170 Million Silver Equivalent Ounces Inferred Mineral Resource
Major Potential Source of U.S. Critical Minerals and Precious Metals
Butte, Montana--(Newsfile Corp. - June 30, 2025) - Silver Bow Mining Corp. (the "Company" or "Silver Bow Mining"), a critical minerals and precious metals exploration company with significant properties within the Butte Mining District, today announced the release of a Mineral Resource Estimate on its flagship Rainbow Block property (Fig. 1). The Company believes the property represents a major potential domestic source of critical minerals essential to U.S. national security and economic competitiveness, supporting the Administration's America First Energy Agenda and directly addressing supply chain vulnerabilities highlighted in the March 20, 2025 Executive Order calling for "Immediate Measures to Increase American Mineral Production. The Mineral Resource Estimate is contained within a Technical Report titled 'Technical Report Summary: Rainbow Block, Butte Mining District, Silver Bow County, Montana, USA' prepared in accordance with the standards set forth in Item 1302 of Regulation S-K issued by the U.S. Securities and Exchange Commission ("S-K 1300") and National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101") Technical Report titled 'Technical Report on the Rainbow Block Property, Butte Mining District, Silver Bow County, Montana, USA', each with an effective date of December 31, 2024, and each prepared by Jacob Anderson, CPG, MAusIMM of Dahrouge Geological Consulting ("Dahrouge").
| Vein Material | AgEq | ||
| Category | Tons (M) | oz (M) | oz/t |
| Inferred | 11.48 | 170.0 | 14.8 |
| Total | 11.48 | 170.0 | 14.8 |
| Vein Material | AgEq | ||
| Category | Tonnes (M) | oz (M) | g/tonne |
| Inferred | 10.4 | 170.0 | 507.4 |
| Total | 10.4 | 170.0 | 507.4 |
Mineral Resource Statement under S-K 1300 and NI 43-101 standards at 31st December 2024, for the Rainbow Block in imperial and metric units
| Metal | Unit | Price (US$) | Recovery |
| Gold (Au) | oz | $2,500 | 100% |
| Silver (Ag) | oz | $25.00 | 100% |
| Zinc (Zn) | lb | $1.31 | 100% |
| Lead (Pb) | lb | $0.90 | 100% |
Commodity prices and metallurgical recoveries utilized in AgEq calculation
Key Highlights:
- 170 million silver equivalent ounces inferred mineral resource at 14.8 oz/ton within 11.48 million tons of vein material conducted under S-K 1300 and NI 43-101 standards
- 100% ownership of 887 acres of patented mineral rights on the Rainbow Block, part of the Company's 3,300 total acres of mineral rights in the Butte Mining District
- 42 veins above current water table and within 1,000 ft of surface
- Established infrastructure with exploration permit in place and underground decline permit amendment in progress
- Over 10,000 miles of historical workings1 demonstrate extraction of ore in the Butte Mining District has had reasonable success where operations had sufficient grade, quantity, and geological understanding
Average Grade by Metal and Contained Metal in the Silver Equivalent (AgEq) Mineral Resource
Average individual metal grades and contained metal for the individual metals included in the AgEq calculation within the AgEq Mineral Resource for the Rainbow Block were calculated using a cut-off grade of 4 oz/t AgEq. Cut-off grades for individual metals have not been applied in determining average grade and contained metal.
| Average Grade and Contained Metal in the AgEq Mineral Resource (Imperial Units) | ||||||||
| Vein Material | Silver (Ag) | Gold (Au) | Lead (Pb) | Zinc (Zn) | ||||
| Tons (M) | Ounces | oz/ton | Ounces | oz/ton | lbs (M) | % | lbs (M) | % |
| 11.48 | 49,155,194 | 4.28 | 553,549 | 0.05 | 287 | 1.25 | 1,053 | 4.59 |
| Average Grade by Metal and Contained Metal in the AgEq Mineral Resource (Metric Units) | ||||||||
| Vein Material | Silver (Ag) | Gold (Au) | Lead (Pb) | Zinc (Zn) | ||||
| Tonne (M) | Ounces | g/tonne | Ounces | g/tonne | Tonnes (M) | % | Tonnes (M) | % |
| 10.4 | 49,155,194 | 146.7 | 553,549 | 1.7 | 0.13 | 1.25 | 0.47 | 4.59 |
Average grade by metal and contained metal in the AgEq Mineral Resource Statement in imperial and metric units
The Mineral Resource Estimate was prepared by Dahrouge Geological Consulting from a comprehensive database including 273 historical drill holes, 8 recent diamond drill holes, and over 15,000 Anaconda Company underground channel samples. The assessment utilized wireframe boundaries to domain the combined drill-hole and channel sampling database into 42 veins, with results reported using a cut-off value of 4 oz/ton AgEq and constrained to 1,000 feet below surface and above the modern water table. Metallurgical recoveries of 100% were assumed for all metals in the Mineral Resource Estimate in the absence of specific metallurgical testing. The Company plans to conduct comprehensive metallurgical studies to determine actual recovery rates, which will inform future resource calculations and development planning.
