
170 Million Silver Equivalent Ounces Inferred Mineral Resource
Major Potential Source of U.S. Critical Minerals and Precious Metals
Silver Bow Mining Corp. 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.
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:
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:
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 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:
Qualified Persons
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.
Figure 1: Aerial image showing the location of the Rainbow Block and other Silver Bow Mining claims in the Butte, Montana district.
Figure 2. Oblique view showing the Mineral Resource Estimate wireframe values in gold, and historic workings in grey.
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