Historic drill core assays reveal high REE grades at Prospech’s Finland project
Prospech (ASX: PRS) has confirmed encouraging results that it has high grades of rare earths elements (REE) at its Korsnas project in Finland.
The company has begun assaying — for the first time — drill cores from drilling at the historic mine, cores which had previously been sampled only by visual examination by the former owner and only that for lead.
Prospech has now received results from six historic cores which the company says confirms expanded zones of REE mineralisation at Korsnas.
One result returned 18.3m at 13,201 parts per million total rare earth oxide (TREO) from 51.7m down hole.
Multiple mineralised zones
Earlier this year, Prospech’s geologists, on inspecting the cores, recognised that the potentially REE mineralised carbonatite was much broader in extent than the historical sampling which focused on the lead shoots.
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.
Other cores now assayed for the first time in the REE search returned 10.9m at 5,634ppm TREO and 16m at 2,296ppm.
Also, one hole (KR-289) located west of the historic Korsnas mine confirmed that multiple mineralised zones exist on the property.
Strong Nd/Pr values
Sampling of the holes has produced an average 26% of TREO to be the vital battery metals neodymium (Nd) and praseodymium (Pr).
Further logging and sampling of historic Korsnas drill core is now being planned.
Prospech says the elevated presence of REE mineralisation in all the samples provides confirmation that previous drilling focused solely on lead exploration, and the REE in drill cores was overlooked.
REE unconnected to lead
That KR-289 hole west of the Korsnas mine carries “great significance” because it revealed the presence of a separate mineralised zone, completely distinct from the mine trend.
“Moreover, it confirms that REE mineralisation occurs independently without the presence of lead,” the company notes.
Prospech reported last month that KR-289’s assay had returned 6.2m at 17,514ppm.
Managing director Jason Beckton said the identification of thicker intersections of REE mineralisation, along with “impressive” Nd/Pr enrichment, underscores the potential of Korsnas.
“These assay results represent some of the most exciting and encouraging findings in the company’s history,” he added.
Tailings to be checked too
The lead mine operators also left behind a tailings storage facility (TSF) containing about 570,000 million cubic metres.
Mr Beckton said the TSF has emerged as a high priority target for REE investigation.
There have been positive assay results from grab samples and now the company is speeding up preparations for 3D sampling.