Transatlantic Provides Update on Drilling at the Historic Miller Gold Mine, Montana

Rhea-AI Summary

Transatlantic Mining Corp. (TSXV: TCO) has provided an update on its drilling program at the historic Miller Gold Mine in Montana. The company has completed 2,069 meters across 25 holes of a planned 3,000-meter Phase 1 campaign. The drilling program includes 8 deep holes under existing workings, 10 exploration holes for north-south extension, and 7 shallow holes testing an old mine dump.

The Miller Mine, historically active between 1901-1948, has shown significant historical grades of 7.94 oz/ton Au (248 g/t Au) and 4.65 oz/ton Ag. A notable historical drill hole (#1) recorded 14.7 oz/ton Au (516 g/t) 300 feet below the lowest workings. The company is now mobilizing an underground drill rig to test the lower target area, with initial assay results expected by early September 2025.

[ "Completed 2,069 meters of drilling across 25 holes in Phase 1 campaign", "Historical high-grade results of 248 g/t Au and 145 g/t Ag", "Recent grab samples from Lower Level Winze showed 27.6 g/t Au", "Company has option to acquire 100% of the Miller Mine" ]

Positive

• None.

Negative

• Results from first 17 holes still pending laboratory analysis
• Historical production was only conducted on small scale with sporadic output

Vancouver, British Columbia--(Newsfile Corp. - August 27, 2025) - Transatlantic Mining Corp. (TSXV: TCO) (the "Company") is pleased to provide an update on drilling at the historic Miller Mine in Montana, USA.

On December 21, 2020 Transatlantic exercised its initial option term to acquire 100% of the Miller Mine located in the Broadwater County in the State of Montana , USA. These claims are approximately 29 miles to the northeast of Townsend in Montana USA with gold mineralization that has been verified on the old levels of the historic Miller mine predominantly mined between 1900 and the 1940's.

Transatlantic is drilling down dip of the historic lower levels to over 100 metres of strike and depth on the principal vein structure as well as exploration along strike north and south. Transatlantic has completed 2,069 metres (m) in 25 holes of a 3,000 m planned program in phase 1 campaign.

The hole depth range is from 10 m to 207 m. Phase 1 comprises of a total of 25 holes. (Hole # 14: Figure 2). Of the 25 holes completed, 8 have been drilled deeper under the existing workings in the upper target area (Figure 1), 10 have explored extension to the north and south and 7 shallow holes have tested an old mine dump. The main target and focus is the vein/s on the contact of the sediment and granodiorite.

Samples from the first 17 holes have recently been submitted to the Laboratory with assays and results projected to be completed end of August early September.

In concert with the surface drilling phase 1, we are now mobilising an underground drill rig today for testing the lower target area (Figure 1).

The target is being well intersected on the sediment granodiorite contact to date," said Transatlantic CEO Bernie Sostak. "We are getting near the end of the phase 1 drilling campaign, and are looking forward to sharing the results with investors."

Figure 1 - Miller Mine Resource Drilling Target Areas

To view an enhanced version of this graphic, please visit:
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Webinar Recording: CEO Bernie Sostak hosts an interactive webinar discussing the company's drill program and future plans at Miller: Click HERE to view.

Fig 2. Drill Rig on Hole 14 at the Miller Mine in Montana, with stockpile in background

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The Miller Gold Mine is located in the Broadwater County in the State of Montana, USA. The mine is approximately 29 miles northeast of Townsend in Montana USA. The presence of gold mineralization has been confirmed by previous sampling in areas of the mine where access is possible. Transatlantic is earning into the historic Miller Gold Property by means of a gold production royalty near Helena, Montana.

A historical Report (*) on the Miller Mine notes that historically, gold bearing ore was mined on a small scale by individual owners with sporadic production between 1901 and 1948. The mine is being re accessed by Transatlantic to review existing ground conditions and infrastructure for ongoing rehabilitation.

Located at the top end of the Confederate Gulch near what is now a ghost town in Diamond City, of which once had a population of + 10,000. Placer gold was abundant and rich in this Gulch.

