Anzá Operational Update

Anzá Operational Update

Accelerating on Multiple Fronts

London, November 4th, 2026. 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 exploration project at Anzá in Colombia (“Anzá” or the “Project”), at which three drill rigs are currently operating.

Orosur CEO Brad George commented:

“Work at Anzá has ramped up in recent times, accelerating on multiple fronts. With a new government and mining administration in place in Colombia, and with a solid balance sheet, we feel confident we can advance development at Pepas while in parallel moving APTA to resource and exploring the exciting Cedro/Yarumo cluster.”

Anzá – Colombia

The Anzá Project in Colombia comprises a number of granted exploration titles and applications totalling roughly 530km2, within the Mid-Cauca copper/gold belt, west of Medellín.

These titles and applications are 100% owned by two Colombian companies, Minera Anzá, and Minera Monte Aguila, both wholly owned subsidiaries of the Company.

Since acquiring 100% control of the Project in late 2024, the Company has focussed its attention on three prospects:

Figure 1. Anzá Project Location

APTADrilling at APTA continues with the rig currently mid-way through hole MAP111.

Results from holes MAP109 and MAP110 are listed below.

Table 1. Drill Results, APTA

Both holes have returned moderate mineralisation and have added to the geological understanding of the APTA deposit.

Figure 2. Section MAP109

Figure 3. Section MAP110

Following the completion of the current hole (MAP111), a decision has been taken to temporarily suspend drilling at APTA and to shift this rig to Pepas. The reasons for this are two-fold: firstly the portability of this rig is better suited to the new target areas at Pepas that have constrained access, and second, this temporary suspension allows time for planning for the transition to a resource drill out program.

The last several holes drilled at APTA by the Company were designed to examine a number of geological questions to assist in planning a future program of drilling, that if successful could move APTA to a mineral resource estimate (MRE).

The Company now feels that it has sufficient information to commence a formal resource drill out program. Planning of the drill out program and development of access tracks mean that this program will likely commence early in the new year.

It is anticipated that drilling will commence within the core of the highest-grade zones in order to define these to a sufficient level of confidence, as well as targeting undrilled zones with the highest potential for mineralisation.

Figure 4. APTA implicit model

Pepas

Ongoing drilling operations at Pepas have been focused on testing areas of silicification and moderate soil geochemistry to the east and northwest of the deposit.

To the east, several holes were drilled with no significant results, while holes to the NW continue to define a large zone of lower-level mineralisation with grades varying from 0.3 to 0.7g/t Au over an extensive area.

While only of moderate tenor, these results nonetheless assist in developing a greater understanding of the regional scale lithostructural features and geological conditions that have led to the emplacement of Pepas.

Table 2.  Pepas Drill results

Figure 5. Pepas region drilling plan

This picture is emerging, and it is currently postulated that the Pepas deposit sits within a large-scale N-S structural corridor that also hosts both APTA and the El Cedro/El Yarumo complex to the south.

It is considered that the Pepas intrusive sources were emplaced into SE-NW secondary cross structures (Figure 6) during Miocene sinistral reactivation of an older Cretaceous dextral transpressional system. The original cretaceous event developed the underlying structural architecture that upon later reactivation, created dilation zones that were then exploited by mineralising systems.

Beyond structural architecture, it is also considered necessary that the host rocks have been pre-prepared by an initial phase of silicification, that rendered the tuffs brittle, so they then fractured under reactivation, producing an attractive trap for later mineralising fluids.

Figure 6. Pepas Tectonic Setting

Mapping and sampling over the last several months has thus focused on identifying repetitions of the Pepas splay that also demonstrate pre-mineralisation silicification.

A number of such positions have been identified, the most attractive being roughly 800m south of the Pepas deposit. As well as an attractive geological position, mapping and sampling has identified extensive areas of veining with rock chip samples returning multiple g/t Au.

The Company is in the advanced stages of planning to begin drilling here in coming weeks.  As noted, it is planned to undertake this work with the rig currently drilling at APTA, due to its greater portability and flexibility. The rig currently at Pepas will then be demobilised.

El Cedro

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

Post resumption of control of the Project in November 2024, the Company completed larger scale surface mapping programs, geochemical surveys and drone mounted magnetic surveys, focusing on identifying structures and hydrothermal features proximal to the intrusions that could have the potential for higher grade metal accumulations.

First drilling commenced at the El Cedro system on August 26th, 2026.

Figure 7. El Cedro location

The Company has previously announced preliminary assay results from the top 267m in two tranches (15th Sept 2026 and 14th Oct 2026) for a combined composite intersection of 267.4m @ 0.65g/t Au from surface, including 61.35m @ 0.93g/t Au from surface.

However as announced, hole CED001 failed at 267m, in such a way that a substantial length of rods were left in the hole, thus rendering the hole unrecoverable. The decision was taken to restart the hole from surface, from the same pad, but to drill down to the failure depth as quickly and cheaply as possible, so that it could then be continued to the original target depth of 500m.