Based on this comprehensive assessment, the Company has established an inferred Mineral Resource Estimate of approximately 170 million silver equivalent ounces. The Company intends to advance this resource through upgraded classification studies, modern metallurgical testing, and evaluation for narrow-vein underground mining utilizing the latest backfill technologies to optimize extraction efficiency and environmental performance.
Management Commentary
"We believe that Silver Bow Mining represents a unique opportunity to strengthen America's critical mineral supply chains while unlocking remaining value from one of the highest-grade silver equivalent deposits in one of the world's most prolific mining districts," said Travis Naugle, Chairman and CEO. "With over 60% of our estimated resource value derived from precious metals, we expect that our project will directly address the U.S. Government's call for immediate measures to increase American mineral production, providing potential for future domestic production of zinc, silver, gold and lead at a time of supply chain pressures. We recognize the importance of key stakeholder engagement with the Butte community, Butte-Silver Bow local and county administration, the State of Montana, and applicable federal agencies to ensure our development approach aligns with both community interests and national security objectives. We are mindful of ongoing remediation efforts in the Butte Mining District and cognizant of addressing impacts from our future mining activities. We will also evaluate the presence of critical minerals previously known to be associated with the Butte zinc veins, including antimony, bismuth, indium, germanium and gallium."
Dr. Quinton Hennigh, Director and globally renowned exploration geologist, added: "The Rainbow Block's exceptional grades and the district's proven geology provide a compelling foundation for resource expansion. We will evaluate the potential for resource growth beyond our current estimate, targeting silver-zinc and copper veins, and copper porphyry potential. The wealth of meticulously collected Anaconda Company data is already directing us to specific areas for immediate resource expansion and porphyry targeting opportunities."
Historic Context
The Butte community has a proud legacy of supplying critical minerals for America's development and defense. Silver Bow Mining's claims cover a portion of the historically significant Butte Mining District, where the local community contributed tremendously to America's first great electrification and both World Wars:
The Butte Mining District has historically produced abundant critical minerals including zinc, copper, manganese, bismuth, gallium, germanium and indium
In 1896, an area five square miles in the Butte Mining District produced 210 million pounds of copper annually, representing 26% of world supply, and 51% of America's copper supply2
Butte's copper mines produced approximately one-third of all copper mined in America between World Wars I and II3
From 1881 to 2019, the Butte Mining District produced: 24.7 billion lbs copper, 702 million oz silver, 4.8 billion lbs zinc and 2.9 million oz gold along with significant molybdenum and manganese4
The U.S. Geological Survey estimates that the remaining resources in the district include 50 billion lbs copper, 720 million oz silver and 5 billion lbs Zinc5
Silver Bow Mining has yet to determine the total extent of resources on the Rainbow Block and on other mineral concessions owned by the Company
Strategic Land Position
Silver Bow Mining has assembled a comprehensive 3,300-acre land package across the historic Butte Mining District, anchored by the flagship Rainbow Block (Fig. 1). This consolidated position provides the potential for significant exploration upside and operational flexibility within one of America's most prolific mining districts.
| Property Block | Mineral Rights | Surface Rights | Status |
| Rainbow Block | 887 acres | 299 acres | Mineral Resource Estimate complete above water table |
| Marget Ann Block | Included in total | 144 acres | Exploration stage |
| Goldsmith Block | Included in total | 330 acres | Exploration stage |
| Travona Block | Included in total | - | Exploration stage |
| Emma Block | Included in total | - | Exploration stage |
| Total District Holdings | 3,300 acres | 773 acres |
Regulatory Framework and Current Permits
Silver Bow Mining operates under Montana's established mining regulatory framework, with the Montana Department of Environmental Quality (DEQ) serving as the primary permitting authority for patented mining claims. The Company holds a current Exploration License which authorizes surface drilling programs and underground rehabilitation activities, including restoration of the Chief Joseph portal and legacy underground workings.
