Bulletin Resources Limited provided an update on its 130km2 Ravensthorpe Lithium Project. The project is located only 12km southwest and along strike of Allkem Limited's Mt Cattlin Lithium Mine. Indicative Metallurgical Testwork Program. BHM Process Consultants Pty Ltd. (BHM) were engaged to undertake indicative diagnostic metallurgical testwork. The testing was designed to investigate the potential for generating saleable lithium concentrate from spodumene bearing pegmatites at Bulletin's Ravensthorpe Lithium Project. BHM see the results from this early phase of metallurgical testwork as highly encouraging and confirm the pegmatite mineralisation at the Ravensthorpe Lithium Project to be of a very high quality and able to achieve saleable product grades at high metallurgical recoveries. BHM further report: The samples provided by Bulletin display that the pegmatites at the Ravensthorpe lithium project are of a high grade, coarse grained nature (2.0% to 4.4% Li2O contained). The tested blended composite which included appropriate mining dilution, yielded potential concentrate at higher than required grades (>6.0% Li2O) at high recoveries of >75% Li2O. A suitable processing method of simple, conventional Dense Media Separation (DMS) is an appropriate treatment pathway given 80 - 90% of the entering lithium units can proceed to the coarse treatment pathway. Upgrades greater than 4 times were observed achieving saleable lithium content grades. It is surmised that the bulk of the processing loss was generated from the "Wall Rock" constituent in the blended composite and not from the pegmatite mineralisation. The rougher flotation response is excellent. Should the remaining fine lithium units prove economically viable, further upgrade potential can be explored in future bodies of work. The potential coarse concentrate's likely penalty elements are considered relatively low including iron at well below the 1.5 % Fe2O3 cut-off. Any fines concentrate generated from flotation is likely to be elevated in iron at 2.4% and will require further processing, lithium cleaner flotation upgrade followed by magnetic separation. Key loss areas can only be further explored and optimised once a potential resource and mine plan is generated to define the pegmatite vs host mineralisation blend ratios. In summary, BHM report the Ravensthorpe Project pegmatites contain spodumene mineralisation that should respond well and generate good recoveries and yields to saleable concentrate grades from standard industry, two stage, coarse and intermediate size fraction DMS processing plants. In a plant scenario, DMS would be utilised to upgrade the wet screened coarse fraction. As a diagnostic test for the DMS circuit, the coarse +1mm fraction from the wet screening underwent Heavy Liquid Separation (HLS) testwork at specific gravities (SG) of 2.85 and 3.00. This work indicates 75% of the Li2O is recovered to the SG 2.85 sinks at a grade of 6.5% Li2O with 0.5% Fe2O3 recovered to this fraction. At the higher SG of 3.0, testwork reported 57% of the Li2O is recovered at grade of 7.0% Li2O with 0.6% Fe2O3. Testwork was planned to examine magnetic separation of the Fe2O3 but was deemed unnecessary given the Fe2O3 grade is well below typical marketing cut-off of 1.5 - 2.0% Fe2O3. It was also noted that the coarse fraction contained low amounts of mica which is typically present in spodumene pegmatites and can cause issues if not removed prior to DMS. The first sighter flotation test provided the best results with 90% of the Li2O yield at a grade of 3.1% Li2O reporting to the combined rougher concentrate. The -1mm fraction appears well liberated at P80 0.15mm and was upgraded from 1.1% Li2O to 3.1% Li2O via rougher concentration. Fe2O3 was elevated in the fine fraction concentrate with a 93% yield and a grade of 2.3% Fe2O3. Fe2O3 in spodumene deposits often preferentially reports to finer fractions and commercially, magnetic separation is used to reduce Fe2O3 grade prior to blending with the coarse product. Flotation is also generally performed in several stages rather than the single stage at testwork level. The additional flotation and magnetic separation work can upgrade lithium content as well as reduce Fe2O3 grade.
Further testwork is recommended on a greater spread of samples and mineralisation in the future once a resource has been established. This will be to confirm or optimise the liberation sizes and assess the variability of deleterious elements and their effect on the product grade and recovery at a higher level of study accuracy.