exploring for rare earth elements using reflectance

Government of Western Australia
Department of Mines and Petroleum
EXPLORING FOR RARE EARTH
ELEMENTS USING REFLECTANCE
SPECTROSCOPY
Sidy Morin-Ka
Lena Hancock
Trevor Beardsmore
John Galt prospect, East Kimberley
Geological Survey of
Western Australia
Background
• REE cannot be seen by naked eye
• Techniques to identify REE are destructive and expensive
• REE produce absorption bands in the visible spectral
range
Copperhead carbonatite, East Kimberley
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Aims
Test if spectral technologies can:
• detect REE & distinguish individual element
• differentiate light REE (LREE) from heavy REE
(HREE)
• be used as an exploration tool
Fluorite, Brockman prospect, East Kimberley
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Hyperspectral technologies
Spectrometers
measure the
intensity of the
reflected light
ASD TerraSpec™
Elements
have a selective
absorption of the
incoming light at
specific wavelengths
Terra satellite (NASA)
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Individual
minerals
can be identified
through their
spectral signature
HyLogger™
Hyperspectral technologies
VNIR
• Visible NearInfraRed
• 380 to 1000 nm
SWIR
• ShortWave
InfraRed
• 1000 to 2500 nm
TIR
• Thermal InfraRed
• 6000-14000nm
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Rare earth oxides
REO
Purity >= 99.99%
Samples from Huntington Hyperspectral Pty Ltd
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Rare earth minerals
Apatite
Bastnasite
Monazite
Parisite
• VNIR features analogous to REO
• All LREE bearing minerals have identical features
• HREE present a different signature
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Xenotime
REE detection
VNIR spectral range is largely free from
interference from common rock-forming
minerals (in exception of FeO)
REE deposits are typically mixes dominated
by either LREE or HREE
View from John Galt prospect, East Kimberley
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
LREE versus HREE
747 nm
LREE
808 nm
872 nm
HREE
656 nm
806 nm
747
872
908 nm
808
656
806
908
Features used by scalars to
detect REE mixes
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Rare earth deposits
Wolverine prospect,
HREE Browns Range
Open pit, Mt Weld
LREE
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Mount Weld
where LREE are found
Mt Weld, drill core CH15 + LREE scalar
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Mount Weld
LREE Scalar
VS
Geochemistry
Total REO from assay plotted in TSG™ Scatter View
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Browns Range
Wolverine prospect,
206218 outcrop, Browns Range
Browns Range dome area, East Kimberley
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Assay results
Browns Range
LREE Wolverine prospect,
206218 outcrop, Browns Range
HREO
Browns Range dome area, East Kimberley
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Assay results
Cable Beach, Broome, Kimberley
Another level of complexity
Preliminary analyses of selected REE phosphates, carbonates and chlorides
Atomic bond may influence VNIR spectral signatures
This remains to be quantified and confirmed
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Another level of complexity
Preliminary analyses of selected REE phosphates, carbonates and chlorides
LREE
Atomic bond may influence VNIR spectral signatures
This remains to be quantified and confirmed
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Conclusion
 VNIR= characteristic and indicative features of the REE
 REE can be detected in any type of natural material
 We can detect & distinguish between LREE and HREE using
empirical scalars
 The VNIR range response of the REE enables the use of portable
devices in the field and airborne devices
However,
Type of REE compounds revealed a complexity not thought previously
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum
Acknowledgments
• First, the speaker would like to thank Dr. Jon Huntington and Huntington
Hyperspectral Pty Ltd for giving us access to the rare earth oxides and
his contribution to the project
• The speaker also thanks the CSIRO Mineral Down Under and Earth
Science and Resource Engineering teams for their feedbacks and the
access to the second group of rare earth oxides
• Moreover, thanks to Peter Downes and the Western Australia Museum
for lending us the rare earth minerals
• To conclude, the speaker also thanks the several companies he had
contact with in order to accomplish this project and particularly Northern
Minerals Limited and Lynas Corporation
Government
Government of
of Western
Western Australia
Australia Department
Department of
of Mines
Mines and
and Petroleum
Petroleum

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