Underground warning system for underground conduits or pipes

摘要

The invention provides a warning to the excavation above a pipe, conduit or cable laid underground by a service utility by the directional drilling method by providing a coloured area of drilling mud and/or soil about the pipe, conduit or cable. A colouring material is added to the drill fluid during the direct drilling operation which then colours the drill mud and/or soil about the pipe, conduit or cable.