East Star Resources PLC plunged 28.5% to a new low of 2p after unveiling results from mineralogy and leaching studies of eight samples at the Talairyk rare earths project in Kazakhstan.
Testing demonstrated that a majority of rare earth elements have been “liberated from primary minerals during the weathering process and are now associated with other mineral phases”, the company said.
Test work at Brighton’s School of Applied Sciences in the UK on a sample from October’s drilling programme showed mineralogy and total rare earth elements concentrations “comparable to ion adsorption deposits globally” with a kaolinite-dominated mineralogy and 815-5,185 parts per million (ppm) of total rare earth elements.
Leach results from ammonium sulphate have lower recovery with peak results that suggested the leachability of the tested samples is not representative of proven ion adsorption clay deposits, it added.
East Star said results from sulphuric acid single-phase leach suggested further test work is required to assess if there is a potential route to commercial extraction.
The company is consulting with metallurgical specialists to assess the next phase of testing.
Chief executive Alex Walker said: “Our understanding of the minerology and potential for economic extraction of rare earth elements from the Talairyk deposit has grown significantly and, while not definitive, it will allow us to plan a low-cost assessment of what additional test work is required to identify if an economic process to leach rare earth elements from the weathered material is possible.”