This method applies to pipeline diameters from 168mm to 2000mm and the boring equipment comes in many different variations and sizes. Smaller machines are commonly used for installing new pipelines, launching from existing manholes or verry narrow starting pits, due to their compactness. An important advantage of the technology is that the pipe installation occurs simoultaneously with the boring itself, which minimizes the extraction of soil and the risk of collapsing. For achieving a higher precision of the boring, some machines are equipped with a laser directional system and offer the means to steer the pilot hole.
The machine consists of a cutting head, augers for transportation of the excavated soil from inside the pipe out and a hydraulic press. The pipeline is installed between a launching and an end pit in sections, one after the other. In the launching pit the machine, mounted on tracks thrusts the pipe and rotates the augers and the cutting head inside. The cutting head shreds the soil in front and forms a tunnel, in which the pipe installation follows. The soil, which is carried out of the pipe into the launching pit by the augers, is transported out of the pit with an excavator. After the first pipe section is installed the machine travels back to the rear end of its track, a new pipe section is mounted and the boring continues. The process is repeated until the cutting head reaches the end pit.