The Commonwealth Project
Acquired on 13 June 2013, the Commonwealth Project is a high grade gold-VMS Project with potential for small scale early production.
Just 95 km north of Orange in New South Wales, the project area covers around 902 sq km and is situated within the prolific Lachlan Fold Belt, a region renowned for its major gold-silver-base metal mines including the Cadia-Ridgeway deposits (Newcrest) containing 70 million ounces of gold and 12 million tonnes of copper (Figure 1).
A review and synthesis of previous data has been completed at the Commonwealth Project including the re-interpretation of 66 drill holes, five low frequency EM surveys and 460 soil samples completed between 1952 and 2007. Previous unknown, high-grade drill intercepts have been identified of up to 30 m at 6 g/t gold from 28 m and including 2 m at 77 g/t gold, in addition to six new targets. New maps and cross-sections have been created for the area (Figures 2 to 6).
There is significant potential to increase the size and extent of the high-grade gold-silver-base metal massive and disseminated sulphide deposits at the Commonwealth Mine and Commonwealth South prospect.
- High grade gold-VMS Project with recorded fresh sulphide production in the early 1900s of 6,476 t at 6 g/t gold, 150 g/t silver, 2% copper, 15% zinc and 7% lead.
- Located within the Lachlan Fold Belt of New South Wales – a prolific gold-copper region of Australia.
- A review and synthesis of previous data is ongoing with re-logging of old drill core and ground geophysical surveys underway to identify new drill targets.
- Previously unknown high-grade drill intercepts have been identified of up to 30 m at 6 g/t gold from 28 m and including 2 m at 77 g/t gold, in addition to six new targets.
- Review of a long section between the Commonwealth Mine and the Commonwealth South Prospect has shown that gold and silver mineralisation is continuous, with the presence of two high-grade shoots (Figure 7). These drill intercepts have not been followed up at depth or along strike, and include:
At the Commonwealth Mine:
4.7 m at 5.5 g/t gold and 253 g/t silver from 54.3 m in CW30; and 9.8 m at 8.4 g/t gold and 357 g/t silver from 54.2 m in CW29.
At Commonwealth South:
30 m at 6 g/t gold and 17 g/t silver including 2 m at 77 g/t gold from 24 m in PHC04; and 26 m at 2.5 g/t gold and 20 g/t silver from 32 m in PHC09.
- A new Exploration Target has been identified between the Commonwealth Mine and the Commonwealth South deposit of:
2.8 Mt to 2.9 Mt at between 7 g/t and 8 g/t gold equivalent for between 640,000 oz and 700,000 oz of gold equivalent (see Notes 1 and 2).
The Commonwealth Mine
The Commonwealth Mine was discovered in 1900 and mined intermittently until the 1930’s. Early production amounted to 470 oz of gold from 480 tons of oxide ore. A blast furnace was installed in 1905 and 6,476 t was mined at a grade of 6 g/t gold, 150 g/t silver, 2% copper, 15% zinc and 7% lead. Operations were suspended in 1908 following flooding and there are no records of significant mining activity since.
In 1985, Cluff Resources Pacific Limited dewatered the mine and completed extensive sampling and mapping of the remnant ore zones as well as four airleg drill holes. The mapping showed that the massive sulphide lens has a true width of between 4 m and 7 metres.
The airleg drill holes returned the following intercepts over about 50 m of strike:
CM85-1: 7 m at 6.2 g/t gold, 346 g/t silver, 0.22% copper, 3.2% lead and 9.2% zinc;
CM85-2: 3 m at 8 g/t gold, 158 g/t silver, 0.1% copper, 0.8% lead and 2.9% zinc;
CM85-3: 6 m at 4 g/t gold, 124 g/t silver, 0.5% copper, 2.5% lead, 18.5% zinc;
CM85-4: 3.2 m at 7 g/t gold, 363 g/t silver, 0.35% copper, 2.9% lead and 18% zinc.
The Commonwealth South Gold Deposit
The mine workings at Commonwealth were developed on the high-grade poly-metallic massive sulphide lenses. However exploration drilling by Cluff and more recently by Endeavour has shown that there is significant potential for bulk-tonnage, lower-grade gold and silver deposits that were unrecognised by early miners.
Together with other drill holes this area has helped define the Commonwealth South gold deposit (Figure 3). These drill intercepts have not been followed up. Historic resource estimates have been completed for the Commonwealth South deposit. However these are not calculated in accordance with the JORC Code and further work is required to properly define resources and reserves.
On ground exploration has commenced and a ground electromagnetic survey has been completed. Initial re-logging and sampling of previous drill core has also been completed. This work suggested the volcanic succession at the Commonwealth Mine was markedly more simple than previously interpreted. Furthermore the lateral continuity represents an improvement of the previous defined geology. New targets identified from the electromagnetic survey are now interpreted to be potential strike equivalents of the massive sulphide horizon.