Lincoln Minerals sniffs out signs of SA base metal riches

Lincoln Minerals has picked up significant signs of base metal mineralisation in a footwall structure with grades running up to 4.8 per cent copper, 12.4pc lead, 3.1pc zinc and 36 grams per tonne (g/t) silver across a 29.5-metre intersection at its Minbrie copper and base metals prospect on the Eyre Peninsula in South Australia.

The mineralisation in the footwall was missed by a project’s previous explorer, Centrex Metals, which was chasing magnetite iron ore up to 2012 but didn’t assay the drill core for base metals.

Lincoln Minerals has picked up signs of significant base metal mineralisation at its Minbrie copper and base metals prospect on the Eyre Peninsula in South Australia.

At that time, Centrex retained the iron rights at Minbrie, while Lincoln kept rights to everything else.

Lincoln was also focussed on its nearby Kookaburra Gully graphite project and was unable to follow up on the Minbrie core by doing its own assaying. The situation changed when the company acquired full access to Centrex’s historical drilling data.

‘Now, with a fresh perspective and systematic exploration, we are well-positioned to unlock the true potential of this underexplored zone.’

Lincoln Minerals chief executive officer Jonathon Trewartha

The promising copper and base metals zone was discovered after Lincoln ran a comprehensive copper-focused review in November of all the historical data, drill core and recent field activities at the project site.

Centrex drilled 263 holes across a nine-year period and along a 12-kilometre northeast strike targeting a steeply northwest-dipping banded iron formation, which is a common structure for hosting magnetite.

Most of the holes were drilled 2 metres past the lower edge of the fault and into a zone of contact with the rock sequence beneath, known as the footwall. Consequently, the lower portion of the drillhole was never properly tested for base metals.

The footwall is made up of dolomite, calc-silicates and graphite-rich material, which all easily react to heat and chemicals, leading to deposits of valuable metals such as gold, silver and copper.

The new discovery was made from assaying the core from a hole drilled in 2011 that pierced the previously untested footwall sequence. It lit up with a 29m intersection of substantial untapped copper, lead, zinc and silver mineralisation. Grades across the whole section averaged 0.8pc copper, 7.5pc lead, 1.9pc zinc and 9.0g/t silver from 131.1m.

Lincoln Minerals chief executive officer Jonathon Trewartha said: “Previous exploration was primarily aimed at magnetite, which meant that many historical drillholes either stopped just short of the key mineralised contact or were not assayed for copper and base metals at all. Now, with a fresh perspective and systematic exploration, we are well-positioned to unlock the true potential of this underexplored zone.”

Lincoln is now kicking off a two-stage exploration program starting with relogging and re-analysing all the historical holes that encroached on the footwall.

Portable XRF analysis and laboratory assays will then be conducted to check the base and precious metal content. The company will also scan the core for traces of additional valuable elements, including rare earths and gallium.

With regulatory approvals for drilling in train, the second phase of exploration will target the drill bit on extending the mineralisation around the discovery hole. It will also test any other high-potential zones along the 12km strike length that come to light from the investigation’s first phase.

Lincoln is excited that the latest findings show Minbrie’s geological profile bears the same hallmarks as other successful base metals projects on the Eyre Peninsula, such as Investigator Resources’ Paris silver-lead deposit and Terramin’s Menninnie Dam lead-zinc-silver deposit.

The area sits within the Gawler Craton, which is a hugely prospective geological feature, hosting world-class iron oxide-copper-gold ore deposits including BHP’s massive Olympic Dam, Prominent Hill and Carrapateena mines.

Lincoln’s revitalised exploration approach has also been helped by newer exploration technology and its improved ability to integrate it within Minbrie’s historical data.

At a fraction of the cost of earlier exploration efforts, the company has created an potentially game-changing opportunity that could pave the way for opening up another monster base metal deposit in the region.

That means 2025 is likely to be a very busy year for the junior miner.

Is your ASX-listed company doing something interesting? Contact: [e-mail]