1. INTRUSION-RELATED GOLD SYSTEMS IN THE NEW ENGLAND FOLD BELT:
The Tooloom Example
Brett McKay
Malachite Resources NL

2. MALACHITE RESOURCES NL
Classification of Intrusion-related gold systems
Geological model
The Tooloom Example
Phoenix
Intrusion-related gold systems in the New England Fold Belt
metallogeny of NEFB
comparison with LFB
Newly recognised prospectivity of NEFB

3. MALACHITE RESOURCES NL
Intrusion-related gold system (IRGS) characteristics:
Au variably combined with Bi, Te, W, Mo, Sb, As
Low sulphide content (<5%)
Reduced mineral assemblage (Po, As, Py, Ilm, no Mag/Hem)
Deposit and metal assemblage zoning: lateral & vertical
Reduced I-type intrusives
Intermediate to felsic
WSnMo provinces
Continental tectonic setting

4. MALACHITE RESOURCES NL
Intrusion-related gold system (IRGS) characteristics:
Sheeted veins, stockworks, breccias, disseminations, skarns, replacements, fissure veins
Lateral and vertical metal zoning
proximal Au-Bi-Te > Au-As > As-Sb-Au > Ag-Pb-Zn distal
W±Mo at depth
Au-Bi-Sb at shallower levels
Examples:
Donlin Creek: 28.5 Moz (measured & indicated resource)
Pogo: 7 Moz (probable reserve)
Fort Knox: 2.4 Moz (proven and probable reserve)

5. IRGS MODEL
Modified from Hart et al., 2002

6. IRGS MODEL
Modified from Lang et al., 2000

7. MALACHITE RESOURCES NL
MAJOR IRGS DISTRICTS:
Paleo-Tethys Closure
Tintina Gold Belt
Bolivia
Eastern Australia
Lang & Baker, 2001

8. MALACHITE RESOURCES NL
THE TOOLOOM EXAMPLE:

9. MALACHITE RESOURCES NL
THE TOOLOOM STORY
HISTORY
Tooloom is a major goldfield, long forgotten
First discovered in 1857 – 10,000 alluvial miners
Coarse gold – many nuggets: largest 140 ozs
Hard rock sources barely touched
Abandoned around 1870  Gympie
Slipped into obscurity – few official records
Minor alluvial gold mining continued until 2001
Phoenix first recognised as a prospect in 2003
DISCOVERY OF PHOENIX GOLD DEPOSIT IN 2005

10. MALACHITE RESOURCES NL Simplified geological map of the Tooloom area
Cullens
Phoenix
Joes Gully
Intrusive centres
Frasers
Simplified geological map of the Tooloom area

11. MALACHITE RESOURCES NL JOES GULLY INTRUSIVE CENTRE$1
JOES GULLY INTRUSIVE CENTRE
extensive alluvial deposits
coarse Au intergrown with qtz
sheeted qtz vein and stockworks outcropping upstream
minor outcropping intrusives and dykes

12. MALACHITE RESOURCES NL FRASERS INTRUSIVE CENTRE
Frasers, Nine Mile, Back Creek
extensive alluvial Au worked – Eight Mile
Au-bearing qtz veins upstream
visible Au in outcrop
nearby intrusives  hydrothermal system?
1 cm
GOLD
Sheeted auriferous quartz veins

13. MALACHITE RESOURCES NL PHOENIX INTRUSIVE SYSTEM
followup of multiple +20 ppb Au BLEG anomalies
discovery of Phoenix Breccia
0.2 – 0.4 g/t Au from initial rock chips
patchy Au in soils, low tenor
coincident As-Sb-Bi-Cu soil anomaly, 1 km diameter
large annular IP chargeability anomaly, > 400 m depth
2 km diameter aeromagnetic low
Creek Zone → Au-Bi-As-Cu soil anomaly
hornfelsed Emu Ck Fm sedimentary rocks  contact aureole
diss. and veinlet pyrrhotite-pyrite-arsenopyrite  elevated Au
26 RC and diamond holes

14. MALACHITE RESOURCES NL PHOENIX SOIL GEOCHEMISTRYAu As
PHOENIX SOIL GEOCHEMISTRY Sb Cu

15. MALACHITE RESOURCES NL Bi in soil over breccia =
PHOENIX PROSPECT
Bi soil geochemistry
Bi in soil over breccia =
gold at depth
Breccia
The Creek Zone:
larger but weaker Bi anomaly (+Au-As-Sb)

