Element 25 Limited announced that it has completed a bulk trial, processing approximately 280 tonnes of Butcherbird manganese ores through the Dense Media Separation (DMS) plant located at the Bootu Creek Manganese Mine in the Northern Territory. The Bootu Creek Mine is owned by E25's off-take partner, OM Holdings Limited (OMH). The test programme was undertaken in mid- June 2022. The 280 tonne trial parcel, made up of six parcels of between 44 tonnes to 49 tonnes each, was transported to the Bootu Creek Manganese Mine via road train for processing through the existing production DMS facility. The six parcels were processed through the DMS drum plant using three different media densities of 2.7, 2.9 and 3.1 g/cm, to provide data on the optimal processing design parameters for Butcherbird material. The trial results clearly indicate that the use of a DMS drum can meaningfully improve manganese product grades by improving the elimination of waste and gangue materials from the product stream. Manganese pricing is positively impacted by higher grades and eliminating sub-grade waste material also reduces the overall haulage and shipping costs of transporting the concentrate to market, thereby reducing overall operating costs. Trial Programme Results: Six parcels of ore were processed. Sample A consisted of five parcels of low-grade Butcherbird post ore-sorter manganese product with the primary feed material sourced from current operational mining faces to provide material for the test programme. Sample B consisted of a single sample of post- scalper ore which had undergone primary screening for the removal of fines material, with the coarse fraction used for the test programme through the DMS circuit. This was then compared to material from the same parcel of scalped ore which was further processed at Butcherbird via the existing process plant. The results from the DMS processing of Sample A resulted in the removal of an additional 3.5-7.3% of waste material by weight from the run-of-mine feed that had undergone processing using the current production circuit. All cut densities yielded a similar result with a slightly better result at the highest cut density of 3.1 g/cm3. The net result is an increase in the final manganese grades from 28.3% Mn to up to 30.9% Mn, equivalent to a 9.1% improvement. Importantly this demonstrates that even for material where the ore-sorters struggle to achieve the optimum product grades, the DMS process is likely to deliver a higher product grade. Sample B comprised sub-grade material which was treated using two different methods. The bulk of the parcel was
processed through the existing plant at Butcherbird, and yielded a below specification grade of 24.4% Mn due to presence of clays and other factors which impacted the effective operation of the ore sorter and its ability to remove the waste material. The ore sorters work using optical colour sensors which measure the Red-Green-Blue (RGB) colour of each feed particle. The sorters classify each particle as either ore or waste according to the algorithm that is currently being used. Consequently, it is very important that material is presented as cleanly as possible as any surficial clays or other
debris can negatively impact the ore sorter effectiveness. The DMS process relies on particle density so surface contamination should have only a minor detrimental impact. Importantly and as expected, the DMS plant was not effected by the presence of clays and other surface effects and successfully upgraded the relatively poor ore-sorter result of 24.4% Mn to an significantly improved grade of 32-33.4% Mn depending on the cut density. As the cut density increases, the product grade increases, also as expected, however there is an associated recovery loss. The optimal density cut is still to be defined, however it is clear from these results that a relatively easily achievable medium density of 2.7 is adequate and the optimal density may be even lower, potentially reducing media costs. Sample B shows that the use of a DMS circuit can increase the manganese grade by an extra 7.55 to 8.92% by the removal of material which is currently part of the tonnage of waste in the Ore Sorter product. This allows manganese
grades to increase from 24.4% Mn to between 32.0 and 33.4% Mn for that material, equivalent to at least a 30% improvement.