Advanced indicator mineral research concept for the CRM exploration in glaciated terrain – INDIKA project

Marja Lehtonen, Pertti Sarala, Anne Taivalkoski, Sari Lukkari, Irmeli Huovinen, Jouko Karinen, Hanna Koskinen, Kari Strand, Rauno Toppila & INDIKA Project Working Group

Critical Raw Materials

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EU Mineral Strategy: Increase of self-sufficiency, production and reserves of critical, high technology metals and minerals

Countries accounting for largest share of EU supply of CRMs

http://ec.europa.eu/growth/sectors/raw-materials/specific-interest/critical_en

• Link to industry• Modern technology• Environment

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Critical metals and minerals in Finland• Finland has a good

potential for CRMs• Production of Co, Pt, Pd

and apatite• Li production by 2022• PGE, Co, P, Nb, REE,

Sb, Be, graphite, Sc, Ta, W, V, Li prospects

• E.g. large pre-glacial bedrock areas (saprolite/saprock) in Northern Finland, with weathered horizon ~100 m in depth

• Till and lithogeochemistry are good indicators for LREE and HREE mineralizations

HREELREE

Production in Finland / Year 2018Cobalt refining production: 12 874 t Cobalt mining production: 1 377 tPlatinum refining production: 1 804 kg Platinum mining production: 1 576 kgPalladium refining production: 1 804 kg Palladium mining production: 1 157 kgApatite concenctrate mining production: 989 073 t Li hydroxide production will start in 2022 (long term estimate 12 000 t/y)

Exploration challenges• Exploration is challenging in the northern and Arctic regions because of the

complex glacial history• Large peat bog and tundra areas; pre-glacial weathered bedrock• Logistical problems, conservation and reindeer herding areas, and sensitive

arctic nature restrict sampling & research• Social license to operate

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Photo by M. Moilanen

Indicator mineral method• Commonly used exploration method in glaciated terrains• Indicator minerals in glacial sediments indicate the presence of a mineralization• Indicators minerals: (a) visually and chemically distinct (b) sufficiently dense to be concentrated

by gravity (c) chemically and physically resistant to survive preglacial weathering and glacial transport (d) more abundant than the actual ore minerals (ore minerals are also indicators!)

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Ice flow

1.5 km 2.0 km0.5 km

Indicator mineral fan (example): Horizontal and vertical distribution of indicators in till

Excavator sample (rectangle) = 20 kgDrilled sample (sphere) = 5-9 kg

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Commodity / Deposit Indicator minerals Chemical composition Average density (gcm-3) Typical size range (mm)Diamond1 Cr-pyrope garnet (Mg,Fe)3(Al,Cr)2(SiO4)3 3.7 0.25-0.5

Eclogitic garnet (Fe++,Mg)3Al2(SiO4)3 4.0 0.25-0.5

Mg-ilmenite (Fe++,Mg)TiO3 4.7 0.25-0.5

Cr-diopside CaMg(Fe,Cr)Si2O6 3.3 0.25-0.5

Chromite (Fe++, Mg)(Cr,Al)2O4 4.8 0.25-0.5

Forsteritic olivine (Mg,Fe)2SiO4 3.3 0.25-0.5Diamond C 3.5 0.25-0.5

Gold2 Gold Au 17.6 0.01-0.25Scheelite CaWO4 6.0 0.01-0.25

Rutile TiO2 4.3 0.01-0.25Sulphides >4.0 0.01-0.25

Magmatic Ni-Cu-PGE3 Cr-diopside CaMg(Fe,Cr)Si2O6 3.3 0.25-2.0

Forsteritic olivine (Mg,Fe)2SiO4 3.3 0.25-2.0

Enstatite (Mg,Fe)2Si2O6 3.2 0.25-2.0

Chromite (Fe++, Mg)(Cr,Al)2O4 4.8 0.25-2.0

Pentlandite (Fe,Ni)9S8 4.8 0.01-0.25

Pyrrhotite Fe(1-x)S (x=0-0.17) 4.6 0.01-0.25

Chalcopyrite CuFeS2 4.2 0.01-0.25

Pyrite FeS2 5.0 0.01-0.25Platinum group minerals (PGM) >8.0 0.001-0.1

Commonly used indicator minerals (McClenaghan, 2013).

