GCR's
West Wyalong property is located over the township of
the same name in central NSW some 430 kilometres west
of Sydney. GCR owns the property 100%, subject to a
2.5% net smelter return royalty to Barrick.
A joint venture agreement has been negotiated with Argent
Minerals Limited (AM) whereby they can earn 70% interest
in the West Wyalong project by spending $1,030,000 by
2013. AM are planning to list on the ASX in early 2008.
Late in 2007 AM drilled three vertical RC holes in
a wheatfield to test anomalous gold and copper geochemical
anomalies and intersected what may be a previously umapped
gold reef. The drilling was planned around an interpreted
intrusive centre within a large (21 milligal) gravity
anomaly. One hole, APG003, intersected 2m at 19.1 g/t
gold from 106m downhole. Holes were also drilled under
old workings on five gold reefs, looking for possible
depth extensions. This strategy was successful at the
Mallee Vale reef in the north of the property, with
an intersection of 4m at 6.11 g/t gold from 28m. The
Pine Ridge reef, in the west of the property, was also
intersected, returning 2m at 1.48 g/t gold from 36m.
The West Wyalong gold field is hosted by the Ungarie
Granite. Historic production of high grade gold was
recorded at more than 440,000 ounces prior to 1920.
In the period of peak mining activity from 1894 to 1907,
371,000 ounces of gold was produced with an average
grade of 44 g/t. GCR focused its early work in this
area and delineated a number of new zones, notably the
Ken Glasson Zone immediately south of Wyalong.
The discoveries of the Cowal Deposit (in excess of 2.5
million ounces) 30 km to the north and Marsden (115
million tonnes at 0.4% copper and 0.15g/t gold) 20 kilometres
to the northeast provided encouragement that large intrusion/volcanic-related
hydrothermal systems existed in the area. This, in addition
to the discoveries at Cadia, near Orange, and Northparkes,
near Parkes showed that the Ordovician age magmatic
arc complexes in NSW were highly prospective for copper
and gold. Within the GCR tenement Geopeko had already
delineated a sulphide-rich hydrothermal system at Narragudgil
(mid 1980s) by testing magnetic anomalies beneath alluvial
cover and further to the south Gold Mines Australia
had also discovered the Mandamah porphyry complex in
the mid-1990s.
The potential for the discovery of very large resources of copper and gold led GCR into a variety of geophysical and geochemical
exploration programs which involved extensive aircore drilling to bedrock through transported cover which is commonly up to 40m thick. |
Joint Ventures
GCR originally earned its 100% interest in the project by spending $1 million under an agreement with Lac Minerals. Barrick, through
its various acquisitions now hold a 2.5% NSR royalty over the ground.
In 1999 Newcrest became involved in exploration on the eastern side of the tenement and undertook extensive drilling. At the Yiddah North
Prospect Newcrest intersected copper and gold-bearing quartz-magnetite stockwork typical of porphyry systems. Mineralisation was weak and
highly dismembered by late shearing and was encompassed and overprinted by broad zones of sericite-pyrite alteration thought to be of late
metamorphic origin. No continuity could be established and Newcrest withdrew.
In 2002, MIM Exploration conducted extensive geophysical surveys using a proprietary system called MIMDAS. After drilling a number of holes,
MIM was acquired by XStrata and the joint venture was terminated.
Geology
The exploration licence is host to a magnetic, magmatic complex of Ordovician age located at a major bend or buttressed zone on the Gilmore
Suture. Geological and geophysical interpretations indicate three domains. These include the Gidginbung Volcanic domain comprising highly
sheared andesitic rocks, the Gidginbung intrusive domain comprising a variety of dioritic intrusions with Gidginbung volcanic screens and
the Bland Diorite domain where diorite bodies intrude basaltic volcanic rocks.
Recent Interpretation
A recent review of geophysical and geological data has been completed. This entailed a review of geophysical data, especially the gravity
data which showed a 21 mgal anomaly in the area of the Pines prospect on the western side of the tenement, and its relationship to elevated
magnetics in the same area. This work was important because this is an area of poor outcrop and deep alluvial and saprolite cover. Geophysical
modeling indicated the gravity anomaly was caused by a deep seated, dense, nonmagnetic body, probably a gabbro. This body is about
600m to the top. The magnetic features observed are shallow, near-surface responses and are located in rocks above the dense (gabbro) body
and within the diorites and basalts of the Bland Domain. |
One of GCR's best gold intersections in aircore
holes lies on the margin of this centre and returned
3m at 0.6g/t gold (WWAC239) near the bottom of the hole
in highly altered kaolinitic material. A hole more than
one kilometre east of this, which lies within the “centre”
and on the flank of a small magnetic high, returned
anomalous copper to 500ppm. |