James Cook University SEG Student Chapter Field Trip Report...

James Cook University SEG Student Chapter Field Trip Report
STOMP fieldtrip to North East Queensland

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September 7-11, 2005

The JCU student chapter of the SEG
ran a fieldtrip to the mining districts of
northeast Queensland in conjunction
with the Structure, Tectonics and Ore
Mineralizing Processes (STOMP)
conference held in Townsville,
September 2005. The field trip visited
historic mining regions and current
ventures to develop a picture of base
metal mining in the region. We aimed
to provide access to new geological
experiences, regional expertise and
mentors at a low cost while promoting
living, studying and working in north
Queensland.

Four members of the JCU SEG student
chapter (James Austin, Louise Fisher,
Julie Graham and Chan Park) and two
conference visitors (Chris Chambers,
an exploration geologist with Newcrest


and Stephanie Maes, a PhD student
from the University of Wisconsin-

Map of NE Queensland showing the field

Madison) took part in the field trip.

trip route, major deposits and areas visited.

Northeast Queensland is host to some of the major gold and base metal mines of Eastern
Australia. There is significant diversity in terms of geological age and mineralisation
styles (Morrison and Beams, 1995). On this trip we would visit gold, zinc, lead and
copper mining operations from porphyry, skarn, VHMS and sheeted vein deposits.

The first day of the field trip focused on gold mining in the historic Drummond Basin
region. Leaving Townsville in the early morning we drove to the Far Fanning mine. Far
Fanning is a 1.6 Mt gold deposit with grades estimated at 2.86 g/t. Early mining is
documented from 1866, peaking between 1895 and 1908. More recently open pit mining
was carried out during the 1980’s with limited underground mining afterwards. The
deposit is hosted within sediments which dip to the south and are cut by variably
porphyritic andesitic dykes and sills. Mineralisation comprises multiple generations of
auriferous quartz veins with or without pyrite, chalcopyrite, sphalerite, calcite and K-
feldspar (Dunham and Skrzecynski, 1990). Veining is principally hosted within quartz
arenite and alteration haloes of sericite, chlorite and silica are observed. We were given


an introduction to the mine and a tour
of the underground workings by
consultant mine engineer Ross
Thomas and current mine owner Pat
Williams.

Leaving Far Fanning we stopped for
lunch in the historic Gold Rush town
of Charters Towers. Our second stop
for the day was a visit to the current
mining operation in the area, run by
Citigold Corporation Limited.
Charters Towers Gold Mines
exploration manager, Jim Morrison,
gave us an overview of past and
present gold mining in the region.
The auriferous veins in the Charters Towers Goldfield are classic examples of
mesothermal gold deposits (Kreuzer, 2002). Historical production from the area
exceeded 6.5 Moz Au.

After a tour of the processing plant we drove to the site of the new decline into the
Warrior East deposit which starts from the old Washington mine pit. We were both
amused and impressed by the sight of a family of ducks in the water at the base of the pit
-evidence of a well remediated mine site. We finished the day with a look at the core
from Kidston mine -which we would visit the following day -before driving to the
historic mining site of Towers Hill to watch the sunset.

Leaving Charters Towers we drove north to our
first stop for the day; Kagara Zinc’s Dry River
Exploration camp. Exploration geologists Geoff
Hodgson and Mike Barr gave us a really good
introduction to the region and deposit geology.
The Balcooma metamorphic belt of northeastern
Queensland, Australia, hosts three Volcanic-
hosted Massive Sulphide (VHMS) deposits;
Balcooma, Surveyor and Dry River South. The
Balcooma area lies in the eastern part of the
Proterozoic Georgetown Inlier in northern
Queensland (Withnall et al, 1991) and is bounded
to the east by the Palaeozoic Broken River
Province.

The Balcooma VHMS deposit is the largest of
three deposits in the Balcooma Metavolcanics.
The deposit was discovered in 1978.
Mineralisation is hosted by metapelite at the

Citigold’s Jim Morrison leads a tour of
processing plant at ‘Black Jack’


Close-examination of chalcocite
in the Balcooma North open pit

contact of two different meta-arenite
sequences. At least three distinct
mineralized ‘horizons’, two Zn-Pb
and one Cu, are present. The Cu
horizon contains massive magnetite

and pyrite-chalcopyrite within an
envelope of variably chloritised
staurolite-bearing metapelite

adjacent to a folded quartz-feldspar
porphyry body. The Zn-Pb horizons
in the metapelite sequence consist of
massive sphalerite-galena-pyritechalcopyrite
within lenses of
quartzite and siliceous
metasediments (possibly originally
siliceous exhalative sediments).
Associated alteration type is quartz-
muscovite schist (Huston et al,
1992).

The region has been an exploration target for over 30 years but it was only after Kagara
purchased the tenements, coincident with a rise in zinc prices and the opening of a zinc
refinery in Townsville that mining operations commenced. The Surveyor deposit was
mined by open pitting, yielding a resource of ~600,000 tonnes at 16.4% Zn. Mining has
also commenced at the Balcooma deposit with a second pit planned at Balcooma North.
Underground mining is planned once supergene ore has been removed. A decline from
the Surveyor pit to the Dry River South deposit had just reached the ore level.

After lunch, generously provided by Kagara Zinc, we examined core from all three
deposits before taking a trip to the Balcooma Pit and ROM pad where we collected
samples.

