Nickel Prospect Update: Early Indications of Significant Mineralisation

/THIS NEWS RELEASE IS NOT FOR DISTRIBUTION TO UNITED STATES SERVICES OR FOR DISSEMINATION IN THE UNITED STATES./

VANCOUVER, May 9, 2023 - Macarthur Minerals Ltd. (TSXV: MMS) (ASX: MIO) (OTCQB: MMSDF) (the Company or Macarthur) is pleased to report an update on the nickel prospectivity at its Lake Giles Project in Western Australia.

• A review of historical drilling assay data has identified 319 drill holes, within MIO tenure, with highly anomalous nickel 0.1% or greater, including 150 drill holes recording 0.2% and greater indicating that there is significant potential for nickel mineralisation.
• Historical drilling mainly targeted iron ore with approximately 50% of the drilling not yet analysed for nickel and associated elements.
• The key geological unit that is interpreted to host the potential for nickel at Lake Giles is a komatiite ultramafic unit with similarities to the Lake Johnston komatiite system hosting the rich Maggie Hays nickel mine (ASX: POS).
• Significant Ni intercepts from historical drilling and trench sampling highlight the potential for economic Ni mineralisation at Lake Giles, including:
• LGRC_0010 (288m): 128m @ 0.17% Ni (from 108m) including 1m @ 0.29% Ni;
• LGRC_0015 (168m): 106m @ 0.15% Ni (from 62m) finished in anomalous Ni;
• LGRC_0018 (370m): 103m @ 0.16% Ni (from 77m) and 23m @ 0.17% Ni (from 235m);
• LGDD_054 (363m): 23.5m @ 0.85% Ni (from 4.5m) including 11.5m @ 1.03% Ni (from 10.5m); and
• Gossanous outcrop with grab samples assaying 2.61% Co and 2.01% Ni.
• Seven advanced targets have been identified that are considered highly prospective for nickel mineralisation and these remain completely untested.
• Further interrogation of the historical geological, geophysical and geochemical dataset is likely to define more highly prospective nickel targets and is likely to lead to the definition of nickel mineralisation within the Lake Giles Project Area.
• 41 diamond drill holes completed by Macarthur in 2019 across the Moonshine and Moonshine North targets have intersected numerous altered komatiites, which are yet to be assayed.
• Macarthur now plans to carry out specific nickel targeted exploration including assaying the geotechnical diamond drill core and selected anomalous RC chips for a broad analytical suite of elements, Downhole Electromagnetic surveying (DHEM) on targeted open holes, as well as further ground-based electromagnetic surveying upon recommendation from Newexco.
• Macarthur is seeking potential partners to accelerate a Ni discovery within the Lake Giles Project.

Cameron McCall, Chairman of Macarthur Minerals commented:

"Since the completion of the Lake Giles Iron Project Feasibility Study, the Company has been actively assessing the nickel prospectivity of the project area and has identified seven nickel prospects within our Lake Giles Project. The region is currently undergoing extensive nickel exploration, with Dreadnought Resources active in the surrounding area. The Yerilgee Greenstones are unique as they remain the only untested Greenstone belt in the Yilgarn Craton for nickel sulphides. There were a few pleasant surprises with broad intercepts of altered komatiites that appear prospective for nickel that were noted within the geotechnical diamond drilling in Moonshine as part of our magnetite feasibility study that we are excited to get analysed with a nickel focus"

The Lake Giles Project ("The Project") is located approximately 150 km northwest of the town of Kalgoorlie, 240km North of Poseidon Nickel Ltd Lake Johnston Nickel Project (ASX: POS) and 190km northwest of the Kambalda nickel province in WA (Figure 1). Additionally, the Lake Giles Project is surrounded by Dreadnought Resources Ltd Central Yilgarn Project (ASX: DRE) where they are actively exploring for nickel and gold.

The Project is owned by Macarthur Iron Ore Pty Ltd, a 100% owned subsidiary of Macarthur Minerals Ltd. ("Macarthur" or "the Company").