Continues…

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VMS deposits4 Chalcopyrite CuFeS2 4.2 0.01-0.25Galena PbS 7.4 0.01-0.25Sphalerite (Zn,Fe)S 4.1 0.01-0.25Pyrrhotite Fe(1-x)S (x=0-0.17) 4.6 0.01-0.25

Pyrite FeS2 5.0 0.01-0.25

Gahnite (Zn,Fe)Al2O4 4.3 0.25-2.0

Spessartine (Mn++,Fe)3Al2(SiO4)3 4.2 0.25-2.0

Staurolite (Fe++,Mg)2Al9(Si,Al)4O20(O,OH)4 3.7 0.25-2.0

Pb-Zn deposits5 Galena PbS 7.4 0.01-2.0(Mississippi Valley type) Sphalerite (Zn,Fe)S 4.1 0.01-2.0

Porphyry Cu deposits6 Sulphides > 4.0 0.25-2.0Andradite Ca3Fe+++2(SiO4)3 3.9 0.25-2.0Diaspore AlO(OH) 3.4 0.25-2.0Barite BaSO4 4.5 0.25-2.0

Alunite KAl3(SO4)2(OH)6 2.7 0.25-2.0

Dravite NaMg3Al6(BO3)3Si6O18(OH)4 3.1 0.25-2.0

Apatite Ca5(PO4)3(OH,F,Cl) 3.2 0.25-2.0

W-Mo deposits7 Scheelite CaWO4 6.0 0.01-0.25

Wolframite (Fe,Mn)WO4 7.3 0.01-0.25Sulphides >4.0 0.01-0.25Bi minerals >6.0 0.01-0.25

References:1. McClenaghan & Kjarsgaard (2007) 2. McClenaghan & Cabri (2011) 3 and 6. Averill (2011) 4. Averill (2001) 5. Oviatt et al. (2013) 7. McClenaghan et al. (2013)

Continues…

Indicator mineral workflow

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Field work / Sampling Preconcentation Laboratory work Microscopy Mineral analysis

Indicator mineralfingerprinting based on quantitativecomposition, traceelement contents, isotopic composition etc.

Indicator mineral methodology revisited for CRM exploration: INDIKA project.

Photo: Kari A. Kinnunen

Efficient concentration of indicator minerals is crucial to achieve statistically relevant results.

INDIKA Project

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• Automated indicator mineral identification methods for the critical mineral exploration• European Regional Development Fund (ERDF) funded project (2016-2019)• Partners: Geological Survey of Finland (consortium leader), Lapland University of Applied

Sciences, and University of Oulu • Companies: Oxford Instruments, Suomen Kaivosyrittäjät ry, and the Gold Prospectors

Association of Finnish Lapland• Project Manager professor Pertti Sarala• Budget 420 000 €

• Development of an exploration concept for critical minerals based on: • Cost-effective techniques for indicator mineral concentration• Automated indicator mineral identification methods • Using new on-site geochemical and mineralogical analysis techniques• Increasing co-operation between research organizations, mineralogical laboratory

facilities and companies in northern Finland

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INDIKA Workpackages

Field testing and documentation• Development of a protocol & data transfer from the fieldConcentration techniques (field/laboratory)• Knelson Concentrator, goldhound, Wilfley table, panning, heavy

liquids, hydroseparation, magnetic separations…Advanced on-site and laboratory analytical techniques• Mobile XRD, portable XRF, hyperspectrum imaging• FE-SEM-EDS (MLA), RAMAN, XRD, XRF, ICPMSCase studies• Sokli P-REE mineralization in Eastern Lapland • Mäkärä Au-REE target in Central Lapland• Rautuvaara Fe-Cu mine tailings area in Western LaplandPiloting• A new exploration target in Vuolijoki, Eastern Finland

GTKP. Sarala

P. Sarala P. Sarala P. Sarala

Field work

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P. Sarala

A. Taivalkoski

Sampling

Sieving

Concentration

On-site analysis

SubsamplingPhotos P. Sarala

Validation in labroratoryMaximum results already on the field: more flexibility in theexploration program & savings in the exploration budget.

