Pilot Tube Microtunneling (PTM)
Pilot tube microtunneling is a hybrid of three trenchless techniques. It uses a guidance system with the accuracy of a microtunnel machine, a slanted or angled steering head similar to a directional drill and an auger similar to an auger bore machine. This process is initiated with the installation of the pilot tubes along the desired line and grade. These tubes are then pushed or cycled out of the bore hole into the exit shaft by a reaming head. The product pipe is installed directly behind the reaming head and used to thrust the reaming head forward.