Tiros Measured and Indicated Resource increased by 37%

ASX: RAU TSXV: RSM OTCQB: RSGOF TSXV Release ASX Release 08 April 2025 09 April 2025

Tiros Measured and Indicated Resource increased by 37% to 1.4 billion tonnes at 12% TiO2 and 4,000 ppm TREO

Resouro Strategic Metals Inc. (ASX: RAU; TSX-V: RSM; FSE: 8TX; OTCQB: RSGOF) ("Resouro" or the "Company") is pleased to announce an update to the Tiros Titanium and Rare Earth Elements Mineral Resource Estimate (“MRE”) for the Central Project Block of the Company’s Tiros Project in Brazil (“Tiros Project” or “Tiros” or “Project”).

Highlights

Measured and Indicated Resources increases by almost 37% to 1.4 billion tonnes:

Measured Resources 367 Mt at 12% TiO₂ and 4,100 ppm TREO,

Indicated Resources 1,000 Mt at 12% TiO₂ and 4,000 ppm TREO,

Total Resources 1,400 Mt¹ at 12% TiO₂ and 4,000 ppm TREO

High-grade mineralisation within the MRE:

Measured Resources 30 Mt at 24% TiO₂ and 9,300 ppm TREO,

Indicated Resources 74 Mt at 23% TiO₂ and 8,900 ppm TREO,

Total Resources 104 Mt¹ at 23% TiO₂ and 9,100 ppm TREO

The Measured and Indicated Resource contained metals content includes:

a) 165 Mt of contained titanium dioxide (TiO₂),

b) 5.5 Mt of contained Total Rare Earths Oxide (TREO) at a Magnet Rare Earths Oxide (“MREO”) ratio of 27%

• Includes 1.5 million tonnes contained MREO

1 Refer Appendix 2 JORC Table 1 for rounding explanation

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Overview

The Mineral Resource Estimate (MRE) update is based on additional assays received from a 46 infill and resource expansion drill program conducted in 2024 (refer to ASX releases dated 6^th February 2025 and 17^th March 2025 – TSX-V 5^th February 2025 and 16^th March 2025). The revised MRE, tabled below, represents an increase of 37% of measured and indicated resources (from step-out drilling) and an improved detail of data (from infill drill holes).

	Resource Category	Million tonnes	TiO % 2	TREO (ppm)
Measured 367 12 4,100
Indicated 1,000 12 4,000
TOTAL 1,400 12 4,000

Table 1: Total MRE tonne and grade using a cut-off grade of 1,000ppm TREO (rounding applied, Appendix 2).

The MRE has an area of high-grade titanium and rare earths mineralisation represented in Table 2 and was modelled by applying a cut-off grade of 8,000 ppm TREO.

	Resource Category	Million tonnes	TiO % 2	TREO (ppm)
Measured 30 24 9,300
Indicated 74 23 8,900
TOTAL 104 23 9,100

Table 2: High-grade tonne and grade based on a cut-off grade of 8,000ppm TREO (rounding applied, Appendix 2).

The high-grade Measured and Indicated Resource has been increased by 37% in total for no change in titanium dioxide grade and similar grades for rare earths, Table 3.

Resource Category	Change in	Change in	Change in
	tonnes	TiO % 2	TREO (ppm)
Measured + Indicated +37% 0% -1%

Table 3: The percentage change in Measured and Indicated resources in the high-grade component of the MRE in tonnes, and grade.

The Central Block MRE represents just under 8% of Resouro’s total tenement holding area in the Tiros region which spans four project areas called Tiros North, Tiros Central, and in the south, Sao Gotardo, and Campos Altos (Figure 3).

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The significance of the current MRE and the potential for further prospective resources across all tenements can be visualised in Figure 1 and Figure 2. The Tiros project MRE is substantially larger and higher-grade when compared selectively to other rare earths projects with similar, characteristics or geographic location. This, combined with the potential for resource expansion from exploration, places Tiros as a globally significant resource of both titanium dioxide (Figure

2) and rare earths (Figure 1).