The Project is primarily an advanced iron ore project, with a completed feasibility study to use conventional open pit mining methods for a series of banded iron formation (BIF) hematite and magnetite prospects.

The Lake Giles tenements cover the Yerilgee greenstone belt located in the central part of the Southern Cross Province of the Yilgarn Archaean Craton. The region is characterized by lenticular greenstone belts often partly enveloped by foliated and gneissic granitoids. Regionally the greenstone belts consist of metamorphosed ultramafic, mafic and sediments, including BIF which are Archean in age and are commonly intruded by mafic, intermediate, and granitic rocks.

The prospective ultramafic rocks of the Project are interpreted to be of Kambalda komatiite type. Serpentinised olivine cumulate rocks sometimes metamorphosed to talc-carbonate occur in many places and are considered to have a high potential for the discovery of nickel sulphides. These have similar characteristics to those of the Forrestania and Lake Johnston greenstone belts. The Lake Johnston nickel mineralised bodies such as Maggie Hays, are hosted within a Kambalda style ultramafic komatiite, which is an upturned volcanic flow against a basaltic basal unit.

In Geoscience Australia's 2016 report¹ on the 'Potential for intrusion-hosted Ni-Cu-PGE sulfide deposits'¹ they highlighted the potential as moderate to high for either or both tholeiitic intrusion-hosted and komatiite-hosted Ni-Cu-PGE sulfide deposits within the Yerilgee Greenstone Belt and hence the Lake Giles Ni Project.

The tenements were briefly and only partially explored for nickel from 1968 to 1972 during the Nickel Boom, and then for gold from 1974 to 1978. Macarthur and its predecessor Internickel Australia Pty Ltd have controlled the area since 2000, undertaking some limited nickel and gold exploration before focusing on iron ore.

A combination of available historical data, recent geological, geophysical, and geochemical data obtained in the course of Macarthur's extensive geological investigation of the Banded Iron Formation ("BIF") for iron ore potential, has indicated that there is potential for nickel sulphide and gold mineralisation within the extensive ultramafic rock package hosting the BIFs that comprise the Macarthur Iron Ore Project.

A review and evaluation of geological, geochemical and geophysical data obtained in the course of Macarthur's extensive geological investigation of the Lakes Giles Project for iron ore potential, has identified extensive and highly prospective nickel exploration targets. This includes several advanced targets considered highly prospective for the discovery of sulphide style nickel, all of which remain completely untested (see Figure 2).

Drilling by Macarthur of the iron formations has demonstrated a potential for disseminated and potentially massive nickel sulphides in these overlying komatiitic ultramafics at Lake Giles, with further potential for concentrated secondary nickel in the weathered profile overlying the fresh komatiites.

Significant Ni intercepts from historical drilling completed by Macarthur have highlighted the potential for economic Ni mineralisation at Lake Giles, including:

• LGRC_0010 (TD - 288m): 128m @ 0.17% Ni (from 108m) including 1m @ 0.29% Ni;
• LGRC_0015 (TD - 168m): 106m @ 0.15% Ni (from 62m), finished in anomalous Ni;
• LGRC_0018 (TD - 370m): 103m @ 0.16% Ni (from 77m) and 23m @ 0.17% Ni (from 235m);
• LGDD_054 (TD - 363m): 23.5m @ 0.85% Ni (from 4.5m) including 11.5m @ 1.03% Ni (from 10.5m);
  and
• Gossanous outcrop with grab samples assaying 2.61% Co and 2.01% Ni.

Forty-one geotechnical diamond drill holes completed by Macarthur across the Moonshine and Moonshine North targets have intersected numerous altered komatiites that appear prospective for nickel, which are yet to be assayed. The drill core is stored on site and requires detailed logging, cutting and analysis. This work will begin shortly.