To support resource expansion activities, Silver Bow Mining has submitted a license amendment to construct a new exploration decline, enabling future underground drilling and bulk sampling programs designed to upgrade and expand the current Mineral Resource Estimate.
Strategic Advantages
Silver Bow Mining benefits from numerous competitive advantages:
Critical Minerals and Precious Metals Focus: Poly-metallic deposit addressing multiple supply chain vulnerabilities simultaneously
Domestic Control: Majority U.S.-owned with full U.S. management, reducing foreign dependency risks
Expansion Potential: Current mineralization remains open along strike, laterally, and at depth, with numerous untested targets providing substantial resource growth opportunities beyond the currently identified veins
Established Infrastructure: Adjacent to Montana Resources' operating Continental Pit with existing processing and transportation networks
Brownfield Development: Extensive legacy underground workings that may facilitate development timeline and capital efficiency
Clear Regulatory Path: Project located entirely on private patented lands under Montana DEQ jurisdiction, providing clear development pathway under experienced Montana mining leadership
Data-Rich Environment: Comprehensive historical mining and metallurgical data from Anaconda Company operations
Experienced Leadership: Led by experienced Montana mine developers and exploration professionals with decades of relevant experience in the state and large system experience in the US and globally
Qualified Persons
- Mr. Jacob Anderson, CPG, MAusIMM of Dahrouge Geological Consulting, is the independent Qualified Person ("QP") pursuant to NI 43-101 and S-K 1300 standards, who prepared the Mineral Resource Estimate and has reviewed and approved the technical information disclosed in this news release.
- Dr. Phillip Nickerson, CPG, Vice President of Exploration for the Company, is a Qualified Person pursuant to NI 43-101 and has reviewed and approved the scientific and technical information disclosed in this news release.
About Silver Bow Mining Corp.
Silver Bow Mining Corp. is a critical minerals and precious metals exploration company focused on silver, zinc, gold, lead and copper targets in Montana's historic Butte Mining District, one of the most significant mineral districts in the U.S.
Forward-Looking Statements
This press release contains statements that are forward-looking in nature. The forward-looking statements within the meaning of applicable securities laws. These statements contained in this press release are based on our current expectations and beliefs concerning future developments and their potential effects on us and involve known and unknown risks, uncertainties, and other factors that may cause actual results to differ materially from those expressed or implied by such forward-looking statements., including but not limited to, our ability to access financing, appropriate equipment and sufficient labor, the future prices of silver and other minerals that may be mined by the Company, the political, economic, permitting and legal environment in which the Company operates; the timing and receipt of governmental, regulatory and third party approval, consents, licenses and permits and their renewals; positive relationships with local groups; and the accuracy of the Mineral Resources Estimates and related information, analyses and interpretations.
Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those expressed or projected in these forward-looking statements. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.
Citations
1. Gammons, C., Metesh, J., & Duaime, T. (2006). An Overview of the Mining History and Geology of Butte, Montana Mine Water and the Environment, p. 70-75
2. Hoffman, L. (2001, June 14-17). The mining history of Butte and Anaconda [Conference presentation]. Mining History Association 12th Annual Conference, Montana Tech, Butte, Montana.
3. Cotler, G., & Gill, B. (1951, March 17). Copper. The New Yorker. https://www.newyorker.com/magazine/1951/03/17/copper
4. Reed, M. & Dilles, J. (2020) Ore deposits of Butte, Montana. Montana Bureau of Mines and Geology, Special Publication 122, p. 1-41.
5. Long, K. R., DeYoung, J. H., Jr., & Ludington, S. (1998). Database of significant deposits of gold, silver, copper, lead, and zinc in the United States (Open-File Report 98-206-A,B). U.S. Geological Survey. https://doi.org/10.3133/ofr98206AB
Contact Information
Silver Bow Mining Corp.
General Inquiries: info@silverbowmining.com
Website: www.silverbowmining.com
Note: All monetary figures are in U.S. dollars unless otherwise stated. Tons ("t") refer to imperial tons, and tonnes refer to metric tonnes. Mineral resource estimates are based on S-K 1300 and National Instrument 43-101 standards. Technical Reports are available at www.silverbowmining.com.
Figure 1: Aerial image showing the location of the Rainbow Block and other Silver Bow Mining claims in the Butte, Montana district.
To view an enhanced version of this graphic, please visit:
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Figure 2. Oblique view showing the Mineral Resource Estimate wireframe values in gold, and historic workings in grey.
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To view the source version of this press release, please visit https://www.newsfilecorp.com/release/257364
SOURCE: Silver Bow Mining Corp.
