Mole ploughing and narrow trenching are not trenchless technologies but they both create narrow temporary trenches for installing small diameter services that minimize the adverse impact associated with traditional underground construction methods requiring wide trenches. These two techniques use plows, cutter chains, or disc to open a furrow or narrow trench in which a flexible pipe or cable is inserted.
Mole ploughs or cable ploughs work best in easily displaceable soils that can be reused as fill. The mole plough machine pushes the spoils removed by the plough back into the hole as the machine feeds the new service into the hole eliminating the need for backfill.
Narrow trenchers are capable of installing utilities in a variety of ground conditions from normal soils to paved surfaces depending on the cutter picks and chain/wheel system selected. Narrow trenches require back fill and may require restoration of surface to preconstruction conditions.