GNS Science

New Zealand’s Clean Technology Mineral Potential

Regine MorgensternRose Turnbull, Matt Hill, Patti Durance, Mark Rattenbury, Rob Smillie, NZP&M

GNS Science

Talk Outline

• What are ‘clean technology’ minerals and how are they used

• The mineral systems concept

• Mappable criteria of the mineral system

• Rare earth element mineral potential of New Zealand

• Lithium mineral potential of New Zealand

• Next steps and opportunities

Source: https://ww2.frost.com/

GNS Science

Introduction

‘Clean-tech’ minerals (aka ‘green’/‘strategic’ minerals or ‘critical elements’) – essential to support New Zealand’s transition to a low-carbon economy

Metals (and mining) are required for a no/low-carbon future

Sources: www.icmm.com; www.stuff.co.nz

Clean technology minerals

• Elements crucial to society for economic growth and/or national security, but which are vulnerable to supply disruption

• No practical substitutes: they are in high demand• There are currently 23 – including Co, Li and REE

GNS Science

Introduction

Clean-tech mineral uses:

Wind turbinesSolar batteriesElectric and hybrid vehicle batteries

Sources: AGI 2018; www.newzealandphoto.info

1x 3 MW turbine = 2 tonnes REE

64,000 electric vehicles by end of 2021

Demand for these clean-tech minerals is high and continues to grow

GNS Science

Introduction

• Commodities of REE, Li and Co are poorly understood• Importantly, what is currently defined as a critical mineral can change

with rapidly evolving technology and social and political changes

Need to understand all of NZ’s mineral wealth resource in order to adapt to future supply and demand constraints of low-carbon technologies

New Zealand’s first clean technology minerals study:• Jointly-funded GNS Science – NZP&M project to examine the potential for REE, Li and

Ni-Co mineralisation at a broad regional scale• To identify areas of higher potential, and rule out other areas based on current

knowledge and data• To identify knowledge gaps so as to improve confidence in REE, Li and Ni-Co potential• Provides a framework for other commodity studies (e.g. Au, Ag, PGE, W, base metals)

GNS Science

The Mineral Systems Concept

• Theoretical model to conceptualise ore deposits at various temporal and spatial scales

• Ore deposits are small expressions of larger earth system processes that occur before, during and after deposit formation

• Derived from the petroleum system concept• Mineral system components:

– Energy source– Fluid, ligand and ore sources– Enrichment and focusing mechanism– Trap– Surface expression

+

+

+

++ +

++

+++

+++

+

NO DEPOSIT

NO DEPOSIT

NO DEPOSIT

Fluids & ligandor ore source

EnergySource

Enrichment &focusing Trap Surface

expression

Regional scale components

District scale

Ore deposit

Source: Hagemann et al. 2016

GNS Science

The Mineral Systems Approach – Intrusion-Related REE

Component Critical processes¥

Constituent processes§

Targeting featuresŦ Scale* Mappable criteria

ǂ

Fluid migration / mixing Zoned alteration facies S-M Key alteration mineral occurrence (e.g. greisenisation, sulphide minerals)Residence time Mineralogical / textural S Sampled rock pathfinder elements

Laterites, saprolite and clays S-M Occurrence of clays (especially halloysite), saprolite, lateritesAccumulation of monazite, zircon, xenotime, allanite, thorite, uranothoriteSampled REEs & pathfinder elements in stream / pan concentrate samplesMapped Quaternary depositsRadioactivity

Fluid-wall rock reactions Alteration + precipitation along structures S-MFluid mixing / dilution Changes in mineral stabilities S

Sampled rock ore elements (i.e. REE content)Key REE mineral occurrence (e.g. monazite)

Pressure decrease Structures, cavities, shallow emplacement S-L Mapped Paleozoic and Mesozoic faultsBoiling / effervescence Volatile loss S-M Hydrothermal alterationChange in temperature Zoned alteration facies / crystallisation sequence S-M Zoned alteration assemblageNormal faulting Cross-cutting dilatational structures / textures S-L Mapped Paleozoic and Mesozoic extensional faultsDelamination Metamorphic core complex / half-graben basins L Mapped Mesozoic core complexes & brecciaDike-swarm intrusion Presence of dikes M-L Mapped/sampled dikes

Igneous fractionationMapped/sampled pegmatitesSampled whole-rock F contentF-rich mineralogy

Degree of partial melting Igneous geochemistry (Fe:Mg, HFSE content, ASI index, low-Ca)Melting of enriched / previously extracted mantle Key mineral occurrence (feldspathoids, alkali amphiboles / pyroxenes)

Mapped intrusive suites in QMAPAeromagnetics

Liquid immiscibility Chemical / mineralogical S-M Mapped/sampled pegmatites, carbonatites, fenitesHeating of country rock Alteration zones S-M Mapped/sampled alteration zones (e.g. sulphide / carbonate minerals)Mantle melting / degassing Involvement of mantle-derived CO2 S Mapped/sampled carbonatites / carbonate mineralsDecompression / ascent Shallow emplacement M-L Mapped geological structuresAsthenospheric upwelling Alkaline igneous rocks / carbonatites M-L Mapped intrusive suites in QMAPDecompression melting Crustal thinning / extension L Crustal / trans-lithospheric structures

