundwater, including the geotechnical work that must consider how water content affects stability. There is also a water stewardship angle to be considered, which focuses on water quality and access in the broader river catchment.
While these elements of the GISTM are yet to be fully explored in projects in the African region, mines are cognisant that a holistic approach to water management is required. They are looking at strategic approaches to managing their impacts on the hydrological cycle, aligned with the water stewardship approach.
TSFs are often located in low-lying areas, which are susceptible to variable rainfall patterns associated with climate change. With the lifespan of TSFs expected to withstand weather conditions over hundreds of years, planners will need to consider water stewardship to mitigate the implications of changing surface water run-off and water quality impacts.
There is much about the GISTM which is not new to the mining sector, but which requires constant, integration, innovation and improvement. The expertise in the sector to do this is often stretched, but there has been clear progress made across many disciplines.