• Miller had an average recovered mine grade of 7.94 Oz /ton Au (248 g/t Au ) and 4.65 Oz /ton Ag ( 145 g/t Ag)(*)
• Hole #1 was drilled 300 feet below the lowest recorded workings and recorded 14.7 Oz /ton Au (516 g/t Au)

The Miller Mine mineralization occurs in quartz veins within and on the contact of a quartz granodiorite stockwork. The discrete veins dip between 30 and 80 degrees whilst the stockwork has multiple veinlets that range in width from a few cms to 2 metres. The contact zone of alteration has been noted as over 15 m wide ( 50 feet ). Mining has been undertaken on both an open cut and underground methodology. The mine is at an elevation of 2000 m ( 6650 feet)

Highlights of previous sampling ( see news release dated June 14, 2023)

Miller Mine - Lower Level

• Opened up Lower Winze Level immediately below the Lower Level.
• First grab samples from Lower Level Winze include 27. 6 g/t Au(**), visual gold has also been observed.
• Extended Lease Agreement to first renewal term with option to purchase by production royalty.

About the Miller Mine and Claim Group:

Transatlantic has access to the Upper and Lower Level of the mine. The Miller Mine is situated amongst patented and unpatented claims at an elevation of 1920 m (6,400 feet) and accessible by roads 50 miles from Helena, Montana USA. Should mining occur at any time, an 8.5% royalty on ounces is to be paid. During the term of the agreement, the Company may purchase the property for US $4,500,000, less the royalty payments made above, with a perpetual 1% NSR to the vendor thereafter.

The gold and silver mineralization generally occurs on the contacts of sediments and igneous intrusive with native gold and sulphides including pyrite often observed amongst the 4 known adits located on the property.

Qualified Person and NI 43-101 Disclosure

Aslam Awan PhD MAusIMM (CP Geo) is the Qualified Person pursuant to National Instrument 43-101 for having reviewed, only the technical information contained in this news release. Mr. Awan is the Principal for AAA Geo Consultants and is Independent of the Company.

Rock Chip Samples may not reflect the average grade of mineralisation

QA/QC and Core Sampling Protocols

(**) The rock chip samples are grabs from the winze level drive of 5 kg in weight. The samples were crushed in whole to plus 70 % passing 2 mm and then split and pulverised with analysis for gold and silver at the Christofferson Laboratory, Smelterville, Idaho USA. The Laboratory is an independent assay and umpire laboratory that follows industry techniques. The samples after being pulverised are analysed with a 15 to 30 gram fire assay charge and gravimetrically finished.

(*) Hemsworth FJ: Report on the Miller Mine Helena Montana ( July 2 1969)

(**) Company News Release dated June 14, 2023

About Transatlantic Mining Corp.

Transatlantic Mining (TSXV: TCO) is an emerging precious and base metal explorer. The Company has a focus on converting projects into mines within stable mining jurisdictions. The Company currently has property interests including an 80% Joint Venture position on the Monitor Copper-Gold project in Montana-Idaho (USA) and 100 % of the Golden Jubilee Gold Project with its associated mining rights. The Company has an extended lease, right to mine and purchase arrangement for the Miller Gold Mine in Montana to 100% ownership by way of payment royalty.

ON BEHALF OF THE BOARD OF DIRECTORS

" Bernie Sostak"

For more information contact:
eeinarson@transatlanticminingcorp.com
604-614-8469

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/264158

FAQ

What is the current status of Transatlantic Mining's (TRRGF) drilling program at Miller Gold Mine?

As of August 2025, Transatlantic has completed 2,069 meters across 25 holes of a planned 3,000-meter Phase 1 campaign, with samples from the first 17 holes awaiting laboratory results.

What were the historical gold grades at the Miller Gold Mine?

The Miller Mine historically averaged 7.94 oz/ton Au (248 g/t Au) and 4.65 oz/ton Ag (145 g/t Ag), with a notable historical drill hole recording 14.7 oz/ton Au (516 g/t).

Where is the Miller Gold Mine located?

The Miller Gold Mine is located in Broadwater County, Montana, approximately 29 miles northeast of Townsend, at an elevation of 2,000 meters (6,650 feet).

What is Transatlantic Mining's ownership status of the Miller Mine?

Transatlantic exercised its initial option term to acquire 100% of the Miller Mine in December 2020, and is earning into the property through a gold production royalty arrangement.

When will Transatlantic Mining (TRRGF) release the drilling results from Miller Mine?

The company expects to receive and release assay results from the first 17 holes by late August to early September 2025.