High Purity Anatase Confirmed Within Weathered Cap

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

22 August 2024

Empire Metals Limited

('Empire' or the 'Company')

High Purity Anatase Confirmed Within Weathered Cap at Pitfield

Defining Pathways to High Value Commercial Products

Empire Metals Limited (LON: EEE), the AIM-quoted resource exploration and development company, is pleased to provide the following update on the highly significant, titanium dioxide mineral deposit recently discovered at the Pitfield Project in Western Australia ('Pitfield' or the 'Project'). This newly identified deposit is located within the near-surface, strongly weathered "saprolite" cap which covers the extent of the giant, 40km long, titanium-rich mineral system at Pitfield, and it is enriched with high-purity anatase which has formed from the weathering of the original titanite-rich, bedded sediments. This finding, confirming that the ore at Pitfield displays very low impurity levels and high TiO₂ grades, is the first step towards proving that the material is a suitable feedstock for high value commercial products including chloride TiO₂ pigment and titanium metal.

Highlights

·    Mineralogical assessment of the strongly weathered sandstones indicates an abundance of high-quality anatase, containing up to 98.5% TiO₂ and accounting for more than 5% of the mass of the near-surface weathered bedrock, being 4 to 5 times higher TiO₂ concentration than that typically found in mineral sand deposits.

·    Anatase, a variant of rutile, is considered a highly valuable mineral and is now emerging as a strategic feedstock for the titanium chloride pigment and titanium metal markets as rutile rich resources decline globally.  Importantly, it is the purity and TiO₂ content of the feedstock and not the specific TiO₂ mineral (rutile vs anatase) in the feedstock that is most important to producing a high value TiO₂ pigment or metal product.

·    Historically, anatase rich orebodies, such as those reported in Brazil and China, have derived from the weathering of carbonatites (igneous rocks containing >50% carbonate minerals) and these ores tend to have high levels of radionuclides and other undesirable contaminants such as niobium, chromium, and phosphorus, all of which make them unsuitable for TiO₂ pigment manufacture.

·    Pitfield represents a different, previously unrecognized class of sandstone-hosted titanium deposit that contains none of the deleterious elements associated with the carbonatite-hosted titanium deposits, making it a source of very high quality anatase well suited to making a high-value TiO₂ feedstock product.

·    Most of the titanium in the soft, friable, weathered sandstone bedrock is contained within the easily extractable, naturally heavy anatase that responds very differently to the main gangue minerals, kaolinite and quartz, and thus is likely to require little further beneficiation to produce a high-quality TiO₂ concentrate.

·    The potentially simpler mineral separation and subsequent less onerous beneficiation processing characteristics of this clean, high-grade anatase-rich ore provides an excellent opportunity for the production of high-quality TiO₂ pigments and/or titanium metal.

·    Metallurgical testwork on the recent diamond drill core samples taken from the weathered cap is underway, currently focusing on simple gravity and froth flotation mineral separation techniques prior to acid leaching and product refining studies.

·    The Company's immediate focus remains on confirming the process route, delineating a maiden Mineral Resource Estimate and defining potential end products and will continue to update the market on the development plan and progress being made in due course.

Shaun Bunn, Managing Director, said: "The discovery of a naturally occurring, concentrated zone of high-quality anatase within the extensive weathered cap provides an enormous opportunity for the Company to accelerate its plans to become the next fully integrated "mine to high-quality TiO₂ product" project. The anatase found at Pitfield has a very high TiO₂ content and is free of deleterious impurities, making it a desirable feedstock for processing to TiO₂ pigment. Anatase can be chlorinated to produce titanium tetrachloride (TiCl₄) under similar conditions required to process rutile, an important precursor to making TiO₂ pigment and titanium metal.   

"Clearly, this discovery will have a material and immediate positive impact on the overall project economics. The strongly weathered cap can be mined first and will be amenable to very low-cost strip mining methods due to its surficial position, broad extent and soft, friable nature due to weathering. The weathering has also converted the gangue silicate minerals to kaolinite and quartz, common minerals that can be simply separated with conventional techniques, providing a clear processing pathway for the recovery of a high-grade TiO₂ mineral concentrate suitable for the production of TiO₂ pigments and titanium metal."

Gerry Colamarino, Managing Director of TiPMC Consulting, commented:

"The latest information provided on the weathered cap is very encouraging for Empire Metals' Pitfield Project. Importantly, the crystal formation of the anatase mineral within the ore does not impact on the final TiO₂ pigment crystal structure, hence anatase potentially represents a novel solution to supply feedstock options for TiO₂ pigment manufacture.

In both the chloride and sulphate pigment processes, the feedstock is converted to an intermediate product (TiCl₄ in the case of chloride, TiSO₄ in the case of sulphate).  The crystal structure of the final TiO₂ product is created downstream: in the case of the chloride process, the oxidation step creates the rutile crystal and in the sulphate process, the calcination process creates the rutile crystal.  Thus, the crystal structure of the feedstock is unrelated to the crystal structure of the final TiO₂ product.

