Lachlan Star Limited (ASX: LSA) has announced compelling new drill targets for Cobar-type copper-gold mineralisation at its North Cobar Project in NSW, with Induced Polarisation (IP) survey results confirming multiple high-priority exploration targets that could signal a significant discovery. These findings add to the company's growing portfolio that already includes high-grade copper potential at their Basin Creek project.
Geophysical Surveys Reveal Promising Drill Targets
The recently completed IP geophysical survey has identified multiple high-potential targets with strong chargeability anomalies (up to 20mV/V) that are coincident with previously identified gravity and magnetic anomalies. These features are particularly exciting as they are located at the intersection of the highly prospective Rookery and Buckwaroon fault systems—the same structural corridor responsible for controlling all major gold and base metal deposits in the region, including MAC Copper's CSA Mine.
The IP anomalies are interpreted to indicate the presence of sulphide mineralisation, creating what the company describes as "compelling walk-up drill targets."
"The acquisition of this IP data was a crucial step in advancing the North Cobar Project, confirming coincident anomalism across multiple datasets and validating the prospectivity of these high-potential targets in advance of near-term drill testing," said Lachlan Star CEO Andrew Tyrrell.
Strategic Location in Prolific Mining District
The significance of these findings is amplified by the project's location immediately north of the Cobar Mining District—an area that has seen renewed interest following MAC Copper's acquisition of the CSA Mine for US$1.1 billion in June 2023.
The target areas lie within the interpreted northerly extensions of the structurally complex Rookery Fault Zone corridor, a metalliferous fault network known to control mineralisation at all significant mines in the district. The underexplored nature of the project area presents an exciting opportunity for new discoveries in a region with proven world-class copper-gold deposits.
Key Target Areas Identified
The survey has highlighted several high-priority prospects with detailed characteristics:
Percival Prospect:
- Features a strong 20mV/V IP chargeability anomaly
- Located on the eastern flank of a significant gravity high
- Anomaly strength increases with depth, suggesting potential deeper mineralisation
- Includes a sub-vertical resistivity feature interpreted as a fault and fluid pathway
Galahad Prospect:
- Displays elevated chargeability anomalies (up to 6mV/V) across multiple survey lines
- Features a dome-like resistivity high with a less resistive core coincident with gravity anomalies
- Strategically positioned at the intersection of the regionally significant Rookery and Buckwaroon Faults
Understanding Induced Polarisation in Cobar-Type Exploration
IP geophysics is particularly effective for identifying Cobar-type copper-gold mineralisation in this region. The importance of geophysical surveys in modern mineral exploration cannot be overstated, as these methods help outline chargeability highs that potentially define zones of disseminated sulphides (often >5-10%), such as pyrite, chalcopyrite, or arsenopyrite, associated with mineralisation.
Most Cobar deposits yield pronounced IP anomalies, even when other geophysical responses are weak. A notable example is the Federation lead-zinc-gold deposit discovered by Aurelia Metals in 2019, which was found through a significant IP chargeability anomaly directly over a blind deposit.
The Science Behind IP Surveys
Induced Polarisation is a geophysical method that measures the capacity of subsurface materials to hold an electrical charge. The technique involves sending electrical currents into the ground and measuring how subsurface materials respond to these currents.
In mineral exploration, two key parameters are measured:
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Chargeability – This parameter measures how well subsurface materials can store electrical energy, similar to a capacitor. Sulphide minerals, which often host valuable metals like copper and gold, typically show high chargeability values. The values are measured in millivolts per volt (mV/V).
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Resistivity – This measures how strongly materials oppose the flow of electric current. Different geological features and mineralisation types display characteristic resistivity patterns that help geologists interpret subsurface structures.
The effectiveness of IP surveys in the Cobar region stems from the distinctive electrical properties of the mineralisation style found there. Cobar-type deposits typically contain disseminated sulphides that produce clear chargeability responses, making IP an ideal technique for targeting these deposits. Integrating IP survey data properly is critical for exploration success, particularly in complex geological settings like those found in the Cobar region.
Next Steps: Drilling on the Horizon
With the integration of the IP survey data now complete, Lachlan Star has generated key drill positions across the priority targets and has commenced preparations for drill testing. The company has submitted the necessary drilling permit applications and anticipates having a drill rig on-ground following the completion of drilling programs at its Basin Creek and Killaloe projects in the coming months.
Why Investors Should Watch Lachlan Star
Lachlan Star represents an opportunity to invest in a company with:
- Multiple high-quality drill targets in one of Australia's most productive copper-gold districts
- Strategic land position near MAC Copper's CSA Mine (acquired for US$1.1B)
- Systematic exploration approach that has rapidly advanced from concept to drill-ready targets
- Upcoming drilling catalysts across multiple projects in the next quarter
- Experienced technical team applying proven exploration methods in a favourable structural setting
The coincidence of multiple geophysical anomalies at the intersection of known mineralised fault systems creates a compelling technical case for follow-up drilling, with results expected in the coming months as the company executes its exploration strategy across its portfolio.
As Lachlan Star advances these targets to the drilling stage, investors should closely monitor developments, particularly as the company positions itself to potentially make a significant discovery in this historically productive mining region. For those considering investment strategies in high-potential mining companies, Lachlan Star's systematic approach to exploration and strategic positioning in prolific mineral districts makes it a company worth watching.
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