Further targets are recommended for follow up based on drill assay anomalies and historical geophysical anomalies associated with potentially significant highly magnetic ultramafic footwall 'bulges', which are interpreted to represent a thickening and embayment of the komatiite flow into the footwall stratigraphy.

Nickel exploration on the Lake Giles tenure is at an early stage. Much of the Lake Giles nickel boom exploration data together with recent observations suggest a favourable environment for the occurrence of nickel mineralisation. An updated knowledge of regolith characteristics together with the factors influencing the primary occurrence of nickel sulphide deposits and their frequent remobilisation during folding and faulting is now likely to result in much more efficient and focused exploration than in the past nickel booms.

Further interrogation of the historical geological, geophysical and geochemical dataset is likely to define more highly prospect nickel targets and has high potential for the definition of nickel mineralisation within the Lake Giles Project Area.

Macarthur is currently preparing to carry out specific nickel targeted exploration including assaying the prospective intervals from the geotechnical diamond drilling for a broad analytical suite of elements, Downhole Electromagnetic surveying (DHEM) on targeted open holes, as well as further ground-based electromagnetic surveying upon recommendation from third party geophysical consultants Newexco Exploration Pty Ltd.

Macarthur is seeking potential partners to accelerate a Ni discovery within the Lake Giles Project.

Released On behalf of the Board of Directors, Mr Cameron McCall, Executive Chairman and CEO

Exploratiion Results

Mr. Tom O'Malley, a member of the Australian Institute of Geoscientists, is a self-employed consultant to Macarthur and is a Qualified Person as defined in National Instrument 43-101. Mr O'Malley has reviewed and approved the technical information relating to exploration results contained in this news release.

Mineral Resources:

The Mineral Resources for the Lake Giles Iron Project disclosed in this press release have been estimated by Mr. David Williams, BSc (Hons), a member of the Australian Institute of Geoscientists. Mr Williams, an employee of CSA Global Pty Ltd and Independent Qualified Person, has reviewed and approved the above technical information relating to the Mineral Resource estimates contained in this release, in the form and context in which it appears.

Mineral Reserves:

The information in this report relating to Mineral Reserves is based on information compiled by Stephen Craig, a Fellow of the Australasian Institute of Mining and Metallurgy. Mr Craig is a full-time employee of Orelogy Consulting Pty Ltd. Mr. Craig 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 an independent Qualified Person as defined by NI43-101. Mr Craig consents to the inclusion in the report of the matters based on their information in the form and context in which it appears.

Macarthur is an iron ore development, gold and lithium exploration company that is focused on bringing to production its Western Australia iron ore projects. The Lake Giles Iron Project mineral resources include the Ularring hematite resource (approved for development) comprising Indicated resources of 54.5 million tonnes at 47.2% Fe and Inferred resources of 26 million tonnes at 45.4% Fe; and the Lake Giles magnetite resource of 53.9 million tonnes (Measured), 218.7 million tonnes (Indicated) and 997 million tonnes (Inferred) as filed in NI43-101 Technical Report for the Feasibility Study². Macarthur also holds 24 square kilometre tenement area iron exploration interests in the Pilbara region of Western Australia. In addition, Macarthur has lithium brine Claims in the emerging Railroad Valley region in Nevada, USA.

Certain of the statements made and information contained in this press release may constitute forward-looking information and forward-looking statements (collectively, "forward-looking statements") within the meaning of applicable securities laws. All statements herein, other than statements of historical fact, that address activities, events or developments that the Company believes, expects or anticipates will or may occur in the future, including but not limited to statements regarding expected completion of the Feasibility Study; conversion of Mineral Resources to Ore Reserves or the eventual mining of the Project, are forward-looking statements. The forward-looking statements in this press release reflect the current expectations, assumptions or beliefs of the Company based upon information currently available to the Company. Although the Company believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and no assurance can be given that these expectations will prove to be correct as actual results or developments may differ materially from those projected in the forward-looking statements. Factors that could cause actual results to differ materially from those in forward-looking statements include but are not limited to: unforeseen technology changes that results in a reduction in iron or magnetite demand or substitution by other metals or materials; the discovery of new large low cost deposits of iron magnetite; the general level of global economic activity; failure to complete the FS; inability to demonstrate economic viability of Mineral Resources; and failure to obtain mining approvals. Readers are cautioned not to place undue reliance on forward-looking statements due to the inherent uncertainty thereof. Such statements relate to future events and expectations and, as such, involve known and unknown risks and uncertainties. The forward-looking statements contained in this press release are made as of the date of this press release and except as may otherwise be required pursuant to applicable laws, the Company does not assume any obligation to update or revise these forward-looking statements, whether as a result of new information, future events or otherwise.

