Latin Resources Ltd (ASX:LRS) continues to deliver consistent results from its expanded program of metallurgical test-work at the 100%-owned high-grade Salinas Lithium Project in Brazil.
So far, crush size has doubled to 12.5 millimetres while recoveries and grade remain high, demonstrating very coarse liberation of spodumene:
- average recovery of 80.5% of Li2O; and
- production of extremely high-grade Li2O concentrate (up to 6.6%) from simple Heavy Liquid Separation (HLS).
The company has also reported exceptionally clean concentrates in the -12.5 millimetre to +6.3 millimetre size range, with concentrates well above 7.0% and as high as 7.96% Li2O achieved.
Overall results show excellent consistency across the width and depth of the known ore body. Also of importance are the consistently low Fe grades in head samples and HLS concentrates, which are promising for the marketability of Salinas concentrates.
“The latest round of test-work is extremely encouraging for our recoveries at Salinas and we are delighted with the consistency of results we have been able to achieve,” Latin Resources’ Geology general manager Tony Greenaway said.
“We are very pleased to report very high recoveries and the production of a high-grade concentrate from simple HLS, and while these results cannot be directly translated to an operational environment, they do have very significant implications for the marketability and the economics of our concentrate.
“We intend to progress this into bulk pilot plant test-work, where we will optimise the flowsheet for the planned detailed PEA program that is planned to be completed by SGS in the first quarter next year.”
Metallurgical test work results at Colina
SGS GEOSOL laboratories, Belo Horizonte, Brazil, undertook a program of HLS test-work on 10 samples representing the total strike length of the current resource drilling program at Salinas.
The company collected a total of 367 kilograms of representative sample: each of the samples included interstitial waste between ore zones to simulate expected mining dilution.
Colina deposit drill collar plan showing metallurgical long section location.
A key objective was to investigate potential variability in metallurgical performance across the deposit and at varying depths. Half of the samples were targeted in the top 50-100 metres of the ore body with the other half of the samples taken from the bottom 100-150 metres of the deposit.
Results were independently reviewed and interpreted by Met Assist Pty Ltd and showed that simple HLS was able to recover an average of 80.5% of the Li2O into a concentrate grading a very high average of 6.30% Li2O.
Very coarse spodumene liberation
Based on the promising initial sighter tests undertaken in July 2022, LRS was confident to conduct the HLS test-work at a much coarser top size of 12.5 millimetres. Size distribution of the prepared samples are shown below:
Mass size distribution of prepared samples.
HLS results for the coarse fraction demonstrated extremely high grades more than 7% Li2O.
Given pure spodumene has a theoretical grade of 8.03% Li2O, this suggests that full liberation of spodumene is achieved even at these coarse grind sizes. It also indicates that spodumene is by far the dominant lithium ore type, and the deposit is not challenged by lower-grade variants such as lepidolite or petalite which can negatively impact final concentrate grades.
Consistency is key
A key objective of this round of test-work was to investigate variability within the deposit. A total of 10 samples were composited and represented approximately 20 metres of total intersection for each sample.
The samples were selected over approximately 500 metres of know mineralisation. Five samples were taken from areas within the top 50-100 metres of the deposit and the other five samples were taken from depths of 100-150 metres within the deposit.
Projected long section showing sample selection across the deposit.
Results demonstrate very close correlation between the two groups of samples with the exception of sample Metsa04, which is believed to be due to a less-than-ideal sample size of 12 kilograms, making this less representative for use in sub-samples taken for HLS.
Other highlights
Fines generation size distributions shown in Table 1 (above) indicate that the amount of fines generated in a 12mm crush is very low with an average of 12.25% of the material reporting to the
The results for the program on the Salinas samples suggest the -0.5mm fraction contains only 10% of the Li2O and therefore potentially up to 90% of the contained Li2O in the deposit would be processed through a future DMS plant.
The Colina composite samples demonstrated very low Iron content in the raw feed sample. Cumulative recoveries of the results for each SG cut point enabled the calculation of expected Iron grades for a concentrate of 6% Li2O.
Li2O and Fe feed grades vs expected Fe grade in a 6% Li2O concentrate.