Lotus Resources confirms high-grade rare earths at Milenje prospect
Trench sampling at Milenje returned up to 25.5% TREO.
Lotus Resources (ASX: LOT) has completed a program of second-stage preliminary exploration at the Milenje rare earth element (REE) prospect, located near to its flagship Kayelekera uranium project in Malawi.
Work comprised trench sampling, a reverse circulation drill program and preliminary mineralogy studies and confirmed high-grade REE mineralisation including total rare earth oxides (TREO) of up to 25.5% with an average of 11.6% from 11 samples; and critical rare earth oxides (REO) of up to 5.6% averaging 2.48%.
Drilling intercepted several anomalous zones of gneisses which showed some elevated REE mineralisation; however, this was reported to be generally lower than the surface (trench) samples.
Lotus said further structural mapping and interpretation would be required to better understand the mineralisation controls.
Previous trenching
Managing director Keith Bowes said the second-stage exploration work was designed to follow up on previous trenching carried out at Milenje in 2020-21.
“Following a review of the program, we believe the structures are more complex than originally anticipated, however the results have provided valuable information on lithologies and structures which we can use to better understand what is controlling the mineralisation at Milenje,” he said.
“We believe an additional low-cost program is warranted during the 2023 field season to validate the latest structural information and we will make a decision on future drilling from there.”
Historic exploration
The Milenje Hills prospect was first identified through ground surveys and mapping in 2014 while the previous owners were exploring for uranium adjacent to Kayelekera.
Lotus followed up the historical work with a geophysical and trenching program in late-2020, which comprised radiometric and magnetometer surveys with mapping to define the extent of the REO and rutile mineralisation (allanite and rutile-bearing rocks) and characterise the host rock’s mineralogy and chemistry.
Based on this work, 23 pits and trenches were excavated, logged and sampled at one metre spacings.
Rare earth assemblage
Lotus said the mineralisation was interpreted to be associated with allanite-rich pegmatite dykes and associated fluid alteration within associated granitoids.
The rare-earth assemblage includes significant portions of neodymium, europium, terbium, dysprosium, yttrium and praseodymium, which are considered to be high-value critical REOs.
The neodymium and praseodymium oxides represent an average 20% of the TREO content of the assayed samples.
These two elements, along with dysprosium and terbium, are essential for the manufacture of permanent magnetics which currently represent up to 90% of REO market value.