Prospech finds rare earths in historic drill cores from long closed Finnish lead mine

Having successfully expanded from Slovakia into Finland in its quest to get a slice of Europe’s critical minerals needs, Prospech (ASX: PRS) reports that it has confirmed potential rare earths elements (REE) at its Korsnas project in the Scandinavian country.

The company is examining historic drill core from 60 holes held at a Finnish government facility.

Historical sampling of these core had been done by only visual inspection of lead mineralisation.

However, fast forward to 2023 and Prospech’s geologists on inspecting the cores recognised that the potentially REE mineralised carbonatite is much broader in extent than the historical sampling which focused on the lead shoots.

One hole returns 17,514ppm REE

Korsnas is one of the projects picked up by Prospech through its 100% acquisition earlier this year of Finnish company Bambta Oy which owned two REE projects (Jokikangas and Korsnas) and the Saarenkyla lithium project.

The Korsnas lead mine produced between 1959 and 1972.

From an academic paper, Prospech tracked down one assay for Korsnas that returned 6m at 17,514 parts per million.

Significantly, while typically the core contained high values of the low-price lanthanum and cerium, its third highest value was for the key battery metal, neodymium, followed by it battery partner praseodymium.

The REE mineralisation was intercepted 64m down hole.

Tailings to be checked too

The lead mine operators also left behind a tailings storage facility (TSF) containing about 570,000 million cubic metres.

Managing director Jason Beckton said that the operators of the mine, which Prospech’s ground tenure surrounds, primarily produced lead, with only a small amount of rare earths concentrated being extracted during the mine’s final years.

“As historical data is combined with new information from the recent site visit, the possibility of a substantial REE occurrence at Korsnas is becoming increasingly evident.”

Mr Beckton added that recent core logging and sampling have revealed that potential zones of REE mineralisation were not sampled if there was no obvious association with visual lead.

And then there are the tailings.

“The old mine TSF provides a readily accessible REE target that can be relatively quickly explored,” he said.