5. Surface expression

1. Energy source

2a. Fluid and ligand source

2b. Ore source

3. Enrichment and focusing mechanism

4. Trap

Alkaline geochemistry

Alkaline igneous rocks / carbonatitesCooling & fractional crystallisation

Alteration rock types (altered, veins, breccia/conglomerate, metasomatic)

Crystallisation of ore / gangue minerals REE mineralogy

Magma cooling Igneous relationships and fractionation M-L

S-M

M-L

M-L

S

Presence of elevated F in magma / hydrothermal fluids

Intra-plate magmatism

Mantle melt generation

Granitic melt generation

Mantle magmatism

Complexing of REEs

Extensive fractionation

Regional extension

Change in physical conditions

Change in chemical conditions

Involvement of F in melt &/or hydrothermal (magmatic / meteoric) fluids

M

Cooling

Chemical / mechanical weathering (± transport & deposition)

Weathering (± erosion) Heavy mineral, Th & U accumulation, black sands, placers, etc. within Quaternary deposits

Building on the REE mineral systems model of Morgenstern et al. (2017)

GNS Science

The Mineral Systems Approach

Mappable criteria• Parts of the mineral system that can

be represented spatially• Represent all five components• Were identified for all three mineral

systems• Data were extracted from existing

databases, open access mineral reports and other published and unpublished literature

• New data were also acquired• GIS-based expert-weighted spatial

modelling approach was used to create the mineral potential maps

Patti will discuss these, and Ni-Co potential, in more detail in her talk

GNS Science

Mineral Potential Maps – REE

Where might REE deposits form in New Zealand?

1. Carbonatites2. Alkaline igneous intrusions3. Placers4. Ion-adsorption5. Laterites6. By-products, co-products, waste-products7. IOCG deposits8. Seafloor deposits

GNS Science

Mineral Potential Maps – REE

Mineral potential modelling of REE mappable components

Mineral system components

Final mineral potential models

Mappable criteria

GNS Science

Mineral Potential Maps – REE

GNS Science

Areas of highest potential:• Placers sourced from REE-rich

alkaline intrusions: West Coast beach sands and paleoplacers

• Alpine Dike Swarm carbonatites: Up to 1.25 wt% light REE

Opportunities to refine the model• Targeted stream sediment sampling

and analysis (West Coast beaches, catchments draining carbonatite dikes around Haast)

• Targeted sampling and analysis of in situ plutonic sources

Mineral Potential Maps – REE

1342 ppm1439 ppm

REE Heavy Mineral Samples(analysed for this study)

500-600 ppm

GNS Science

Mineral Potential Maps – Lithium

Where might lithium deposits form in New Zealand?

1. Pegmatites2. Brines3. Hydrothermally altered clays

No known occurrences of Li-rich minerals

No prior exploration for lithium (except for extraction from geothermal brines)

GNS Science

Mineral Potential Maps – Lithium

Mineral potential modelling of lithium mappable components

Mineral system components

Final mineral potential models

Mappable criteria

GNS Science

Mineral Potential Maps – LithiumWEST COAST COROMANDEL TAUPO-BAY OF PLENTY

STEWARTISLAND

CANTERBURY

TVZ

Hohonu Range

Lyell RangeCVZ

Mount SomersVolcanic Group

GNS Science

Mineral Potential Maps – Lithium

New areas of interest• Taupo Volcanic Zone: Hydrothermally

altered rhyolitic lake deposits, extensional faults, current hydrothermal activity

• Hohonu Range, Lyell Range: Fractionated granitoid rocks = potential for pegmatites

Opportunities to refine the model• Targeted analyses of lithium & key

pathfinder elements from samples in Petlab

• Sampling of pegmatites/hydrothermally altered clays in prospective areas

Taupo Volcanic Zone

Hohonu Range

Lyell Range

GNS Science

Summary

• This project has proven successful in identifying broad areas with higher potential and ruling out other areas based on current knowledge and data

• REE potential: highest in West Coast alkaline plutons and in placer deposits derived from them

• Lithium potential: highest in central North Island, and West Coast granitoids Available as Mineral Reports to download from www.nzpam.govt.nz

• Revealed data gaps, and the potential to improve the models with further sampling and analysis• Very low or no potential areas (grey) are unlikely to change with further work

• Some areas of low potential (blue-green) may increase with additional studies/analyses

• Areas of moderate-high potential (yellow-red) are good starting points for further detailed studies

GNS Science

Next Steps

• Address data gaps from these studies in regions identified as having high potential (e.g. targeted geochemical sampling of hydrothermally altered clays in the Taupo Volcanic Zone)

• Undertake similar studies for other critical minerals using the same approach, to develop a national-scale, consistent dataset (e.g. Au, Cu, PGE, W, aggregates)

• Consider offshore critical mineral potential (e.g. Co, Cu, REE, phosphate) using the same mineral systems approach

• Advocate for the collection of consistent, seamless national-scale datasets

Watch this space!