Toledo, G, Gómez, M & Cádiz, R 2026, 'Governance for the safe closure of tailings storage facilities: the Engineer of Record perspective', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-11, https://doi.org/10.36487/ACG_repo/2615_103
(https://papers.acg.uwa.edu.au/p/2615_103_Toledo/)
Abstract: The Global Industry Standard on Tailings Management (GISTM) defines safe closure as the condition in which a tailings storage facility (TSF) presents no ongoing material risks to people or the environment – a condition confirmed by the Independent Tailings Review Board (ITRB) and formally approved by the Accountable Executive (AE). Reaching that state requires satisfying two simultaneous dimensions: a risk dimension, which requires that the facility's failure modes be identified, evaluated and treated under the As Low As Reasonably Practicable (ALARP) principle throughout all life cycle phases; and a governance dimension, which requires that roles and responsibilities be clearly defined so that closure decisions are grounded in engineering analyses with documentary traceability.
This paper examines how the Engineer of Record (EoR) – the role with an explicit mandate for technical continuity across the full TSF life cycle – contributes to the governance dimension of safe closure. The analysis draws on an interpretive review of the GISTM and its Conformance Protocols (ICMM 2021), the ICMM Mine Closure Good Practice Guide (3rd edition) (ICMM 2025b), the ICOLD Bulletin 194 (ICOLD 2025) and the SME Tailings Management Handbook (SME 2022), complemented by the experience of the EoR technical team in closure and post-closure assessments.
The central argument is that safe closure requires the convergence of GISTM tailings governance and ICMM closure governance in the closure plan, and that the technical basis built by the EoR throughout the life cycle – documented in the Design Basis Report (DBR) and its closure-specific version (CDBR), the Construction Record Report (CRR), the Construction versus Design Intent Verification (CDIV), the Deviance Accountability Report (DAR), the Operations, Maintenance and Surveillance (OMS) with its critical controls and Trigger Action Response Plan (TARPs), periodic safety reports and risk assessments – is the condition that enables that convergence to rest on a solid and auditable foundation. Progressive closure and the definition of technically verifiable success criteria are an essential part of that basis: without them, the ITRB cannot confirm safe closure nor the AE formally approve it, and relinquishment remains an aspiration rather than a technically achievable state. The central contribution of the paper is a traceable linkage between the failure modes identified under GISTM Req. 5.4, the design measures documented under Req. 5.6, and the verification criteria recorded in the closure plan – a chain that the EoR must build and maintain across the life cycle as the technical condition for safe closure confirmation.
The paper concludes with practical guidelines for the EoR, the TSF operator, and GISTM conformance assessment bodies.

Keywords: safe closure, Engineer of Record, GISTM, ALARP, closure governance, tailings governance, TSF life cycle, closure plan