`

                                      Anzá Activity Accelerating

·    Commencement of drilling at El Cedro

·    Increase in Project size

·    Further drill results from Pepas West and APTA

·    Auger drilling at Pepas West

London, September 2nd, 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").

Anzá - Colombia

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

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

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

·    Pepas - a shallow, high-grade deposit of gold mineralisation for which the Company has calculated a Mineral Resource Estimate ("MRE"), announced February 10^th 2026.

·    APTA - a high-grade deposit of gold mineralisation that has to date seen approximately 40,000m of drilling since 2012, with drilling ongoing. 

·    El Cedro - a cluster of gold/copper porphyry intrusions in the south of the Project area at which drilling has just commenced. 

Figure 1. Anzá Project

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. An extensive area of anomalous soil geochemistry was delineated, as well as channel samples and rock chip samples with assays up to 10g/t Au and 2% Cu.

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 largely confirmed Anglo American's previous work and mapped several large dioritic intrusions and associated epithermal systems.

Post resumption of control of the Project, the Company undertook larger scale surface geochemical surveys during 2025 and early 2026, focussing on identifying structures and epithermal features proximal to the intrusions that could have the potential for higher grade metal accumulations.

Following an extensive period of permitting, socialisation and logistical planning, the first drilling campaign ever undertaken at El Cedro, began in late August 2026, initially targeting the eastern flank of the northern intrusion and the bounding structures and veins.

                                            Figure 2.  El Cedro location

Drilling has only just begun, however a porphyry intrusion was immediately intersected, demonstrating attractive stockwork veining, silicification and potassic alternation. This first hole, CED001, is planned to reach a depth of 500m which is expected to take roughly five weeks to complete.

                                         Figure 3.  El Cedro core

Project Size

Several new licence applications have recently been submitted, taking the total under application to 360km2.  When combined with 170km2 of granted titles, the total Project area is now approximately 530km2.

Several of these new applications lie within forest reserve, or along the banks of the Cauca River and have been made for strategic reasons including to secure the Company's position along the main access road.

Pepas West

The Company's primary focus since reassuming control of the Project in late 2024, was to explore the immediate area of Pepas, ultimately leading to the publication of a maiden MRE for the Pepas gold deposit on February 10^th, 2026.  

Following completion of the MRE drillout in late 2025, the Company then embarked on a semi-regional drilling program around the Pepas deposit. The objective of this drilling program was to better understand the larger scale litho-structural controls that led to formation of the Pepas deposit, such that, in combination with additional mapping and sampling in the wider region, vectors toward additional mineralisation might be developed and ounces added to inventory.

The Company achieved immediate success with a new zone of shallow mineralisation being identified roughly 100m to the west of Pepas - with first results announced on April 14^th, 2026.

Latest drilling at Pepas West (PEP106 and PEP107) have continued to define this zone with the picture now emerging of a surficial, heavily oxidised and possibly remobilised zone of medium grade mineralisation.

Table 1. Latest drill Intercepts, Pepas West and APTA

Figure 4.  Plan of holes, Pepas West

Figure 5. Section, PEP106, PEP107

Figure 6. Long Section, Pepas West

The Company is of the view that Pepas West is worthy of follow up, however the geometry of the zone (surficial, thin and broad) would likely require a large number of shallow holes, a situation that is not well suited to traditional diamond drilling as too much time would be lost in rig moves.  As a result, the diamond rig that has been at Pepas since late 2024, has been relocated to other prospects in the immediate vicinity while geological teams trial the application of an auger system to rapidly take samples of unconsolidated material down to a depth of roughly 10m. 

A trial sampling program has been designed (Figure 7.) the results of which, when completed, will be assessed to determine if this methodology has the potential to move Pepas to Resource status.

Figure 7. Auger trial plan

In addition, subject to results, the auger system may then be employed on a wider scale around Pepas to explore for similar shallow mineralisation that may perhaps be hidden beneath a thin veneer of barren transported cover.

APTA

The APTA prospect in the centre of the Project area has over 40,000m of drilling by various companies since 2012. This work has identified a substantial epithermal gold system.

The current drill plan at APTA is designed to better understand the geological controls upon the previously defined high-grade mineralisation that may then assist in planning a future resource drill out program if results warrant. 

The latest hole, MAP108, was drilled off section from the previous hole and intersected a broad interval of low-grade mineralisation and has provided valuable insight into the delineating structures that control higher grades.

Figure 8. APTA Plan

Drilling is currently focussed on understanding the shallower reaches of the APTA deposit which have thus far seen little further exploration.

Figure 9. APTA drill section

Orosur CEO Brad George commented:

"The Anza project is now ramping up with three rigs running, one at each of Pepas, APTA and El Cedro and planned to remain for  some time.  More prospects are also being advanced to the drill stage, demonstrating the extraordinary potential of this licence holding."

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 McDougall
Tel: +44 (0)20 3657 0050

Flagstaff Communications and Investor Communications

Tim Thompson
Alison Allfrey
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 2022/2026 Programme*

Drill Hole Details - APTA 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 Anza 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 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.