Kagara exploration geologist Mike Barr
explains the mine-scale geology of the
Balcooma North Lead-Zinc deposit


Trip Leader, Julie Graham explains the
regional geology of the Kidston area.


Our second stop and base for the
evening was at the Oaks Rush camp,
formerly the mine camp for the
Kidston mine. We drove out to the
two pits that comprised the former
mine (it ceased operation after 17
years in 2001). The stockwork
veining that hosted the gold could be
clearly observed in the far wall of the
pit.

Driving back to the camp we came
across an old Stamping Battery, which
had operated from 1909 to 1948.


Leaving Oaks Rush we continued on our drive
north, reaching Kagara Zinc’s Mount Garnet
Mine in time for lunch (again generously
provided by Kagara). Mine geologist Andrew
Beaton gave us an introduction to the deposit – a
Zn-Cu deposit hosted by a garnet, pyroxene and
magnetite dominated skarn (Beaton, 2004). The
skarn formed by metasomatic replacement of a
marble lens on the faulted contact between
Precambrian mylonites and arkosic sediments
(Butera, 2001). We were given a tour of the pit

Kagara mine geologist, Andrew

and were able to obtain samples containing

Beaton explains mineralisation

crinoid stems that had been replaced by sulphides.

textures of the Mount Garnet

Our visit finished with a tour of the processing

Zinc-Copper deposit

plant.

In the late afternoon we drove out of town in search of a waterhole in which to escape the
heat. What we found, however, was the rusted but majestic remains of a tin dredge
sitting in a dry river bed – yet another part of the regions mining history. We spent the
night in Mt Garnet and drove the next day to our final destination – Chillagoe, where we
visited Kagara Zinc’s core yard. After an introduction to regional geology by exploration
geologist Charlie Georges we examined core from various Au-Cu-Zn skarn resources
including the Mungana, Monte Vedeo and King Vol prospects.

Later in the afternoon we visited the Muldiva Cu-Zn gossan and historical workings and
the Au-Pb-Ag Eclipse breccia pipe. We stopped at the open pit of the Red Dome Cu-Au


mine (which produced 12.8Mt @ ~2g/t Au and
0.5% Cu in the ten years to June 1996 (Nethery and
Barr, 1998)) and also looked at historical workings
at the Girofla deposit and Lady Jane breccia pipe.
Our final stop for the day was to gain an overview
of the Mungana resource drilling program. The Red
Dome and Mungana deposits and associated
alteration have been described at ‘telescoped’
overprinting systems, from VMS to epithermal in
style. It has been proposed that all the deposits in
the region may have been part of a single porphyry
system at the time of gold deposition and later
offset by strike-slip faulting (Nethery and Barr,
1998).

Over the course of the field trip we gained an
insight not only into the geology of the region but
into the economics that make one prospect viable
and others not. We also developed an
understanding of the historical and continuing role

Smelter ruins near Chillagoe

of mining in the communities that we visited.


Acknowledments

Thanks go to all the geologists and mining companies for giving us access to their sites
and knowledge and particularly to Kagara Zinc for hosting us on three successive days
and for providing lunch! The SEG provided funding of $500 allowing us to significantly
reduce the cost to students.

References

Beaton, A., 2004. Development of the Mount Garnet zinc project from mineral
resource to concentrate production. NQEM 2004 Symposium, Townsville, May 2004 –
AIG Bulletin No. 40. pp. 41-46

Butera, K., 2001. The evolution of the Mount Garnet Zn-Cu skarn, North
Queensland. Unpublished Honours Thesis, James Cook University.

Dunham, P.B. and Skrzecynski, R.H., 1990. Far Fanning gold deposit. In
Hughes, F.E ed. Geology of the Mineral Deposits of Australia and Papua New Guinea,
pp. 1467-1470. Australasian Institute of Mining and Metallurgy; Melbourne.

Huston, D.L., Taylor, T., Fabray, J. and Patterson, D.J., 1992. A comparison of
the geology and mineralization of the Balcooma and Dry River South volcanic-hosted
massive sulfide deposits, Northern Queensland. Economic Geology, 87, pp. 785-811.

Kreuzer, O.P., 2002. A structural analysis of auriferous veins in the Charters
Towers Goldfield, northeast Queensland. Deformation, fluid flow and mineralisation
(Rick Sibson Symposium), pp. 19-26.

Morrison, G.W. and Beams, S.D., 1995. Geological setting and mineralisation
style of ore deposits of Northeast Queensland. In Beams, S.D., ed. Mineral Deposits of
Northeast Queensland: Geology and Geochemistry. EGRU contribution 52, pp. 1-32.
James Cook University.

Nethery, J.E. and Barr, M.J., 1998. Red Dome and Mungana gold-silver-copperlead-
zinc deposits. In Berkman, D.A. and Mackenzie, D.H. eds. Geology of Australian
and Papua New Guinean Mineral Deposits pp. 723-728. Australasian Institute of Mining
and Metallurgy; Melbourne.

Withnall, I.W., Black, L.P. and Harvey, K.J., 1991. Geology and Geochronology
of the Balcooma area: Part of an early Palaeozoic magmatic belt in North Queensland.
Australian Journal of Earth Sciences, 38, pp. 15-29.