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The Recovery of Copper Cores from High Tension Cables

Rook Services has developed an innovative technique for recovering and recycling copper cores from redundant cables, whilst simultaneously and safely removing the oil contaminated paper sheathing. Recycling of the copper makes the process economic, realizing environmental benefits and avoiding the local disruption caused by conventional excavation and removal. The system creates a void within the cable's casing that can be used by utilities as a duct for additional services. We can also increase the size of the duct, or install a new larger duct with our conventional pipe bursting technique. The process has been so successful it is now the subject of a patent application.

Overview of our process

Using ground radar scanners we are able to identify the location of existing cables, enabling us to carry out an assessment to confirm the cable is not live. Excavating pits are constructed approximately 100m apart to house our hydraulic rigs, one of which pulls, whilst the other pushes. The pits are then lined with a plastic sheeting and an oil absorbent material to contain any minor spillages from cable sections that are exposed before removing the outer casing. The casing is secured to the rigs with bespoke clamps and then the copper core is fed through the rigs and gripped in specially designed jaws within the hydraulic rams. The coordinated simultaneous operation of the rigs then removes the core along with the sheathing. The action of both pulling and pushing avoids the problem of the ductile copper core stretching, necking and thus prevents the paper sheath from Jamming in the casing. The copper core is cut into transportable sections and recycled, whilst the oil contaminated sheathing is removed off site for safe disposal.

Cleaning of the newly available ducting can now be carried out with steam, or high pressure/low volume cleaning systems. If there is a need to increase capacity the existing casing can be replaced at this stage with a new larger duct, ready for use by the service provider. This extraction cycle is repeated for every 100m section of cable until all the copper cores are recovered. This exclusive process is very green, providing new options for the operators of high voltage cables (EHV) which have reached the end of their operational life allowing the environmentally safe recovery of an extremely valuable resource, without the drawbacks associated with conventional removal by excavation.

System developments

The original method of copper extraction has been recently redesigned to include for, entire recovery of the original cable using a dry system. This utilizes the cable as a “guide” to slide rods around the outside. An additional a case system has been developed. The Case system is derived from the principle of pipe ramming, reinvented using hydraulic rigs to the install a case around the outside of a cable. The cable is removed from the cases and the cases are left in the ground.