Opening new fronts at Anzá

• Aeromagnetic survey commenced over Pepas
• Access north of Pepas being developed
• Pepas metallurgical samples submitted for preliminary analysis
• Planning advanced major soil program at El Cedro

London, March 10th, 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.

ANZÁ Project

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

As such, the Company has only been back in control of the Project for less than four months.

Figure 1. Mid-Cauca Belt

Prospects

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.

Post the MMA acquisition in late November 2024, the Company more than doubled its land holding in the mid-Cauca belt to 400km2, by virtue of gaining ownership of a large number of licence applications held by MMA. This makes the Company one of the major land holders in one of the world's most exciting gold belts.

These applications have yet to be properly assessed by the Company as most financial and management resources have thus far been directed to drilling at Pepas.

Figure 2. Main prospects, licences pre-MMA acquisition

Pepas Prospect

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

Later holes were then rotated clockwise from PEP012 to begin to test what was considered by Company geological teams to be the controlling trend of SE to NW. The primary objective of the first phase of drilling by the Company was to attempt to understand the geological controls upon mineralisation first identified in 2022, so as to provide guidance for later step out drilling.

Holes drilled and announced to date (PEP012 to PEP027) have all intersected substantial sequences of gold mineralisation, largely from surface, thus far manifested as a thick wedge of silicified tuffs within the keel of two converging faults. Chemical analysis suggests the mineralisation to be possibly a variant of a high sulphidation epithermal style, but with just over 1100m drilled thus far, there is yet insufficient information to fully define its genesis, structural controls or source. By definition, this style of mineralisation, is the shallower expression of a deeper source, which has yet to be examined as drilling has focussed on the high grade near surface material.

Figure 2. Plan of holes

Of these current five holes, two (PEP023 and PEP024) were drilled some distance from the currently defined core deposit, to test a small, medium grade outcrop of silicified material. Moderate intersections were recorded in complex series of veins in a different domain to previous drilling. This opens up a new target and will require more work.

Hole PEP025 was drilled on section with PEP014, 021 and 022, to complete this section and to better define a central high-grade core around which a future resource might be developed.

Hole PEP026 was drilled in the NW end underneath the discovery hole PEP001, to test a structure identified in early drilling. Broken ground was intersected in shallower sections, before a substantial gold intersection lower in the hole.

PEP027 was drilled beyond the SE margin of previous drilling to test the depth extent of a large, silicified outcrop that was mapped to the south of the current area of focus, with a substantial thickness of gold mineralisation being intersected. The nature of this material suggests a later phase of mineralisation from the two main events seen to date, one that is slightly lower in grade than that so far defined. However, this zone appears thick and on surface, outcrop extends some distance southward and will be followed up in later drilling extending southward.

Drill intersections for these most recent five holes are as follows:

Table 1. Drill Intercepts

Discussion

Drilling thus far has been largely focussed within an area of roughly 150m x 150m. This has been done intentionally, both because the thick, high-grade mineralisation is potentially amenable to being moved to an economic resource very quickly, even within a small area, but also to allow time for development of targets and physical access toward the north where previously announced surface geochemistry has suggested substantial extension potential.

As announced on February 4th 2025, previous surface geochemistry collected by MMA, has identified a large, highly anomalous region to the north of the current Pepas mineralisation. Company geological teams have begun to expand on this work, resulting in the identification of a large, highly mineralised channel sample some 200m north of the limit of current drilling (Figure 4).

The Company is advanced in planning to move the drill rig into this zone, however this requires not only greater geological understanding to direct drilling, but also the development of physical access for rigs and machinery.

While access work continues, the Company has just begun a drone aeromagnetic survey over the Pepas area, designed to provide high resolution geophysical data to assist in increasing understanding of the structural architecture of the Pepas deposit. This survey is expected to be completed within a week, with data being made available later in March. It is hoped these data may shed light on the sense of movement of later faults that would seem to have broken up the mineralisation, as well as providing vectors to a deeper source.

Figure 4. Pepas soil sampling

Metallurgy

Last week a bulk composite sample of Pepas mineralisation was sent to a metallurgical laboratory in Canada for the first phase of metallurgical testing for Pepas. This work will be preliminary in nature, designed to provide guidance and parameters for future feasibility related metallurgical work.

Holes Drilled post MMA transaction

14 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

El Cedro

The El Cedro (and El Roble) prospect lies to the south of the same integrated licence that hosts both Pepas and APTA, and is roughly 4km south of the APTA base camp.

Work on the area began some years ago before Orosur's tenure, when Anglo American undertook reconnaissance mapping and sampling, identifying a highly prospective gold/copper porphyry system.

Little work was then undertaken until late 2021, when the Company's previous JV partner MMA re-entered the area to carry out mapping, sampling and ground geophysics that largely confirmed Anglo American's previous work and mapped several large dioritic intrusions and associated epithermal systems. Sampling was limited to creeks and drainages, and several small areas in the centre of the zone. However, wide areas of gold anomalism were identified in soils and channel samples, with assays above 5g/t Au identified across a large area, with associated copper and molybdenum anomalism (Figure 5).

Older airborne magnetic data suggests the presence of a large intrusive complex demonstrating a "ring" structure, often seen in such environments.

The Company is currently in the advanced stages of logistical planning and socialisation to allow a large-scale sampling program to commence as soon as possible. Work will concentrate on confirmation of the previous phases of work by Anglo American and MMA and expanding the scope with ridge and spur soil sampling over a 2km x 2km area.

It is hoped work can commence in March.

Figure 5. El Cedro Sampling - historical and planned - over airborne magnetics

Orosur CEO Brad George commented:

"Anzá has come a long way in no time at all. Pepas began with a bang and is now well into the phase of serious geological work to assess its size and metallurgical characteristics. In parallel, we are now commencing work at El Cedro to hopefully confirm this as a large gold porphyry system. Added to APTA and El Pantano we hope to soon have multiple major gold irons in the fire during a bouyant gold market - all owned 100%."