• First new hole at APTA (MAP-106) returns 229.7m @ 0.88g/t Au.

• Numerous higher-grade intervals within broader intersection, including:

o 6.85m @ 2.15g/t Au

o 59.2m @ 2.15g/t Au

o 7.65m @ 7.07g/t Au

o 4.7m @ 3.95g/t Au

• Results have substantially enhanced the prospectivity of APTA with three areas of potential requiring follow up.

LONDON, GB / ACCESS Newswire / June 9, 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 totalling roughly 330km², within the Mid-Cauca gold belt, west of the city of Medellín.

These titles and applications are owned by two Colombian companies, Minera Anzá, and Minera Monte Aguila, both wholly owned subsidiaries of the Company. The latter of these 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 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 almost 39,000m of historical drilling, and at which drilling has recently recommenced.

• El Cedro - a cluster of gold porphyry intrusions in the south of the Project area that are currently subject to mapping and sampling programs, with a view to potentially being drilled in the near term.

APTA
The APTA prospect in the centre of the Project area has seen almost 39,000m of drilling by various companies since 2012. This work has identified a substantial epithermal gold system.

The last phase of drilling was undertaken by the Company's previous JV partner, MMA, from late 2020 through early 2022, at which time the abatement of Covid related operational restrictions allowed MMA field crews to begin to explore the wider Anzá project area. Results from the final holes of this phase of work were announced on 27^th June 2022.

Upon assuming control of the Project in November 2024, the Company focused most of its resources on exploration at the Pepas prospect, ultimately leading to a MRE being calculated and announced in February 2026.

However, during this drill-out phase, Company field teams also undertook mapping and sampling programs at the El Cedro prospect and desktop reassessment of significant previous drilling undertaken at the APTA prospect.

APTA was the original prospect upon which the Anzá Project was based. Gold mineralisation was originally discovered underneath a small artisanal gypsum mine, leading to sporadic drilling through to 2022. Despite many holes intersecting substantial intervals of very high-grade gold mineralisation, there remained substantial debate as to the underlying geological model and controls upon mineralisation. As a result, despite almost 39,000m being drilled, no MRE was ever calculated.

Work by Company geological teams in early 2026, developed new geological concepts whereby gold mineralisation was thought to be constrained within silicified sediments and volcaniclastics bound by two large faults roughly 100m apart, that together make up the Aragon fault zone and acted as conduits for gold bearing fluids.

Hole MAP-106 was collared outside the fault zone to the west and oriented to intersect the footwall fault, thought to be the main fluid conduit which would then intersect the mineralised zone at a much shallower depth than previous drilling, eventually targeting previously defined mineralisation at depth. However, the footwall fault zone presented substantial drilling challenges resulting in some redrilling and adjustment to the planned azimuth, with the final hole being referred to as MAP-106A.

The hole intersected gold mineralisation almost immediately upon passing the footwall fault, at a vertical depth of roughly 70m, with mineralisation continuing for a considerable distance for a composite intersection of 229.7m @ 0.88g/t Au (Table 1)

Within that broad lower grade intersection there were numerous higher-grade intersections consistent with and expanding upon previous drilling (Table 2). The exact controls upon these higher-grade zones are still being assessed but are likely, as with Pepas, to be related to various phases of silicification and mineralising events within the volcaniclastic core.

Table 1. Drill intersection MAP106A

Table 2. Previous historical intersections, APTA

The desktop review and the results from MAP-106A have modified the Company's thinking of the origins of APTA and substantially increased its prospectivity, with three areas of potential now requiring follow-up (Figure 3).

Figure 3. APTA follow-up

Firstly, this hole has confirmed and expanded the potential scale of the deeper, higher-grade mineralisation that was defined by previous drilling (Area A). Previous work has defined a mineralised zone over 1km in length and up to 100m in width, although poddy in nature. This hole has greatly assisted in better understanding the controls upon this mineralisation and future drilling will be planned to expand and then infill this zone.

Secondly, no shallow drilling has ever been undertaken within the fault bound mineralised zone, and minimal surface geochemistry has been undertaken as the zone is hidden by barren transported cover. However, one small, mineralised outcrop was mapped historically, opening the possibility that gold mineralisation could extend to near surface (Area B). A program of shallow drilling will be developed to better understand this shallow, bulk tonnage potential.

Thirdly, a narrow, hanging wall mineralised vein (Area C) had been defined by previous drilling but never examined as previous work was focused on the thicker mineralisation at depth. However, this vein seems to show reasonable continuity, as well as sufficient grade and thickness to potentially be amenable to exploitation. Additional drilling will be required to expand the scale of this vein system.

Orosur CEO Brad George commented:

"APTA was always tantalising but misunderstood as previous drilling was never pulled together into a coherent picture. After almost 15 years, this is now being done, and looking exciting."

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
Caroline Rowe / Jen Clarke / 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 - APTA prospect since 2020 *

*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.

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

Samples 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 0.1g/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.

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact [email protected] or visit www.rns.com.

SOURCE: Orosur Mining Inc