Borehole mining update: A century from 1926 to 2026 – What’s next? - ME Feature Article

Borehole mining (BHM) is a remotely operated waterjet mining method carried out through wellbores drilled and cased from the surface directly into the production interval. Mining operations are performed using a waterjet tool composed of at least two concentric tubular columns, which create two hydraulic passages: one for pumping high-pressure water down, and the other for transporting the produced slurry to the surface. At the lower end of the dual column, a bottom head is installed, equipped with a hydromonitor that generates a powerful water jet, and an eductor (jet pump). The tool is suspended from a drill rig via a swivel, enabling its rotation and advancement along the borehole. While the waterjet continuously cuts the rock and produces slurry, the eductor lifts the slurry to the surface. In a slurry collection tank or pond, the cuttings are separated and the clarified water is recycled. As ore is extracted, BHM stopes are typically formed that may remain open for an extended time before caving in.