Hanna Koskinen 2018: MSc thesis on pXRD,University of Oulu

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Original Sample12 litres

Wet Screening2mm

Wilfley Table / Knelson

Concentrator

Concentrate: LIMS

Dry Screening:63-100 & 100-160

µm

Heavy Liquidd=3.3 gcm-3

63-100 and 100-160 µm

>3.3 gcm-3

Frantz 0.3 A NONMAG

Sample prep / FESEM

Frantz 0.5 A NONMAG

Sample prep / FESEM

Sokli heavy mineral concentrate63-100 microns

Mineral Grain count Vol-%Monazite 1800 11.70Fe-oxide 1708 16.28Zircon 1666 11.45Baddeleyite 877 6.69Rutile_Ti-Ox 669 11.29Epidote 651 17.92Pyrochlore 529 4.12Apatite 303 5.56Clinozoisite 228 6.39Chlorite 129 0.41Staurolite 84 2.34Zirkelite 66 0.37Almandine 61 0.34Mg-Hornblende 54 1.10Total 9226 100.00

Test samples were used for optimization. Heavy mineral distributioninto grain size, density and magnetic fractions was studied. Up to 300 times enrichment of indicators was achieved. Modal mineralogymeasurements were carried out by automated FE-SEM-EDS.

Laboratory & analytical work

GTK

Recognized indicator minerals

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Indicator mineral Chemical FormulaAllanite CaCe(Al2Fe2+)[Si2O7][SiO4]O(OH)Apatite Ca5(PO4)3(OH,F,Cl)Bastnäsite (Ce,La,Nd,Y)(CO3)FCerianite CeO2Cerite (Ce,La,Ca)9(Mg,Fe3+)(SiO4)3(SiO3OH)4(OH)3Cobaltite CoAsSColumbite (Fe2+,Mg,Mn)Nb2O6Monazite (Ce,La,Nd,Sm)(PO4)Pyrochlore Ca2Nb2O7Thorite Th(SiO4)W-rutile (W)TiO2Xenotime Y(PO4)Baddeleyite ZrO2Zirkelite (Ca,Th,Ce)Zr(Ti,Nb)2O7Zircon Zr(SiO4)

Mäkärä Au-REE target• Zircon, monazite, apatite, allanite, xenotime• Zircon up to 30% in concentrate fractions, monazite

3%

Sokli P-REE target• Zircon, monazite, pyrochlore, baddeleyite, apatite,

allanite, xenotime, zirkelite• Pyrochlore up to 11% in concentrate fractions,

monazite 12%, zircon 21%, baddeleyite 8%

Rautuvaara tailings area• W-rutile, monazite, cobaltite, apatite, allanite,

xenotime, zircon, baddeleyite, thorite• W-rutile up to 2% in concentrate fractions

M. Lehtonen

INDIKA: Results

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• New, tested and documented method for CRM exploration

• Piloting of the method at Vuolijoki 25.-26.6.2018• Bedrock source for REE bearing surface boulders

discovered• On-site analytical methods

• Mineralogical information obtained already duringthe field work

• Data needs to be validated in the laboratory• Future research opportunities

• Field conditions challenging for sample processingand preparation > Mobile field laboratories needed

• Indicator mineral concentration techniques• Several processing methodologies were tested and

documented• Methodologies can be adapted to various

exploration targetsP. Sarala

INDIKA: Future goals and opportunities

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• Increasing exploration activity in Finland for theCRMs• Service concept development

• Creating new business opportunities• New local services• Developed methods applicapble also for

”traditional” minerals/metals exploration• Strengthening cooperation within R&D sector

• Research institutes, universities, companies• Strengthening mineral potential mapping

• New research technologies > Geological knowledge> New ore deposits

• Using modern technology to discover rawmaterials needed for the modern technology.

P. Sarala

5/13/2019

Thank you for your attentionFor more information, please contact:

Pertti Sarala, Project managerpertti.sarala@gtk.fi

Marja Lehtonenmarja.lehtonen@gtk.fi

Anne Taivalkoski, Project secretaryanne.taivalkoski@gtk.fi

http://www.gtk.fi/tutkimus/tutkimushankkeet/indika.html