Orosur Mining Inc - Operational Update.  Exploration Footprint Expanding

·    Assays for three holes from the Pepas MRE infill and metallurgical program include:

o PEP065 - 33.3m @ 2.84g/t Au

o PEP065B - 33.8m @ 2.79g/t Au

o PEP066 (met hole) - 112m @ 5.25g/t Au from surface

·    Resource consultants plan to be on site next week to begin the MRE process.

·    Soil geochemistry completed at El Cedro, high grade potential confirmed.

·    Second Porphyry identified at El Cedro - to be examined in future programs, with a view to drilling early in 2026.

·    Airborne magnetic/radiometric survey planned over area.

·    Drill rig arrives at the El Pantano Project Argentina to commence first drill program.

London, October 30th, 2025. Orosur Mining Inc. ("Orosur" or the "Company") (TSXV/AIM:OMI), is pleased to announce an update on the progress of exploration activities at the Company's gold exploration projects at Anzá in Colombia ("Anzá) and El Pantano in Argentina.

Anzá - Colombia

The Anzá Project in Colombia comprises a number of granted exploration titles and applications totalling roughly 330km2, within the Mid-Cauca gold belt, west of the city of Medellin.

These titles and applications are owned by two Colombia companies, Minera Anzá, and Minera Monte Aguila, both of which are wholly owned subsidiaries of the Company. The latter of these companies was acquired by Orosur in November 2024 from the Company's previous JV partners, Newmont Mining and Agnico Eagle Mines.  Orosur thus owns 100% of the Anzá Project.

Since acquiring 100% control, the Company has focussed its attention on three prospects:

·    Pepas - a shallow, high-grade body of gold mineralisation that the Company is endeavouring to move to an initial Mineral Resource Estimate in the near term.

·    APTA - a high-grade body of gold mineralisation that has to date seen 38,000m of drilling, but is not yet sufficiently understood geologically to allow a MRE to be calculated.  The Company plans to undertake additional drilling at APTA in late 2025 with the objective of advancing it toward an MRE as quickly as possible.

·    El Cedro - a large gold porphyry system in the south of the Anza Project area. The Company has just completed a large sampling program and plans to undertake a maiden drill program here in early 2026.

Figure 1. Anzá Project

Pepas

As announced on 14^th July 2025, the Company took the formal decision to commence infill drilling at its Pepas gold prospect at Anzá, with the objective of moving Pepas to a NI43-101 compliant Mineral Resource Estimate (MRE) by the end of the year.

Drilling progress has recently slowed largely due to issues related to broken ground in hole PEP065 and the need to reconfigure the drill rig for PQ metallurgical drilling followed by the subsequent expected slower pace of advance for this larger diameter core.

Hole PEP-066 was a hole drilled to provide material for detailed metallurgical testing - the hole was drilled using a wider diameter PQ bit to provide additional material for testing and was drilled through the centre of the ore body so as to provide material representative of all mineral domains thus far identified. In order for all domains to be intersected, it was necessary to drill into known ore zones, and thus PEP-066 was drilled very close to several previous holes that had returned high grade intersections.

These three holes have all returned exceptional high grade gold assay results.

Table 1. Latest drill Intercepts, Pepas Prospect

* Hole PEP065 collapsed in broken ground and was redrilled as PEP-065B from the same pad, at a steeper angle

Figure 2.  Plan of holes

Figure 3. Section, PEP065 and 65B

Figure 4. Section, PEP066

El Cedro

The El Cedro prospect lies to the south of the same integrated licence that hosts both Pepas and APTA and is roughly 4km south of the APTA base camp.

Work on the area began some years before Orosur's tenure, when Anglo American undertook reconnaissance mapping and sampling, identifying a highly prospective gold/copper porphyry system.

Little work was then undertaken until late 2021, when the Company's previous JV partner MMA re-entered the area to carry out mapping, sampling and ground geophysics that confirmed Anglo American's previous work and mapped several large dioritic intrusions and associated epithermal systems.

The Company subsequently began a large-scale soil geochemical survey in May 2025, planned to cover most of what was thought to be the extent of the porphyry system.  Soil samples were taken at roughly 25m intervals, along ridges and spurs for ease of access and to ensure soils were residual.