1. Macarthur Minerals Ltd.. (2019, December 05). Replacement Prospectus. Western Australia: TSXV Release.
   
   
2. Macarthur Minerals Ltd.. (2020, March 24). Macarthur set to advance Moonshine nickel prospect with EIS co-funded drilling. Western Australia: TSXV Release.
   
   
3. Macarthur Minerals Ltd.. (2020, March 25). Macarthur seek Venture Partner to further explore its nickel projects in Western Australia. Western Australia: TSXV Release.

Grab sample by Macarthur was announced to the TSX on March 5, 2018, "2.6% COBALT AND 2.0% NICKEL DISCOVERED AT MACARTHUR MINERALS' LAKE GILES IRON ORE PROJECTS IN WESTERN AUSTRALIA". This detailed the locations and setting of the grab samples.

The majority of the soil and auger samples were captured by Amax Exploration (Australia) Inc, who held 74 separate Mineral Claims over a period from mid-1968 to late 1970. Together they were termed the Johnson Rocks claims. Amax continued with its nickel exploration program elsewhere and in 1969 discovered an outcropping nickel gossan that led to the discovery of the Forrestania nickel deposits, also in the Southern Cross Province, approximately 300km to the south.

Initial exploration during 1968 and 1969 included reconnaissance geological mapping, gridding and soil sampling. This was followed up with ground magnetics surveys, IP (induced polarisation) surveys, auger drilling and finally two programs of percussion drilling. A comprehensive final report is available (Wamex report A3911). All geochemical samples were assayed for Ni and Cu, and the auger samples were also assayed for Cr, Co and Zn. Most of the data has been able to be transcribed into digital format.

Soil samples were taken at 100 foot intervals over most of the gridded area. The ~80 mesh fraction of each sample was analysed for copper and nickel and the results plotted and contoured at a scale of 1000 feet = 1 inch

Auger drilling here, however provided serpentinite nickel values. Copper was contoured at 90 ppm and was found to coincide with anomalous nickel values at nine locations in the three grid areas that covered large portions of the Lakes Giles Project, see Figure 3.

These surface sample locations are shown in Figure 3.

Clark Hill, Moonshine and Snark MLEM and FLEM Surveys - Macarthur Minerals 2018. Between the 30th of May and the 24th of June 2018, Moving Loop Time Domain Electromagnetic (MLEM) and Fixed-Loop Electromagnetic (FLEM) surveying was undertaken at the Lake Giles Project for Macarthur Iron Ore Pty Ltd (Macarthur).

Surveying covered three prospect areas; Clark Hill, Moonshine and Snark. Surveying was designed to detect bedrock conductor sources proximal to the basal contact of mapped ultramafic flows/sequences identified by Macarthur from nickel and copper in soil geochemistry and airborne magnetics. Surveying was completed by Vortex Geophysics under the supervision of Newexco Services Pty Ltd. See Figure 4.

Drilling from 2,369 drill holes has been databased and broken down by Macarthur tenement in Table 2 and nickel target area in Table 3.

The Macarthur drilling includes 70 diamond and partial diamond drill holes, with the distribution shown in Figure 5. The drill holes containing nickel assays are also displayed in Figure 6.

All drill collars are further listed in Appendix 2.

SOURCE Macarthur Minerals Ltd.