CEO.CA Chairman's Briefing

Extension of Pepas West

• Results from six holes released, including:

  • PEP101 - 6.4m @ 2.81g/t Au from surface

  • PEP102 - 6.85m @ 2.18g/t Au from surface

  • PEP103 - 10.2m @ 5.77g/t Au from surface

  • PEP104 - 19.8m @ 1.77g/t Au from surface

  • PEP105 - 15m @ 2.03g/t Au from surface

• Confirmation of extensive, flat lying body of mineralisation - will test different drilling techniques to accelerate definition.

LONDON, UK / ACCESS Newswire / August 5, 2026 / Orosur Mining Inc. ("Orosur" or the "Company") (TSXV:OMI)(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 totalling roughly 330km², 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 body of gold mineralisation that has to date seen approximately 40,000m of drilling, with drilling ongoing.

• El Cedro - a cluster of gold porphyry intrusions in the south of the Project area. Extensive mapping and sampling programs have been undertaken and a rig is currently being mobilised to commence the first drill program ever undertaken at the prospect.

Figure 1. Anzá Project

Pepas
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.

Drilling has continued sporadically at Pepas West, with occasional pauses to allow access tracks to be developed, however results from these six additional holes (PEP100 to PEP105) continue to demonstrate an extensive zone of surficial, high grade gold mineralisation.

Table 1. Latest drill Intercepts, Pepas West Prospect

Figure 2. Plan of holes, Pepas West

Initial drilling at Pepas West had suggested the zone was geologically similar to Pepas, with the same mineralising events, but with a different, parallel structural setting.

Recent drilling, however, is developing a more complex picture with the higher-grade surficial mineralisation seemingly a mix of in situ and heavily weathered material that has potentially remobilised downslope from Pepas.

While deeper zones remain unresolved, a picture is emerging of a flat lying, surface mineralised zone of perhaps 10m thick, over a wide area, with mineralisation starting from near surface, grading between 1 and 5g/t Au, and often obscured beneath a thin veneer of barren transported soil.

The zone is extensively weathered, with scattered enclaves of fresh quartz veins, with very little residual geological or structural texture remaining and, as such, the original litho-structural setting is difficult to determine. Additional drilling and geological studies will be undertaken to endeavour to understand the genesis of Pepas West.

The Company considers this free digging, flat lying, surficial, high grade oxide gold mineralisation to be a high priority in a near-term production scenario, from the point of view of cost and time required to define, develop and mine. Thus, instead of the currently employed diamond-core drilling, the Company will examine the potential of utilising a smaller auger rig to more rapidly define the volume and grade of this extensive surface zone, while also examining the potential for an auger system to be used on a regional basis to sample beneath transported cover. This trial is expected to commence in coming weeks.

The current diamond rig will remain on site and be focussed on deeper drilling around Pepas West and other targets.

Figure 3. Long Section, Pepas West

Figure 4. Section PEP101

Figure 5. Section PEP102, PEP103

Figure 6. Section PEP104, PEP105

Orosur CEO Brad George commented:

"The geological nature of Pepas West is complex as a result of mixing of totally weathered and transported material. However, the grade is there which in the end is all that matters. With Pepas entering feasibility and permitting, additional cheap ounces are worth their weight in gold."

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

Orosur Mining Inc
Louis Castro, Chairman,
Brad George, CEO
info@orosur.ca
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
orosur@flagstaffcomms.com
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*

*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 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.

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SOURCE: Orosur Mining Inc