Microtunneling is defined as a remotely-controlled, guided, pipe-jacking operation that provides continuous support to the excavation face by applying mechanical or fluid pressure to balance groundwater and earth pressures.

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• ​Microtunneling requires jacking and reception shafts at the opposite ends of each drive.

• A microtunnel boring machine (MTBM) is pushed into the earth by hydraulic jacks mounted and aligned in the jacking shaft. 

• The jacks are then retracted and the slurry lines and control cables are disconnected. 

• A product pipe or casing is lowered into the shaft and inserted between the jacking frame and the MTBM or previously jacked pipe. 

• ​Slurry lines and power and control cable connections are made, and the pipe and MTBM are advanced another drive stroke. 

• This process is repeated until the MTBM reaches the reception shaft. 

• Upon drive completion, the MTBM and trailing equipment are retrieved and all equipment removed from the pipeline.

• Precise control of line and grade is accomplished using the guidance system and steering jacks to locate and steer the MTBM during a microtunneling drive.