Positive Results from Initial Processing Testwork

Empire Metals Limited / LON: EEE / Sector: Natural Resources

4 September 2024

Empire Metals Limited

('Empire' or the 'Company')

Positive Results Achieved from Initial Processing Testwork on Pitfield Titanium Ore

Empire Metals Limited (LON: EEE), the AIM-quoted resource exploration and development company, is pleased to provide an update on the mineralogical and metallurgical studies being carried out on titanium rich ores from the Pitfield Project in Western Australia ('Pitfield' or the 'Project'). The Company's evaluations to date, which incorporate both historical research and current international knowledge and expertise, have identified a number of highly prospective processing routes which are the focus of on-going metallurgical testing and flowsheet development.  The testwork is being conducted at a range of independent and government research laboratory facilities, utilising both commercial scale equipment and reagent industry vendors. The range of work programmes is extensive and the understanding being generated from this breadth of work is integral to the identification and optimisation of a preferred process flowsheet and the development of a final product specification for the Project.

Highlights

·    Empire's metallurgical testwork objective is to develop a processing flowsheet that will enable the development of a fully integrated, mine to high-value titanium product facility thus achieving our corporate goal of making Pitfield a globally significant and secure supplier to the titanium pigment and titanium metal industries.

·    A multifaceted mineralogical and metallurgical testwork programme has now been expanded, engaging international and locally based expert consultants, and utilising Australian based government and commercially owned laboratory facilities.

·    Testwork conducted to date has been on the fresh bedrock titanite ore.  However, the discovery of concentrated, high-purity anatase in the overlying weathered bedrock cap has shifted the testwork focus, requiring the collection of new samples from the diamond drill core which have now been composited and submitted to the laboratory for crushing/grinding ahead of mineral concentration testwork.

·    Titanite ore testwork has been focused on separating the Ti-bearing minerals from the low value, gangue minerals, a key step in the development of an economic process flowsheet for Pitfield, with positive results achieved during the initial gravity separation stages on the titanite-rich fresh bedrock.

·    Preliminary sighter leach tests on titanite ore samples utilising hydrochloric acid (HCl) have been successful with the contained titanite mineral grains completely dissolving within 6 hours in an atmospheric pressure HCl leach at 80 degrees Celsius.

Shaun Bunn, Managing Director, said: "I am extremely excited by the progress being made by our development team, led by our Process Development Manager Ms Narelle Marriott, and well supported technically by titanium industry specialists, Dr Trevor Nicholson and Mr Eugene Dardengo. We have commenced research studies with CSIRO and Curtin University scientists, both groups being located here in Western Australia, aimed at providing important information on the nature and origin of the mineralisation as well as the various routes through which to extract the titanium. Through the mineralogical studies completed to date at AXT and CSIRO (announced 22 August 2024), we now have an increasingly detailed understanding of the mineralisation, both for the fresh and the weathered titanium minerals, as well as for the gangue minerals.

"We have also been working closely with titanium industry and market consultants, TiMPC, which are providing invaluable commercial guidance into what types of products are most desired by the major titanium industry players and how Empire can market its high-purity products towards the high-value end of the market. With new knowledge being generated about Pitfield's ore geology and the titanium industry market requirements, plans for the next phase of testwork are being tailored towards the development of a commercial process flowsheet optimized for Pitfield anatase and titanite ores."

Mineralogical and Metallurgical Update

Ore Characterisation

Two ore types have now been identified within the host sandstone bedrock at Pitfield: an unweathered or "primary" titanite-rich ore type present within the fresh sandstone bedrock, and a weathered or "secondary" anatase-rich ore type present within the overlying, near-surface cap of weathered sandstone bedrock. The Company's development team has initially focused on ore characterisation in order to achieve a fundamental understanding of the dominant primary and secondary titanium ore minerals (titanite and anatase respectively), the nature of other associated titanium-bearing minerals (Fe-Ti Oxides) and the principal gangue minerals within the near-surface weathered cap (hematite, quartz and kaolinite). In particular the ores are being characterised by mineral percentages, the association between minerals, the mineral grain size and mineral composition including looking for any impurities.