The potential for a high TiO₂ grade product with low contaminants from Pitfield provides potential customers a multitude of options to optimize the value in use of the product.  The potential Pitfield product can be mixed with lower grade feedstocks or used independently to reduce consumption of reaction chemicals.

Given the early development phase of the project uncertainties continue to exist and further test work is required to explore the variables required by the chloride process, including particle size, bulk density and the digestibility of the anatase products.  Still, an anatase sourced feedstock from Pitfield offers a new and exciting potential alternative to today's available feedstocks."

Mineralogical Study Results

The diamond core drill campaign carried out through February and March 2024 provided important samples for ongoing metallurgical and mineralogical studies, particularly the near-surface core that was successfully recovered. Sections of this core, taken from two drillholes each at the Cosgrove and Thomas prospects, were submitted for Tescan Integrated Mineral Analyzer ('TIMA') analysis and Scanning Electron Microscope ('SEM') microprobe work to determine the mineral assemblage within the strongly weathered zone.

As previously reported (RNS: 5 June 2024) the results of the TIMA analysis on the diamond core, and also selected RC drillhole samples taken from the same target areas show a dominance of titanium dioxide minerals, rutile and(or) anatase, within the upper levels of the weathered cap, with little to no titanite (CaTiSiO₅) and only minor ilmenite (FeTiO₃) observed. Follow up mineralogical assessment using X-Ray Diffraction analysis shows that anatase is the more abundant titanium dioxide mineral.  Anatase is known to form by weathering of titanite and may itself be further altered to rutile by weathering. However, the rutile mineral grains observed to date appear to be primary rutile sources rather than an alteration product of anatase resulting from weathering. 

A typical cross section showing the progression of strongly weathered saprolite to transitional sandstones to fresh bedrock from surface, and their respective titanium mineral assemblages, is shown in Figure 1.

Figure 1.  Cross Section from DD24COS002 showing strongly weathered saprolite, transitional and fresh bedrock zones with respective titanium mineral assemblages.

Mineralogical data from weathered samples at Pitfield

The initial mineralogical and metallurgical studies carried out on fresh bedrock drill samples confirmed titanite as the most abundant Ti-bearing mineral, accounting for approximately 67% of the total contained TiO₂ and making up approximately 20% of the potential ore by mass at Pitfield (RNS: 5 March 2024).

The recent discovery of a new titanium dioxide mineral enriched deposit, located within the weathered "saprolite" cap covering the extent of the giant, 40km long mineral system, has shifted the focus of the mineralogical studies to this weathered cap. This in turn has required a change in analytical techniques to include X-Ray Diffraction (XRD), which is required to accurately identify the relative amounts of rutile and anatase, given that both are titanium dioxide minerals that differ only in terms of crystal structure.

XRD analysis was undertaken on samples from an RC drillhole (RC24COS018) which was drilled at the Cosgrove prospect. This RC drillhole was chosen as it contained up to 13.5% TiO₂ in the weathered zone, as well as some zones of lower (<4%) TiO₂ content. Empire provided 20 laboratory "pulp" samples (ground to <75µm) for XRD analysis that represented the top 40m of the drillhole. 

The top 40m of the drillhole has been logged as:

·    0-2m laterite;

·    2-32m saprolite*; and

·    32-40m transitional sandstone, partially weathered.

*diamond drill core from a nearby hole indicates that this saprolite is a highly weathered sandstone with intensity of weathering decreasing downhole to the "transitional sandstone" noted above.

The XRD data provided important mineralogical and geological insights into the weathering that has occurred at Pitfield and indicates that the dominant titanium mineral in the weathered zone is anatase. The anatase has formed due to the weathering of the original titanite-rich, bedded sediments over time.  The absence of titanite within the strongly weathered zone (0-22m) can be seen in Figure 2.  Below 22m the amount of titanite increases from ~1% of rock mass to 15% of rock mass as the bedrock becomes less weathered and transitions into fresh rock. The anatase content is high in the top 28m, generally above 5%, and at around the 32m mark there is a transition from strongly weathered to less weathered rock where the anatase content diminishes.

Figure 2: XRD data for titanium minerals within RC24COS018

The XRD results also confirmed that the weathering is having a strong effect on other minerals present in the host sandstones. Hematite, quartz and kaolinite are the dominant gangue minerals within the strongly weathered sandstones, whereas albite and chlorite are common within the transitional to fresh bedrock sandstones (Figure 3).

Figure 3.  XRD data for host rock gangue minerals within RC24COS018

The mineralogical analyses indicate that kaolinite is a weathering product of albite and chlorite whereas quartz is also derived from the weathering of albite and chlorite as well as from titanite.  The titanium released by the weathering of titanite went to form the anatase that is now concentrated in this weathered cap zone.  The calcium released in the weathering of titanite was removed from the zone of strong weathering (see further explanation below). It is important to note that the process of weathering, which is essentially a natural, low temperature, weakly acidic leaching process, has efficiently and thoroughly leached titanium from titanite to form a more concentrated titanium mineral product, anatase, which supports the Company's processing tenet that titanium can be simply leached from titanite to similarly form a more concentrated, higher value commercial titanium product.

