DEPOSIT EMAS “NON KONVENSIONAL” Peluang Eksplorasi di Indonesia

Sukmandaru Prihatmoko

Turquoise Hill Resources/ PT AGC Indonesia

Yogyakarta, 1 Juni 2013

1

GOLD DEPOSIT MODELS

AND

WORLD GOLD ENDOWMENT

•

“Clans” of GOLD DEPOSITS

(After Poulsen et al, 2000)

INTERMEDIATE

SULFIDATION

ORE DEPOSIT MODELS (after Corbett & Leach, 1998)

Conventional Deposit Models in

Indonesia

TECTONIC CONTROLS OF GLOBAL Au RESOURCES

(Goldfarb, 2009) Metamorphic hosted

Slate and greenstone belts

IOCG

Sedimentary Exhalative

Paleoplacer ?

SOME IMPORTANT GOLD MODELS

• Porphyry copper-gold and skarn gold

• Epithermal gold (high-, intermediate- and low-sulfidation)

• VMS (volcanogenic massive sulfides)

• Carlin type gold (and Carlin-like deposits)

• Orogenic gold (mesothermal, slate belt, Achaean lode gold)

• IOCG (Iron Oxide Copper Gold)

• Witwatersrand (paleoplacer)

• Sedimentary Exhalative (Sedex)

• Placer/ alluvial gold

Non Conventional Deposits

GOLD DEPOSITS >/= 150t *

(Goldfarb, 2009)

PRESERVATION OF PORPHYRY+EPITHERMAL AND OROGENIC Au

(Goldfarb, 2009)

PORPHYRY CONTRIBUTION TO WORLD Au ENDOWMENT

PORPHYRY BELTS Recent and ancient (?)

(Wurst, 2010)

PRESERVATION OF PORPHYRY+EPITHERMAL Au

(Circum Pacific)

(Goldfarb, 2009)

PRESERVATION OF OROGENIC Au

(Goldfarb, 2009)

2

INDONESIA GOLD ENDOWMENT

MAGMATIC ARCS AND CRUSTAL BLOCKS

(Carlile and Mitchell, 1994)

MAGMATIC ARCS AND REGIONAL GEOLOGY

(from various sources)

SIMPLIFIED MAGMATIC ARC AXES

INDONESIA GOLD ENDOWMENT (status by May 2013) Au (Moz)

Deposit Type

N = 110

(published paper, news releases, and unpublished reports

TOTAL Au: 237 Moz ~ 6,723 tonnes

SIMPLIFIED MAGMATIC ARC AXES Total Au: 237 Moz

Papua Arc

113.52 Moz

Moon Utawa Obi Arc

0.51 Moz

Halmahera Arc

3.83 Moz

SIMPLIFIED MAGMATIC ARC AXES Total Au: 237 Moz

North Sulawesi Arc

14.88 Moz

West Sulawesi Arc

4.09 Moz Central Kalimantan Arc

10.94 Moz

Schwanner Arc

0.46 Moz

SIMPLIFIED MAGMATIC ARC AXES Total Au: 237 Moz

Western Sunda Arc

12.44 Moz

Aceh Arc

5.12 Moz

Meratus Sumatera Arc

0.38 Moz

SIMPLIFIED MAGMATIC ARC AXES Total Au: 237 Moz

Eastern Sunda Arc

68.69 Moz

Banda Arc

1.53 Moz

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NON CONVENTIONAL GOLD DEPOSITS OROGENIC GOLD

SOME IMPORTANT GOLD MODELS

• Porphyry copper-gold and skarn gold

• Epithermal gold (high-, intermediate- and low-sulfidation)

• VMS (volcanogenic massive sulfides)

• Carlin type gold (and Carlin-like deposits)

• Orogenic gold (mesothermal, slate belt, Achaean lode gold)

• IOCG (Iron Oxide Copper Gold)

• Witwatersrand (paleoplacer)

• Sedimentary Exhalative (Sedex)

• Placer/ alluvial gold

Non Conventional Deposits

OROGENIC GOLD ENVIRONMENTS

(Goldfarb, 2009)

