Mine Closure and Life of Asset Planning

Responsible mine closure is central to how MMG mine for progress. We plan for closure from project development and continue refining our approach throughout operations. This includes designing landforms to be safe, stable and non‑polluting, restoring ecosystems and supporting communities in a predictable transition to post‑mining futures.

Closure plans bring together geochemistry, hydrology, geotechnical stability and ecology. MMG model acid and metalliferous drainage (AMD) potential, design cover systems to limit oxygen and water ingress, and engineer landforms that shed water safely, resist erosion and blend with the landscape. Tailings facilities are managed across the life cycle with decommissioning in mind, including beach slopes, drainage networks, buttresses and spillways that support safe closure.

Where feasible, rehabilitation starts early. MMG salvage topsoil and growth media, protect it from erosion and compaction, and reapply with organic amendments to establish native vegetation. Species are selected for local provenance and function. This includes groundcover for rapid stabilisation, shrubs and trees for structure and plant choices that support keystone fauna. Material balance planning ensures sufficient clean rock and soil, while selective placement encapsulates reactive materials.

Surface water is managed through contouring, channels and sediment control structures that protect downstream ecosystems. Where geochemical risks are present, MMG deploy low‑permeability covers, alkaline amendments, strategic water diversions and passive treatment systems such as constructed wetlands to manage acidity and metals. Monitoring informs performance and guides adaptive improvements.

Mine closure is a social process as much as a technical one. MMG design programs that support workforce transitions, local enterprise development and economic diversification. Final land uses are co‑developed with host communities and Traditional Owners, taking into consideration conservation areas, agriculture, forestry, recreation trails or renewable energy infrastructure where suitable. This enables the repurposing of existing roads, buildings and utilities to support local priorities.

MMG incorporate climate projections – drainage sized for extreme rainfall, drought‑tolerant species, vegetation spacing and firebreaks appropriate to bushfire risk – and embed nature outcomes in landform and habitat design. Opportunities for carbon sequestration through reforestation or soil improvement are considered where consistent with final land uses.

After decommissioning, monitoring tracks landform stability, vegetation establishment, water quality and biodiversity against agreed criteria. Maintenance addresses issues (for example, gully repair, infill planting) to keep the site on a positive trajectory. Adaptive management supports continuous improvement and long‑term environmental and social outcomes.