Orosur Mining Inc - opening new fronts at Anzá

·    Assays from five more holes at Pepas, including:

o PEP025 - 62.5m @ 5.4g/t Au

o PEP026 - 28.4m @ 2.52 g/t Au

o PEP027 - 79.15m @ 2.0g/t Au

·    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 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 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. 

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.

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

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.

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

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, the Company restarted drilling at the Pepas prospect 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.

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 4^th 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%."

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, a small exploitation permit 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 and verified 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.

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.