ALDE.V · 2025-10-30 12:00:00

Aldebaran PEA for the Altar Project Reports 48 Year Mine Life, After Tax NPV (8%) of US$2 Billion, and 20.5% IRR

Economic Studies

TSX-V: ALDE, OTCQX: ADBRF

October 30, 2025

Aldebaran PEA for the Altar Project Reports 48 Year Mine Life,

After Tax NPV (8%) of US$2 Billion, and 20.5% IRR

VANCOUVER, CANADA (October 30, 2025) – Aldebaran Resources Inc. (“Aldebaran” or the “Company”)

(TSX-V: ALDE, OTCQX: ADBRF) is pleased to announce the results of a Preliminary Economic Assessment

(“PEA”), prepared in accordance with National Instrument 43-101 standards, for the Altar copper-gold project located

in San Juan, Argentina. The base case scenario utilizes a 60,000 tonnes per day (“tpd”) concentrator, processing

mineralized material from both open pit and underground sources. The results of the PEA are reported on a 100%

basis, while Aldebaran owns an 80% interest in the project, with the remaining 20% held by Sibanye-Stillwater Ltd.

All dollar amounts referenced herein are in US dollars unless otherwise noted.

HIGHLIGHTS

Long life operation with significant production:

• 48-year mine life, including 3 years of construction

• First 20 years1: Average annual production of 121,445 tonnes copper equivalent2 (“CuEq”)

o 108,579 tonnes copper (“Cu”), 43,199 ounces of gold (“Au”), and 570,217 ounces of silver (“Ag”)

• First 30 years1: Average annual production of 116,294 tonnes CuEq

o 105,897 tonnes Cu, 33,866 ounces of Au, and 557,239 ounces of Ag

• LOM: Average annual production of 101,413 tonnes CuEq

o 92,891 tonnes Cu, 27,020 ounces of Au, and 525,192 ounces of Ag

Robust economics with leverage to commodity prices:

• Using base-case metal prices of $4.35/lb Cu, $2,500/oz Au, and $27/oz Ag, the project has an after-tax NPV

(8%) of $2.0 billion, an IRR of 20.5% and a payback period of 4 years

• Total LOM gross revenue of $44.7 billion (before TC/RCs, payabilities and transport) and total LOM free

cash flow of $10.7 billion

• Using spot prices of $5.00/lb Cu, $3,963/oz Au, and $47/oz Ag, the project has an after-tax NPV (8%) of

$3.34 billion and an IRR of 28.0%4

Attractive capital intensity:

• Initial capex for the project is $1.59 billion

o Upfront capital is minimized by taking a staged approach to the tailings storage facility and

underground construction

• Capital intensity of $15,713/t of average annual CuEq metal produced3

• NPV @ 8% / Initial Capex ratio of 1.27x

Competitive cost profile:

• Cash Costs (C1) of $1.71/lb payable Cu for the first 20 years1, $1.87/lb payable Cu for the first 30 years1,

and $2.02/lb payable Cu for the LOM

• All in Sustaining Costs (“AISC”) of $2.25/lb payable Cu for the first 20 years1, $2.42/lb payable Cu for the

first 30 years1, and $2.59/lb payable Cu for the LOM

Combined Open Pit and Underground Operation:

• Production from the open pit pays back the initial capital, while development of the underground is ongoing

• Underground mining pulls forward better grade mineralization earlier in the mine life, to increase production

and generate cash flow

• ~80% of the resources (by tonnage) in the mine plan are categorized as Measured and Indicated, with the

remaining ~20% categorized as Inferred

John Black, Chief Executive Officer of Aldebaran, commented: “This PEA confirms that the Altar project has the

potential to become a long-life, high-quality copper operation capable of generating substantial production and cash

flow. Our objective was to define a mine plan that delivers a minimum of 100,000 tonnes of CuEq per year, while

maintaining a compact operational footprint and a disciplined approach to capital. The results of this study clearly

achieve those objectives and demonstrate that Altar is a technically and economically robust project. This PEA

represents a major milestone for the Company and provides the foundation for our upcoming application for inclusion

under Argentina’s RIGI investment framework. With the political environment in Argentina shifting toward pro-

business and pro-development policies—as underscored by the recent mid-term election results—the timing for

advancing a project of Altar’s scale could not be better. The country is positioning itself to emerge as a significant

copper producer at a time when global demand for the metal continues to rise. In addition to the base case

concentrator scenario, our collaboration with Nuton, a Rio Tinto venture, demonstrates Nuton® Technology as a

potentially viable processing alternative at Altar. Utilizing Nuton® Technology, life-of-mine capital expenditure and

operating costs were reduced, leading to higher life-of-mine free cash flow. When you combine the economic results

with the ESG benefits of Nuton’s sulphide leaching technology, the Nuton case is quite compelling and warrants

further evaluation. The next 12 to 18 months will be transformative for the Company, with multiple key catalysts—

including a resource update, completion of the PFS, and the proposed Centauri Minerals spin-out—positioning us to

unlock significant value for our shareholders.”

