Orosur Mining Inc - Exceptional results at Pepas

·    Assays from nine more holes at Pepas and surrounds. Best results include:

o PEP040 - 10.25m @ 1.35 g/t Au

o PEP041 - 31.75m @ 2.01 g/t Au

o PEP042 - 3.25m @ 4.89 g/t Au

o PEP044 - 38.50m @ 6.01 g/t Au

o PEP045 - 62.3m @ 12.76 g/t Au

o PEP046 - 53.2m @ 3.36 g/t Au

·    Geological studies developing new concepts for later testing.

London, July 17^th 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 flagship Anzá Project ("Project") in Colombia.

Colombia - ANZÁ Project

The Anzá Project is now 100% owned by the Company following completion of a Share Purchase Agreement ("SPA"), announced 28^th November 2024, whereby the Company purchased all of the shares of its previous JV partner; Minera Monte Aguila ("MMA").

The Project, which is located 50km west of Medellin, is easily accessible and boasts excellent infrastructure including water, power and communications as well as a large exploration camp. 

The Project sits within the prolific mid-Cauca belt, Colombia's primary gold belt, and is located along strike between several world class gold/copper deposits including Buritica, Quebradona and Guayabales/Marmato (Figure 1).

From September 2018 to November 2024, the Anzá Project was under the control of its previous JV partner MMA, itself a 50/50 venture between the world's two largest gold miners, Agnico Eagle Mines and Newmont Mining.

Figure 1.  Mid-Cauca Belt

Prospects

The Company is currently focussed on three prospects within the Anzá Project - Pepas, APTA and El Cedro. All three prospects are within the same granted exploration title that is broken into two, non-contiguous pieces (Figure 2).

Drilling is currently being undertaken at the Pepas prospect in the northern extent of the Anzá Project (pre-acquisition) over 10km north of the central base camp at APTA. In parallel, mapping and sampling is being undertaken over the El Cedro porphyry system in the south of the project area.

Figure 2. Main prospects, licences pre-MMA acquisition

Pepas Prospect

Pepas was discovered by MMA in late 2021 by BLEG sampling and geological mapping, followed by 11 diamond drill holes in 2022 (PEP001 to PEP011).

After completion of the transaction to buy MMA ("Transaction"), the Company restarted drilling at Pepas in late-November 2024.

Drilling commenced with hole PEP012, which was positioned to confirm previous high-grade results in holes PEP001, PEP005 and PEP007 drilled in 2022.

Figure 3.  Plan of holes

Drilling at Pepas, post Transaction, has largely concentrated on a small central core, where a body of high-grade gold mineralisation is being defined from surface.   Additional drilling has also been undertaken around this central core to understand the wider geological context and as the commencement of a larger scale exploration program.

Of the nine holes discussed in this announcement, six (PEP038 to PEP043) were drilled around but outside the Pepas core, while three (PEP044 to PEP046) have been drilled as part of the previously announced infill program that is designed to move Pepas to a Mineral Resource Estimate (MRE).

PEP038 was drilled to the north at what is referred to as Pepas North.  This was the third of three holes drilled here as the first move to this area, following up positive surface geochemical results. This hole was drilled orthogonal to the two previous holes, to provide the maximum lithological and structural information.  PEP038 returned a result of 16.8m @ 0.68g/t Au. As with the two previous holes in this vicinity, this hole demonstrates the scale of the epithermal system that hosts Pepas and has provided valuable information to understand the controls of this system.

PEP039 was a speculative exploration hole drilled a substantial distance to the south and west of the Pepas core, following up zones of surface silicification. No substantial results were returned.

PEP040 was drilled outside the known Pepas envelope to the SW, to test lower-level shallow mineralisation previously identified by earlier drilling. The hole returned a small intersection of 10.25m @ 1.35g/t Au from surface (figure 4) that indicates the potential for a body of satellite mineralisation, adjacent to the Pepas core, that will require additional follow up.

Figure 4. PEP040 and PEP046 section

PEP041 was drilled outside the currently known Pepas envelope to the north to test the northward extension of the mineralisation first identified by earlier drilling undertaken by the Company's previous JV partner MMA.  This hole returned a positive intersection of 31.75m @ 2.01 g/t Au, opening this area for potential extension (figure 5).

Figure 5. PEP041 Section

PEP042 was drilled to the NE of the currently known central core of mineralisation as a conceptual hole to test geophysical zones that were identified by the recent airborne magnetic survey. No surface geochemical work has yet been undertaken in this area. Several thin zones of encouraging gold mineralisation were encountered in this hole, well outside the known mineralised core (figure 6).  This result has substantially increased the potential of this area and will now be followed up with surface mapping and sampling, and potentially later drilling.

Figure 6.  PEP042 Section

PEP043 was drilled outside the known mineralised envelope to test areas of surface silicification.  No substantial intersections were recorded

Holes PEP044, PEP045 and PEP045 were all drilled as part of the previously announced MRE infill program at Pepas.

A plan for this program has been developed to infill Pepas to sufficient degree to potentially allow a high level (measured and indicated) MRE to be calculate, but also to assist in understanding the controls upon mineralisation and to better define the very high-grade zones that have the potential to add substantial ounces.

Results from these holes were exceptional, with PEP044 returning 38.5m @ 6.01g/t Au, PEP045 returning 62.3m @ 12.76g/t Au and PEP046 returning 53.2m @ 3.36g/t Au (figures 4 and 7).

The Company feels these results vindicate its decision to begin the resource drilling phase at Pepas, with these exceptionally thick, and high-grade results, substantially upgrading the potential for contained ounces beyond what had been assumed at the commencement of the process.  In addition, the results, particularly that of PEP045, have provided valuable insight to the primary controls upon this mineralisation, suggestive of the main feeder zone being a series of steeply dipper structures along the SW margin of the zone.  The depth extent implications of this theory will be tested in later drilling

Figure 7. PEP044 and PEP045 section

Drill intersections for these most recent holes are as follows:

Table 1. Latest drill Intercepts, Pepas Prospect

Geological Modelling

As previously announced, Company geological teams, in cooperation with an external consultant are currently engaged in a comprehensive review and reinterpretation of all drilling undertaken on the Anzá project since its inception in roughly 2012, with particular focus on the APTA and Pepas prospects as these both have near-term resource potential.

The results thus far are highly encouraging, with recent insights suggesting substantively different genetic theories to that put forward by the previous owners of the ANZÁ project and the Company's previous JV partner.  These concepts are being finalised now, which will lead to exploration plans being formalised to run in parallel with the ongoing resource infill program at Pepas.

Holes Drilled post MMA Transaction

26 holes have been drilled at Pepas since the MMA Transaction in November 2024.

Assay results are tabulated below.

Table 2.  Results to date, post MMA Transaction

Orosur CEO Brad George commented:

"The latest results at Pepas are exciting.  Not only do we continue to expand the area of potential that will require drill follow-up, but the commencement of resource drilling has exceeded all expectations, with some of the thickest and highest grade intersections seen anywhere in the world. We have only just begun."

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

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 2022/2024 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, Argentina and Nigeria.

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, 2024. The Company's continuance as a going concern is dependent upon its ability to obtain adequate financing, to reach profitable levels of operations and to reach a satisfactory closure of the Creditor´s Agreement in Uruguay. These material uncertainties 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.