Exploring Lithium: Deposits and Strategies

Aug 6, 2024

Overview of Lithium Deposits and Exploration

Acknowledgements

  • Traditional land acknowledgment: Gadagal people of the Aurora nation.
  • Presentation by Edward Bunker, mineral exploration geologist at CGG.

Presentation Structure

  1. Fundamentals of lithium's physical and chemical properties.
  2. Current motivations for lithium exploration.
  3. Overview of different types of lithium deposits.
  4. Integrated lithium mineral system perspective.
  5. Case studies in lithium exploration.

Fundamentals of Lithium

  • Lithium behaves like a large iron lithophile (similar to large iron lithophiles).
  • Properties of lithium:
    • Small ionic radius.
    • Highly electropositive.
    • Low melting and boiling points.
    • Highly water soluble.
  • Lithium's concentration:
    • Reason for low lithium content in seawater (0.2 ppm).
    • Concentration in deep-sea clays higher than seawater.

Economic Lithium Systems

  • Cornish Lithium: brine in Cornwall (200-220 ppm lithium).
  • Salar de Atacama: higher lithium concentration (order of magnitude higher).
  • Thacker Pass: lithium clay type system.
  • Mount Holland: hard rock spodumene deposits.

Motivation for Lithium Exploration

  • Demand driven by the shift towards electric vehicles, mobile phones, and laptops.
  • Anticipated demand increase by eightfold in the next decade.
  • Supply vulnerabilities due to limited production countries:
    • Australia, Chile, Argentina, and China dominate the market.

Types of Lithium Deposits

Hard Rock Deposits

  • Classic mining method associated with granite-related pegmatites.
  • Benefits:
    • Conventional exploration methods.
    • High-grade ore.
    • Located in permissive mining jurisdictions (Australia, Canada).
  • Downsides:
    • Energy intensive mining process (10% of global energy).
    • High waste generation (only 0.3% lithium in mined rock).

Lithium in Clays

  • Occurs in places like Thacker Pass.
  • Similar exploration methods but often faces resistance due to local communities and ecological concerns.

Brine Extraction from Evaporative Basins (Salars)

  • Low energy refinement using solar evaporation.
  • Long extraction times (18 months to 2 years).
  • Local water impacts and ecological concerns.

Unconventional Lithium Brines

  • Diverse geological settings.
  • Opportunities for geothermal extraction and co-production of other minerals.
  • Minimal waste, but uncertain commercial viability.

Integrated Lithium Mineral System

  • Conceptual model showing how lithium moves at and near the Earth's surface.
  • Key processes:
    • Fractional crystallization in magmatic systems.
    • Weathering and subsequent transport in water systems.
    • Accumulation in endorheic basins.

Case Studies

  • Paleo Salars: ancient lithium-rich basins explored using satellite technology.
  • Direct Lithium Extraction Technologies: multiple methods to extract lithium with varying efficiencies.
  • Oil Field Brines: lithium enrichment observed in some oil fields; ongoing research into sources and mechanisms.

Conclusions and Future Directions

  • Need for exploration and innovation to meet rising lithium demands.
  • Exciting prospects in brine-hosted systems for sustainable lithium production.
  • Importance of understanding geological contexts to optimize extraction processes.