Pan Asia Metals buoyed by promising new Reung Kiet lithium metallurgy results

Pan Asia Metals’ (ASX: PAM) development plans for the Reung Kiet lithium prospect in Thailand have received a significant boost with promising new metallurgy results.

Recent test-work involving flotation recovery of lithium mica concentrates has identified improving returns in the lead-up to a pre-feasibility study Reung Kiet.

Managing director, Paul Lock, said the test-work undertaken by mineral processing specialist Nagrom was aimed at verifying previous studies carried out by China’s BGRIMM Technology Group.

“We are pleased that this program reaffirms and, in some areas, improves upon previous results, which bodes well for the economics of the Reung Kiet project,” Mr Lock said.

“With this confirmatory test-work completed, we can now progress onto post ore sorting test-work and process refinement after which we are confident in achieving further improvements to recoveries and concentrate grades.”

Targeting lepidolite/mica-rich pegmatites

The Reung Kiet lithium project is a hard rock lithium project with lithium hosted in lepidolite/mica-rich pegmatites.

Pan Asia is targeting the processing of lepidolite as a source of lithium as previous studies have found that lithium carbonate and lithium hydroxide projects using lepidolite as their plant feedstock have the potential to be placed near the bottom of the cost curve. Lepidolite has also been demonstrated to have a lower carbon emission intensity than other lithium sources.

China is the only jurisdiction where lithium chemicals are being commercially produced from lepidolite ‘ores’.

A hard rock lithium carbonate equivalent (LCE) cost curve study undertaken by Wood Mackenzie demonstrated the cost competitiveness of lepidolite as a source of LCE and that China produced approximately 50,000t of lithium carbonate equivalent from lepidolite in 2021, representing about 18% of global hard-rock LCE production.

Test-work overview

Nagrom’s recent test-work was undertaken on two separate composites made up of fresh and weathered mineralisation derived from laboratory ‘coarse crush rejects’ (100% <3.35mm) from 1⁄2 HQ sized drill core selected from chosen drillholes.

The fresh composite sample was derived from 278 individual samples from 16 holes. This sample returned a head assay of 0.64% lithium oxide.

The weathered composite sample was derived from 133 individual samples from 11 holes. It returned a head assay of 0.80% lithium oxide.

These samples were initially utilised by Beijing General Research Institute of Mining & Metallurgy (BGRIMM) – a specialist on assessing lithium mica ‘lepidolite’ deposits in China.

The samples remaining from the BGRIMM test-work were subsequently delivered to Nagrom testing facilities in Perth, which utilised almost identical test-work conditions to those employed by the Chinese firm.

The beneficiation process

A beneficiation process utilised fresh material consisted of milling to P80 of 0.11mm, involved three cleaning flotation products.

The flotation test selected concentrate returned a grade of 3.09% lithium oxide at total lithium recovery of 76%. The concentrate is composed of approximately 90% lepidolite-muscovite.

The beneficiation process of weathered material consisted of milling to P80 of 0.15mm, using four cleaning flotation stages, returned a lithium oxide (lithium oxide grade of concentrate measuring 3.11% and a recovery of 71%.

Nagrom’s studies identified that the recovery of lithium-bearing minerals from the fresh mineralisation is similar to that of weathered mineralisation.

Importantly, Nagrom’s studies demonstrated that relatively high recoveries of lithium to concentrate are achievable utilising industry standard methods with both the fresh and weathered mineralisation undergoing similar comminution and beneficiation.

This has resulted in concentrate grades of plus 3.0% lithium oxide with lithium recoveries of plus 70% for both materials tested.

Further flotation test-work on sample products derived from ‘ore- sorting test-work’, which has proven to reduce the amount of low-grade siltstone in the potential ROM feed, is now being conducted by Nagrom.

Pan Asia expects this will lead to an increase in the overall lithium grade of the feed.

The company’s own historical test-work suggests that this should result in better lithium recoveries and a higher concentrate grade.

Various blends to be tested

Additional test-work is also planned to be conducted on various blends of weathered and fresh mineralisation. Ore sorting test-work is also planned to be undertaken on weathered mineralisation.

Pan-Asia believes this may also result in better recoveries and a higher concentrate grade. Metallurgical samples are also being prepared from drillhole samples derived from the nearby Bang I Tum prospect.

Meanwhile, lithium mica concentrates produced by BGRIMM’s test-work are undergoing roasting and conversion test-work to produce lithium carbonate at ALS Global in Perth under supervision if Lithium Consultants Australia.

The process route being tested is an alkaline salt roast, which is commonly referred to as a sulphate roast. This is the process predominantly used in China and therefore, as there is an operating track record, the process has been de-risked.

Reung Kiet drill program concludes

Pan Asia has also confirmed that a resource drilling program at Reung Kiet has been wrapped up.

Drilling attention has now moved to the Bang I Tum prospect located around 9km north of Reung Kiet.

The company is aiming drill up to 15,000m of diamond core at Bang I Tum with the objective of assessing a recently reported exploration target and adjacent prospects, with the ultimate aim of defining a mineral resource to complement that at Reung Kiet.

Earlier this month Pan Asia unveiled an updated Bang I Tum exploration target of 16 to 25 million tonnes at 0.40-0.70% lithium oxide, a significant 80 to 100% increase in tonnage to the previous exploration target of 8 to 14 million tonnes at 0.5-0.8% lithium oxide.