Figure 1: Bubble chart of Tiros total and high-grade MRE for rare earths in comparison to selected peer projects in relation to tonnage of measured and or indicated mineral resources against average grade. The bubble size reflects the metal content calculated as total resource tonnes times average resource grade, refer Appendix 1.

This MRE update marks a significant milestone for the Company, establishing it as home to one of the world’s largest and most significant resources of both titanium dioxide and rare earths. It also highlights a very high-grade mineralisation zone, which will be the focus of the Company’s initial scoping study and subsequent feasibility studies, along with the related economic assessments.

The scale of the titanium resource can be visualised in the Figure 2. Tiros represents one of the largest contained titanium resources when compared to resources by country and contains more than 50% of Brazil’s total known titanium resources.

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Figure 2: Comparing Tiros to a selection of the largest titanium resources by country that are similar in deposit style and satisfy a similar JORC classification. It excludes igneous or metamorphic hard rock resource classifications. China is included for reference but does not have resource with a JORC guideline classification. The Resource for ‘Brazil Other’ are additional to Resouro’s resources. (Source USGS “Critical Minerals of the United States - Titanium, 1802-T, 2017, and this announcement for Tiros data).

Commenting on the increased Mineral Resource Estimate, Resouro’s Executive Chairman, Chris Eager, said:

“The Tiros project continues to deliver amazing results, in terms of large tonnage of high TiO2 and TREO grades within continuous near surface layer of friable material with constant grade and thickness. The next step is to work toward a Proved and Probable Minable Reserves from the 1.4 billion tonnes Measured and Indicated Resource. The flat lying layer of friable material at Tiros translates to ease of mine planning with no drilling or blasting and a low stripping ratio. This facilitates environmentally friendly cut and fill mining with continuous rehabilitation equating to low mining costs with consistent supply of tonnes and grade to a processing plant. Designing and optimising a plant for one consistent feed would assist in maintaining consistent recoveries and processing costs.”

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Figure 3. Resouro’s mineral right holding at Tiros North, Tiros Central, Sao Gotardo and Campos Altos.

Key Resource Parameters

Atticus Geoscience (“Atticus”) has modelled this MRE utilising the results of 152 drill holes across the Tiros central tenements (refer to Figures 4 and 5) including 78 diamond drill holes, 29 air core holes, and 25 auger holes undertaken by Resouro (2023 to 2025) and one (1) diamond drill hole and 19 air core historical drill holes undertaken by previous tenement owners (Vicenza and Iluka, 2011 and 2016).

A conservative assumption of 1,000 ppm TREO (refer to Figure 10) cut-off was applied to the resource estimation which delivered an MRE (Measured and Indicated) of 1.4 billion tonnes @ 4,000 ppm TREO comprising an outstanding 1,100 ppm MREO (oxides of Pr, Nd, Tb, and Dy) and 12% TiO2.

The MRE was limited by aerial topography covering 3,300 ha, which represents approximately 7% of the Resouro tenements that comprise the Project area. The MRE excludes neighbouring Resouro-owned tenements, which indicate further potential for expansion.

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Figure 4: Plan view of the Resouro tenements including the Tiros Projects with the Tiros Central block shown that is the subject of this mineral resources estimate

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Figure 5: Plan view of the Tiros Central block showing drill holes locations

Mineral Resource Estimate

The current Mineral Resource Estimate (Measured and Indicated), at Tiros, applying a 1,000 pm TREO cut-off, presents 1.4 billion tonnes at 12% TiO2 and 4,000 ppm TREO containing 1,100 ppm MREO with a high-grade zone identified as summarised in Table 4. Drilling data to support the high-grade (HG) and medium grade (MG) is detailed in the JORC Table 1 in the Appendix 2. The grade-tonnage curve for the mineral resource estimation is shown in Figure 10.

