Springer, D, O'Kane, M & Meek, I 2026, 'What have we learned from writing the book? Implementation of the International Network for Acid Prevention guidance to deliver successful cover systems', 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. 1-10, https://doi.org/10.36487/ACG_repo/2615_27 (https://papers.acg.uwa.edu.au/p/2615_27_Springer/) Abstract: Designing and implementing effective cover systems for tailings storage facilities (TSFs) and mine rock stockpiles (MRSs) remains a central challenge in mine closure, requiring integration of sound geotechnical, geochemical and hydrological principles with practical construction and long-term performance considerations. Following almost 10 years of implementation of the guidance provided in the International Network for Acid Prevention (INAP) Global Cover System Design – Technical Guidance Document (2017), a series of cross-disciplinary lessons has emerged that strongly reinforce the significance of this industry leading, best practice guidance. These insights highlight the importance of robust conceptualisation, transparent closure objectives and the need to design with clear awareness of both fixed and flexible system constraints. Lessons drawn from operational sites demonstrate recurring themes related to future land use, climate, material limitations, water management, landform stability, vegetation establishment and construction planning and quality execution. Together, these insights reinforce the basis for the INAP-applied framework structured around ‘8 ways to ensure success’ in cover system design. A critical learning is that successful cover system performance begins with clear definition of landform and closure objectives, followed by a realistic assessment of climate drivers, hydrological pathways and material properties. Elements such as climate and intrinsic material behaviour cannot be changed, while others such as material availability, hydrogeological setting, post-mining land use and timeframes are difficult to modify but must be carefully characterised to support credible design outcomes. Construction practices, by contrast, represent an area where significant influence can be exerted to enhance long-term performance, provided appropriate quality control and verification processes are in place. The INAP lessons emphasise the need for conceptual models that accurately represent water and oxygen fluxes, landform behaviour and long-term surface evolution, supported by field data and monitoring results. The lessons learned by Okane over the past 30 years in the planning, design and execution of cover systems for TSFs and MRSs aligned with INAP guidance principles can deliver successful cover systems through integrated, evidence-based design informed by site-specific understanding, adaptive management and a commitment to long-term performance.