The future mine integrates systems thinking to realise the environmental benefit of design options through cross-value chain collaboration to identify and assess solutions from mining through to rehabilitation. Mine-to-mill modelling can demonstrate the impact from NPV, future rehabilitation cost and emissions reduction perspectives. Various current and emerging design considerations may provide value when considering reducing lifecycle impact and optimising for progressive rehabilitation.
Designing for progressive rehabilitation
Planning for progressive mine site rehabilitation is integral to mine planning and approvals. The cost and complexity of rehabilitation is multi-factored, but key elements include:
- Extent of area disturbed for mining and mine infrastructure, including tailings dams
- Geochemical and geophysical properties of mine waste, including acid mine drainage potential and stability of waste deposition
- Availability of topsoil for rehabilitation
- Water availability for plant growth support
- Future land use agreements with governments and communities.
Mining, comminution, minerals processing and tailings management options that may lower the cost and extent of rehabilitation activities include:
- Emerging precision mining technologies to reduce waste extracted from the mine, and land area disturbed
- Ore pre-sorting to reduce waste rock being crushed – reducing tailings volumes
- Appropriate minerals processing solutions are highly dependent on the ore body, but options that can reduce impact include:
- In-situ leaching (emerging approach)
- Heap leaching in lieu of flotation (reduces tailings),
- Coarse flotation (reduces percentage of ultrafines in tailings)
- Lower footprint minerals processing plants
- Relocatable minerals processing plants with minimised concrete
- Separation of acid mine drainage potential wastes from other waste and tailings, for targeted management
- Alternate gold recovery reagents
- Tailings solutions including co-disposal (improved stability), deposition in mine voids, dry stacking, and emerging tailings circular economy options, such as using tailings to create topsoil or construction materials
Reducing emissions through lifecycle thinking
Greenhouse gas (GHG) emissions from mineral processing infrastructure can be reduced through lifecycle thinking throughout the design process, from concept and layout development, through to detailed design. Options for design emissions reduction include:
- Full lifecycle design option assessment at concept stage to optimise mine planning, site layout and processing options for reduced emissions
- Footprint reduction through optimised layout and processing circuit design
- Use of fly ash in concrete construction
- Recycled steel for reinforcement
- Optimised transport volumes for sea and inland transport
- LED lighting
- Solar powered site water transfer pumping in day only
- Solar powered street and access way lighting
- Electrification of plant systems – i.e. reclaim and stacker systems
- Renewable energy inclusion in mine site supply
- Alternative processing options to match power demand to power supply from renewable power.
Responsible construction and operations
What does responsible delivery of mine site construction projects and mineral processing plant operations look like? Some activities for responsible delivery are business as usual, such as:
- International organisation for standardisation (ISO) qualification ISO14001 for compliant systems, monitoring and audits
- Waste separation and recycling processes.
As industry is focussing more squarely on reducing emissions, we are seeing efforts focussed on:
- Reducing diesel usage in generators and site vehicles, through low emission fuels, or electrification
- Renewable powered site facilities
- Increasing inclusion of recycled, lower emission, and circular economy materials in construction such as steel, concrete, asphalt and sand.
See our approach here.