This survey has just been completed, with gold assay results identifying a substantial, gold bearing system, with highly anomalous geochemical responses over a large, well preserved zoned porphyry system, with soil samples assays at times exceeding 1g/t Au.

Figure 5. El Cedro Soil Samples

Company geological teams have examined these new geochemical data, in conjunction with historical mapping information and airborne geophysical data collected in 2012.  An outcome of this work is the hypothesis that El Cedro may in fact consist of multiple porphyry intrusions, with a second potential intrusive system being identified to the south of the known El Cedro porphyry, within the same regional structural corridor.

Of additional interest is apparent associated epithermal systems marginal to both porphyries, with high-grade gold in rock chips having been previously recorded in veins.

Figure 6. El Cedro, multiple porphyry bodies, soils and rock chips

Figure 7. Regional tectonic setting

The Company is now planning additional mapping and soil sampling programs over this southern porphyry.  In addition, it has been determined that the older airborne geophysical data, while of value, were of moderate quality and thus it is planned that a more detailed helicopter aeromagnetic and radiometric survey will be undertaken in November or December this year to provide an added layer of lithostructural information about these intrusive systems, the associated epithermal systems, and APTA to the north.

It is expected that drilling at El Cedro could commence in first quarter of calendar 2026.

NI-43-101 Technical Report

The Company's geological consultants are currently well advanced in reviewing all exploration work undertaken at Anzá since the last NI43-101 technical report was published in 2019. An external team is due on site in the first week of November to finalise this program and to observe and assess all of the QAQC processes and procedures.

The primary objective of this work program is the development of an updated NI43-101 Technical Report which may, if deemed appropriate by the consultants, include a Mineral Resource Estimate for the Pepas prospect.

El Pantano - Argentina

The El Pantano Project is an early-stage gold/silver exploration project in Santa Cruz province, southern Argentina.

The Project comprises approximately 550km2 of contiguous granted licences in the prolific Deseado Massif of Santa Cruz, roughly 45km from Anglo Gold's Cerro Vanguardia mining camp and 90km SE of Newmont Mining's giant Cerro Negro mine.

The El Pantano Project is subject to an Exploration & Joint Venture ("JV") agreement ("Agreement") with private Argentinean company DESEADO DORADO S.A.S and its shareholders ("Deseado"), the details of which were announced on February 15^th 2022.

The Company currently owns 51% of El Pantano, having met its obligation to spend US$1m in exploration expenditure by February 2025. The Company is now in Phase 2 of the joint venture, whereby it may earn an additional 49% equity in the project (taking the Company to 100% ownership) by investing US$2m in the two years to February 2027.   Upon such an event, the original vendors would retain a 2% NSR royalty, 1% of which the Company could purchase for US$1m at its discretion.

At the time the JV commenced, the El Pantano project was a largely untouched grass roots gold/silver exploration project.  Some historical sampling and geophysics had been done in the SE of the project, but 80% of the project area had never been explored and no drilling had ever been undertaken anywhere within the Project area.

The Company entered the JV on the basis of regional geological data and field mapping that indicated the potential for a major, previously unknown district-scale low-sulphidation epithermal system. 

Post signing, the Company immediately began the process of geological mapping, geochemical sampling and geophysics across the licence package. 

This work was completed in late 2024, with all work to date confirming our geological hypothesis that El Pantano is a highly prospective, untouched epithermal system.

Figure 8.  El Pantano geology and geochemistry

The Company has taken the decision that the Project is drill ready.  A camp has been established in this remote region and a diamond drill rig will arrive on site this week, with a plan to commence drilling in coming days.

The Company has planned a 3000m diamond drilling campaign across various sections of the identified 25km long epithermal structure, targeting geochemical and geophysical anomalies.  It is expected this program will continue into late January 2026, allowing for the Christmas break.

This drilling program is designed purely to be reconnaissance in nature.  No drilling has ever been undertaken on the El Pantano property, and while surface geological data are encouraging, information related to the vertical zonation is required to develop the exploration model.

Orosur CEO Brad George commented:

"Post our recent capital raising, Orosur is now free to explore.  Our strategy of geological selection, 100% ownership and examining near term production is paying dividends, positioning us well in this buoyant gold market".