Kevin B. Heather, Chief Geological Officer of Aldebaran, commented: “The PEA represents a significant

milestone for the Altar project. In addition to achieving the goals John stated above, we were also focused on

maximizing NPV and IRR, hence we elected to move forward with a mine plan that included a combination of open-

pit and underground block caving. The block cave, commencing production after the open pit pays back the initial

capital, allows us to pull forward higher-grade material in the mine plan and to maintain constant CuEq production

numbers, while keeping throughput at 60,000 tpd. Moreover, it keeps the overall footprint of the operation smaller,

which is a key consideration for development projects. Our approach to capital expenditures was to stage capital

outlays where possible, to ensure initial capital expenditures were kept manageable. Where possible, capital was paid

out of cash flow to present a more prudent and attractive development opportunity. We will now begin to shift our

focus to the PFS, which will be the next step in de-risking the Altar project. To that end, our 2025/2026 field program

is now underway, with most of the work focused on collecting the additional data necessary for the upcoming PFS.

This includes additional infill drilling, geotechnical drilling, lab-based geotechnical stress and strain test work, Acid

Based Accounting (ABA) test work, environmental monitoring, water wells, water balance studies, community

engagement, and more. While this work is ongoing, we will also be exploring several opportunities that we have

identified that could potentially unlock additional value from the Altar Project.”

PEA Overview

When available, readers are encouraged to read the PEA in the Company’s technical report (“Technical Report”)

prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“43-101”)

in its entirety, including all qualifications, assumptions and exclusions that relate to the PEA and mineral resource

model. The Technical Report is intended to be read as a whole, and sections should not be read or relied upon out of

context.

The PEA envisions a combination of open-pit and underground mining, followed by processing via a conventional

copper flotation circuit having a nameplate processing capacity of 60,000 tonnes per day. This results in a mine life

of 48 years with an average annual production of 102,742 CuEq tonnes for LOM, 116,539 tonnes CuEq for the first

30 years, and 121,748 CuEq tonnes for the first 20 years. Table 1 presents key operating and financial highlights from

the PEA, using base study case assumptions of $4.35/lb Cu, $2,500/oz Au and $27/oz Ag. Figure 1 displays annual

CuEq production for the LOM, while Figure 2 displays projected cash flows.

