Tailings and waste rock
We are committed to designing, operating and managing our tailings storage facilities in a safe, sustainable and responsible manner throughout the lifecycle of our mining operations.
Our management approach
Our mining operations generate mining-related waste including tailings and waste rock. Tailings are a by-product of the mining process, consisting of fine-grained processed rock or soil left over from the separation of the commodities of value.
Responsible tailings management throughout the mine life cycle is a critical part of managing and minimising the risks from waste produced during the mining process.
In line with best practice, management accountability of the tailings storage facility (TSF) sits with the MinRes Executive team, with the Board maintaining oversight of all tailings management.
Potential consequences of a TSF failure can range from impact to sensitive receptors due to seepage to catastrophic release of solids and water.
To reduce the risk of TSF failure, a rigorous regulatory process is followed in Western Australia. All TSF details - including design, technical data, analyses, construction method, quality control and operational procedures - must conform to the Department of Energy, Mines, Industry Regulation and Safety's TSF Code of Practice and design, management and operational guidelines published by the Australian National Committee on Large Dams and other relevant bodies.
We are committed to operating in line with the 15 principles and 77 requirements set out by the Global Industry Standard on Tailings Management (GISTM), published by the International Council on Mining and Metals, the United Nations Environment Program, and the Principles for Responsible Investment.
In compliance with the GISTM, we have a Tailings Storage Facility Policy, which outlines our commitment to designing, operating and managing our TSFs safely and responsibly.
We conduct comprehensive tests on waste rock from our mining activities to guide operational management, rehabilitation, and mine closure planning and design.
Our tailings management process is informed by surveillance and monitoring programs, conducted across all TSFs, with active TSFs undergoing daily inspections, annual audits and external design reviews.
Ongoing surveillance programs collect key information such as the geological and structural features of the TSFs and their foundations, enabling early detection of any potential deterioration.
We focus on the safety of our TSFs through all phases of the lifecycle with consideration of factors impacting all key stakeholders through project conception, planning, design, construction, operation, closure and post closure.
This includes proximity to employees, communities and infrastructure, and the geological conditions and deposition of the tailings.
Our TSF management is incorporated into broader site management systems in a safe and compliant manner consistent with regulatory requirements, applicable guidelines and standards.
We engage external design engineers for each facility and independent reviews are undertaken by external engineers.
Additional assurance is provided by our technical specialists, with support from external experts.
Our risk-informed approach includes the below overarching operating practices to provide a robust approach for sustainable tailings management:
- Site operational controls, surveillance and monitoring.
- Technical and operational support provided by internal subject matter experts.
- Design, operational support and risk review provided by external Engineer of Record.
- Regular inspection, review and reporting by independent experts.
- Board oversight of risks.
We are confident in the safety and security of our TSFs and are committed to continually reviewing our facilities and procedures to maintain a high standard of safety at our operations.
We take into consideration learnings from our peers to promote continual improvement and ensure the most suitable approach to performance and risk management.
We currently manage four active TSFs, three decommissioned TSFs and one TSF in care and maintenance. All facilities are in remote areas and significant distances from local communities and infrastructure.
Wodgina
- TSF3 Extension (TSF3E): A partially lined valley fill-type TSF.
A continual surveillance program collects information on the hydrological and structural features in the dam and its foundation, among other operational data, enabling early detection of any deterioration of the tailings dam structure posing a potential risk. - Atlas in-pit TSF: This in-pit tailings disposal in a mined-out pit void represents a reduced risk when compared to an above-ground TSF, as the potential of discharge of tailings to the environment is negligible. Mitigating factors to flooding risk include current mine drainage infrastructure in and around the Atlas pit, net site water use requirements, along current optimised return water pumping protocols to promote beach formation and consolidation.
- TSF1 – 3: Three decommissioned TSFs remain at the Wodgina operation, all capped with waste rock.
Mt Marion
- Ghost Crab In-pit TSF: This in-pit tailings disposal in a mined-out pit void represents a reduced risk when compared to an above-ground TSF, as the potential of discharge of tailings to the environment is negligible.
Mitigating factors to flooding risk include current mine drainage infrastructure in and around the Ghost Crab pit and net site water use requirements.
Koolyanobbing
- C Pit In-pit TSF: This in-pit tailings disposal represents the lowest tailings disposal risk of current industry methods – a combination of filtering the tailings (substantially reducing the moisture content) and disposing in a mined-out pit void.
Disposal of tailings into this pit began in FY23, which involves placement of filtered lithium tailings from Albemarle’s lithium hydroxide monohydrate production plant in Kemerton, Western Australia.
Coobina
- Coobina TSF1: The Coobina Chromite mine (Pilbara Chromite Pty Ltd) is currently in care and maintenance. TSF1 is a paddock-type storage, inactive and stable.
