(1) A type of Directional DrillingA steerable system for the installation of pipes, conduits and cables in a shallow arc using a surface launched drilling rig. Traditionally the term applies to large scale crossings in which a fluid-filled pilot bore is drilled using a fluid-driven motor at the end of a bend-sub, and is then enlarged by a washover pipe and back reamer to the... or Guided BoringMethod for the installation of pipes, conduits and cables using a surface-launched drilling rig. A pilot bore is drilled using a rotating drill string and is then enlarged by a back reamer to the size required for the product pipe. The necessary deviation during the pilot boring is provided by a slanted face to the drill head, an asymmetric drill... technique using pressurized fluid jets to provide the soil cutting action. (2) A process using high pressure water to wash out the face of a utility crossing without any mechanical or hand excavation of the soils in the face. This process has also been used to remove the material in open pit mining.
