Hyperspectral Core Logging - Australian Institute of ... · Spectrometry Electromagnetic spectrum...

Hyperspectral Core Logging

AIG Drilling Workshop Mary Harris Project Geoscientist – Rio Tinto Exploration October 2015, Woodend

©2015, Rio Tinto, All Rights Reserved

Spectrometry

Electromagnetic spectrum Image taken from absoluteastronomy.com


Spectrometry

Electromagnetic spectrum Image taken from absoluteastronomy.com

VNIR

Fe-oxides Mn-oxides Hydroxides

REEs

400nm – 1,000nm

SWIR

Hydroxyls Water

Carbonates Sulphates

Micas Amphiboles Tourmalines

1,000nm – 2,500nm

TIR

Carbonates Silicates Olivines

Pyroxenes Garnets

5,000nm – 14,000nm Spectral geology uses

the VNIR, SWIR and

TIR parts of the

electromagnetic

spectrum to identify

minerals


Understanding spectra

Absorption features in the VNIR portion of the

spectrum represent mineral colours (e.g. the presence

of azurite will result in an absorption feature in the blue

portion of the spectrum), as well as sub-atomic and

electronic transitions (i.e. changes in iron from ferric

(Fe3+) to ferrous (Fe2+)). In the VNIR features are often

broad and their slope is important.

Ferric Ferrous VNIR

SWIR

Absorption features in the SWIR portion of the spectrum are

associated with sub-molecular vibrations generated by bending

and stretching of molecular bonds within minerals. The bonds

affected are hydroxyl (OH), water (H2O), carbonate (CO3) and

ammonia (NH4). In the SWIR, features are generally steep and

narrow.

Image courtesy of Scott Halley


Hyperspectral core logging systems


Corescan

• Process: Individual core boxes scanned row

by row. Height profiler aids in data processing

and QC

• Result: Mosaicked high resolution

hyperspectral imagery and photography

• Data Delivery: Web-based imagery

(Coreshed) & composited interval data (csv)

Image courtesy of Corescan


Corescan

• Process: Individual core boxes scanned row

by row. Height profiler aids in data processing

and QC

• Result: Mosaicked high resolution

hyperspectral imagery and photography

• Data Delivery: Web-based imagery

(Coreshed) & composited interval data (csv)

Wavelength range

Spatial resolution

Spectral band width

Spectral resolution

Spectral bands

Scan time

VNIR – SWIR

50um (photography) 500um (spectra)

3.5nm

5nm

510

~5 min/metre



TerraCore International (TCI)

• Process: Individual core boxes scanned as a

single image. Post-processing removes

background tray and slices into rows

• Result: Hyperspectral imagery and

photography

• Data Delivery: Web-based imagery (ALS

Coreview, TCI Intellicore)







photography



Image taken from TCI







photography



Wavelength range

Spatial resolution

Spectral band width

Spectral resolution

Spectral bands

Scan time

SWIR

100um

6.3nm

10nm

256

~1 min/tray ©2015, Rio Tinto, All Rights Reserved

Image taken from TCI

HyLogger (CSIRO)

• Process: Point scan along each row of a tray

and core photography

• Result: Core photography and spectral files

• Data Delivery: Interpretation of spectral files

using TSG accompanied by photography


HyLogger (CSIRO)






Image courtesy of CSIRO ©2015, Rio Tinto, All Rights Reserved

HyLogger (CSIRO)






Wavelength range

Spatial resolution

Spectral band width

Spectral bands

Scan time

VNIR – SWIR – TIR

200um (photography) 8mm (spectra)

1.4nm – 9nm

Up to 1000

~1 min/tray

Image courtesy of CSIRO ©2015, Rio Tinto, All Rights Reserved

Mineral classification

• Identification of minerals to generate class maps

©2015, Rio Tinto, All Rights Reserved Image courtesy of Corescan

Composition and crystallinity

• Track changes in composition and crystallinity in host rock and structures

Image courtesy of Corescan ©2015, Rio Tinto, All Rights Reserved

Veins and structures

• Map vein mineralogy down-hole

Image courtesy of Corescan ©2015, Rio Tinto, All Rights Reserved

Support for geological logging

• Overlay these images

on core photography to

support core logging



Domaining

• Stacked class map with mineral matches highlighting broad changes in alteration


Domaining

• Assist in alteration logging


Paragenesis

Late paragonitic white mica

(pale blue) cross-cutting

pervasive phengitic

muscovite

Later unaltered quartz vein


Paragenesis

Late paragonitic white mica

(pale blue) cross-cutting

pervasive phengitic

muscovite

Later unaltered quartz vein

Strong phengitic alteration

of quartzite zoning into

higher temperature

paragonitic mica in clasts of

breccia

Montmorillonite alteration of

matrix in breccia


Advantages of hyperspectral core scanning

Deliver data in real time to geologists

to support drill core logging





High quality core

photography





High quality core

photography

High spatial

resolution data





High quality core

photography

High spatial

resolution data

Systematic and

unbiased data collection



Integration with other datasets

to build more robust 3D models



High quality core

photography

High spatial

resolution data

Systematic and




Integration with other datasets

to build more robust 3D models



High quality core

photography

High spatial

resolution data

Systematic and


Adding value down the chain


Questions…


Hyperspectral Core Logging - Australian Institute of ... · Spectrometry Electromagnetic spectrum...

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