Several different mineralogical analysis techniques are being used, including TIMA analysis, XRD, SEM microprobe, and microscope petrography. These services have been undertaken at various independent and government owned laboratories including Automated Mineralogy Incubator (AMI), Bureau Veritas (BV) and Australia's national science agency, CSIRO.

CSIRO's Geoscience Drill Core Research Laboratory is unique worldwide, offering a range of multi-disciplinary techniques for visualising and classifying multi-element geochemical data from drill holes, core and samples. These highly specialised techniques, utilising equipment such as the Minalyzer and the HyLogger, will aid the Company's geoscientists by providing rapid interpretation of the large data volumes generated from our drilling as well as generating key geometallurgical characteristics.

Figures 1-3. (from clockwise) Narelle Marriott, Empire's Process Development Manager, reviewing data from the SEM at the AMI laboratory in Perth.

The HyLogger spectral scanner  and the Minalyzer, both located at CSIRO's Perth laboratories.

The mineral characterisation studies have included a wide range of samples from the exploration drilling programmes completed to date, and include mineralised core samples from the fresh, transition and weathered zones of bedrock intercepted in the sampled drill holes; and also multiple large (+80 kg) composite samples collected from the diamond drill core and crushed and blended for metallurgical testwork.

These large diamond core composite samples will be used to test a wide range of mineral processing and hydrometallurgical techniques. The use of larger composite samples is important as it allows comparison between processing methods for testwork undertaken at multiple laboratories.

Once testwork has determined a specific flowsheet as favourable, then additional samples will be prepared from historical or new drilling to test ore variability, test flowsheet variables and to produce bulk samples for engineering and environmental studies.

Multiple programmes of work are underway, as part of the metallurgical flowsheet development, discussed in detail below. The programme has been designed to consider all aspects of a flowsheet required from delivery of ore to the plant to a final saleable product to market.

Process Flowsheet Development

The strategy has been to consider a wide range of high-potential mineral processing and hydrometallurgical techniques when designing the on-going testwork programme. The process flowsheet and related testwork considers four separate, albeit related, components as defined in Figure 4 below.

The same testwork processes will be used to separately test the anatase-rich secondary ore and the titanite-rich primary ore, as the mineral assemblage (inclusive of the gangue minerals) is entirely different as a result of the strong, near surface weathering.

Figure 4.  Process Flowsheet components under development

Comminution

Comminution is an initial mineral processing step aimed at breaking up the mined ore into small enough particles that the valuable minerals are no longer in the same composite particle as the gangue minerals. This allows the next step of mineral concentration to happen more efficiently.  Information gained in the ore characterisation stage has guided the development of this process flowsheet stage. Mineral grain size and mineral association are used to determine target particle sizes. The images from SEM and microprobe work have provided insight into the physical occurrence of titanium bearing minerals within the sandstone matrix, thereby focusing the testwork on equipment and the techniques which can selectively liberate the titanium bearing minerals without over-grinding, such as mineral sizers, scrubbers, high pressure grinding rolls, hammer mills and stirred milling.

Standard comminution tests have already been undertaken on samples from the fresh bedrock and the weathered zone to provide information on rock competency and energy input for breakage requirements.  The weathered zone was confirmed to be very soft and the fresh bedrock, whilst more competent, is expected to fracture easily due to the bedding layers within the sandstone sediments. Planning is underway for a full range of comminution tests on both the weathered and fresh rocks, pending receipt of full diamond 'PQ' drill core.

