Orosur Mining Inc Declares Pepas MRE Drilling Close to Completion

Drilling at El Pantano in Argentina hits mineral system

• Assays for 5 holes from the Pepas useful resource drilling program, together with:

• Useful resource modelling and NI43-101 report course of underneath method

• First holes from El Pantano drilling program affirm a low sulphidation epithermal mineral system – awaiting assays.

LONDON, GB / ACCESS Newswire / December 12, 2025 / Orosur Mining Inc. (“Orosur” or the “Firm“) (TSXV:OMI,OTC:OROXF)(AIM:OMI), is happy to announce an replace on the progress of exploration actions on the Firm’s exploration initiatives at Anzá in Colombia (“Anzá) and El Pantano in Argentina (“El Pantano”).

Anzá – Colombia

The Anzá Mission in Colombia includes various granted exploration titles and functions totalling roughly 330km², throughout the Mid-Cauca gold belt, west of the town of Medellin.

These titles and functions are owned by two Colombian firms, Minera Anzá, and Minera Monte Aguila, each of that are wholly owned subsidiaries of the Firm. The latter of those was acquired by Orosur in November 2024 from the Firm’s earlier JV companions, Newmont Mining and Agnico Eagle Mines. Orosur thus owns 100% of the Anzá Mission.

Since buying 100% management, the Firm has focussed its consideration on three prospects:

• Pepas – a shallow, high-grade physique of gold mineralisation that the Firm is endeavouring to maneuver to an preliminary Mineral Useful resource Estimate (‘MRE’) within the close to time period.

• APTA – a high-grade physique of gold mineralisation that has thus far seen 38,000m of drilling, however just isn’t but sufficiently understood geologically to permit a MRE to be calculated. The Firm plans to undertake extra drilling at APTA in 2026, with the target of advancing it towards an MRE.

• El Cedro – a big gold porphyry system within the south of the Mission space. The Firm has accomplished a big soil sampling program and plans to undertake a maiden drill program right here in early 2026.

Determine 1. Anzá Mission

As introduced on 14^th July 2025, the Firm had taken the formal resolution to begin infill drilling at its Pepas gold prospect at Anzá, with the target of transferring Pepas to a NI43-101 compliant Mineral Useful resource Estimate as shortly as doable.

The Firm’s exterior geological and useful resource consultants visited the Anza website firstly of November to hold out the mandatory QAQC verification of drilling and sampling and to work with the Orosur geological workforce within the growth of a brand new NI43-101 technical report for the Anza venture, which can embody a MRE for the Pepas Prospect.

One consequence of this go to was the advice by the consultants for an extension of the ultimate phases of the MRE drill-out program, with a number of extra holes inside and out of doors the Pepas deposit to outline the boundaries of the present deposit envelope and acquire a greater understanding of the dimensions and controls of beforehand outlined high-grade zones.

Holes drilled outdoors the deposit envelope have returned the decrease grade halo mineralisation as anticipated and have supplied precious data as to the character of the among the controlling buildings of Pepas. The one gap of this present batch drilled contained in the deposit envelope (PEP-067) returned a results of 83.7m @ 4.29g/t Au from floor.

Desk 1. Newest drill Intercepts, Pepas Prospect

Determine 2. Plan of holes

Determine 3. Part, PEP067

It’s anticipated that the Pepas drill-out program will proceed for the following few days and the ensuing MRE and technical report can then be accomplished throughout January 2026.

Metallurgy

As a part of the MRE course of, a big diameter PQ drill gap was accomplished particularly to supply ample materials for a complete metallurgical testing program. These samples have been despatched to the metallurgical testing facility of ALS International in British Columbia, the place the work is now properly superior. It’s hoped this program could also be accomplished by the tip of the yr and thus feed into the Technical Report and MRE.

Wider Exploration – Anza

The Firm had beforehand introduced that it had deliberate to undertake an in depth airborne magnetic survey over the EL Cedro and APTA prospects in December, as a device to supply extra steering for drilling in early 2026. The Firm is partaking with contractors to fee the survey.

Mapping, sampling and trenching can also be underway within the environs of the Pepas deposit, as a part of an ongoing program to probe for extensions and/or repetitions of Pepas. As soon as the present useful resource drilling program is accomplished in coming weeks, it’s doubtless the rig shall be shifted to targets being developed round Pepas.

El Pantano – Argentina

The El Pantano Mission is an early-stage gold/silver exploration venture in Santa Cruz province, southern Argentina.

