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Orosur Mining Inc – Colombia update

Corporate Updates

Orosur Mining Inc – Colombia update

 Assays reported from four additional holes.

 High grade gold intersections – 23.75m @ 17.40g/t Au (including 0.4m @

948g/t Au), 29.45m @ 2.50 g/t Au.

 Five rigs are currently operating, but assay delays continue.

 Regional field work underway in search for new drill targets.

 Historical data assessed against NI43-101 for future resource modelling.

London, May 4th, 2021 . Orosur Mining Inc. (“Orosur” or the “ Company”)

(TSX/AIM:OMI), is pleased to announce an update on the progress of Minera Anzá’s

drilling campaign currently underway at the Company’s Anzá project in Colombia.

Results of further four holes.

Assay results for four additional diamond drillholes have been received from the ALS

laboratory in Lima, Peru, MAP-079, 080, 081 and 082.

Significant results from MAP-079 and MAP-082 include:

MAP-079 23.75m @ 17.40g/t Au, 1.84g/t Ag, 0.19% Zn

MAP-082 29.45m @ 2.50g/t Au, 1.95g/t Ag, 1.08% Zn

MAP-080 and MAP-081contained no significant intersections.

Full results are detailed in table 1:

Hole No

From

(m) To (m)

Interval

(m) Au (g/t) Ag (g/t) Zn (%)

MAP-079 252.90 254.90 2.00 2.67 1.22 1.58

including 253.70 254.10 0.40 7.98 1.9 0.91

MAP-079 270.45 294.2 23.75 17.40 1.84 0.19

including 271.00 271.40 0.40 948** 57.7 0.7

including 271.40 271.80 0.40 11.60 1.01 0.02

including 286.40 294.20 7.80 3.25 1.28 0.45

including 288.50 289.60 1.10 8.83 1.80 0.79

Including 292.65 294.2 1.55 7.33 1.46 0.66

MAP-079 315.50 320.60 5.10 1.78 17.25 0.09

including 317.40 318.5 1.10 5.56 25.26 0.22

MAP-082 170.10 175.90 5.80 0.93 8.10 1.69

MAP-082 201.90 209.25 7.35 0.68 1.77 0.79

MAP-082 220.60 223.00 2.40 1.54 2.27 2.72

including 222.20 223.00 0.80 3.97 0.78 0.05

MAP-082 227.20 256.65 29.45 2.50 1.95 1.08

including 236.75 237.05 0.30 3.99 1.68 0.56

including 245.65 251.10 5.45 11.42 6.89 4.60

MAP-082 270.50 273.40 2.90 0.57 7.30 5.96

MAP-082 287.90 289.15 1.25 1.64 0.38 0.08

MAP-082 291.85 293.13 1.28 1.06 1.09 1.55

MAP-082 295.70 298.14 2.44 0.85 0.38 0.39

MAP-082 302.77 305.20 2.43 0.45 0.55 0.10

Table 1. Drill Intercepts*.

(* Intersections are reported as down-hole widths. The Company does not yet have sufficient drilling

information to accurately calculate true widths of drill hole intersections.

** Initial assay of this sample returned 1000g/t Au. The intersection was re-sampled and re-assayed

using a screen fire assay method to assess and if necessary, remove the impact of nugget effect.)

All holes were drilled to better define the geological controls upon gold and base

metal mineralisation that had been identified during previous drilling campaigns, but

also to extend or to close off such mineralisation.

All were successful in addressing their objectives and have added important

additional information to the understanding of the litho-structural controls upon the

mineralisation at APTA that has allowed later drilling to be better focussed.

Figure 1. Section of hole MAP-079

Figure 2. Section of hole MAP-082

Figure 3. Plan of drilling

Drilling Summary

The company currently has five diamond drill rigs operating at the APTA prospect, with

close to 6,000m having been completed since November 2020 across 18 holes, both

completed and underway.

Drilling is now focussed on a combination of understanding the geological controls

upon mineralisation , expansion of the mineralised zones , and infill drilling to

demonstrate continuity. Visually, results continue to appear positive, but the Company

remains subject to delayed assay results , with over 2000 samples currently in the

laboratory awaiting assay.

It was noted previously that assay turnaround times from the ALS laboratory in Peru

had blown out substantially from normal expectations as a result of Covi d-19 related

staff shortages at the laboratory. This performance had begun to improve in February

and March. However, Peru, like most countries in the region is now experienc ing a

major third wave of Covid-19 and as a result, laboratory turnaround times are now well

in excess of previous delayed schedules. There is no indication that this will improve

in the near term.

Regional Exploration

Following a lull in February and March, Colombia is now experiencing a very serious

third wave of Covid-19, especially in the major cities of Bogota and Medellin, where

curfews and lockdowns are now in place. However, mining has been declared an

essential industry and as such is permitted to continue, which the Company has been

able to do via strict Covid operating protocols and an exhaustive testing regime.

Given the success thus far of its operating protocols, the Company has taken the

decision to expand its regional field work across its wider licence package in order to

identify targets for future follow up.

The licence and application package at Anzá cont ains over 20km of strike of the

Aragon Fault, which is thought to control mineralisation at APTA, and potentially a

similar strike length of the N -S Tocuman Fault that may be the primary conduit from

the La Cejita intrusive complex to the north of APTA. However, almost all exploration

work undertaken thus far by the Company and previous operators has been focussed

on roughly 500m strike at the APTA prospect with some minor work at Charrascala.

