| abstract |
An abrasive-fluid jet apparatus and process for drilling holes in rock having a rotary drill bit with multiple abrasive-fluid jet nozzles in the face of the bit and a stationary drill head housing torque generation apparatus and a rotary mounting holding the rotary drill bit beneath and in rotatable relation to the drill head. Abrasive supply facilities and fluid supply facilities are located at ground level for separate supply of the abrasive and the fluid to the abrasive-fluid jet nozzles. It is preferred that the abrasive be supplied to the nozzles in the form of slurry or foam. The apparatus and process of this invention permits deep hole drilling at lower fluid pressures than and without surface structures required by current deep drilling apparatus and techniques. |