Abstract: A method for replacing an existing buried pipe of a crackable, fracturable material. By the application of a local intense pressure, the pipe is cracked and fractured into irregular fragments which are spread outwardly to provide space for a new replacement tubular assembly which is moved into the space as the pipe is fractured and the fragments spread. At least a portion of the outward spreading of the fragments occurs under the action of the intense local pressure. An apparatus used to carry out the method may be pushed and/or pulled through the existing main, and the pushing force may be applied by percussive action.

Abstract: An apparatus for replacing an existing buried pipe of a crackable, fracturable material. The apparatus has a fracturing structure which applies an intense local pressure to crack and fracture the existing buried pipe into irregular fragments. This fracturing structure can include one or a plurality of blades, some of which may be retractably and expandably movable. The structure which exerts the intense local pressure is also operable to effect at least some outward movement of the fragments. An expansion structure moves the fragments radially outwardly, generally about the axis of the existing main, to provide a passage for a replacement tubular assembly. The apparatus is moveable through the existing main by the action of either a pushing or a pulling force, and the pushing force may be applied by percussive action.

Abstract: A mole 1 for replacing an existing main, for example a cast iron gas main, with a new main. The mole 15 is of steel and is inserted into and along the existing main 94. The mole 51 has a front portion comprising a head 52 and a cylindrical body portion and a rear portion 53 having a clamp 54 for clamping a new main to the mole 51. The head 52 has a cutting face 55 for engaging the internal wall of the existing mole 51 therealong. The new main which in use is clamped to the mole 51 is towed along behind the mole 51 to replace the fractured old main 94.