When rock is cut mechanically, as opposed to a drill and blast system, a single machine can break, load, and often transport the rock from the working area in a continuous mechanized process. Often the rock encountered in hardrock mining operations is too hard to cut with conventional mechanical cutting technology. Mining and Construction Technologies, through a cooperative research project with the U.S. Bureau of Mines, and with funding from the State of California, is investigating whether the application of water-jet-assisted cutting to mechanized cutting bits can improve this cutting process. Several attempts to reduce cutting forces through the use of water-jet-assisted cutting at pressures of 70 MPa (10,000 psi) or less proved unsuccessful underground. In this project, a novel drag bit was designed, and an arrangement for mounting the water jet nozzles close to the rock face was developed. In underground tests, cutting two types of hard rock ranging in unconfined compressive strength from 105 to 245 MPa (15,000 to 35,000 psi), the use of the water jet assist significantly reduced bit force reductions in the range of 30 to 40 pct. Another advantage noted was a reduction in bit wear when the jet-assisted cutting was employed.