Silver Bow Mining intersected high-grade polymetallic mineralization at the Rainbow Block project in Butte, Montana, returning 4.0 metres grading 994.2 grams per tonne silver equivalent from drill hole SBM26-03.

A second surface hole, SBM26-04, intersected multiple mineralized veins outside the current resource boundary, returning 2.0 metres grading 693.1 grams per tonne silver equivalent from the Jessie Vein and 1.6 metres grading 502.0 grams per tonne silver equivalent from the State Vein. Silver Bow has three surface rigs operating, completing approximately 13,500 feet of the planned 25,000-foot Phase I program.

Silver Bow designates the Rainbow Block as its flagship asset, holding approximately 4,210 acres of patented mineral claims and 1,427 acres of surface lands. To support future underground exploration, the company initiated the rehabilitation of the Chief Joseph portal and decline in May 2026.

In August 2026, Silver Bow agreed to acquire the Jefferson County Metallurgical Complex, planning to apply its 1,000-tonne-per-day processing circuit to treat material from the Rainbow Block.

“The 4-meter intercept in SBM26-03 grading 994.2 g/t AgEq, including a 2.3-meter core at 1,586.1 g/t AgEq, is the strongest interval we have drilled to date at the Rainbow Block,” said Phillip Nickerson, PhD, CPG, Vice President of Exploration. “We believe we are still in the early stages of characterizing the scale and extent of the mineralized system at the Rainbow Block.”

— Phillip Nickerson, PhD, CPG, Vice President of Exploration

The company plans to complete an updated Mineral Resource estimate for the project in the first half of 2027, incorporating ongoing drill results alongside historical assay information from previous operators.

Read the full announcement: Silver Bow Mining Intersects 994.2 g/t AgEq Over 4.0 m, including 1,586.1 g/t AgEq Over 2.3 m, from the Rainbow Block in Butte, Montana