Mineral Concentration

Testwork is ongoing at a number of commercial laboratories for the mineral concentration of the Pitfield primary ore samples. This programme is testing a wide range of physical and chemical unit processes that can separate out gangue minerals from Ti-bearing minerals. Multiple unit processes and combinations that can be used on the Pitfield ores are being tested to determine how best to separate the Ti-bearing minerals from the non Ti-bearing minerals. Additionally the minerals within the non Ti-bearing stream will be further assessed for their suitability as potentially economic by-product streams.

As a first stage, screening and size analysis has been undertaken to investigate the opportunity to produce a throwaway waste stream within the comminution circuit, with the objective of reducing the size and energy requirements of the overall comminution circuit. Some coarse rejection of gangue minerals was achieved and the suitability of an initial first stage utilising scrubbing and jigs is now under consideration.

It should be noted that the majority of the testwork conducted to date has been on composite samples produced from primary titanite ore. With the discovery of an anatase-rich secondary ore deposit in the near surface, weathered zone the testwork focus has shifted to developing an understanding of the metallurgical characteristics of the minerals within these weathered secondary ores. This has necessitated further sampling of the diamond core recovered from the Q1 2024 drill programme. These samples have now been composited and submitted to the laboratory for crushing/grinding ahead of mineral concentration testwork.

The key mineral concentration techniques currently under investigation include:

Gravity separation testwork is being undertaken at Allied Mineral Laboratories (AML). AML is an independent mineral processing research facility located in Perth, Western Australia and specialises in mineral separation processing testwork and flowsheet design. The initial gravity tabling tests have been focussed on producing a low-grade mineral waste stream and a titanium-rich mineral concentrate for further downstream processing. This research testwork is being supported by bench scale heavy liquid separation and mineralogical analysis to determine the optimal separation at different specific gravities.

Early indications that the primary titanite ore will respond well to gravity concentration are encouraging. Heavy liquid separation at a specific gravity cut of 2.9 g/ml rejected 35% of the mass and 46% of the gangue silicates.  Only 10% of the titanite was rejected in this stream. Further testwork on the optimal specific gravity cut size and the liberation size to minimise titanite losses is planned.

Magnetic separation testwork is being undertaken at both the Bureau Veritas (BV) mineral laboratory and at Longi, who is a leading manufacturer of industrial magnetic separation equipment.  The research testwork underway is focused on separating weakly magnetic minerals, like ilmenite, from non-magnetic minerals such as quartz or hematite.

Froth Flotation testwork is being undertaken at both ALS Metallurgy and Arnofio Flotation Services. Both flotation laboratories bring a wide range of experience in froth flotation techniques. To date, the Company has completed over 60 diagnostic flotation tests, investigating a range of physical conditions and flotation chemicals.

Figures 5-8 (clockwise from top left) : crushed primary titanite ore prepared for testwork programmes, Empire Metals' Process Development Manager observing flotation testwork, close up of a flotation test, gravity table test in progress and the Longi laboratory scale WHIMS magnetic separation unit. 

Hydrometallurgy

Hydrometallurgical processing, commonly referred to as leaching, is the process whereby the mineral particles are partially dissolved and the elements of interest are separated from other impurities present.

A number of different approaches to this stage of the process flowsheet have been identified from published research, standard industrial practice and existing leaching operations. Bench-scale testwork is determining the leach response of both the titanium ore minerals and the associated gangue minerals, initially focused on bringing the titanium into solution, and then looking to optimise the leach solution chemistry and define the process steps for product finishing. The testwork is assessing acid types (HCl and H₂SO₄) and their consumption, options for reagent recycling, impurity management and options for producing a final high-purity titanium product.

Leaching options include a range of temperatures, under either atmospheric or low pressure leaching conditions. Previous research on leaching titanite ores indicated that either sulphuric or hydrochloric acid can be effective.  Preliminary sighter leach tests on Pitfield primary titanite ore samples have now been completed with positive results. Titanite was shown to completely dissolve within 6 hours in a concentrated HCl leach at 80 degrees C. Further testwork will be undertaken on the mineral concentrates generated from the gravity and/or flotation testwork programmes.

