Apparatus for assembling a liner

Apparatus according to any one of the preceding claims wherein the guide surface comprises a guide ring having an outer circumference defining one of the boundaries and an inner circumference defining the other boundary.

Apparatus according to any one of the preceding claims wherein the longitudinal sections of flexible material are adapted to be joined one to another at adjacent longitudinal edges with a connector assembly.

Apparatus according to any one of the preceding claims in combination with a recovery head and a pipe string to assemble a shroud about the pipe string behind the recovery head for lining a passage created by the recovery head to prevent material in the surrounding environment from collapsing onto the pipe string.

A recovery head comprising a chamber for receiving material to be recovered, a screen associated with the chamber for screening material entering the chamber, and a propulsion means for propelling the recovery head through a formation containing the material to be recovered, the propulsion means comprising an endless track having a first run which is exposed to the exterior of the recovery head for driving engagement with the environment through which the recovery head is to pass and a second run within the confines of the recovery head so as not to be exposed to that environment.

A guide structure presenting a guide surface about which a length of flexible material can be turned, the guide structure presenting a guide surface extending between first and second boundaries with at least one of the boundaries being arcuate, characterised in that the two boundaries are substantially of equal length.

A guide ring structure presenting a guide surface about which a length of flexible material can be turned, the guide surface having an outer circumference and an inner circumference, characterised in that the outer and inner circumferences are of substantially equal length.

A guide structure presenting a guide surface over which a length of flexible material can be turned, the guide surface extending between first and second boundaries, characterised in that the length of an arc between any two points which are on the first and second boundaries and which are aligned with each other in the direction of travel of the length of sheet material across the surface is substantially constant.

Apparatus for assembling a liner in combination with a recovery head and pipe string to assembly a shroud defined by the liner about the pipe string behind the recovery head for lining a passage created by the recovery head.

Apparatus for assembling a liner substantially as herein described with reference to the accompanying drawings.

Apparatus for assembling a liner in combination with a recovery head and pipe string to assembly a shroud defined by the liner about the pipe string behind the recovery head for lining a passage created by the recovery head, substantially as herein described with reference to the accompanying drawings.