The Lachlan Copper-Gold Project is located approximately 100km north of Condobolin in central Lachlan Orogen New South Wales and extends for up to 160km north along regionally significant Gilmore Suture. This area of central NSW is well endowed with gold and base metal mines and deposits, with estimated past production and current resources in excess of 104 million ounces of gold, 20 million tonnes of copper, 29 million tonnes of zinc and 26 million tonnes of lead.
The Lachlan Copper Gold Project (“Lachlan Project”) consist of 11 separate and mostly contiguous tenements and tenement applications over a strike extent of some 160km along the regionally significant Gilmore Suture (Figure 1) in the central Lachlan Orogen of NSW.
Through pegging of new applications; joint ventures with Peel Mining Ltd (“Peel”), and Bacchus Resources Pty Ltd (“Bacchus”) and separate purchase agreements, Talisman has secured an interest in over 2,800km2 covering the Cambelego-Mineral Hill rift sequence. This package of volcanic and sedimentary rock is highly prospective for copper-gold and base metal mineralisation associated with major structures (“Cobar Style”); Volcanic Associated Massive Sulphide (“VAMS”) base metal deposits; and high and intermediate Sulphidation epithermal gold deposits.
The Cambelego-Mineral Rift sequence host a number of high-grade deposits including the Mt Boppy Gold deposit, the historic Bobadah and Babinda copper-gold mines; and the Mineral Hill copper and base metal mine. Small scale mining of copper, gold and base metals has occured throughout Talisman’s Lachlan Project, as evidenced by the many historic mine shafts (Figure 2).
Historic exploration data for the area comprises sporadic isolated surface sampling (soil, rock-chip and auger samples), and limited RC and diamond drilling. The majority of thiswork was completed by a number of explorers throughout the 1970’s, 1980’s and early 1990’s, with some of the most recent work completed in 2010 and 2011. Talisman’s review of the data has highlighted that there has been no coordinated, systematic regional exploration across the tenement package, which until now has been fragmented and under the control of multiple exploration companies.
Talisman, in association with specialists Consultants, has undertaken a regional structural and geological interpretation of the area as part of its first pass exploration work. This work included a detailed geological review of the known major mineral deposits in the district which has provided valuable insight to the major regional controls on mineralisation.
The nature of the cover, lithology and mineralisation styles within the Lachlan Copper-Gold Project area means geophysical targeting techniques such as EM, IP and gravity surveying are effective tools in defining drill targets. Talisman intends to build a strong database of soil sampling, auger sampling, geological and structural mapping and geophysical surveys to develop and prioritise targets for drilling.
As a result of the work undertaken to date, Talisman has highlighted several high priority areas within the wider Boona Project Area (Figure 1), for initial focus where more detailed geological interpretations have been completed or are underway.
Boona Project Area
Blind Calf Prospect (100% Talisman Tenure)
The Blind Calf Prospect is located within Talisman’s 100% tenure approximately 5km to the South West of the Mineral Hill Mine (Figure 3) and is a high priority for near term on-ground exploration drilling.
Figure 3: Detailed geology and prospectivity map of the Boona Project Area
The Blind Calf Prospect, comprises a cluster of 13 historic (early 1900’s) mining shafts, developed on a series of shear hosted sulphide rich quartz lodes with mapped outcrop strike extents of between 40m to 100m and widths of 5m at surface.
Drilling by previous explorers in early 2011 has confirmed that these lodes contain significant high-grade copper mineralisation, with results including:
Talisman is aiming to complete a detailed 3D sectional modelling of these and other historic results from the Blind Calf Prospect, which is currently underway and will form the basis of a targeting process for a planned RC and diamond drilling program aimed at confirming the high-grade nature, thickness and strike extent of the identified lodes.
Other Prospect Areas
The area surrounding and along strike to the south east of the Mineral Hill copper and base metal mine forms part of the Bacchus Joint Venture where TLM is earning up to an 80% interest (Figure 3). This is another high priority area identified from both the regional geological review and the compilation of historic results.
The Mineral Hill gold and base metal mine (historic production of some 395,000oz Au and 32,500t Cu), comprises a series of shear hosted sulphide rich lodes with varied mineralogy, including copper rich lodes, lead-zinc lodes, and gold only systems.
Talisman’s tenements contain the southern strike extensions of the Mineral Hill host volcanic sequence (Figure 3). The volcanic sequence extends for over 10km into Talisman’s tenure, with a number of historic copper and gold occurrences documented in the NSW government database along an anticline structure mapped by Talisman. Results of rock chip sampling by previous explorers of gossanous base metal (Pb/Zn) outcrop adjacent to small scale historic mine shafts along this structure include 5.87% Pb2, 23.0% Pb3 and 3.7g/t Au3. This same anticline structure also has an extensive coincident historic gold and base metal soil (MMI) anomaly which extends for over 3km along strike.
Talisman believes that the Mineral Hill lodes and the mineralisation seen at Blind Calf and surrounding area (rock chip results of 8.2% Cu4, 3.7% Pb4 and 4.7% Cu4), may be part of a larger mineralising system in this area associated with the Mineral Hill Volcanics (Figure 3) and the regional Gilmore Suture, over which Talisman hold significant tenure.
This region, which comprises a moderate amount of sub-outcrop and shallow cover sequences, is highlight amenable to surface geochemical sampling/shallow auger sampling, along with airborne and surface geophysical techniques. This will enable rapid, low-cost initial exploration over large areas to draw out and prioritise prospective target areas.
Talisman has continued to work closely with the relevant local landholders to secure access across its tenure. Talisman’s culture of inclusive communication and engagement with all stakeholders has seen it establish a strong community licence to operate in the area, while securing access to all of the currently identified high priority areas.
Talisman will continue to build a regional data set including geochemical, geophysical and geological data, to enhance the understanding of the regional and localised control on mineralisation. In conjunction with this regional prospect generative work, Talisman will continue to test the highest priority targets as they become apparent with RC and/ or diamond drilling, detailed surface and down-hole geophysical surveys.
1 For full details, refer to Kidman Resources (ASX: KDR) ASX announcement “Mineralisation Extended at Blind Calf” dated 07 July 2011
2 Result taken from work completed by Geopeko and Mount Conqueror Minerals, GS2000/292.R00042454. Geological Survey of NSW DIGS reporting system
3 Result taken from CRA Exploration Pty Ltd report GS1978/259.R00023043. Geological Survey of NSW DIGS reporting system
4 Result taken from Triako Resources Ltd report R000300065. Geological Survey of NSW DIGS reporting system