Pepas MRE drilling near completion Drilling at El Pantano in Argentina hits mineral system
Pepas MRE drilling near completion
Drilling at El Pantano in Argentina hits mineral system
• Assays for five holes from the Pepas resource drilling program,
including:
o PEP067 – 83.7m @ 4.29g/t Au from surface
• Resource modelling and NI43-101 report process under way
• First holes from El Pantano drilling program confirm a low sulphidation
epithermal mineral system - awaiting assays.
London, December 12th, 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 exploration projects at Anzá in Colombia (“Anzá) and El
Pantano in Argentina (“El Pantano”).
Anzá – Colombia
The Anzá Project in Colombia comprises a number of granted exploration titles and
applications totalling roughly 330km2, within the Mid-Cauca gold belt, west of the city
of Medellin.
These titles and applications are owned by two Colombia n companies, Minera Anzá,
and Minera Monte Aguila, both of which are wholly owned subsidiaries of the
Company. The lat ter of these was acquired by Orosur in November 2024 from the
Company’s previous JV partners, Newmont Mining and Agnico Eagle Mines. Orosur
thus owns 100% of the Anzá Project.
Since acquiring 100% control, the Company has focussed its attention on three
prospects:
• Pepas - a shallow, high-grade body of gold mineralisation that the Company is
endeavouring to move to an initi al Mineral Resource Estimate (‘MRE’) in the
near term.
• APTA - a high-grade body of gold mineralisation that has to date seen 38,000m
of drilling, but is not yet sufficiently understood geologically to allow a MRE to
be calculated. The Company plans to undertake additional drilling at APTA in
2026, with the objective of advancing it toward an MRE.
• El Cedro - a large gold porphyry system in the south of the Project area. The
Company has completed a large soil sampling program and plans to undertake
a maiden drill program here in early 2026.
Figure 1. Anzá Project
As announced on 14th July 2025, the Company had taken the formal decision to
commence infill drilling at its Pepas gold prospect at Anzá, with the objective of moving
Pepas to a NI43-101 compliant Mineral Resource Estimate as quickly as possible.
The Company’s external geological and resource consultants visited the Anza site at
the start of November to carry out the necessary QAQC verification of drilling and
sampling and to work with the Orosur geological team in the development of a new
NI43-101 technical report for the Anza project, which will include a MRE for the Pepas
Prospect.
One outcome of this visit was the recommendation by the consultants for an extension
of the final stages of the MRE drill -out program, with several additional holes within
and outside the Pepas deposit to define the boundaries of the current deposit envelope
and obtain a better understanding of the size and controls of previously defined high-
grade zones.
Holes drilled outside the deposit envelope have returned the lower grade halo
mineralisation as expected and have provided valuable information as to the nature of
the some of the controlling structures of Pepas. The one hole of this current batch
drilled inside the deposit envelope (PEP-067) returned a result of 83.7m @ 4.29g/t Au
from surface.
Hole Number From (m) To (m) Interval
(m) Au (g/t)
PEP067 0 83.7 83.7 4.29
including 21.6 39.05 17.45 7.12
Including 61.7 72.5 10.8 8.06
PEP068 0 8 8 0.67
17.4 22 4.6 0.37
47.55 51 3.45 0.34
PEP069 0 2.25 2.25 0.96
PEP070 0 2 2 1.34
37.7 40.45 2.75 1.11
84.1 149.4 65.3 0.68
PEP071 0 3.2 3.2 0.42
71.35 78 6.65 0.45
Table 1. Latest drill Intercepts, Pepas Prospect
Figure 2. Plan of holes
Figure 3. Section, PEP067
It is expected that the Pepas drill-out program will continue for the next few days and
the resulting MRE and technical report can then be completed during January 2026.
Metallurgy
As part of the MRE process, a large diameter PQ drill hole was completed specifically
to provide sufficient material for a comprehensive metallurgical testing program. These
samples have been sent to the metallurgical testing facility of ALS Global in British
Columbia, where the work is now well advanced. It is hoped this pr ogram may be
completed by the end of the year and thus feed into the Technical Report and MRE.
Wider Exploration – Anza
The Company had previously announced that it had planned to undertake a detailed
airborne magnetic survey over the EL Cedro and APTA prospects in December, as a
tool to provide additional guidance for drilling in early 2026. The Company is engaging
with contractors to commission the survey.
Mapping, sampling and trenching is also underway in the environs of the Pepas
deposit, as part of an ongoing program to explore for extensions and/or repetitions of
Pepas. Once the current resource drilling program is completed in coming weeks, it
is likely the rig will be shifted to targets being developed around Pepas.