The Mission includes roughly 550km² of contiguous granted licences within the prolific Deseado Massif of Santa Cruz Province, roughly 45km from Anglo Gold’s Cerro Vanguardia mining camp and 90km SE of Newmont Mining’s big Cerro Negro mine.

El Pantano is topic to an Exploration & Joint Enterprise (“JV”) settlement (“Settlement”) with non-public Argentinean firm Deseado Dorado S.A.S and its shareholders (“Deseado”), the main points of which have been introduced on February 15^th 2022.

The Firm at the moment owns 51% of El Pantano, having met its obligation to spend US$1m in exploration expenditure by February 2025. The Firm is now in Section 2 of the three way partnership, whereby it could earn an extra 49% fairness within the venture (taking the Firm to 100% possession) by investing US$2m within the two years to February 2027. Upon such an occasion, the unique distributors would retain a 2% NSR royalty, 1% of which the Firm might buy for US$1m at its discretion.

Following a number of years of floor discipline work, the Firm commenced the primary section of drilling ever undertaken throughout the venture space in early November 2025. Between 3,000-4,000m is deliberate throughout the breadth of the venture space as a reconnaissance program designed to handle various geological questions:

• Check sources of geochemical anomalism

• Assess quite a lot of Induced Polarisation responses

• Intersect, if doable, mineralised buildings indicative of the low sulphidation epithermal mannequin being postulated at El Pantano

• Acquire understanding of the vertical variations within the system, particularly in relation to the potential for fluid boiling.

In a normal sense, the broad goal of this system is to find out if a mineral system is current at El Pantano, and if that’s the case, develop exploration plans for additional work.

Determine 4. El Pantano geology and geochemistry

Samples from the El Pantano venture are despatched to the preparation facility and hearth assay laboratory of Alex Stewart Laboratories in Perito Moreno to be assayed for gold. Pulps are then despatched to the bigger Alex Stewart facility in Mendoza for multi-element evaluation.

To this point, seven holes have been accomplished with samples from the primary 5 submitted to the laboratory in Perito Moreno for hearth assay gold evaluation, to be adopted by multi- factor evaluation, together with silver, from the Mendoza facility.

Visually, a number of of the holes have intersected extraordinarily encouraging buildings displaying textures and mineralogy according to what’s seen in different low sulphidation epithermal programs within the area. Specifically, the presence of colloform banding in a number of intersected slim veins is a key indicator typically seen within the core of low sulphidation epithermal programs.

Preliminary interpretation would counsel that vein textures are indicative of decrease temperatures, albeit with some examples of upper temperature overprinting. This is able to counsel that present drilling remains to be larger within the system, above the boiling zone.

Fig 5. Colloform banding, El Pantano

The Firm is assured that it has achieved its normal goal of proving the existence of a considerable mineral system. That is a particularly constructive and strange end result for the primary drilling program on a grass roots venture. The problem, nonetheless, is figuring out the place, throughout the mineral system, financial widths and grades might have been deposited.

Drilling is progressing quicker than anticipated and thus it’s deliberate that this program shall be accomplished towards the tip of January 2026. As soon as full, all new and historic information shall be compiled as the important thing element to a focusing on program that can develop the following section of labor.

Orosur CEO Brad George commented:

“Pepas is now within the last mile of its MRE course of and the items are coming collectively for a January report. Within the meantime, we’re lining up targets for when the rig is freed up later in December. Drilling at El Pantano, as with every undrilled venture, was excessive danger, however now we have hit what we hoped to hit – a beforehand unknown mineral system. Now we have to focus in, and given the size of the system, that may be a problem….however a superb problem”.

For additional data, go to www.orosur.ca, observe on X @orosurm or please contact:

Orosur Mining Inc

Louis Castro, Chairman,
Brad George, CEO
information@orosur.ca
Tel: +1 (778) 373-0100

SP Angel Company Finance LLP – Nomad & Joint Dealer

Jeff Keating / Jen Clarke / Devik Mehta
Tel: +44 (0) 20 3470 0470

Turner Pope Investments (TPI) Ltd – Joint Dealer

Andy Thacker/Man McDougall
Tel: +44 (0)20 3657 0050

Flagstaff Communications and Investor Communications

Tim Thompson
Mark Edwards
Fergus Mellon
orosur@flagstaffcomms.com
Tel: +44 (0)207 129 1474

The knowledge contained inside this announcement is deemed by the Firm to represent inside data as stipulated underneath the Market Abuse Rules (EU) No. 596/2014 (‘MAR’) which has been included into UK legislation by the European Union (Withdrawal) Act 2018. Upon the publication of this announcement by way of Regulatory Info Service (‘RIS’), this inside data is now thought of to be within the public area.

