US Richmond Mountain gold-silver mine drilling hits high-grade ore

Dakota Gold has discovered additional high-grade ore bodies within the planned open-pit mining area at its Richmond Hill project in South Dakota, US, Mining.com reported.

The company announced Monday that step-out hole RH26C-432 intersected 26 m of 11.36 g/t gold and 14.92 g/t silver from a depth of 75 m.

Hole RH26C-437 intersected 38 m of 2.89 g/t gold and 8.18 g/t silver from a depth of 145 m.

The company recently completed its 2026 drilling program at Richmond Hill, comprising 112 holes — including infill, step-out, and geotechnical holes — for a total of 17,273 m. Gold and silver assay data from more than 350 holes completed year-to-date will be used in a prefeasibility study, with results expected to be released before December 31.

The results disclosed Monday "expand the footprint of high-grade mineralization outside the measured and indicated resource area and should enable resource growth ahead of the prefeasibility study," said Eric Winmill, mining analyst at Scotia Capital.

Key Highlights

Other intercepts include:

◎Hole RH26C-452 intersected 16 m of 1.63 g/t gold and 12.03 g/t silver from a depth of 79 m.

◎Hole RH26C-448 intersected 22 m of 0.61 g/t gold and 55.85 g/t silver from a depth of 11 m.

Dakota Gold stated that the Richmond Hill prefeasibility study has identified critical long-lead procurement items. The largest is a substation, for which the company has secured a construction schedule through Black Hills Energy.

Dakota Gold added that step-out drilling in the northeastern portion of Richmond Hill remains open in all directions.

Richmond Hill is located approximately 320 km west of Pierre, the state capital of South Dakota, within a 180 km² land package the company controls near the historic Homestake mining district. The property hosts a large oxidized gold system amenable to conventional open-pit mining and heap-leach processing.

The Homestake mine produced approximately 40 million oz of gold over more than 145 years before ceasing operations in 2002.

Mine Developer

An initial resource estimate in February 2025 outlined measured and indicated resources of 244.7 million mt at 0.46 g/t gold and 4.83 g/t silver, with inferred resources of 230.6 million mt at 0.35 g/t gold and 3.09 g/t silver.

According to an S-K 1300 preliminary assessment, the Richmond Hill project is expected to have a mine life of 28 years, producing 2.6-3.9 million oz of gold, with an after-tax net present value of $1.6 billion to $2.1 billion, an after-tax internal rate of return of 55%-59%, and initial capital of $384 million. The project is expected to commence production in 2029.