TOOLOOM

Location and History – The Tooloom Gold Project encompasses an old and largely forgotten goldfield, located in the far north of New South Wales, about 40km east of the Queensland town of Stanthorpe and roughly 120km inland from the coast. Gold was first discovered at Tooloom as early as 1857 and within a few years there were up to 10,000 miners chasing the coarse grained free gold, including many nuggets, that could be found in the alluvial deposits of Tooloom Creek, its tributaries and other nearby drainages. The largest nugget recorded at Tooloom was found at Billy May’s Point on Tooloom Creek and contained 140 ounces of gold. Mining of alluvial gold continued intermittently at Tooloom until 2001.

Malachite’s interest in Tooloom was sparked by the widespread occurrence of the alluvial gold, the presence of gold/quartz vein composites as nuggets recovered in the then current alluvial mining operations in the district and the presence of large bodies of altered and mineralised intrusive rocks, some with minor old hard rock gold workings. Over the past ten years or so Malachite has conducted a systematic exploration program at Tooloom that has taken the project from the conceptual, grass roots stage to its present advanced state, with numerous hard rock prospects identified, some with drilling, and a small gold resource outlined at the largest prospect, known as Phoenix.

The project is wholly owned by Malachite and encompasses about 150 km² of prospective ground in three mining leases and a surrounding exploration licence (EL 6263). Much of the Tooloom area is rugged, with up to 400m of relief. The southern part of the goldfield is forest covered, while in the north the topography is less severe and much of the land has been cleared. Cattle grazing is the main land use throughout, although some timber harvesting occurs in the wooded areas, crops are grown on a large alluvial flat in the north and some previously cleared areas have been converted to plantation timber.

All significant prospects at Tooloom are located on ground where native title has been extinguished. Even so, Malachite has signed a Memorandum of Understanding with the Githabul People, who are the traditional owners of the Tooloom area, setting out a basis for goodwill and cooperation for mutual benefit. A representative of the Githabuls provides cultural heritage clearance when required.

Geology – The Company’s work at Tooloom has shown that gold mineralisation generally appears to be of intrusive-related gold deposit (“IRGD”) type, analogous to the deposits of the Tintina belt in Alaska and the Yukon.

The Tooloom goldfield lies within the Emu Creek Block, a tectonic unit within the New England Fold Belt of north eastern NSW. Rocks in the area consist mainly of gently folded conglomerate, sandstone, siltstone, carbonaceous siltstone and tuff of the Emu Creek Formation, thought to be of Permo-Carboniferous age. Regionally these sedimentary rocks are intruded in a number of places by granitic to dioritic igneous rocks of Permian to Triassic age. This setting and age relationship are quite similar to those of gold mineralisation at Gympie, some 260 km to the north in Queensland. Within the Tooloom project area mapping by Malachite has identified several previously unrecorded bodies of intrusive rocks, including felsic porphyry, quartz diorite porphyry, hornblende diorite porphyry, diorite, microdiorite and dolerite. Hydrothermal alteration and sulphide mineralisation are well developed in many of the intrusives and in their sedimentary wall rocks.

To the east and north, the Emu Creek Formation and the intrusive rocks are overlain unconformably by Jurassic-aged coal measure sediments of the Clarence – Moreton Basin and they in turn are overlain locally by Tertiary basalt lava flows. Perched fossil alluvial deposits (“deep leads”) occur on some of the ridges beneath and projecting out from under the Tertiary basalt. Some of the deep leads have been worked for gold. The region displays a strong structural grain, clearly visible in the aeromagnetic image, with dominant NNE and NW structures which affect drainage and commonly control mineralisation. Dilation zones occur in many places and some contain intrusions of porphyry, bodies of hydrothermal breccia or sheeted auriferous quartz veining.

Mineralisation – At Tooloom gold mineralisation is clearly associated with intrusive centres, with a variety of expressions in different host rocks and structural settings. The gold is characteristically coarse grained, except at Phoenix. Panning of anomalous soil samples commonly reveals gold particles of the order of 1mm or so in size. Sulphide minerals are generally present with the gold, most commonly arsenopyrite, pyrite and pyrrhotite. Minor chalcopyrite has been observed at Frasers and Phoenix, while stibnite is well developed at Phoenix.

In terms of alteration mineralogy the main secondary minerals observed are sericite and carbonate, commonly quite intensely developed. In some cases the sericite is relatively coarse grained and the host rock is reminiscent of greisen. Silica flooding is evident within some intrusive host rocks and in some sediment-hosted structures gold is accompanied by banded quartz, carbonate, sericite and chlorite alteration.

Exploration Targets – At the present time there are four separate targets at Tooloom that are ready for drilling. These are:

1. PHOENIX – a giant, gold-bearing sulphide system, with 7,000m of existing drilling and a best intersection of 48m @2.21g/t Au; the highest individual (1m) gold assay is 16.5g/t Au and the highest antimony assay (over 1m) is 8.38% Sb; a small resource of the order of 125,000 ounces of gold and 3,500 tonnes of antimony has been estimated for mineralisation in a breccia pipe that forms part of the Phoenix system; that resource estimate was made in-house and does not meet the standards required by the JORC Code; it is thus indicative only.
    
2. PINE GULLY – a ‘Gympie-style’ high grade vein, not yet drilled; gold occurs in a mineralized fault zone, expressed by fault breccia, anastomosing quartz veins and sheared and fractured sandstone and carbonaceous siltstone of the host Emu Creek Formation.
    
3. BACK CREEK – gold occurs in a quartz vein stockwork system several hundred metres across; visible free gold can be seen within quartz veins in some outcrops; there is no prior drilling.
    
4. JOES GULLY – alluvial gold mining was taking place in Joes Gully until 2001; coarse grained free gold was being recovered, including composite gold/vein-quartz nuggets; the upstream source of this gold has not been positively identified, although a possible candidate exists in an outcropping quartz vein stockwork system; a previous attempt to test this stockwork by reverse circulation percussion drilling was unsuccessful and a small footprint diamond rig will be employed in future.

More Information

To download a pdf file [3.5Mb] summarising exploration results to date at Tooloom and describing the four drill-ready targets please click here.

To visit a photo gallery of Tooloom please click here.

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