Neither TSX Enterprise Change nor its Regulation Providers Supplier (as that time period is outlined in insurance policies of the TSX Enterprise Change) accepts accountability for the adequacy or accuracy of this launch.

Drill Gap Particulars – Pepas prospect 2022/2024 Programme*

Drill Gap Particulars, El Pantano Mission 2025 onward

* Coordinates WGS84, UTM Zone 18

About Orosur Mining Inc.

Orosur Mining Inc. (TSXV:OMI,OTC:OROXF)(AIM:OMI) is a minerals explorer and developer at the moment working in Colombia and Argentina.

Certified Individuals Assertion

The knowledge on this information launch was compiled, reviewed, verified and authorised 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 professional particular person as outlined by Nationwide Instrument 43-101.

Orosur Mining Inc. employees observe normal working and high quality assurance procedures to make sure that sampling methods and pattern outcomes meet worldwide reporting requirements.

Drill core is cut up in half over widths that change between 0.3m and 2m, relying upon the geological area. One half is stored on website within the Minera Anzá core storage facility within the case of the Anza Mission, or on website in non permanent racks within the case of the El Pantano Mission, with the opposite despatched for assay.

Trade normal QAQC protocols are put in place with roughly 10% of whole submitted samples being blanks, repeats or Licensed Reference Supplies (CRMs).

Samples for holes PEP-001 to PEP-011 have been despatched to the Medellin preparation facility of ALS Colombia Ltd, after which to the ISO 9001 licensed ALS Chemex laboratory in Lima, Peru.

Samples from PEP-012 onwards are despatched to Medellin laboratory of Actlabs for preparation and hearth assay, with some pattern then despatched to the Canadian Actlabs facility for multi factor assay

Samples from the EL Pantano venture are despatched to the preparation facility and hearth assay laboratory of Alex Stewart Laboratories in Perito Moreno to be assayed for gold. Pulps are then despatched to the bigger Alex Stewart facility in Mendoza for multi-element evaluation.

30 gram nominal weight samples are then topic to fireside assay and AAS evaluation for gold with gravimetric re-finish for overlimit assays of >5 g/t. ICP-MS Extremely-Hint stage multi-element four-acid digest analyses may undertaken for such parts as silver, copper, lead and zinc, and many others.

Gold intersections are reported utilizing a decrease cut-off of 0.3g/t Au over 3m.

Intersections are quoted as downhole thicknesses. True thicknesses are unknown.

Ahead Trying Statements

All statements, apart from statements of historic truth, contained on this information launch represent “ahead trying statements” throughout the that means of relevant securities legal guidelines, together with however not restricted to the “secure harbour” provisions of the USA Non-public Securities Litigation Reform Act of 1995 and are based mostly on expectations estimates and projections as of the date of this information launch.

Ahead-looking statements embody, with out limitation, the persevering with concentrate on the Pepas prospect, the exploration plans in Colombia and the funding of these plans, and different occasions or circumstances which will happen sooner or later. There will be no assurance that such statements will show to be correct. Precise outcomes and future occasions might differ materially from these anticipated in such forward-looking statements. Such statements are topic to vital dangers and uncertainties together with, however not restricted to, these described within the Part “Dangers Components” of the Firm’s MD&A for the yr ended Might 31, 2025. The Firm’s continuance as a going concern relies upon its skill to acquire ample financing. This materials uncertainty might solid vital doubt upon the Firm’s skill to understand its belongings and discharge its liabilities within the regular course of enterprise and accordingly the appropriateness of the usage of accounting rules relevant to a going concern. The Firm disclaims any intention or obligation to replace or revise any forward-looking statements whether or not because of new data, future occasions and such forward-looking statements, besides to the extent required by relevant legislation.

This data is supplied by RNS, the information service of the London Inventory Change. RNS is authorised by the Monetary Conduct Authority to behave as a Major Info Supplier in the UK. Phrases and circumstances regarding the use and distribution of this data might apply. For additional data, please contact rns@lseg.com or go to www.rns.com.

SOURCE: Orosur Mining Inc

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