FLUID FLOW ENVIRONMENTS AND GOLD

(Goldfarb, 2009)

KEY REGIONAL

EXPLORATION TARGETS

• Major Structures

• Metamorphic Grade

• Physical or chemical trap

CRUSTAL SCALE DEFORMATION (SHEAR) ZONES

(Goldfarb, 2009)

YILGARN CRATON (WA)

CRUSTAL SCALE DEFORMATION (SHEAR) ZONES

(Goldfarb, 2009)

YILGARN GOLD ENDOWMENT

(Goldfarb, 2009)

METAMORPHIC HOSTED

ORE DEPOSITION POST DATES METAMORPHISM OF HOST ROCKS

(Goldfarb, 2009)

STRUCTURAL STYLES

(Goldfarb, 2009)

WALL ROCK ALTERATION

(Goldfarb, 2009)

• Sericitzation, carbonization, (de-) silicification, sulfidation

• Discoloration (bleached halo: >10s cm to 10sm

• Chlorite + albite + CO2 + H2O + Au(HS)2

• Sericite + Fe-Mg carbonates + sulfides + Au

• Carbonate spots

• Sulfide porphyroblasts (pyrite + arsenopyrite; </- 3cm

SERICITIC ALTERATION

SULFIDATION

HIGH TEMPERATURE OROGENIC GOLD

WESTERN AUSTRALIA (YILGARN) MODEL

(Goldfarb, 2009)

CENTRAL ASIA GOLD (CERCAMS, 2011)

(Goldfarb, 2009)

CENTRAL ASIA GOLD ENDOWMENT

(Goldfarb, 2009)

TIEN SHAN BLOCK, CENTRAL ASIA

(Redmond et al, 2011)

MID-LATE PALEOZOIC Au in TIEN SHAN (290Ma)

(Yacubchuk et al, 2005)

KUMTOR OROGENIC GOLD

(Redmond et al, 2011)

KUMTOR OROGENIC GOLD

(Redmond et al, 2011)

KUMTOR OROGENIC GOLD

KUMTOR OROGENIC GOLD

Ore >7g/t Au Ore – hosted in shale

VICTORIA SLATE BELT, AUSTRALIA

(Phillips & Hughes, 1998)

VICTORIA SLATE BELT, AUSTRALIA

(Goldfarb, 2009)

TYPICAL REEF STYLES

VICTORIAN SLATE BELT

(from various sources)

TYPICAL REEF STYLES

VICTORIAN SLATE BELT

(from various sources)

EXPLORATION

TARGETING

(ARX, 2005)

EXPLORATION

TARGETING

(ARX, 2005)

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OROGENIC GOLD POTENTIAL IN INDONESIA

OROGENIC GOLD: Key regional exploration targets

Major structure

Metamorphic grade

Physical and/ or chemical trap

FOR INDONESIA SETTING

Continental fragments (Gondwana origin drifted during

Mesozoic)

Suture and mega shear zones

Mineral (gold) occurences

CONTINENTAL

FRAGMENTS ?

2. Sikuleh

3. Paternoster

4. Mangkalihat

5. West Sulawesi

6. Semitau

7. Luconia

8. Kelabit–

Longbowan

14. East Sulawesi

15. Bangai– Sula

16. Buton

17. Obi– Bacan

18. Buru– Seram

19. West Irian Jaya

(Metcalfe, 2006)

SUTURE ZONES ?

(Metcalfe, 2006)

7. Bentong-Raub

14. Median Sumatra

17. Woyla

19. Meratus

20. Boyan/ Lupar

MESOZOIC ACCRETIONARY COMPLEX (Parkinson et al, 1998)

NEOGENE SUTURE ZONES (Hall and Wilson, 2000)

METAMORPHIC COMPLEXES and SUTURE ZONES

(Djaswadi & Yudawinata, 1995)

Idenberg – 0.76 Moz

Buru ???

Bombana ???

Poboya ???

Awak Mas???

Timburu ???