Orosur Mining Regulatory News (OMI)

Orosur Mining Inc - drilling and sampling expands Pepas

· Assays from five more holes at Pepas. Best results include:

o PEP028 - 31.35m @ 1.61 g/t Au

o PEP032 - 92m @ 1.68 g/t Au from surface

including 11.85m @ 6.84 g/t Au and 7.7m @ 5.05 g/t Au

· Channel sampling at North Pepas expands high grade anomalous zone, best surface sample of 27.23 g/t Au.

· Access to North Pepas complete - drilling to commence soon.

· Soil sampling at El Cedro underway

London, April 23rd, 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 ("The 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 28th 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.

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.

Most drilling conducted to date by the Company has focussed on a central, high-grade core around the first discovery holes. This has been an intentional strategy based on several rationale:

· To understand the mineralisation and its litho-structural controls.

· To allow time for surface mapping and sampling to expand the anomalous zone and provide targets.

· To allow time for permits and physical access to be developed to other parts of the prospect.

· To examine the potential of moving a small part of Pepas to resource status which could be beneficial in the context of the Colombian permitting system and a pre-existing environmental exploitation permit over part of these licences.

Figure 3. Plan of holes

PEP028 was drilled at the northern extend of the central core, as a scissor hole to PEP015, (Figure 4) to define the position of the Tesorito South fault and thickness of transported cover in this location. This was necessary to assist in moving toward a resource if future results warrant. This hole confirmed previous drilling and recorded a thick sequence of medium grade mineralisation.

Figure 4. Section, PEP028 and PEP015

Holes PEP029 and PEP030 were drilled from the same pad, some distance from the central core and likely NW of the primary geological trend, testing a different geological horizon and several mildly anomalous outcrops. Both intersected thick sequences of lower grade mineralisation. Both of these holes and other work, suggest the potential for a large, reasonably consistent low-grade halo of roughly 0.3g/t Au around a higher-grade core.

Hole PEP031B was the redrill of PEP031 which became stuck in broken ground. This hole was drilled in the SE of the prospect, slightly off trend to test the downdip extension of a large moderate-grade silicified outcrop that was interpreted to be a later phase of mineralisation from the two phases that are thought to create the very high-grade mineralisation of earlier holes.

Hole PEP032 was drilled in the southern section of the prospect, at different angle to previous drilling. The hole was planned as infill for resource modelling purposes and returned a very thick intersection of moderate grade mineralisation from surface.

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

Table 1. Latest drill Intercepts, Pepas

North Pepas

Surface ridge and spur soil sampling undertaken previously by MMA, had identified a large, highly anomalous region to the north of the current Pepas mineralisation. The Company has been following up this work with more targeted and diagnostic channel sampling along tracks or other exposures, looking to sample and assay in-situ saprolite or fresh rock (where present). Such exposures are rare in the Pepas area due to soil cover and can be difficult to locate through thick vegetation. 

Results from one large channel sample undertaken by the Company, some 200m north of the current extent of drilling were announced on 4th February 2025, returning 105m @ 1.15 g/t Au, with some individual samples exceeding 5 g/t Au. 

Figure 5, Pepas soil and Channel samples

Ongoing mapping by field crews has identified another smaller exposure some 20m to the east, down slope in thick scrub. Channel sampling of this exposure has returned an average sample interval of 49m @ 2.59 g/t Au, including a 10m section of 6.93 g/t Au, with a number of samples exceeding 10g/t Au, and the highest 1m sample being 27.23 g/t Au (Figure 6).

Figure 6. North Pepas Channel Sampling

Crews continue to search for more such exposures, with current focus to the west and north.

North Pepas lies across a property boundary from the current drilling at Pepas, requiring both negotiation of land access with the property owner and then development of physical access to the area for drilling machinery. These have now been completed, and it is thus expected that drilling can commence at North Pepas in the next few weeks.

A drone based airborne magnetic survey was recently completed over the Pepas prospect. Preliminary data have been received but final data should be available this week. These data should be of assistance in understanding controls upon mineralisation at Pepas, and thus future drill targeting across the prospect. It is likely however that the first hole at North Pepas will be targeted to test depth extensions of the channel samples set out above.

El Cedro

The El Cedro 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 7).

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

Several weeks ago, the Company commenced a large-scale ridge and spur soil sampling program covering most of what is thought to be the extent of the porphyry system, with a view to confirming and extending the previous work and if positive, to move toward drill targets in the medium term.

The sampling program is currently approximately 25% complete, with work expected to continue into May. In addition, teams have identified several abandoned artisanal tunnels across the prospect. Where safe to do so, some tunnels have been mapped and sampled, identifying a number of intrusive related epithermal vein systems.

Due to the requirement for more complex assay techniques not available in Colombia, samples are being first assayed for gold via fire assay in Medellin, before being sent to Canada for full multi-element analysis.

Results are thus expected to start becoming available within weeks.

Figure 7. El Cedro Sampling - historical and planned - over airborne magnetics

Holes Drilled post MMA transaction

21 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 Anzá Project is progressing well, with Pepas continuing to be defined and new fronts being opened northward of Pepas, and to the south at El Cedro."

For further information, visit www.orosur.ca, follow on X @orosurm or please contact:

Orosur Mining Inc

Louis Castro, Chairman,

Brad George, CEO

info@orosur.ca

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 PopeTel: +44 (0)20 3657 0050

Flagstaff Communications and Investor Communications

Tim ThompsonMark EdwardsFergus Mellon

orosur@flagstaffcomms.com

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, several small exploitation permits 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.

All drill core is HQ.

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.