There are different trenchless tunnelling techniques and new methods are always developed. This method (pilot tube method) is very similar to Horizontal Directional Drilling method and they are from the same family. Source: Trenchless Solutions & LinkedIn Marcio Leao #hdd #horizontaldirectionaldrilling #tunnelengineering #artoftunnelling #tunnel #tunnelengineeringisthefuture #tunnel #tunnelling #tunneling #tunel #civilengineering #miningengineering #knowledge #learntunnelling #tunnelphoto #geote