Pepas moving into MRE drilling programme

• Orosur moving to parallel streams - exploration and resource drilling.
• Rig now infill drilling Pepas as precursor to MRE.
• Decision based on positive conceptual studies.
• Geological consultants on site to develop required geological models for both Pepas and APTA.

London, July 14th 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.

The Company announces that it has taken the formal decision to begin a work program that, if successful, is designed to allow a Mineral Resource Estimate (MRE) to be calculated at its Pepas gold prospect, within the Anzá gold project area in Colombia.

This decision has been taken on the basis of external conceptual studies that suggest the location and physical characteristics of the gold mineralisation so far defined at Pepas, in the context of record high gold prices, may offer potential nearer term production opportunities.

This decision does not stop exploration at Pepas, the wider Anzá project or the Company's El Pantano project in Argentina. The Company is confident that both exploration and resource definition streams can be run in parallel within the limits of the Company's financial, human and technical resources. The primary impact is that the single drill rig currently employed on the Project has been diverted toward infill drilling within the current boundary of known high grade gold mineralisation at Pepas. During this time, geological studies and additional surface field work will be undertaken at Pepas and other prospects so that targets are ready for the rig to move back to regional exploration once the resource infill is completed.

Colombia - ANZÁ Project

Figure 1. Mid-Cauca Belt

Prospects

Pepas and North Pepas Prospects

The Pepas prospect is in the far north of the Anzá project and was discovered by the Company's previous JV partners, 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, the Company restarted drilling at Pepas in late-November 2024.

Since reassuming control of the Project in December 2024, the Company has released assay results from 26 holes (PEP012 to PEP037), most of which were concentrated in and around the central core of near-surface high-grade gold mineralisation.

Figure 3. Plan of holes, core Pepas zone.

This small, but thick and high-grade zone of mineralisation has developed very quickly since the Company reassumed control, and while the surrounding areas remain largely unexplored, the Company feels that what has thus far been defined is worthy of economic study, especially in the current gold price environment.

Geological Modelling and Economic Studies

As previously announced, encouraged by the exceptional results at the Pepas prospect, the Company has begun the process of geological modelling and preliminary economic assessment at Pepas.

The characteristics of Pepas that encouraged the Company to begin the process of conceptual study are its high grade, surficial nature, thickness, availability of power to site, proximity to the main regional highway without having to pass through villages, and the existence of numerous nearby mines and processing facilities that might offer the opportunity for third party toll treating.

The Company carried out its own internal geological resource models and high-level concept studies, the results of which the Company felt were sufficiently positive that it then engaged an external mineral consulting firm to model preliminary pit shells in order to assess if Pepas warranted further study. The results of this high-level conceptual study were positive and have led to the Company making the formal decision to examine Pepas in more detail, with the ultimate objective of determining if a near term production option can be developed at Pepas in its current form.

Resource Drilling

The first stage in this process is the creation of a Mineral Resource Estimate (MRE) at Pepas, that can then be used as the basis for later economic evaluation. To that end, one of the outputs of recent work was the development of an infill drilling plan that, if successful, could be sufficient to allow an MRE to be calculated. Ultimately, the amount of drilling required to develop an MRE will be subject to results and may be modified during the infill drilling process. However, at this preliminary stage, the Company feels that between 1,500m and 2,000m of additional drilling should be sufficient.

The single drill rig that the Company has on site at Anzá, has been moved back to infill drilling at Pepas. On current production rates, it is expected that this plan should be completed in November 2025, assuming no major modifications being necessary following analysis of results.

Once completed, subject to results and the availability of consultants for the required QAQC visits to the Project, the Company is targeting December 2025 for completion of this process and publishing of an MRE at Pepas.

Geological Assessment

In addition to drilling information, an MRE, in accordance with NI43-101, also requires a robust and defensible geological model to underpin the interpolation and extrapolation of information between and beyond drill holes. To date, the Company has not been able to develop such a model at Pepas due to the speed with which drilling and results have progressed since the Company reassumed control in December 2024. Drilling thus far has focussed on defining a shallow, potentially economic orebody, with Company drilling since December 2024 limited to some 80m vertical depth.

To satisfy this MRE requirement, an external geological consultant, specialising in structural geology and metamorphic petrology, has travelled to the Anzá project to spend several weeks with Company geological staff examining all of the historical drilling undertaken at Pepas and APTA since the Company acquired the project in late 2014.

The objectives of this visit and program are three-fold:

• Develop a geological model to underpin a potential MRE at Pepas.
• Understand the wider Pepas epithermal system, and in particular, define the litho-structural controls upon the exceptionally high-grade mineralised zone at Pepas and plan a targeting methodology to guide exploration toward finding repetitions and source feeder zones.
• Develop a geological model to explain the controls upon the very high-grade mineralisation historically defined at the APTA deposit at Anzá to facilitate an MRE being defined at APTA.

APTA

The APTA deposit lies in the centre of the Anzá project and has been the subject of most exploration activity on the project, with some 38,000 metres of drilling having been completed.

APTA is thought to be a hybrid mineralised system with an earlier VMS system being overprinted by later epithermal events. However, most historical work at APTA has been undertaken either by the Company's predecessor (Waymar Resources) or by its previous JV partner (MMA), both of which focussed on drilling, with minimal geological interpretation.

Numerous thick, high-grade gold intersections have been recorded at APTA (Table 2), that have defined several distinct high-grade ore pods, separated by lower grade halo material. Internal and external modelling have suggested that a NI43-101 MRE could potentially be possible at APTA as it stands now, but with limited understanding of the controls upon these high-grade pods, any MRE would be conservative. Therefore, one of the objectives of the current geological site visit by, is to work with internal geological teams to better understand these high-grade zones and so allow any future MRE to better reflect the impact of these zones.

An outcome of this geological study may be the recommendation for more drilling to underpin this new geological model, and as such any move toward an MRE will be dependent upon outcomes of this study and any subsequent work programs.

Wider Exploration Work

As noted, moving Pepas toward an MRE is not a fundamental shift in the Company's direction, but rather a temporary adjustment to drilling priorities for several months. While this process is underway, field mapping and sampling will continue at other prospects in readiness for the rig moving back to exploration once the infill is complete.

Drilling at Pepas North and elsewhere in the Pepas region has indicated that Pepas is part of a much larger epithermal system consisting of wider scale low grade halo mineralisation and at least one discrete high-grade pod. One stated outcome of the current geological visit is to derive an understanding of the controls upon the high-grade zones, and as importantly, the likely source feeder zones. The outcome of this study will likely be a work program of surface sampling and mapping that may provide drill targets around Pepas.

As announced, soil sampling at the El Cedro porphyry system at Anzá has been delayed due to seasonal rains and road access issues. Sampling will recommence once access has been reestablished.

The Company's early stage El Pantano gold exploration project in Argentina is drill ready. The Company is currently negotiating with local drill companies and examining options for camps, with a view to commencing drilling before the end of the calendar year.

Best drill intersections at Pepas - previously announced

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

Assay results are tabulated below.

Table 1. Best drill intersections, Pepas.

Best drill intersections at APTA - previously announced.

Table 2. Best intersections, APTA

Orosur CEO Brad George commented:

"The Company has made huge strides in the seven months since reassuming ownership and control of Anzá. To be now able to consider moving to a MRE and thence into feasibility in such a short space of time is unheard of, and testament to the tremendous work by our team on the ground."