DOMAIN	Category Million Tonne TiO % TREO (ppm) MREO (ppm) 2					MREO/TREO ratio
HG (High Grade)	Measured	30	24	9,300	2,500	27%
	Indicated	74	23	8,900	2,300	26%
	M + I 103 23 9,100 2,400					26%
	Inferred	33	22	8,300	2,200	26%
MG (Medium Grade)	Measured	340	11	3,700	1,000	28%
	Indicated	930	11	3,600	1,000	28%
	M + I 1,300 11 3,600 1,000					28%
	Inferred	470	11	3,400	920	27%
TOTAL (HG+MG)	Measured	367	12	4,100	1,100	28%
	Indicated	1,000	12	4,000	1,100	27%
	M + I 1,400 12 4,000 1,100					28%
	Inferred	500	12	3,700	1,000	27%

Table 4: Values in the Mineral Resource Statement have been rounded (refer Appendix 2 JORC Table).

Explanatory Note: This announcement has been drafted to comply with the regulations of the Canadian Investment Regulatory Organization and, as such, the Company is

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complying with TSX Policy 3.3 Appendix 3E, National Instrument 43-101 – Standards of Disclosure for Mineral Projects, that disclosure of Mineral Resources or Mineral Reserves must not disclose any information about a mineral resource or mineral reserve unless the disclosure

(a) uses only the applicable mineral resource and mineral reserve categories set out in sections 1.2 and 1.3;

(b) reports each category of mineral resources and mineral reserves separately, and states the extent, if any, to which mineral reserves are included in total mineral resources;

(c) does not add inferred mineral resources to the other categories of mineral resources; and

(d) states the grade or quality and the quantity for each category of the mineral resources and mineral reserves if the quantity of contained metal or mineral is included in the disclosure.

The Company therefore makes statements in this document that does not aggregate inferred resources into measured and indicated but does report inferred resources separately.

Geology and Interpretation

Titanium dioxide and rare earths oxide mineralization are hosted in the Capacete Formation, belonging to the Mata da Corda Group. Titanium dioxide is associated with the mineral anatase, originating from the alteration of perovskite.

The rare earths minerals are distributed throughout the Capacete formation and are a particular mineralogical feature of this volcano-stratigraphic horizon. The Capacete Formation a relatively thin stratigraphic unit (refer Figures 6, 7, 8, and 9) that is comprised of interbedded fine and coarser grained volcanic derived deposits, including what may be ash tuffs, reworked coarse sediments and volcanoclastic breccias.

The formation is the erosion product of the rocks of the Patos Formation, also belonging to the Mata da Corda Group. The Patos Formation represents a voluminous stratigraphy of Upper Cretaceous kamafugite pyroclastic flows and deposits, hosted in the Brasília Belt, southwest of the São Francisco Craton.

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Figure 6: Section view (A-A) of the Tiros deposit showing the major lithological units (ARG - Areado Group, CAF – Capacete Formation, URG – Urucuia Group/ Tertiary Cover, DLO – Detritus-Lateritic Overburden), and drill holes coloured by TREO, and TiO2 coloured in the bars.

Figure 7: Section view (B-B) of the Tiros deposit showing the facies of the principal lithologic units, (ARN - Arenite, CGL – Conglomerate, GGV – Gravel/ Sediments Gravel, LAT – Laterite, MAR – Magnetic Arenite, SOG – Soil General, SSD – Sand/sediment Sand), and drill holes coloured by TREO, and TiO2 coloured bars.

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Figure 8: Section view (C-C) of the Tiros deposit showing the weathering / oxidation model, (FRS – Fresh, MOX – moderately oxidised, SOX – Strongly Oxidised, WOX – Weakly Oxidised), and drill holes coloured by TREO and TiO2 as coloured bars.

Figure 9: Section view (D-D) of the Tiros deposit showing the block model coloured by TiO2% within the major lithological units. (only the Capacete (CAF) formation has been blocked and estimated).

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Drilling Techniques

Three (3) types of drilling were carried out on the Project: diamond, air core and auger drilling. The following is a breakdown of the three types of drill holes used in the MRE.

Historical drilling included Vicenza (2011), who completed a single diamond drill hole (HQsize), oriented vertically and reaching 82.45 m. Nineteen 75 mm diameter air core drill holes were undertaken by the Iluka-Vicenza JV and totalled 914 m with depths of up to 60 metres.