Table 1. PEA Summary

Metric Unit Base Case

Mine Life (including construction) Years 48

After Tax NPV - 8% M USD 2,009

IRR (after tax) % 20.5%

Payback Years 4

Averal annual production (LOM) tonnes CuEq 101,413

Averal annual production (LOM) M lbs CuEq 224

Averal annual production (years 1-30) tonnes CuEq 116,294

Averal annual production (years 1-30) M lbs CuEq 256

Averal annual production (years 1-20) tonnes CuEq 121,445

Averal annual production (years 1-20) M lbs CuEq 268

LOM Gross Revenue5 M USD 44,738

LOM Free Cash Flow M USD 10,632

Initial capital M USD 1,593

Capital Intensity USD/tonne CuEq 15,713

NPV/Initial Capex Ratio 1.27

Construction Period Years 3

LOM capital M USD 5,651

C1 Cash Costs (LOM) USD/lb Cu Payable 2.02

C1 Cash Costs (years 1-30) USD/lb Cu Payable 1.87

C1 Cash Costs (years 1-20) USD/lb Cu Payable 1.71

AISC (LOM) USD/lb Cu Payable 2.59

AISC (years 1-30) USD/lb Cu Payable 2.42

AISC (years 1-20) USD/lb Cu Payable 2.25

Throughput tonnes per day 60,000

LOM Cu Recovery % 87.76%

LOM Au Recovery % 57.00%

LOM Ag Recovery % 50.00%

LOM Open pit strip ratio waste/mineralized 1.53

LOM Open pit mineralized tonnes mined M tonnes 223

LOM Open pit Cu grade % 0.44%

LOM Open pit Au grade g/t 0.07

LOM Open pit Ag grade g/t 1.18

LOM Block cave mineralized tonnes mined M tonnes 768

LOM Block cave Cu grade % 0.50%

LOM Block cave Au grade g/t 0.07

LOM Block cave Ag grade g/t 1.61

LOM Recovered Cu M lbs 9,420

LOM Recovered Au M Oz's 1.24

LOM Recovered Ag M Oz's 24.16

Figure 1 – LOM CuEq Production and C1 Cash Costs

Figure 2 – Project Cash Flows

Mineral Resource Estimate

On November 25, 2024, the Company announced an updated mineral resource estimate (“MRE”) for the Altar project

(see Table 2). The PEA is based on the MRE; however, the PEA production profile is based on a subset of the MRE,

utilizing different metal prices, operating costs, and mining methods.

Table 2. 2024 Altar Resource Estimate - $13.99 NSR Cut-off (0.24% CuEq)

Average Grade Contained Metal

Material

Type

Category Tonnes

(000's)

(%)

(g/t)

(ppm)

(M lbs)

(M Ozs)

Supergene

Measured 121,884 0.55 0.08 1.07 21 289 1,475 0.3 4.2

Indicated 80,007 0.36 0.06 0.93 19 123 639 0.2 2.4

Total M&I 201,891 0.47 0.07 1.01 20 223 2,114 0.5 6.6

Inferred 24,850 0.46 0.07 1.01 19 213 251 0.1 0.8

Mixed

Measured 109,510 0.38 0.07 1.22 23 192 913 0.2 4.3

Indicated 19,208 0.32 0.06 1.11 23 139 136 0.0 0.7

Total M&I 128,718 0.37 0.07 1.20 23 184 1,049 0.3 5.0

Inferred 1,386 0.29 0.07 1.00 13 111 9 0.0 0.0

Hypogene

Measured 549,385 0.41 0.10 0.98 20 120 4,966 1.7 17.3

Indicated 1,517,339 0.42 0.05 1.33 54 114 13,882 2.6 64.9

Total M&I 2,066,724 0.41 0.07 1.24 45 116 18,848 4.3 82.2

Inferred 1,189,513 0.37 0.04 1.26 46 96 9,572 1.6 48.2

Total

Measured 780,779 0.43 0.09 1.03 21 156 7,354 2.3 25.8

Indicated 1,616,554 0.41 0.05 1.31 52 115 14,657 2.8 68.0

Total M&I 2,397,333 0.42 0.07 1.22 42 128 22,011 5.1 93.8

Inferred 1,215,749 0.37 0.04 1.25 45 98 9,832 1.7 49.0

Notes:

a. The Altar mineral resource was updated during 2024.

b. All mineral resources are contained in pit geometries.

c. Mineral resources for Altar are based on metal prices of $3.75/lb copper, $1,800/oz gold, $23.00/oz silver.

d. There are no mineral reserves at Altar at this time.

e. Cut-off grades are based on calculations of net smelter return (NSR) assuming the processing by flotation to produce a

copper concentrate and smelting of that concentrate.

f. The Altar NSR is defined as:

Copper Contribution:

• Float recoverable copper grade x 22.0462x(3.75-TCRC) less 1% smelter deduct

• Floatation recoverable copper grade = (copper grade – 0.01) *0.92

Gold Contribution:

• (Gold grade in ppm x 0.55 /31.1035) x (1800-4.00) less 1 gram smelter deduct

Silver Contribution:

• (Silver grade in ppm x 0.50/31.1035) x (23.00 -0.30) less 30 grams smelter deduct

g. Arsenic grades vary by block in the model and smelter terms, including arsenic penalties, vary by block. Average smelter

terms, including arsenic penalties for the 2024 Altar Mineral Resource, is approximately $0.71/lb copper.

h. The equivalent copper cutoff grade of 0.24% CuEq was calculated based on the economics discussed in these footnotes and

differs from the calculation of CuEq discussed elsewhere in this press release. The equivalent copper cut-off grade

calculation is approximate due to the complexities of arsenic penalty calculations by block.

i. Tables may not balance exactly due to rounding.

j. The Qualified Persons for the mineral resources are John Marek RM-SME, and Jacob Richey PE, of Independent Mining

Consultants, Inc.