This process has progressed largely as planned, with the new hole (CED001A) currently well beyond the failure depth of 267m.

It was originally planned that no core would be recovered in the redrilled hole until it reached the depth of the failure. However, as the dip and azimuth of the new hole has deviated slightly from the original, the physical separation between the two is now sufficient to provide useful geological information and thus core began to be recovered again at downhole depth of 200m.

Should drilling progress continue to be positive, the original plan to drill two more holes from this pad remains intact.

New Rig

Given recent drilling difficulties, the Company has begun to examine alternative contracting options. Should this progress, it is anticipated that a second rig could be mobilized to El Cedro in the near term. Local logistics need to be finalized, but the intention is for this rig to be positioned at a second pad that has been previously identified at El Cedro, leaving the current rig to continue at its present location.

CED001 (and CED001A) were positioned on the eastern flank of the El Cedro intrusive system, to examine proximal hydrothermal features that had been exposed in the adjacent creeks.

The second pad is located directly over the intrusive system and with holes intended to test the higher-level cupola of the El Cedro intrusive and veins mapped in old artisanal shafts with grades up to 8g/t Au, before then testing the intrusion itself.

Contract discussions are advancing, but not yet completed. If completed as hoped, the new rig could be mobilized to site in coming weeks.

Figure 8. Planned second pad at El Cedro

El Yarumo

El Yarumo (previously referred to as El Roble) is a newly defined exploration

target located approximately 2.4 km northwest of El Cedro, in the southern part of the Anzá Project (Figure 9)

Systematic geological mapping and surface sampling have defined a structurally controlled area of approximately 500 m × 500 m, hosting multiple subparallel, WNW-trending quartz-sulphide veins and hydrothermal breccias. Veining has been mapped at eight outcrops across a strike length of over 500m, with multiple stacked veins occurring at several locations.

Figure 9. El Cedro and El Yarumo

Mineralisation is characterised by pyrite, arsenopyrite, Fe-rich sphalerite and locally chalcopyrite. Combined historical and recent surface sampling have returned more than 64 samples exceeding 0.1 g/t Au, including 20 samples above 1 g/t Au, with a maximum value of 10.67 g/t Au. Gold mineralisation is frequently observed in association with arsenopyrite-bearing quartz-sulphide veins.

In addition, gold-in-soil anomalies reaching 0.8 g/t Au broadly coincide with the mapped mineralised corridor, further supporting the exploration potential of the area.

Figure 10. El Yarumo Geology

The observed vein textures and mineral assemblages provide evidence of multiple hydrothermal events, including successive episodes of quartz-carbonate veining, sulphide deposition, hydrothermal brecciation and structural reactivation. These features suggest an evolving, multistage mineralising system. The vein mineralogy and textures show geological similarities to epithermal vein mineralisation documented at the Marmato deposit, some 120km south of Anzá in the Mid Cauca belt.

The Company feels that El Yarumo represents a high-priority drill target and planning is underway to develop access and complete the permitting process to allow for drilling likely in Q1 2027, subject to availability of rigs and drilling crews.

Progress on Pepas PTO

As previously announced, the Company has completed the final draft of the required Programa de Trabajos y Obras (Plan of Works) (“PTO”) for the Pepas deposit.

The PTO is a substantial Colombian document that outlines a proposed mining plan that is then submitted to the relevant Colombian authorities, marking the commencement of the permitting and approval process for the development of a mining operation.

A range of processing and transport options have been examined, but all based upon a conceptual base mining case of 500t per day (approximately 175,000t per year) with Pepas material potentially being blended with surrounding lower grade material outside the MRE, suggestive of potential production of approximately 25,000 oz per year for 10 years.

Following recent elections in Colombia, a new administration was established in early August, leading in turn to the appointment of key leadership positions within the mining and associated ministries and departments. The Company will soon present the PTO to these relevant authorities and discuss how these development options fit within the new administrations’ vision for the sector. It is then planned to commission a Preliminary Economic Assessment (PEA) compliant with NI43-101 and undertaken in parallel with the necessary environmental and social permitting activities required to underpin a development at Pepas.

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

Orosur Mining Inc

Louis Castro, Chairman,

Brad George, CEO

[email protected]

Tel: +1 (778) 373-0100

SP Angel Corporate Finance LLP – Nomad & Joint Broker

Jen Clarke / Caroline Rowe / Devik Mehta

Tel: +44 (0) 20 3470 0470

Turner Pope Investments (TPI) Ltd – Joint Broker

Andy Thacker/Guy McDougallTel: +44 (0)20 3657 0050

Flagstaff Communications and Investor Communications

Tim ThompsonAlison AllfreyFergus 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.

Hole Details Pepas Prospect

Hole Details APTA Prospect

Drill Hole Details – El Cedro Prospect

*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.

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 in the case of the Anzá Project, or on site in temporary racks in the case of the El Pantano Project, 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 and MAP-106 onwards are sent to Medellin laboratory of Actlabs for preparation and fire assay, with some sample then sent to the Canadian Actlabs facility for multi element 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 geological 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.