Australian Vanadium Limited (ASX: AVL, 'the Company' or 'AVL') is pleased to provide an update on ongoing detailed physical beneficiation testwork for the Gabanintha Vanadium Project near Meekatharra in Western Australia.
The aim of the testwork program is to determine comminution parameters for the high-grade vanadium ore at Gabanintha as well as accurately determining the recovery and quality of the vanadium ore concentrate. Together these pieces of information will allow AVL to define the process flowsheet for the planned Pre-Feasibility Study (PFS).
The definitive comminution and beneficiation test program is being conducted on diamond core previously collected by the Company. The core materials have been separated into high-grade and low-grade ore types. The major focus is on the recovery of a vanadium concentrate from the High Grade Zone.
The High Grade Zone of massive-magnetite is located at the base of the mineralised intrusion. This High Grade Zone is the focus of current economic studies due to its potential for high-yield, high-grade vanadium-iron concentrate suitable for traditional roast-leach vanadium recovery. This method of vanadium recovery is the most common and well understood process for high-grade vanadium-titanium-iron ores globally and is currently used by all current global producers of vanadium from magnetite sources, including Largo Resources, Bushveld Vametco and Glencore's Rhovan operations.
The metallurgical testwork was based on 24 massive-magnetite composites from Gabanintha diamond drill core. The composites were selected as discrete intervals within 10 diamond drill holes with a 173m depth range (ranging from 14m from surface to 187m measured orthogonal to earths surface) across 915m of Northing thereby representing a significant portion of the current Measured and Indicated Resource area. The sampling specifically takes into account the distinction of the oxidation state within the high grade layer.
Wet Low Intensity Magnetic Separation (WLIMS) was used to separate magnetic material from gangue material. A nominal feed size of P80 = 106 micron (i.e. 80% of material passing 106 micron) was targeted for the composites. The results indicate a primary magnetic concentrate grade and yield using low-intensity magnetic separation techniques highly attractive to the conventional salt roast vanadium recovery process.
Highlights of the work include: Fresh high-grade WLIMS at 1500 Gauss (1500G) indicate exceptional concentrate recovery, capturing 92.3% of vanadium in a 1.42% V2O5 concentrate before optimisation. The average concentrate (10 composites) had an overall mass recovery of 72.9% with 57.3% Fe and a very low silica content of 0.55% SiO2.
Transitional high-grade WLIMS (1500G) and Rare Earth Magnetic Separator (REMS) (2700G) combined concentrate product captured 89.2% of vanadium in a 1.40% V2O5 concentrate before optimisation. The average concentrate (8 composites) had an overall mass yield of 72.9% with 50.8% Fe and 2.44% SiO2 grade.
Transitional concentrate grades of up to 1.72% V2O5 (Comp 17) and 1.66% V2O5 (Comp 16) were achieved, indicating significant upside across the deposit.
Further work is already underway to optimise concentrate grade and lower silica and alumina in transition and fresh feed material. A number of opportunities have been identified to further enhance the concentrate quality and these are currently being tested in the laboratory.
Comminution Test Work
A series of standard detailed comminutions tests have been completed. These tests allow the determination of energy requirements to prepare a consistent sized ore for later processing in any operations. This entailed crushing and grinding, density and abrasiveness testing.
Highlights of the first stage of detailed comminution test work completed are: Consistent energy consumption of 6.9 kWh/t was established to break material in a AG/SAG milling scenario with a closing screen size of 2.8mm.
Density correlation strongly supports use of regressed density with iron grade in magnetite. Average density of 3.6 is applicable to oxide, transition and fresh high-grade materials.
Abrasion index work indicate ore only 'slightly abrasive', indicating modest wear of comminution equipment.
Next Steps: Further improvements to concentrate grade and quality
Managing Director Vincent Algar commented, 'The definitive work to date in the current program is providing us with great confidence that Gabanintha can produce a significant quantity and quality of vanadium concentrate to feed a conventional vanadium roast-leach process. We will continue to optimise the recovery to achieve the simplest possible flowsheet to take to our PFS. The results of this round of testwork confirms the Company's view that Gabanintha will be able to supply high quality V2O5 products to meet the needs of the energy storage and steel making customers. With increasing market demand for vanadium right now, AVL will be accelerating its development activities to bring vanadium products to the market as soon as possible.
New test work is already underway to further optimise the work reported here, with a view to simplifying the process flowsheet which will form part of the up-coming PFS on the concentrate plant. The optimisation of feed quality and yield has significant implications for downstream project economics by ensuring the lowest use of water, reagents and power. The objective is for Gabanintha to provide the highest quality processing feed possible from the entire high-grade orebody via the simplest circuit design.'
As part of the optimisation work on the transitional and oxide ores, a follow-on set of testwork is currently underway in consultation with Wood Group Consultants and conducted at Bureau Veritas Laboratories. The testwork includes: Density and size fraction analysis (previously shown to reduce silica content); Reverse silica flotation; Re-run of REMS (transition) and WHIMS (Oxide) tests with cleaning to preclude entrainment of silica and alumina seen in previous tests, Quantitative Mineralogy to confirm mineral associations, and Recovery of sulphide phase containing nickel, copper, cobalt, present in non-magnetic fraction of fresh composites.
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Australian Vanadium Limited holds 100% of the Gabanintha Project near Meekatharra in Western Australia. Gabanintha hosts a declared Mineral Resource at Gabanintha comprising 179.6Mt at 0.75% Vanadium Pentoxide (V2O5), made up of a Measured Mineral Resource of 10.2Mt at 1.06% V2O5, an Indicated Mineral Resource of 25.4Mt at 0.62% V2O5 and an Inferred Mineral Resource of 144Mt at 0.75% V2O5.
The Mineral Resource includes a distinct and globally significant, massive magnetite high-grade zone of 92.8 Mt at 0.96% V2O5 consisting of a Measured Mineral Resource of 10.2Mt at 1.06% V2O5, an Indicated Mineral Resource of 4.8Mt at 1.04% V2O5 and an Inferred Mineral Resource of 77.8Mt at 0.94% V2O5.