Mining

The proposed mining method is divided into open-pit mining for the near-surface part of the deposit and underground

caving for the deeper parts. The open pit will use well-known truck and shovel operations with 12.5-m bench intervals.

Haul trucks will be used for hauling mineralized material to the crushing plant and long -term stockpile facilities.

Waste rock will be hauled to the closest waste rock storage facility. Underground operations will handle material in

bulk using well established block caving methods. Open-pit mining will occur during the first 9 years of operation (in

the Altar Central area), while underground development is underway. The mining profile for the project can be seen

in Figure 3.

Open pit mining operations will use a smaller-scale equipment fleet that includes 8 m3 hydraulic excavators and 100t

capacity SANY haul trucks to allow for narrower bench phases and haul roads, steeper pit slopes, which will facilitate

getting into the better-grade, highest-margin mineralization sooner. Underground block cave mining will occur in

three areas: Altar East, Altar United, and Altar Central (beneath the open pit). Each underground cave is divided into

two lifts, an upper and lower, which will be sequenced as follows: Altar East Upper, Altar United Upper, Altar Central

Upper, Altar East Lower, Altar United Lower and Altar Central Lower. Underground access to the block caving

mining areas will be through a portal and conveyor drift from the south of the proposed pit (twin declines). To develop

the first block cave lift at Altar East, two 3000 m declines are required plus associated development beneath the cave

lift.

Figure 3. Mining profile for the LOM

Processing

Extensive metallurgical test work has demonstrated that the contained copper and gold can be effectively recovered

in a traditional flotation concentrator that would produce a single gold-bearing copper concentrate using industry-

accepted technologies. The flowsheet includes primary crushing followed by grinding in a SAG (semi-autogenous

grinding) mill/ball mill grinding circuit, rougher flotation, regrinding of the rougher concentrate and three stages of

cleaner flotation. The concentrator would be constructed with a capacity to process 60,000 tpd and operated on a 365

day/year, 24 hour/day schedule. A simplified process flowsheet can be seen in Figure 4. LOM average recoveries for

Cu, Au and Ag are 87.76%, 57% and 50% respectively. The grade of the concentrate produced is 26% for the LOM.

Arsenic in the concentrate is expected to range from 0.5% to 2.2%. Aldebaran hired the CRU Group, a global leader

in commodity research and market analysis, to complete a study analyzing the placement of arsenic-bearing

concentrates into the marketplace, which showed that blending capacity for arsenic-bearing copper concentrates

worldwide has increased materially in recent years, and penalties paid for arsenic-bearing concentrates have decreased

substantially. The PEA utilizes CRU’s view on arsenic penalties.

Figure 4. Processing Circuit

Capital and Operating Costs

The capital cost estimate prepared for the PEA includes an installation cost associated with the site infrastructure,

open pit mine and concentrator plant, a growth capital associated with the installation of the block caving underground

mining operation, and the sustaining capital associated with the production plan. The LOM summary of capital is

presented in Table 3, while the capital profile for the LOM is presented in Figure 5.

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Cyclone Feed

Sump

Cyclone Ball Mill

U'flow

O'flow

Flotation Reagent Regind Mill

Conditioners

Rougher Flotation Ro. Conc. Regrind Cyclone

Scav Conc. Sump

U'flow

Scavenger Flotation Regrind Cyclone

Cl Scav Conc.

Scav. Tailing O'flow

Process Water O'flow Tailing Thickener Cl -1 Flotation Cl Scavenger Flot. Cl Scav Tailing Tailing Storage

Tank Facility

U'flow Cl-2 Tail

Cl-2 Flotation

Tailing Storage

Facility Cl-3 Tail

Cl-3 Flotation

Conc. Thickener

Conc. Filter

Conc. Load-Out

Table 3. Altar Capital Cost Summary

Type Unit Cost

Initial Open Pit Capex M USD 350

Initial Processing Capex M USD 579

Initial Infrastructure Capex M USD 665

Total Initial Capex M USD 1,593

Growth UG Capex M USD 227

Total Initial + Growth Capex M USD 1,821

Sustaining Capital M USD 3,830

Total LOM Capital M USD 5,651

Figure 5. Capital Profile for the LOM

Operating costs were estimated for the open pit mining operation, block caving mining operation, the concentrator

processing operation, and G&A. A summary of the estimated operating costs is presented in Table 4. The buildup of

LOM C1 cash costs and AISC can be found in Tables 5 and 6, while operating costs by year can be found in Figure

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