Sustainability Report 2021

At the end of FY21, the estimated total cost of rehabilitating and restoring the environmental disturbance that has occurred as a result of our Nova Operation amounted to A$44.6M. Identifying the gaps IGO recently completed a gap analysis of the existing MCP at our Nova Operation, to understand the current knowledge gaps and establish a future workplan. This gap analysis identified and established 15 future workplans that will improve our understanding of current closure knowledge and address the gaps. The project was collaborative and ensured engagement with all key subject matter experts across the business. We have also completed modelling, stability and erodibility testing of the TSF and waste rock dump at the Nova Operation to better understand landform stability and inform closure planning. The overall objective of the study was to develop two-dimensional rehabilitation profile shapes that are erosion stable in the long-term. This project has helped define key operational, rehabilitation and closure planning objectives, including: • rehabilitation batter shape for both the waste rock dump and TSF • maximum storage capacity of the waste rock dump • mine closure capping configurations for both the waste rock dump and TSF; and • the required volume of materials to deliver the mine closure cover system. It has also informed and helped determine: • field trials to test capping and landform batter designs • PAF (potentially acid forming) material management and rehabilitation parameters; and • if the existing embankments sheeted with TSF footprint and borrow pit materials are likely stable in the short and long-term. An embankment upgrade plan has been established to take non-acid forming (NAF) material from the eastern stockpile to ensure a minimum factor of safety of 1.8 slope around the entire TSF. Materials balance assessments have also been undertaken to determine the availability of NAF waste rock to increase the TSF embankment factor of safety and ensure an appropriate design cover for the TSF at closure. Mine closure planning is an ongoing process, and we will continue our work to inform knowledge gaps to ensure we achieve closure objectives. Engagement and collaboration We work with industry and other international organisations on sharing best practice for mine closures. IGO was a key contributor to the Western Australian Biodiversity Science Institute’s Framework for Developing Mine-site Completion Criteria in Western Australia. This project was carried out to support the prioritisation of data collection and monitoring activity to enable the development and assessment of completion criteria. It reinforces the importance of engagement and collaboration within the industry to inform best-practice mine closure planning. Engagement with stakeholders, both internal and external to IGO, is a critical part of the planning process. The potential impacts of closure are an ongoing consideration in our engagement with governments and local communities, including how closure can affect our support of community development initiatives and local business. In recognition of the potential impacts of mine closure to the environment, community and the economy, we have increased our effort in the closure planning process. Mine rehabilitation fund IGO, like many other mining companies, pay a levy to the Western Australian Government’s Mining Rehabilitation Fund for the purpose of funding the closure of abandoned mine sites i.e., sites where liability rests with the government because of business failure or other historic reasons. In FY21, IGO’s levy payments totalled A$107,498. REGULAR MINE CLOSURE ENGAGEMENT Mine Plan – Define Domains Mine Closure Plan Closure Cost Liability Report Internal and External Closure Cost Analysis Demolition and Earthwork Scope Final Landforms Engineered Designs Completion Criteria (Basis of Design) Development IGO SUSTAINABILITY REPORT 2021— 81