After combing through historical drilling data at its Minbrie project on South Australia’s southern Eyre Peninsula, Lincoln Minerals (ASX: LML) has uncovered a previously unidentified high-grade copper-lead-zinc target zone from a 2011 drilling campaign conducted by Centrex Metals looking for magnetite iron ore.
The high-grade hit has prompted further investigation into the potential for a new discovery.
The intercept was 12m grading 1.4 per cent copper, 12.4 per cent lead, 2 per cent zinc and 13.2 g/t silver from 139m, with internal assays peaking at 1m running 4.8 per cent copper, 31 per cent lead, 3.1 per cent zinc and 36 g/t silver from 145m.
Notably the 12m hit was inside a larger 29.5m hit grading 0.8 per cent copper, 7.4 per cent lead, 1.9 per cent zinc and 9.0 grams per tonne (g/t) silver from 131.1m.
Lincoln is now reworking a 2011 drilling campaign that focused on targeting banded iron formations when the drilling unexpectedly intersected significant sulphide mineralisation, which was left unassayed. The potential for these unexamined sections to contain additional mineral wealth was revealed only through the company’s recent detailed review.
Although more drilling and geophysical work needs to be done to confirm the size of the discovery, the company believes the mineralised 29.5m section - typified by high-grade massive and disseminated sulphide copper and base metals - could be hinting at a structure with similar hallmarks to an iron an oxide-copper-gold system. A deeper review of local and regional geology will guide future exploration strategies.
Minbrie’s mineralisation, characterised by chalcopyrite, galena and sphalerite, sits at the southern end of the copper-rich Gawler Craton. The region is globally recognised for its iron oxide-copper-gold systems such as the world-class deposits of Olympic Dam, Prominent Hill and Carrapateena. The deposits are all associated with extensive faulting and structural complexity, which are key indicators of high-grade mineral deposits.
The Eyre Peninsula has a rich history as a copper, lead and silver mining region. Directly to the west of Minbrie, the biggest silver and lead mine on the peninsula, Miltalie, operated from 1860 to 1914 with ore grades of up to 61.5 per cent lead and 118.5 g/t silver.
About 100km across the Spencer Gulf, on the western seaboard of the Yorke Peninsula, the township of Moonta hosted the Moonta Mine, which, from 1875 to 1923 was the biggest producer of copper for the British Empire, accounting for more than 30 per cent of its supply.
Minbrie also benefits from its proximity to infrastructure, including export terminals such as Port Pirie and major road transport routes and utilities, which may reduce potential development costs. The prospect is also a quick barge trip away from Nyrstar’s Port Pirie multi-metals processing facility which has been in continuous operation for more than 130 years.
The exceptional assay results from Minbrie are another example of the quality of Lincoln’s exploration tenement portfolio and demonstrate the potential of a significant copper and base metal system. With copper’s pivotal role in the green energy transition, this project represents a significant opportunity for Lincoln and our shareholders.
Lincoln Minerals CEO Jonathon Trewartha
With the newfound results at hand, Lincoln is pushing out the boats to get all the relevant land access permits and clearances sorted, expected by the first quarter of 2025. Drilling will commence shortly thereafter. The unassayed sections of the previous drill cores will be re-evaluated to see what other secrets the samples may hold.
The company will then plan a focused 2-3 drill hole program for early 2025 to define the mineralisation’s geometry and extent.
Although its most recent focus has been on its giant Green Iron magnetite project, the high-grade Kookaburra graphite project and its uranium exploration portfolio - all on the Eyre Peninsula - the discovery of highly mineralised massive sulphides at its Minbrie prospect has serious potential for the company.
Not only was the discovery almost free, the style of mineralisation and the structural setting tick all the early boxes for an explorer such as Lincoln that is looking for a significant find.
Is your ASX-listed company doing something interesting? Contact: office@bullsnbears.com.au