Auger drilling undertaken by Resouro totalled 9 drill holes of 100 mm diameter, totalling 86.5 m and with depth of the holes up to about 15 metres. Air core drilling by Resouro totalled 23 holes totalling 1,425.5 m and up to depths of 85 metres. Diamond drilling (HQ-size) by Resouro totalled 78 drill holes totalling 5290 m with depths up to 110 metres. All holes were vertical and with depths below 110 m, therefore no trajectory measures were collected, and deviation of the holes is presumed to be negligible.

Sampling and Sub-Sampling Techniques

Samples were taken from diamond, air core, and auger drill holes. All drilled material was sampled, with nothing being discarded. The sampling intervals were chosen based on geological description during logging of the drill core and pulverized cuttings. The samples were collected according to industry best practice procedures.

Measures to ensure sample representativity, include setting up of a specific sampling procedure and having a dedicated-on-site full-time survey team. A QA/QC program was implemented across all drilling campaigns and in the resampling of air core holes.

Best practices of drill core recovery and depth marker audits were adhered to during drilling and sampling. The diamond drilling recovery was verifying by matching the drill core lengths against the recoveries recorded in the core boxes. For auger and air core drilling, verification was undertaken by weighing chip bags using industry standard work procedures.

Diamond drill core samples (HQ-size core), with an average length of 1.00 metre, were split in half using a spatula, and then in half again, with one quarter of the material sent for chemical analysis and the remaining three quarters stored in the secure core storage shed. The historical air core sample cuttings are from 1m long intervals, originally analysed with a portable XRF by Iluka-Vicenza Joint Venture, were re-analysed by Resouro sending 1.0 kg average weight samples to SGS laboratories in Belo Horizonte. Auger samples are all 1.0 metre long with all material being sent for analysis. The sampling and QA/QC were planned by the geologists and care was taken to avoid any contamination between neighbouring samples.

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Sample Analysis Method

All drilling and sampling data has been verified, validated and imported into a SQL Server cloud-based data management system, including data and meta-data on the collar, survey, lithology, alteration, density and assay samples. Information from all the drill holes in the resource area were used in the geological modelling and resource calculation, a total of 5,615 samples.

The majority of the samples have been analysed in the SGS Geosol laboratories, using the laboratory method ICP95A for the major rock component elements and their oxides, and the laboratory method IMS95A for the rare earth elements ("REEs"): Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Er, Ho, Lu, Tm, Yb, and Y, as well as U and Th. For the purpose of evaluating their distribution and modelling, the REEs have been grouped by calculating and combining assay values for the heavy ("HREO") and light ("LREO") oxide factions and then summing these values to obtain a Total Rare Earth Oxide ("TREO").

The calculation of the HREO, the LREO and TREO is completed within the database and exported as three new columns ready for analysis and modelling. Below are the details of the formula used in calculating the HREO, LREO and TREO:

HREO: ([Dyppm]*1.1477) + ([Erppm]*1.1435) + ([Euppm]*1.158) + ([Gdppm]*1.1526) + ([Hoppm]*1.1455) + ([Luppm]*1.1371) + ([Tbppm]*1.1761) + ([Tmppm]*1.1421) + ([Ybppm]*1.1386) + ([Yppm]*1.2699)

LREO: ([Ceppm]*1.1712) + ([Lappm]*1.1727) + ([Ndppm]*1.1664) + ([Prppm]*1.2081) +
([Smppm]*1.1596) MREO: has been reported as a metal equivalent, using the calculation of: MREO: ([Prppm]*1.2081) + ([Ndppm]*1.1664) + ([Tbppm]*1.1761) + ([Dyppm]*1.1477)
		MREO:
	([Prppm]*1.2081) + ([Ndppm]*1.1664) + ([Tbppm]*1.1761) + ([Dyppm]*1.1477)

TREO: HREO + LREO

Estimation Methodology and Cut-off Grade Selection

The estimation of the mineral resource is broken down into the following stages:

• Validation of the information utilized in the resource and database compilation.
• Interpretation and 3D modelling of the lithology, oxidation and mineralization.
• Development of the estimation domains.
• Compositing of grade within the domains.
• Exploratory data analysis.
• Block model definition.
• Interpolation of grade within the defined domains.

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