El Pantano – Argentina
The El Pantano Project is an early-stage gold/silver exploration project in Santa Cruz
province, southern Argentina.
The Project comprises approximately 550km 2 of contiguous granted licences in 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 giant Cerro Negro
mine.
El Pantano is subject to an Exploration & Joint Venture ( “JV”) agreement
(“Agreement”) with private Argentinean company Deseado Dorado S.A.S and its
shareholders (“Deseado”), the details of which were announced on February 15 th
2022.
The Company currently owns 51% of El Pantano, having met its obligation to spend
US$1m in exploration expenditure by February 202 5. The Company is now in Phase
2 of the joint venture, whereby it may earn an additional 49% equity in the project
(taking the Company to 100% ownership) by investing US$2m in the two years to
February 2027. Upon such an event, the original vendors would retain a 2% NSR
royalty, 1% of which the Company could purchase for US$1m at its discretion.
Following several years of surface field work, the Company commenced the first phase
of drilling ever undertaken within the project area in early November 2025. Between
3,000-4,000m is planned across the breadth of the project area as a reconnaissance
program designed to address a number of geological questions:
• Test sources of geochemical anomalism
• Assess a variety of Induced Polarisation responses
• Intersect, if possible, mineralised structures indicative of the low sulphidation
epithermal model being postulated at El Pantano
• Gain understanding of the vertical variations in the system, especially in relation
to the potential for fluid boiling.
In a general sense, the broad objective of the program is to determine if a mineral
system is present at El Pantano, and if so, develop exploration plans for further work.
Figure 4. El Pantano geology and geochemistry
Samples from the El Pantano project are sent to the preparation facility and fire assay
laboratory of Alex Stewart Laboratories in Perito Moreno to be assayed for gold. Pulps
are then sent to the larger Alex Stewart facility in Mendoza for multi-element analysis.
To date, seven holes have been completed with samples from the first five submitted
to the laboratory in Perito Moreno for fire assay gold analysis, to be followed by multi-
element analysis, including silver, from the Mendoza facility.
Visually, several of the holes have intersected extremely encouraging structures
showing textures and mineralogy consistent with what is seen in other low sulphidation
epithermal systems in the region. In particular , the presence of colloform banding in
several intersected narrow veins is a key indicator often seen in the core of low
sulphidation epithermal systems.
Preliminary interpretation would suggest that vein textures are indic ative of lower
temperatures, albeit with some examples of higher temperature overprinting . This
would suggest that current drilling is still higher in the system, above the boiling zone.
Fig 5. Colloform banding, El Pantano
The Company is confident that it has achieved its general objective of proving the
existence of a substantial mineral system. This is an extremely positive and unusual
result for the first drilling program on a grass roots project. The challenge, however, is
identifying where, within the mineral system, economic widths and grades may have
been deposited.
Drilling is progressing faster than anticipated and thus it is planned that this program
will be completed toward the end of January 2026. Once complet e, all new and
historical data will be compiled as the key component to a targeting program that will
develop the next phase of work.
Orosur CEO Brad George commented:
“Pepas is now in the final mile of its MRE process and the pieces are coming together
for a January report. In the meantime, we are lining up targets for when the rig is freed
up later in December. Drilling at El Pantan o, as with any undrilled project, was high
risk, but we have hit what we hoped to hit – a previously unknown mineral system.
Now we need to focus in, and given the scale of the system, that is a challenge….but
a good challenge”.
For further information, visit www.orosur.ca, follow on X @orosurm or please contact:
Orosur Mining Inc
Louis Castro, Chairman,
Brad George, CEO
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/Guy McDougall
Tel: +44 (0)20 3657 0050
Flagstaff Communications and Investor Communications
Tim Thompson
Mark Edwards
Fergus Mellon
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 (Withdrawa l) 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*
Hole ID Easting (m) Northing (m) Elevation asl (m) Dip (°) Azimuth (°)
PEP-001 403384 705000 1001 -50 150
PEP-002 403384 705000 1001 -60 290
PEP-003 403240 705142 1001 -49.60 95.2
PEP-004 403508 705671 838 -59.8 99.8
PEP-005 403373 704990 1008 -49.8 94.6
PEP-007 403374 704990 1008 -69.9 170
PEP-008 403232 704803 971 -50 60
PEP-009 403032 705057 1055 -50 80
PEP-010 403375 705106 982 -50.31 190.4
PEP-011 403573 704939 1001 -50.3 255
PEP-012 403415 704890 997 -56 352
PEP-013 403413 704887 997 -50 43