The Curnamona Craton in far western New South Wales and eastern South Australia is host to the rich Broken Hill silver-lead-zinc deposit as well as a number of other mineral deposits. The craton comprises the Olary, Broken Hill and Euriowie blocks which contain strongly deformed and metamorphosed sedimentary and igneous rocks representing sedimentary and volcanic sequences deposited in rift basins about 1,700-1,600 million years ago. Subsequent erosion and deposition of younger cover sequences has resulted in much of the craton being obscured, particularly to the west of the Barrier Range in NSW. These younger rocks are prospective for a range of minerals including lead-zinc-silver (within the Adelaidean) and uranium (within the Tertiary palaeochannels).

Operating mines and developments such as the Broken Hill lead, zinc and silver mine, Beverly / Four Mile uranium mine and the Honeymoon uranium deposit attest to the prospectivity of the region.

Variscan has a number of projects in this region: Mundi Plains (Teck Australia), Junction Dam (Teck Australia, Marmota Energy and Eaglehawk), Callabonna and Quinyambie (Red Metal) and Hillston (Perilya).

Mundi Plains and Junction Dam

The Mundi Plains project (EL 6404) in New South Wales and Junction Dam (EL 4509) in South Australia are located 40 kilometres and 55 kilometres respectively northwest of Broken Hill. Both projects are covered by the Teck joint venture in which Teck Australia Pty Ltd is earning an 80% interest in the mineral rights of the Adelaidean and Proterozoic basement rocks. In addition, Junction Dam is covered by the Marmota Uranium joint venture in which Marmota Energy Limited has earned a 100% interest in the uranium rights within the younger sequences that cover the basement rocks.image4
Tenements within the Broken Hill region showing the Dome 5 prospect 

Teck Joint Venture

At Mundi Plains, exploration by Teck within the Adelaidean sequence around the Dome 5 prospect, recorded high grade lead-zinc-silver drill intersections considered to be Mississippi Valley Type (MVT) epigenetic mineralisation similar to that found in the Lennard Shelf of WA.

Previous drilling (see figure below) at Dome 5 defined narrow, high grade intervals of lead-zinc-silver mineralisation approximately 330 metres below the surface including 0.8 metres at 4.9% lead, 19.2% zinc and 83g/t silver in hole DF6 and 0.7 metres at 3.1% lead, 20.5% zinc and 60g/t silver in DF2. Mineralisation is principally hosted within the basal conglomerate and carbonates of the Adelaidean metasedimentary sequence beneath unconsolidated Tertiary sediments of the Mundi Mundi plain.

A five hole programme of follow-up drilling with results suggesting that the mineralisation system, though extensive, is weakening to the west, but remains open to the south east. The possibility of a higher grade zone within the area of known mineralisation cannot be ruled out based on the current widely spaced drilling.


Drilling and interpreted mineralized corridor at the Dome 5 Prospect



Cross section through Dome 5 showing MVT lead-zinc-silver intersections

The Polygonum - Mammoth copper-gold and lead-zinc-silver prospects are also part of Teck Joint Venture. This highly prospective zone was identified through historical drilling by a number of companies (including past explorers CRA and Inco), yet no drilling has been conducted in the area in the past decade. The prospects lie along a well known mineralised horizon, the Bimba Formation, which in South Australia includes the Portia (gold) and Kalkaroo (copper, gold) deposits successfully explored by Havilah Resources NL in recent years. This highly prospective zone stretches for over 50km in strike length within the tenements and the historical drilling includes some significant intersections in copper-gold and lead-zinc-silver mineralisation.

A new exploration program has been planned, including geophysics and drilling, to follow up the previous mineralised drill intersections (including 3.8 metres at 9.25% zinc + lead) targeting stratabound lead-zinc-silver mineralisation in the Bimba and within the overlying garnet-rich metasediments, believed to be the lateral extension of the Broken Hill ore horizon. A review of data has highlighted the possibility that the Polygonum-Mammoth area is part of third order basin which, elsewhere in the world, are recognised as important controlling basins for hosting major stratabound lead-zinc-silver deposits.


Polygonum/Mammoth - Bimba horizon and structures over magnetics



Section A-A' showing historical lead-zinc-silver intersections above the Bimba horizon 

Marmota Joint Venture

Within the Marmota joint venture area, exploration over the Junction Dam project for sedimentary uranium deposits within the Tertiary Yarramba Palaeochannel by Marmota Energy has defined thin but high grade uranium mineralisation within the same lithological units that host other significant deposits such as Honeymoon to the west.

