Several large mining companies have published details of how they manage their tailings storage facilities (TSFs) as requested by the Church of England Pensions Board and the Swedish Council on Ethics for the AP Funds, representing 96 institutional investors.

Anglo American published details of its 91 managed TSFs and an additional 62 TSFs at non-managed joint venture operations in which it has an interest.

“We have confidence in the integrity of Anglo American’s managed TSFs, which are subject to the highest global safety and stewardship standards, using appropriate advanced technologies, such as satellite monitoring, fiber optics and micro-seismic sensors,” said Mark Cutifani, CEO of Anglo American. “As an industry, we have a clear ethical and moral imperative to do everything possible to ensure that TSFs are managed to the highest standards of safety.” Cutifani said the company is also looking at several technologies to reduce the volume of waste material and its ability to remove water from that material and store it in a drier form.

Anglo American completely revised and updated its technical standard for TSF safety management in early 2014. The standard is updated as appropriate and goes beyond regulatory and other industry requirements in all host jurisdictions, the company said. This mandatory global standard mitigates the long-recognized principal risk that TSFs pose, sets minimum requirements for design criteria, monitoring, inspection and surveillance, and was peer-reviewed by international specialists, according to Anglo American.

Of the 91 TSFs managed by Anglo American, 40 are in active use, 33 are inactive or in care and maintenance, and 18 are closed or rehabilitated. In terms of the method of tailings storage, 39 use wet deposition while 52 use either dry-stacked or in-pit deposition.

In addition to the requested defined information, Anglo American has also published its full Group Technical Standard in respect of Mineral Residue Facilities and Water Management Structures, available at www.angloamerican.com/tsf.

Glencore has also launched a microsite that provides detailed information its TSFs in response to the request. TSFs have been part of Glencore’s catastrophic hazard evaluation program for a number of years and have drawn on external expertise applying leading standards from CDA (Canadian Dam Association), ICOLD (International Commission on Large Dams) and ANCOLD (Australian National Committee on Large Dams), the company said.

“Our group-wide dam integrity and safety assurance program involves an assessment against more than 100 dam safety and leading practice criteria,” the company said. “As part of our approach, we utilize the services of Klohn Crippen Berger, one of the world’s leading experts on TSF assurance, to independently audit and assess the integrity and safety of our TSFs.” Glencore said it also conducts regular dam safety inspection at all assets. The Glencore TSF microsite can be accessed at www.glencore.com/sustainabilirty/Tailings.

Gold Fields Ltd. also responded to the request and released a TSF management disclosure document, available at www.goldfields.com. It currently manages 32 tailings facilities, of which 12 are active and one will be commissioned imminently. A further two are managed by joint venture operations. Gold Fields said it maintains measures to manage its TSFs’ safety, including compliance with the International Council on Mining and Metals’ (ICMM) Tailings Governance Position Statement.

All Gold Fields’ TSFs, as well as associated pipeline and pumping infrastructure, are subject to an independent, external audit every three years — or more frequently where required by local circumstances or regulations — as well as regular internal inspections, monitoring and formal annual Engineer of Record reviews.

During 2017 and 2018, external and internal reviews of its alignment with the ICMM position statements on water and tailings management were carried out. The conclusion was that the company is aligned with both position statements. Gold Fields said it is also evaluating moving away from the construction of upstream facilities to center-line or downstream designs, considering filtered and dry stacked tailings, as well as in-pit tailings disposal.