The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.

The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.

A blade drive shaft assembly (100) for a road saw comprising a shaft (120), a first mounting plate (125), a spacer removably fitted (126) on the shaft (120), a second mounting plate (127) removably fitted on the shaft (120), a mounting plate fixing adapted to secure the second mounting plate (127) to the shaft, a first circular saw blade mounted between the first mounting plate and the spacer (126), and a second circular saw blade mounted between the second mounting plate (127) and the spacer (126), wherein the first mounting plate (125) is integrally formed with the shaft (120) from a single piece of metal. A road saw incorporating the assembly is also described, as well as a method of forming, filling and compacting a trench and a method of making a blade drive shaft assembly.

A caisson or casing 107 for installing a sheet 102/103 into a ground or underwater location, the caisson 107 having a shaped wall 107.1, which is open for a predetermined length and is adapted to receive and connect to an excavation means 3 within the confines of the caisson or casing 107. In at least one embodiment, the system includes a drilling assembly 3 for insertion of a caisson or casing 1, the drilling assembly 3 having one or more expanding drill bits 4 which are adapted to be driven by a drilling or rotation motive device 5, the expanding drill bits 4 being adapted to be arranged with respect to the caisson or casing 1 in use, so as form a hole or bore which substantially conforms to, or substantially overlaps with, the shape of the caisson or casing 1.

A caisson or casing 107 for installing a sheet 102/103 into a ground or underwater location, the caisson 107 having a shaped wall 107.1, which is open for a predetermined length and is adapted to receive and connect to an excavation means 3 within the confines of the caisson or casing 107. In at least one embodiment, the system includes a drilling assembly 3 for insertion of a caisson or casing 1, the drilling assembly 3 having one or more expanding drill bits 4 which are adapted to be driven by a drilling or rotation motive device 5, the expanding drill bits 4 being adapted to be arranged with respect to the caisson or casing 1 in use, so as form a hole or bore which substantially conforms to, or substantially overlaps with, the shape of the caisson or casing 1.

A system and method for installing a membrane-lined wall for levee reinforcement or leak prevention. The installation system may comprise a sled positioned above the trench having a length, and may comprise a frame and support members, and a weight suspension system mounted on the frame to lower an elongated weight into the trench. The liner installation sled may also include a liner roller rotatably mounted on the frame, the liner roller adapted to hold a roll of a liner above the surface on a first side of the trench when the liner installation sled is in an installation position relative to the trench, wherein a longitudinal axis of the roll of liner can be aligned with the length of the trench. The elongated weight is usable to force the liner into the trench.

A system and method for installing a membrane-lined wall for levee reinforcement or leak prevention. The installation system may comprise a sled positioned above the trench having a length, and may comprise a frame and support members, and a weight suspension system mounted on the frame to lower an elongated weight into the trench. The liner installation sled may also include a liner roller rotatably mounted on the frame, the liner roller adapted to hold a roll of a liner above the surface on a first side of the trench when the liner installation sled is in an installation position relative to the trench, wherein a longitudinal axis of the roll of liner can be aligned with the length of the trench. The elongated weight is usable to force the liner into the trench.

De-trenching apparatus (100) for extracting a buried line, such as a cable or pipeline, is disclosed. The de-trenching apparatus comprises a channel (112) configured to receive a buried line to be extracted, the channel comprising a first flared opening (114) at a front end of the de-trenching apparatus and a second flared opening (115) at the rear end of the de-trenching apparatus, the first and second flared openings each having a curved surface (111) configured to support the line during extraction, and material removal means for removing material from around the buried line ahead of the de-trenching apparatus.

The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.

The present invention relates to a system and method for uncovering and removing pipeline from the seafloor using a subsea trenching system using pressurized water to uncover pipe, a subsea shear carried by a barge to cut lengths of the pipeline, and a grapple carried by a barge to lift cut lengths of pipeline for placement on a pipe haul and recovery barge.