The U.S. Bureau of Mines has designed, built, and tested an abrasive jet borehole miner for hard rock. It integrates an abrasive jet cutter with a downhole slurry pump and is in the form of an assembly that is suspended in a well and is rotated by a turntable at the well head. This device generates a 68.9-Mn/m2, 75.7-Lpm (10,000- psi, 20-gpm) collimated jet containing 7.26 Kg/min (16 lb/min) of abrasive. This jet erodes the rock in the borehole wall and forms a slurry. The addition of the abrasive greatly enhances the erosive power of a 68.9-Mn/m2, 75.7-Lpm (10,000-psi, 20-gpm) jet of water without abrasives. The slurry is pumped to the surface by a downhole eductor. The abrasive jet borehole miner was tested in a simulated well in the laboratory and in a taconite mine. Samples of charcoal granite, Duluth Gabbro, and Sioux quartzite were cut, and the cuttings were pumped in the laboratory. Taconite was cut and pumped from a borehole in an open pit mine.