LCA for Mining and Metals

Metals are fundamental to modern infrastructure, technology, and the energy transition itself—wind turbines, batteries, and electric vehicles all require significant metal inputs. Life Cycle Assessment of mining and metals reveals the substantial environmental impacts of primary production and the critical importance of recycling for reducing these impacts.

Why LCA for Mining and Metals?

Energy transition materials: Decarbonization requires vast quantities of copper, lithium, cobalt, rare earths, and other metals.

High-impact sector: Primary metal production is extremely energy and resource intensive.

Recycling imperative: Secondary (recycled) metals typically have 60-95% lower impacts than primary production.

Supply chain foundation: Metal LCA data underpins assessments for construction, transportation, electronics, and more.

Social dimensions: Mining involves significant social and environmental justice considerations.

Methodological Considerations

System Boundaries

Metal LCA typically covers:

Primary boundary question: Include mining site preparation, closure, and long-term monitoring?

Functional Unit

Common functional units:

• "1 kg of metal, at refinery gate, [purity specification]"
• "1 kg of metal product (e.g., sheet, wire)"
• "1 kg of metal in application (accounting for alloys)"

Grade and form matter—pure aluminum differs from aluminum alloy.

Allocation Challenges

Multi-metal ores: Many ores contain multiple valuable metals (e.g., copper ore contains gold, silver, molybdenum)

Allocation approaches:

• Mass allocation: By metal mass extracted
• Economic allocation: By market value (common)
• No allocation: System expansion for co-products

Economic allocation is standard in the industry but creates volatility—copper footprint changes when gold prices change.

Major Metals

Steel

Global production: ~1.9 billion tonnes/year Primary routes:

• Blast furnace/basic oxygen furnace (BF-BOF): 70% of production
• Electric arc furnace (EAF): 30% of production

GWP comparison:

Decarbonization pathways:

• Direct reduced iron (DRI) with hydrogen
• Carbon capture on BF-BOF
• Increased EAF with clean electricity

Aluminum

Global production: ~70 million tonnes/year Primary production: Hall-Héroult electrolysis—extremely energy-intensive

GWP by region:

Recycled aluminum: 0.5-1.5 kg CO₂e/kg (95% energy savings)

Copper

Global production: ~25 million tonnes/year Ore grades declining: Average ore grade has fallen from 2% to <0.6%, increasing energy per kg metal

Life cycle stages:

• Mining and concentration: 30-50% of impacts
• Smelting: 20-40% of impacts
• Refining: 10-20% of impacts

GWP: 2-5 kg CO₂e/kg (highly variable by ore grade and process)

Critical for energy transition: Electric vehicles, wind turbines, grid infrastructure all require substantial copper.

Critical and Battery Metals

Lithium:

• Brine extraction: Lower energy but high water use
• Hard rock mining: Higher energy
• GWP: 5-20 kg CO₂e/kg (highly variable)

Cobalt:

• 70% from DRC, often as copper/nickel co-product
• Significant social concerns (artisanal mining)
• GWP: 5-15 kg CO₂e/kg

Nickel:

• Class 1 (high purity): For batteries
• Laterite vs. sulfide ores have different impacts
• GWP: 8-20 kg CO₂e/kg

Rare earth elements:

• Complex separation processes
• Radioactive waste concerns
• Highly concentrated supply (China)

Impact Categories

Climate Change

Primary metal production is energy-intensive:

• Process energy (heat, electricity)
• Process emissions (carbon anodes in aluminum)
• Fuel for mobile equipment

Land Use and Biodiversity

Mining transforms landscapes:

• Surface disturbance
• Waste rock and tailings
• Habitat fragmentation
• Post-closure restoration (variable success)

Water Use and Quality

Consumption: Ore processing requires significant water Pollution: Acid mine drainage, heavy metal leaching Regional sensitivity: Water scarcity in mining regions (Chile, Australia)

Human Toxicity and Ecotoxicity

• Heavy metal releases
• Dust emissions
• Tailings dam failures (catastrophic potential)

Social Dimensions

While not standard in environmental LCA, social considerations are critical:

• Labor conditions
• Indigenous rights
• Community impacts
• Artisanal and small-scale mining (ASM) conditions

Recycling and Circular Economy

Secondary vs. Primary Metal

Methodological Issues

Scrap quality: Pre-consumer vs. post-consumer, contamination levels

Allocation approaches:

• Cut-off: Scrap enters burden-free
• End-of-life recycling: Credit for avoided primary production
• PEF Circular Footprint Formula: Shared responsibility

Closed-loop vs. open-loop: Steel from cars may become construction steel (quality sufficient); aluminum from cans stays in cans (closed-loop possible)

Collection and Recovery

Recovery rates vary by application:

Product design significantly affects end-of-life recovery.

Data Sources

Industry Associations

LCI Databases

Case Study: Embodied Carbon in Electric Vehicles

Metals contribute significantly to EV manufacturing impacts:

Implications:

• Battery metal sourcing dramatically affects vehicle footprint
• Aluminum-intensive body structures: Higher if primary, lower if recycled
• Recycling rates and second-life battery use extend value

Key Takeaways

1. Primary metal production is highly energy-intensive; impacts vary dramatically by process and location
2. Recycling reduces impacts by 60-95% for most metals—circular economy is essential
3. Ore grade decline means increasing energy per kg for primary metals
4. Location of production (especially for aluminum) can matter more than process choice
5. Allocation method significantly affects multi-metal mine footprints
6. Industry associations provide free LCI data for major metals
7. Social dimensions are critical but not captured in standard environmental LCA

Resource List

Industry Data

• worldsteel LCI Data
• International Aluminium Institute
• International Copper Association
• Nickel Institute

Research Organizations

• CSIRO (minerals research)
• Minviro (mining LCA consultancy)

Standards and Guidance

• ISO 14040/44 (general LCA)
• ICMM guidance on LCA in mining
• Responsible Minerals Initiative

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Metals form the foundation of modern infrastructure. Primary production impacts are substantial, making recycling and circular design critical for sustainability.