16. MALACHITE RESOURCES NL
PHOENIX PROSPECT
Breccia pipe
70K Tonalite
IP anomaly
Main gold in soil anomaly
Shear zone (controlling position of Phoenix Breccia?)
Emu Creek Fm sedimentary rocks

17. MALACHITE RESOURCES NL
PHOENIX PROSPECT:
Phoenix Breccia:
85 m true width, +300 m outcrop length
elongate, pipe-like geometry
eg g/t Au
polymictic, angular to subrounded clasts
was up to 20% open-space
qtz-carb-sulphide infill, at least two episodes
jig-saw textured, limited vertical movement
weak to locally intense Se alteration → Au grades

18. MALACHITE RESOURCES NL The Phoenix breccia in outcrop
PHOENIX PROSPECT
The Phoenix breccia in outcrop

19. MALACHITE RESOURCES NL The Phoenix breccia in drill core
PHOENIX PROSPECT
The Phoenix breccia in drill core

20. MALACHITE RESOURCES NL The Phoenix breccia in drill core
PHOENIX PROSPECT
The Phoenix breccia in drill core
Late stibnite veins
Sulphide infill of open-space in breccia

21. MALACHITE RESOURCES NL
IRGS CHARACTERISTICS OF PHOENIX SYSTEM:
Au-Bi-Sb-As association
reduced mineral assemblage → Po-As-Py, no Mag/Hem
low sulphide content <5%
possible vertical metal zoning:  Sb-Py, slight  Au with depth
located in mineralised contact aureole of buried intrusive?
I-type, mod. reduced, felsic-intermediate intrusives in project area
continental tectonic setting, post-orogenic
W-Sn-Mo province (NEFB)
mid-way between proximal and distal
potential for range of other deposits
PHOENIX is part of a large Intrusion-related Gold System

22. Present erosional level at Phoenix
IRGS MODEL
Present erosional level at Phoenix
Phoenix
Modified from Lang et al., 2000

23. MALACHITE RESOURCES NL
IRGS in NEW ENGLAND FOLD BELT
Au, W, Sb, Sn, Mo and base metal occurrences
Associated with intrusives:
post orogenic
I-type
reduced
felsic to intermediate
low magnetic
mid-Permian to early Triassic
Veins, stockworks, pipes, disseminations, greisens, skarns
Tooloom

24. MALACHITE RESOURCES NL IRGS in NEW ENGLAND FOLD BELT
Favourable granite geochemistry:
Clarence River Supersuite → Tooloom
Moonbi Supersuite → Timbarra; Tooloom?
Uralla Supersuite
Nundle Supersuite
Gundle Belt
Coastal Belt
Various unnamed leucogranite intrusives
Various deposits associated with intrusives:
Kingsgate Mo-Bi; Glen Eden Mo-W-Sn; Taronga Sn

25. MALACHITE RESOURCES NL IRGS in the NEW ENGLAND FOLD BELT
Eg. Timbarra
best studied IRGS in NEFB (Mustard, 2001 & 2004)
disseminated Au in miarolitic carapace of monzogranite of Moonbi Supersuite
strong Au correlation with Bi, Ag, Te
weak Au correlation with Sb, Mo, As
proximal i.e. within mineralising pluton
only 60 km south-southwest of Phoenix
Moonbi Supersuite outcrops in vicinity of Tooloom

26. MALACHITE RESOURCES NL IRGS in the NEW ENGLAND FOLD BELT
Comparison of NEFB  LFB
LFB:
Intensive exploration for porphyry Cu in ’s
Arizona ‘light-bulb’ model
unprospective for large Cu deposits
later success with application of new model
 Ordovician shoshonitic intrusives
 Northparkes, Cadia

27. MALACHITE RESOURCES NL
IRGS in the NEW ENGLAND FOLD BELT
Comparison of NEFB  LFB
NEFB:
Very little exploration though application of wide-ranging geological model
Large Au deposits in Qld part  Cracow, Mt Morgan, Gympie
NSW part regarded as unprospective
IRGS will rediscover the NEFB as prospective for large Au deposits
PHOENIX could do for the NEFB what Northparkes did for the LFB!

28. INTRUSION-RELATED GOLD SYSTEMS IN THE NEW ENGLAND FOLD BELT:
The Tooloom Example
Brett McKay
Malachite Resources NL