A term applied to auger boring systems which are similar to microtunneling, but with the guidance mechanism actuator sited in the drive ShaftA pit or wall sunk from the ground surface into a tunnel for the purpose of furnishing ventilation or access to the tunnel. (e.g. a hydraulic wrench which turns a steel casing with an asymmetric face at the cutting head). The term may also be applied to those auger boring systems with rudimentary articulation of the casing near the head activated by rods from the drive pit.