The quality of the concentrates produced in the mineral separation/concentration step will affect the performance of the subsequent leaching step. As such, both testwork programmes will require a feedback loop so that there is the opportunity to optimise the mineral concentrate quality in order to improve the outcomes of the titanium extraction step.

Product Finishing

A high-grade, high-purity titanium dioxide product suitable as feedstock for chloride pigment production or conversion into titanium metal sponge, has been identified as the most desirable final product for the project. The possible process chemistries in the leaching step provide a good synergy with this type of final product. The potential optionality to produce a range of different products, depending on market demand, will be investigated in the testwork programme. Additionally, any opportunity to produce a viable by-product and to reduce waste streams is being explored.

Flowsheet Design

The extensive range of testwork programmes currently underway form an important screening process which will help shape the next phase of research testwork. From these results an in-depth understanding of the ore is being obtained that will guide the next phases of testwork and consequently the process flowsheet design. Results so far have shown a high potential for a multi-stage mineral separation process flowsheet, likely to include both gravity and flotation unit processes. A further mineral extraction processing step using hydrometallurgical leaching techniques is likely to form the back end of the process flowsheet and allow for production of a high-grade, high-purity titanium dioxide product. Testwork is well advanced on the primary titanite ore samples and a parallel testwork programme is now underway on the secondary anatase ore.

The Pitfield Project

Located within the Mid-West region of Western Australia, near the northern wheatbelt town of Three Springs, Pitfield lies 313km north of Perth and 156km south of Geraldton, the Mid West region's capital and major port. Western Australia is ranked as one of the top mining jurisdictions in the world according to the Fraser Institute's Investment Attractiveness Index published in 2023, and has mining-friendly policies, stable government, transparency, and advanced technology expertise. Pitfield has existing connections to port (both road & rail), HV power substations, and is nearby to natural gas pipelines as well as a green energy hydrogen fuel hub, which is under planning and development (refer Figure 9).

Figure 9. Pitfield Project Location showing the Mid-West Region Infrastructure and Services.

Since commencing its maiden drill campaign in March 2023, the Company has completed a total of 107 drillholes for 17,003m (including seven diamond core holes for 2,025m), of which 67 RC drillholes and six diamond core drillholes were drilled within the Cosgrove and Thomas prospects (Figure 10). The drilling shows a high-grade (>5% TiO₂), more than 1km wide central core running on a north-south trend through both mineral prospects, which could join between the two prospects thereby representing a potential total strike length of more than 20km. Significantly, the RC drillhole results clearly indicate elevated TiO₂ grades are present within the top 40m (RNS: 15 May 2024).

Figure 10.  Grey-scale magnetics map overlain by airborne gravity survey results with the location of RC and Diamond Core drillholes and the Cosgrove and Thomas Exploration Target.

Market Abuse Regulation (MAR) Disclosure

Certain information contained in this announcement would have been deemed inside information for the purposes of Article 7 of Regulation (EU) No 596/2014, as incorporated into UK law by the European Union (Withdrawal) Act 2018, until the release of this announcement.

**ENDS**

For further information please visit www.empiremetals.co.uk  or contact:

About Empire Metals Limited

Empire Metals is an AIM-listed exploration and resource development company (LON: EEE) with a primary focus on developing Pitfield, an emerging giant titanium project in Western Australia.

Exploration activity at Pitfield has confirmed the discovery of a new giant mineralised system extending over 40km by 8km by 5km deep. Drilling campaigns have confirmed high-grade TiO₂ mineralised zones across thick bedded intervals to a vertical depth of ~350m, confirming Pitfield as a world class, district-scale titanium mineral system.

Empire is now accelerating the economic development of Pitfield, with the objective of becoming a leading producer of high value titanium dioxide products.

The Company also has two further exploration projects in Australia; the Eclipse Project and the Walton Project in Western Australia, in addition to three precious metals projects located in a historically high-grade gold producing region of Austria.