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
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)
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 positive 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 did 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, Idaho for an ICP analysis.
Figure 2: Map of the Big Elk Prospect, a subset of the Monitor Project
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 Company 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. Subsequent 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.