Microtunnel boring machine
Appearance
Microtunnel Boring Machines (MTBM) are very similar to tunnel boring machines but on a smaller scale. These machines generally vary from 24” to 60” but smaller and larger machines have existed. The main differences between MTBM and TBM operations are 1- MTBM is operated by remote control and 2- MTBM usually has the tunnel liner pushed behind the machine instead of built as the machine advances
For additional Information see:
Microtunneling Tunnel boreing machine http://www.insituform.com/howwedoit/microtunneling_insituform.htm