Orosur drills 62.3m @ 12.76g/t Au at Pepas

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 17th 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

Figure 1. Mid-Cauca Belt

Prospects

Figure 2. Main prospects, licences pre-MMA acquisition

Pepas Prospect

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

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."