At the Saffron prospect Marmota has discovered a significant zone of uranium mineralisation. A number of drill holes have reported grade-thickness accumulations in excess of 0.045 m% eU3O8 and up to 0.242 m% eU3O8. Marmota has recently reported that it had calculated an Inferred Resource estimate of 4.36 million tonnes for the Saffron deposit for a contained 1,510 tonnes of U3O8 (3.33 million pounds).

In addition, drilling at the recently identified Bridget and Yolanda prospects generated strong results. Marmota believes that these two prospects offer substantial expansion potential.

Marmota has earned an 100% share of the uranium rights at Junction Dam with Variscan holding a 3.75% net profits interest in the property.


Uranium Prospects at Junction Dam 

Callabonna and Quinyambie

EL 5360 (Callabonna) and EL 4289 (Quinyambie) are located in the northern part of the Curnamona Craton in South Australia, about 180 kilometres north of Leigh Creek. Exploration is managed by Red Metal Limited in joint venture.

The primary exploration target is uranium mineralisation in basement rocks and roll-front type uranium deposits hosted in the Tertiary sedimentary sequences. The Callabonna and Quinyambie tenements cover the highly prospective Tertiary Namba and Eyre sedimentary formations which host the known uranium mines and deposits in the region.

Processing and interpretation of high resolution airborne electro-magnetic data (REPTEM) has successfully mapped the previously unrecognised, northward extension of the Paralana fault system into the Frome joint venture projects. The Paralana fault system is a deep seated, long-life structural zone which is interpreted to play an important role in the localisation of prospective sand sequences and uranium mineralisation at the Beverley and Four Mile deposits.

Drilling has intersected prospective palaeochannel sands and a small gamma anomaly in hole L26 suggest potential for uranium roll front further east down the channel. This represents a new uranium target which will be the focus of step out drilling.


Interpreted Woolatchi channel - oxidised palaeochannel sands within Namba Formation shale sequences. W-series are historic drill holes. L-series are Red Metal holes 


The Hillston project (EL 6363) in NSW is located about 20 kilometres south of Cockburn on the NSW-SA border. Exploration is being managed by joint venturer Perilya.

The Hillston tenement has potential for the discovery of both IOCG mineralisation and Broken Hill style, high grade lead-zinc-silver mineralisation. EL 6363 lies in the southern Curnamona belt embracing an extensive strike length of Thackaringa Group rocks which host a number of important base metal-gold prospects and mines. 


Within NSW, Variscan maintains active exploration within the Lachlan Orogen, one of Australia’s most important metallogenic regions. Key projects include the Ghost Rider and Achilles projects near Cobar in central NSW.


Key tectonic belts of NSW with major deposits of the Lachlan Orogen 

Cobar Region

Variscan has one joint venture over the Achilles project located in central-west NSW. Kidman Resources (ASX: KDR) will earn an 80% interest by the expenditure of $300,000. Variscan is 10% free-carried to DFS.

The Achilles project is located within the southern area of the Cobar Basin, one of Australia's pre-eminent mineral regions. The discovery of significant Cobar-type deposits at Hera, Nymagee (YTC Resources) and Mallee Bull (Peel Exploration) have further highlighted the prospectivity of the Cobar region for polymetallic deposits.

The key prospect is at Mt Boorithumble, 26 kilometres north-northwest on strike from the Browns Reef project owned by Kidman Resources. Browns Reef has a significant zinc-lead-silver resource and is thought to be of Cobar-type mineralisation. At Mt Boorithumble, a 900 metre long lead anomaly (maximum assay 0.24% lead) defined by auger and RAB drilling in the Preston Formation (Cobar Group equivalent) sediments and Ural Volcanics has been tested by one diamond drill hole and two percussion holes. The single diamond drill hole BO1 returned a best intersection of 3 metres at 1.95% lead, 2.0% zinc, 1.20% copper, 0.5g/t gold and 150g/t silver from 117 metres. Later percussion holes drilled 170 metres northeast and 140 metres southwest of BO1 respectively did not effectively test the horizon.

Good potential remains to follow up the mineralised intersection as well as to test other parts of the lead anomaly and further along strike.


Geology and key prospects of Achilles