Much of the remainder of the licence package remains essentially untouched.

Several regional programs are underway or planned:

 Bulk Leach Extractable Gold (BLEG) sampling programs have been underway

across the wider APTA licence and surrounding areas for some weeks. BLEG

is a sampling method capable of detecting extremely low levels of gold and is

a broad scale regional tool for identifying attractive zones for further follow up.

 Detailed geological mapping and sampling has been ongoing across the APTA

licence for some months. The scope of this work is to better understand the

local lithology and structures that are controlling mineralisation in the APTA

area.

 Several field teams have mobilised to the NE of the project area, outside the

APTA licence, which is postulated to host the NE extension of the Aragon Fault,

to conduct major mapping and sampling programs

NI43-101 Data Assessment

The Company has engaged international mining consulting firm CSA Global (UK) to

advise in an external expert capacity, with the first task being to carry out an analysis

of all previous drilling to ensure that it was completed in a manner consistent with the

Canadian standard NI43-101 and thus amenable to be included in a resource estimate

in the future.

The outcome of this work was positive, with CSA noting that all previous drilling was

of a high standard, and that with some minor modifications would be amenable to be

included in a resource estimate in future when that is warranted.

Orosur CEO Brad George commented:

“Operationally, in spite of the Covid -19 situation in Colombia, our protocols and the

tremendous efforts of our teams in the field have allowed us to continue to operate at

near full capacity – a situation that we will endeavour to continue. However, while our

field operations continue at pace, we have no control over external services such as

assay laboratories and unfortunately, assay delays are continuing.

Geologically however, the picture at APTA is becoming clearer, and we anticipate

being able to develop a more detailed understanding of the poly -metallic

mineralisation at APTA once the substantial sample backlog begins to be cleared in

coming weeks and months”.

For further information, 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 / Caroline Rowe

Tel: +44 (0) 20 3 470 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 Regulation ( “MAR”). Upon the publication of this announcement via

Regulatory Information Service, this inside information is now considered to be in the public domain.

Drill Hole Details – 2020/2021 Programme*

Hole ID Easting (m) Northing (m) Elevation asl (m) Dip (°) Azimuth (°)

MAP-072 400088 694745 1075 -55 293

MAP-073 400018 694503 1097 -58 295

MAP-074 399981 694684 1110 -58 295

MAP-075 400168 694723 1024 -55 295

MAP-076 400019 694527 1107 -50 295

MAP-077 400168 694723 1024 -69 295

MAP-078 399917 694719 1112 -50 295

MAP-079 399995 693976 960 -55 295

MAP-080 400231 694580 966 -55 295

MAP-081 400045 693950 920 -55 295

MAP-082 400176 694797 1020 -50 296

MAP-083 400176 694797 1020 -60 310

MAP-084 400045 693950 920 -57 321

MAP-085 400167 694552 1000 -46 247

MAP-086 400067 694360 1068 -54 295

MAP-087 400027 694168 988 -54 290

MAP-088 400168 694723 1024 -55 341

MAP-089 400067 694360 1068 -59 317

* Coordinates WGS84, UTM Zone 18

About Orosur Mining Inc.

Orosur Mining Inc. (TSX: OMI; AIM: OMI) is a precious metals developer and explorer focused on identifying and

advancing gold projects in South America. The Company operates in Colombia and Uruguay.

About the Anzá Project

Anzá is a gold exploration project, comprising three exploration licences, four exploration licence applications,

and several small exploitation permits, totalling 207.5km2 in the prolific Mid-Cauca belt of Colombia.

The Anzá Project is currently wholly owned by Orosur via its subsidiary, Minera Anzá S.A.

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.

The Anzá Project is subject to an Exploration Agreement with Venture Option dated September 7th, 2018, as

announced on September 10th, 2018, (the “Agreement”) between Orosur’s 100% subsidiary Minera Anzá S.A

(“Minera Anzá”) and Minera Monte Águila SAS (“Monte Águila”), a 50/50 joint venture between Newmont

Corporation (“Newmont”) (NYSE:NEM, TSX:NGT), and Agnico Eagle Mines Limited (“Agnico”) (NYSE:AEM,

TSX:AEM).

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 Ltd and

a qualified person as defined by National Instrument 43-101.

Orosur Mining 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 20% of total submitted samples being

blanks, repeats or Certified Reference Materials (CRMs).

Samples are sent to the Medellin preparation facility of ALS Colombia Ltd, and then to the ISO 9001 certified ALS

Global laboratory in Lima, Peru.

30 gram nominal weight samples are then subject to fire assay and AAS analysis for gold with gravimetric re-

finish for overlimit assays of >10g/t. ICP-MS Ultra-Trace level multi-element four-acid digest analyses is 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 exploration plans in Colombia and the funding from

Monte Águila of those plans, Monte Águila´s decision to continue with the Exploration and Option agreement, the

ability for Loryser to continue and finalize with the remediation in Uruguay, the ability to implement the Creditors’

Agreement successfully as well as continuation of the business of the Company as a going concern and other

events or conditions that may occur in the fut ure. 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

implementation of the Creditor´s Agreement in Uruguay. These material uncerta inties 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. There c an 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, those as described in Section “Risks Factors” of the MDA and the Annual

Information Form. The Company disclaims any intention or obligation to update or revise any forward -looking

statements whether as a result of new information, fut ure events and such forward-looking statements, except to

the extent required by applicable law.