TIMA analysis uses X-Ray spectra to generate chemical compositions of minerals to determine mineralogy, whereas XRD analysis uses the crystal structure to determine mineralogy and is a more accurate determination for specific minerals. In the case of anatase versus rutile, TIMA identifies both as titanium dioxide minerals and cannot distinguish between the two, as that is a function of crystal structure, not mineral chemistry. The follow up XRD analyses, reported herein, were necessary to accurately establish the relative presence of anatase versus rutile in the weathered cap samples and determined that anatase is the dominant TiO₂ mineral present.

The TIMA results from the four diamond holes drilled in Q1 2024 at the Cosgrove and Thomas prospects show similar trends to the XRD results with regard to titanium dioxide minerals and titanite within the weathered cap zone, with elevated amounts of titanium dioxide but very little titanite present. The TIMA data indicate that the anatase is more concentrated just below the bedrock surface where weathering of the host sandstone is strongest, decreasing downwards through the weathering profile (refer Figure 4).

Figure 4: TIMA data for the weathered zones showing predominant titanium minerals

The TIMA and XRD data sets also clearly support strong weathering patterns with the decrease to absence of certain minerals susceptible to weathering, such as albite and chlorite, and increases in their weathering end-product minerals, kaolinite and quartz, within the same zone of strongly weathered sandstone (refer Figure 5 for TIMA mineral plots).

Figure 5: TIMA data for the weathered zones showing predominant gangue minerals.

Overall, the mineralogical data support the empirical observations from the logging of drill core that shows significantly more kaolinite within the near-surface zone of strongly weathered sandstones than in the fresh, unweathered sandstones below. It also highlights the lack of calcium bearing minerals within the weathering zone, the more mobile calcium having been effectively removed during weathering through natural leaching processes (Figure 6).

Figure 6.  Photo of DD24COS002 from core tray #3 showing kaolinite veining (white) in strongly weathered zone around 5m-6m depth.  Note the weathered reddish sandstone contains the hematite and anatase minerals.

CSIRO Microprobe data on Anatase from Weathered Zone Samples

Published anatase compositions from a variety of mineral deposits globally show a broad range of variations in contained impurity elements. Anatase ores are most commonly derived from the weathering of carbonatites (igneous rocks containing >50% carbonate minerals); such ores commonly have significant impurity levels of radionuclides, alkaline earth metals, rare earth metals, phosphates, niobium and silica, which make then unsuitable for TiO₂ pigment manufacture.  However, high purity, high TiO₂ anatase ores can make very desirable TiO₂ feedstocks but are far less common.

Microprobe data from testing completed at CSIRO on the Pitfield weathered zone samples show that the anatase present has very high TiO₂ contents (up to 98.5% TiO₂), with variable but minor amounts of iron, silica, alumina and vanadium_, and importantly negligible radionuclides, niobium, chromium, phosphorous or other potentially deleterious elements.

The Pitfield anatase samples show the amount of variability for the following impurities for TiO₂ contents ranging between 85% -98.5% TiO₂ :

_·      Al₂O₃ - 0.03 to 2.89%

·    FeO - 0.865 to 4.65%

·    SiO₂ - 1.48 to 8.67%

·    V₂O₃ - 0.07 to 0.99

Commercial Implications for a High Purity Anatase Ore

These results indicate a high purity for potential Pitfield anatase ores from the near surface weathered cap zone, in contrast to many known anatase ores, particularly those mined from carbonatite deposits. If future mineralogical test results continue to verify these initial results it will place Pitfield anatase ores within a very desirable class, as high grade anatase (90-98% TiO₂) ores are considered to be a comparable to rutile , as it is the purity of the feedstock rather than the feedstock mineral that is most important, and both rutile and anatase can be used to make high value products, such as chloride TiO₂ pigment and titanium metal.

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 7).

Figure 7. 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 8). 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 8.  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.

Competent Person Statement

The technical information in this report that relates to the Pitfield Project has been compiled by Mr Andrew Faragher, an employee of Eclipse Exploration Pty Ltd, a wholly owned subsidiary of Empire. Mr Faragher is a Member of the Australian Institute of Mining and Metallurgy. Mr Faragher has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves'. Mr Faragher consents to the inclusion in this release of the matters based on his information in the form and context in which it appears.

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.

About TiPMC Consulting

TiPMC is a leading expert in the TiO₂ and pigments industry, providing technical and pricing and marketing information to a very wide range of industry participants. Gerry Colamarino is the Managing Director of TiPMC and has 45+ years of international experience at DuPont, Iluka Resources, and Bloom Energy.

Empire Metals has engaged TiPMC as a consultant to provide technical and marketing expertise to the Company.