For further information, visit www.orosur.ca, follow on X @orosurm or please contact:

Orosur Mining Inc

Louis Castro, Executive Chairman

Brad George, CEO

[email protected]

Tel: +1 (778) 373-0100

SP Angel Corporate Finance LLP - Nomad & Joint Broker

Jeff Keating / Jen Clarke / Devik Mehta

Tel: +44 (0) 20 3470 0470

Turner Pope Investments (TPI) Ltd - Joint Broker

Andy Thacker/James Pope
Tel: +44 (0)20 3657 0050

Flagstaff Communications and Investor Communications

Tim Thompson
Mark Edwards
Fergus Mellon

[email protected]

Tel: +44 (0)207 129 1474

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 ('MAR') which has been incorporated into UK law by the European Union (Withdrawal) Act 2018. Upon the publication of this announcement via Regulatory Information Service ('RIS'), this inside information is now considered to be in the public domain.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Drill Hole Details - Pepas prospect 2022/2025 Programme*

*  Coordinates WGS84, UTM Zone 18

About Orosur Mining Inc.

Orosur Mining Inc. (TSXV: OMI; AIM: OMI) is a minerals explorer and developer currently operating in Colombia and Argentina.

About the Anzá Project

Anzá is a gold exploration project, comprising three exploration licences, and a large number of licence applications, totalling 399km2, in the prolific Mid-Cauca belt of Colombia.

The Anzá Project is currently wholly owned by Orosur via its subsidiaries, Minera Anzá S.A. and Minera Monte Aquila S.A.S.

The project is located 50km west of Medellin and is easily accessible by all-weather roads and boasts excellent infrastructure including water, power, communications and large exploration camp.

Qualified Persons Statement

The information in this news release was compiled, reviewed, verified and approved by Mr. Brad George, BSc Hons (Geology and Geophysics), MBA, Member of the Australian Institute of Geoscientists (MAIG), CEO of Orosur Mining Inc. and a qualified person as defined by National Instrument 43-101.

Orosur Mining Inc. staff follow standard operating and quality assurance procedures to ensure that sampling techniques and sample results meet international reporting standards.

Drill core is split in half over widths that vary between 0.3m and 2m, depending upon the geological domain. One half is kept on site in the Minera Anzá core storage facility, with the other sent for assay.

Industry standard QAQC protocols are put in place with approximately 10% of total submitted samples being blanks, repeats or Certified Reference Materials (CRMs).

Samples for holes PEP-001 to PEP-011 were sent to the Medellin preparation facility of ALS Colombia Ltd, and then to the ISO 9001 certified ALS Chemex laboratory in Lima, Peru.

Samples from PEP-012 onwards are sent to Medellin laboratory of Actlabs for preparation and assay.

30 gram nominal weight samples are then subject to fire assay and AAS analysis for gold with gravimetric re-finish for overlimit assays of >5 g/t.  ICP-MS Ultra-Trace level multi-element four-acid digest analyses may also undertaken for such elements as silver, copper, lead and zinc, etc.

Gold intersections are reported using a lower cut-off of 0.3g/t Au over 3m.

Intersections are quoted as downhole thicknesses.  True thicknesses are unknown.

Forward Looking Statements

All statements, other than statements of historical fact, contained in this news release constitute "forward looking statements" within the meaning of applicable securities laws, including but not limited to the "safe harbour" provisions of the United States Private Securities Litigation Reform Act of 1995 and are based on expectations estimates and projections as of the date of this news release.

Forward-looking statements include, without limitation, the continuing focus on the Pepas prospect, the exploration plans in Colombia and the funding of those plans, and other events or conditions that may occur in the future. There can be no assurance that such statements will prove to be accurate. Actual results and future events could differ materially from those anticipated in such forward-looking statements. Such statements are subject to significant risks and uncertainties including, but not limited to, those described in the Section "Risks Factors" of the Company's MD&A for the year ended May 31, 2025. The Company's continuance as a going concern is dependent upon its ability to obtain adequate financing. This material uncertainty may cast significant doubt upon the Company's ability to realize its assets and discharge its liabilities in the normal course of business and accordingly the appropriateness of the use of accounting principles applicable to a going concern. The Company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events and such forward-looking statements, except to the extent required by applicable law.