TCO.V · 2025-07-14 12:00:00

Transatlantic Samples 36.1% Cu over 2.6 metres at Monitor Project - Big Elk Prospect

Drill Results Sampling & Geoscience Results

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Transatlantic Samples 36.1% Cu over 2.6 metres at

Monitor Project - Big Elk Prospect

Vancouver, B.C. July 14, 2025 - Transatlantic Mining Corp. (the “Company”) ( TCO:TSX.V) is

pleased to provide an update on its exploration activities at the Big Elk and Anvil prospects,

key targets within the larger Monitor Copper -Gold Project. The project is located

approximately 8 kilometers south of Taft, Idaho, USA and continues to demonstrate

prospectivity.

Highlights of the Exploration Program:

● High-Grade Surface Samples at Big Elk: An outcrop sample returned 36.1% copper

(Cu) over 2.6 metres, with another gossanous sample yielding 6.6% Cu, confirming

significant mineralization.

● Drilling Validates Targeting: Initial 1,100 metres of drilling confirmed the geometry of

known mineralized structures, including intersecting historical workings, which

provides critical insights for future targeting.

● Anvil Prospect Potential: Recent underground samples at Anvil indicate multiple

copper fissure veins within a complex system.

"We are very pleased with the successful outcomes of our exploration at Big Elk, which has

confirmed our geological understanding and the presence of copper mineralization," said

Bernie Sostak, CEO of Transatlantic Mining. "Our initial magnetic survey results and new

Lidar data are providing compelling insights, supporting delineation of fissure veins and

offering a clearer picture of the historical workings. This comprehensive information,

covering both Big Elk and Anvil, is actively being integrated into an updated NI 43-101 report

for the Monitor Project, positioning us strongly for our next targeted drill campaign and the

discovery of additional veins within the claim package."

Webinar:

Transatlantic CEO Bernie Sostak will host an interactive webinar discussing the company’s

exploration programs and future plans on Wednesday, July 16, 2025, at 9:am PT . Register

in advance for this meeting via the following link:

https://us02web.zoom.us/meeting/register/HGAW8MmQSpqph3pg-hcw1Q

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Geology and Mineralization

At the Big Elk prospect, copper mineralization is found within steeply dipping fissure veins

that form along second -order structures within a prominent shear zone, trending

approximately N40W to N70W. These veins, typically up to 1.8 metres wide, are characteristic

of the broader Coeur d’Alene mining district. In this eastern and southeastern part of the

district, where the Monitor Project is situated, veins are typically copper -rich with reduced

silver, lead, and zinc content, suggesting formation under higher-temperature conditions or

closer proximity to the hydrothermal source. These copper-rich veins are generally less than

5 meters wide, extend to significant depths, and primarily contain chalcopyrite, pyrite, calcite,

siderite, and quartz. Hydrothermal alteration, notably pervasive siderite zoning and

bleaching, is a defining characteristic of the mineralized zones, with disseminated siderite

sometimes extending hundreds of meters into the wall rocks.

Exploration Results

Building on this geological understanding, the Company conducted a systematic exploration

program, implementing industry best practices to confirm the property's geological and

mineralogical characteristics.

Initial surface sampling at the Big Elk prospect yielded encouraging copper results. An

outcrop sample excavated next to a historic shaft returned 36.1% Cu over 2.6 metres (see

Figure 1). Further surface assessment included a surface sample of gossanous copper with

iron in the stockpile, which assayed 6.6% Cu. ( *See also historical reports)

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Figure 1: High-grade copper showing from the Big Elk Prospect at Transatlantic Mining’s

Monitor Project.

The initial drill program at Big Elk comprised fourteen holes totaling 1,100 metres, designed

to test copper anomalism found on earlier surface geological reconnaissance and further

confirm the orientation of the mineralized system. Hole depths ranged from 21 metres to

111 metres in 14 holes. Ten of these holes intersected voids where historical mining had

taken place, providing valuable insights into the geometry and continuity of the veins. While

the drilling did not intersect new vein material to yield p ositive analytical results, it

successfully confirmed the geometry (strike and dip) of the vein system mined along the Big

Elk workings, providing essential data for the planning of subsequent drilling campaigns

(Figures 2 and 3). Four exploration holes di d not encounter visible mineralization and were

not sampled. There are no historical mine plans at the Big Elk prospect, and the drilling was

targeting the uncovered subcrop to determine extensions along strike and down dip. All

samples collected were subsequently sent to Christofferson Labs, LLC. in Smelterville, Idaho,

USA for analysis of gold and then to American Analytical Laboratories in Osburn, I daho for

an ICP analysis.

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Figure 2: Map of the Big Elk Prospect, a subset of the Monitor Project

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Figure 3: Map of the Big Elk Prospect, a subset of the Monitor Project (Table 1,2)

Overall, the Company's exploration efforts confirmed the strike and dip of the vein mined

along the Big Elk workings. Surface samples indicate the veins contain copper mineralization.

Furthermore, through mapping and sampling of the Anvil working, the Comp any has

identified additional veins within the claim block. Both the Big Elk and Anvil prospects

represent historical workings on fissure veins within the larger shear zone, confirming the

presence of multiple veins within the shear zone that encompasses the entire project.

Sampling, Analysis, and Quality Assurance/Quality Control (QA/QC)

All samples, including those from surface across the Big Elk Vein subcrop and remnant

copper mineralization in the outlying dump area (Table 1), as well as drilling, were sent to

Christofferson Labs, LLC in Smelterville, Idaho, USA for gold analysis. Subse quent ICP

analysis was performed at American Analytical Laboratories in Osburn, ID. All drilling and

sampling results for the Big Elk prospect are detailed in Table 2. All analytical procedures

adhered to industry-standard protocols, and results have passed internal QA/QC checks.

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Table 1: Surface Sampling across subcrop Big Elk Vein

Sample ID Sample

Type

From

(m) To (m) Length (m) True

Width (m) Cu % Au g/t Ag g/t Description

MON_231019_1 channel 0 2.6 2.6 2.4 36.1 0.93 29.55 Big Elk shear vein

subsurface outcrop

MON_230808_1 dump* N/A N/A N/A N/A 6.6 0.14 5.1

Gossanous

copper/iron at dump

on Big Elk drill pad

*Surface rock grab samples, such as those described herein, are selective by nature and are not necessarily indicative of average

grades or the full extent of mineralization.

Table 2: Drill hole summary from Big Elk drilling

Hole ID

Number of

Samples

Assayed

From (m) To (m) Downhole

Length (m)

True

Width (m) Intersection Target

BEP_01 5 22.9 25.1 2.2 2.2 Stope Big Elk Vein

BEP_02 11 No Significant

Intersection Big Elk Vein

BEP_03 11 No Significant

Intersection Big Elk Vein

BEP_04 4 8.8 11.3 2.5 2.5 Stope Big Elk Vein

BEP_05 8 No Significant

Intersection Big Elk Vein

BEP_06 1 23.2 24.7 1.5 1.5 Stope Big Elk Vein

BEP_07 3 18.9 20.7 1.8 1.8 Stope Big Elk Vein

BEP_08 3 16.5 17.4 0.9 0.9 Stope Big Elk Vein

BEP_09 6 23.2 23.8 0.6 0.6 Stope Big Elk Vein

BEP_10 10 No Significant

Intersection Big Elk Vein

BEP_11 N/A No Sample Exploration Hole

BEP_12 N/A No Sample Exploration Hole

BEP_13 N/A No Sample Exploration Hole

BEP_14 N/A No Sample Hole Abandoned,

Incomplete

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com