Announcement • Jun 14
Ardea Resources Limited Announces Kalgoorlie Nickel Project Feasibility Study Update
Ardea Resources Limited present a progress report regarding its ongoing Definitive Feasibility Study (DFS) at the Kalgoorlie Nickel Project (KNP) Goongarrie Hub. The current DFS programs are specifically independent of throughput and product material, with these parameters being dependent upon the future Strategic Partner requirements. In previous releases to the ASX, Ardea has provided updates on KNP resource definition and affirmed its intention to participate in the high-growth Lithium Ion Battery (LIB) market through the production of either Mixed Hydroxide Precipitate (MHP) intermediate or a refined Precursor Cathode Active Material (PCAM) product. The Feasibility Study for the KNP - Goongarrie Hub has been focussing on Material Types to allow the mineralisation to be matched to the High Pressure Acid Leach (HPAL), Atmospheric Leach (AL) and Neutraliser circuits, maximising resource utilisation from a well understood and proven flow sheet. The purpose of this summary is to elaborate on the current feasibility work streams and the underlying factors for these enhancements. With the significant increase in financial, corporate and legal requirements around the KNP Strategic Partner process, notably since the awarding of Major Project Status for the KNP in March 2022, Ardea needed to expand the responsibilities of the CFO position and move from a part-time to full-time role. The transitioning from 2017 IPO part-time CFO/Company Secretary Sam Middlemas to full-time CFO Rebecca Moylan is underway. Rebecca has a diverse range of commercial and financial experience, including international exposure, the specific financial and corporate experience with accounting qualifications as now required by Ardea. Sam's excellent strategic input will be on-going for Ardea and the KNP, through him continuing his role as Company Secretary. The Goongarrie Hub is located 70km northwest of the mining city of Kalgoorlie-Boulder and is Ardea's most advanced project, within the broader KNP. The Goongarrie Hub includes the Goongarrie deposits from south to north, Scotia Dam, Big Four, Goongarrie South and Goongarrie Hill, along with Highway some 30km to the north and Siberia North, approximately 10km to the southwest. Historic and current Ardea drilling over the Goongarrie Hub includes: 4,088 RC holes for 197,430m for resource estimation. 128 core holes for 7,961m for verifying RC drilling, resource estimation and metallurgy test work. 100 sonic holes for 4,634m for resource estimation and metallurgical test work. 2 Calweld holes by Vale Inco for 50m for metallurgical pilot run samples. 4 mud rotary holes by Ardea for 296m for hydrogeology aquifer pump tests. The current Ardea resource review of the Goongarrie Hub concluded: A total of 4,322 drillholes for 210,371m of drilling has been completed across the Goongarrie Hub deposits primarily focused on Mineral Resource definition augmented with significant diamond and sonic drilling to verify the results from the RC drilling, provide material for metallurgical test work and samples for SG determinations. The RC drilling across the deposits is sufficient to define Measured and Indicated Mineral Resources capable of supporting the project development based on mining studies completed as part of the Ardea PFS in 2018 and an Ardea internal mining optimisation study completed in 2019. 228 diamond and sonic drill holes for 12,595m of drilling provide broad confirmation of the mineralisation tested with RC drilling and an abundance of material for metallurgical test work, Material Type characterisation and SG measurements. Material Types can be clearly differentiated as amenable to either HPAL or AL circuit. Where the allocation is at all equivocal, current bench-scale test work at ALS metallurgical laboratory suggests HPAL is the preferred option. The Ardea review supports that there is minimal, if any requirement for further drilling to upgrade the Goongarrie Hub Mineral Resource Estimate (MRE) of 561Mt at 0.68% nickel and 0.044% cobalt. Current independent mineral resource reviews of the Goongarrie Hub may form a view that some infill drilling is required, presumable to upgrade specific proposed pit areas from Indicated to Measured JORC Code (2012) status for conversion to Proven and Probable Reserve. At the instigation of the leadership group, a "cold eye" flowsheet review was commissioned. This revealed the following opportunities: Increased resource utilisation through inclusion of an Atmospheric Leach (AL) stage. Improved overall process continuity and stability. Reduced reagent costs. Reduced energy consumption. Lower Green House Gas emission intensity. Reduced water consumption. These were supported by process initiatives that included: Utilisation of in-pit mineralised neutraliser, with screening of crushed in-pit saprock at 75 microns generating 23% Fines for potentially expanding AL production volumes and 77% "run-of-mine" magnesite neutraliser (termed "Scats"). Atmospheric leaching of serpentine-type mineralisation, initial tests at ALS successful. Expanding production volumes to allow for twin parallel HPAL autoclaves for a combined 3Mtpa throughput. Water treatment and recycling. Matching the acid, steam, and power circuits to maximise value-adding from the sulphur reagent. A revised version of the SysCAD© metallurgical process model was generated and used for updating of mass balances, mechanical equipment lists and process flow diagrams. This was complemented by the in-house development of spreadsheet-based models, which were calibrated against the SysCAD© model and used for fast-turnaround process options analysis. The process updates were announced in the 15 November 2021 ASX release, and incorporated twin HPAL autoclave trains, each treating 1.5 Mtpa dry goethite solids, and a single AL train, processing 0.5 Mtpa of nickel- bearing serpentine (it should be noted that these figures may alter in the course of a future optimisation process or in response to Strategic Partner requirements). As per the current mass balance model, overall nickel and cobalt production is generated from approximately 3.5Mtpa plant feed to produce an MHP intermediate product. The underlying model assumptions are being checked in the current metallurgical test work program, which was announced to the ASX on 31 May 2021.