Definition of a tailings storage facility
Tailings storage facilities (TSFs) are constructed buildings. The dam or comparable structure, together with any related tailings delivery system, is included in a TSF. The phrase refers to the entire establishment, which could comprise one or several tailings dams.
A tailings storage facility (TSF) is primarily designed to properly confine tailings in order to accomplish solid sedimentation and consolidation, as well as to permit water recovery or removal with minimal environmental damage.
The way water is managed, as well as during rehabilitation and closure, is essentially different between the design and operation of a TSF and a water dam. Water storage should not be done in a TSF. When a TSF is intended to keep water permanently (as in the case of sub-aqueous tailings disposal), its design must also adhere to the same criteria as water reservoirs.
The types of TFSs
There are different types of TSFs:
- surface facilities, including paddock style or valley fills, can comprise multiple dams (or cells) that have continuous, structurally similar interconnected walls
- in–pit facilities
- dry stack facilities
According to @BHP Three main categories of TSF construction exist. Each construction design is related to the various factors such as: Location, Geology, seismicity, climatic conditions, construction materials and the nature of the tailings. Thus we have:
- Upstream construction
- Downstream construction
- Centerline construction
The challenges in TFSs dimensionning
The dimensioning of tailings storage facilities (TSFs) faces several significant challenges, primarily related to environmental safety, technical complexity, and regulatory compliance. These challenges can be categorized into several key areas:
Environmental and Safety Concerns
- Risk of Failure: TSFs have historically experienced higher failure rates compared to water storage dams, with an estimated failure rate of 1.2% over the past century. This translates to about one to two failures annually worldwide, often resulting in severe environmental impacts and societal consequences.
- Hydrological Safety: Effective water management is crucial. The need to minimize the water content in stored tailings is essential to reduce the risk of liquefaction and other stability issues. This includes implementing drainage systems to manage pore pressure and prevent instability during seismic events.
- Long-Term Environmental Impact: TSFs can pose long-lasting environmental risks, not only during operational phases but also post-closure. The potential for acid mine drainage and other contaminant releases necessitates careful planning and monitoring.
Technical Challenges
- Complex Design Requirements: The design and construction of TSFs require a deep understanding of geotechnical and hydrological principles. Factors such as the characteristics of the tailings, their transport methods, and deposition techniques significantly influence the TSF’s stability and performance.
- Material Properties: The behavior of tailings, which can be non-Newtonian fluids, complicates the design process. Tailings can exhibit contractive behavior under certain conditions, affecting their stability and the overall design of the facility.
- Best Available Technology (BAT): The selection of BAT for TSFs involves evaluating various methods for processing, storage, and post-closure management. This requires a comprehensive understanding of both the technical aspects and the regulatory landscape.
Regulatory and Governance Issues
- Regulatory Compliance: Increased scrutiny from regulatory bodies has led to more stringent requirements for TSF design and operation. Mining companies must navigate complex regulations while striving for economically viable solutions.
- Governance and Management: Poor governance and insufficient investment in TSF safety have historically contributed to failures. Establishing robust management frameworks that integrate safety, environmental protection, and community engagement is critical for sustainable TSF operation.
Conclusion
The dimensioning of tailings storage facilities involves navigating a complex interplay of environmental safety, technical challenges, and regulatory compliance. Addressing these challenges requires innovative approaches to design, ongoing monitoring, and a commitment to sustainable mining practices. As the industry evolves, the focus on reducing the environmental footprint and enhancing the safety of TSFs will remain paramount.
Bibliography
Fernández Rubio, R., & Kleinmann, B. (2021). Introduction to this Special Issue on Tailings Storage: Challenges and Technologies. Mine Water and the Environment, 40(1), 1–5. https://doi.org/10.1007/s10230-021-00757-3
Guidelines-for-design-and-management-of-tailings-storage-facilities.pdf. (n.d.). Retrieved August 7, 2024, from https://earthresources.vic.gov.au/__data/assets/pdf_file/0010/463681/Guidelines-for-design-and-management-of-tailings-storage-facilities.pdf
(PDF) Closure and Rehabilitation of Tailings Storage Facilities. (n.d.). Retrieved August 7, 2024, from https://www.researchgate.net/publication/251460895_Closure_and_Rehabilitation_of_Tailings_Storage_Facilities
