Pipe Bursting Used to Rehab Damaged Duct in United Kingdom

In the competitive world of utility contracting and equipment sales/supply altruism is something that might seem something of a rarity, particularly in the difficult economic conditions currently being experienced across the United Kingdom, and globally. So, why would anyone expect a renowned equipment provider to undertake a pipe bursting project FOC (free of charge)?

This was a questioned asked of U Mole (part of the Groundforce division of Vp plc) following works on recently completed on such a basis at the Stretham Engine Trust site on the Waterbeach Level near Ely, Cambridgeshire, United Kingdom.

The Stretham Engine was built in the 17th century as one of a series of engines that were designed to drain water from Fenlands to create quality farmland. It is now the only remaining example of these machines that, while not now fully operational due to land shrinkage around the site, which has occurred due to the draining process, shows the ingenuity that was brought to bear to effectively manage the land drainage scheme and provide the required and highly prized farmland. The machinery is also the only example left in the area with not only the beam engine that drove the bucket/scoop wheel water lift apparatus but also the boilers and valve arrangements and gauges that controlled the engine and its operation.

Run as a charitable trust, and as with many charity organisations in these difficult times, the Trust relies on members, donations and visitors fees to fund its continuation and when unexpected and potentially huge bills arise the question of survival is always there.

This was the case recently at the Stretham Engine where a connecting duct passing from inside one of the buildings on the site to the nearby river was in need of replacement because it was not operating effectively due to heavy silting. The duct formed part of the river level monitoring system.


The Engine was designed to work so that water from a well at the site that drained the surrounding peat soils was lifted using a scooped wheel. This water was deposited into the adjacent river, called Old West River. Without going into too much detail, as part of the drainage operation, water level monitoring of the difference in level between the well and river had to be continuous to effectively operate the drainage system correctly. Within this set up there was a cable, linked to a float mechanism in the river that runs to a gauge inside the Mill that indicates the river level at all times. The duct within which the cable for this system ran was the one that was silt filled.

Having looked at the problem, the Trust management approached U Mole after seeing one of its van in the area advertising the trenchless options it offers to the industry in the hope that the company might be able to provide information on how to effectively replace the damaged duct without damage to these historic buildings and their contents.

Russell Fairhurst, managing director of U Mole, visited the site to see what was possible and found that a pipe bursting option would be applicable to the replacement required. Also, given the financial constraints on such an important historic site to the area, he agreed that the cost of the works was something that the U Mole company would take on itself and so agreed to complete the work free of charge. U Mole not only provided the machinery necessary for the project but also the workforce and new pipe.

During the site visit, Russell agreed that the job to replace the damaged 3-in. diameter cast iron pipe could be done using one of the company’s PB30 cable based pipe bursting units. It was decided that a 63-mm diameter duct would be used as the replacement pipe. While the choice of pipe was not the preferred one for any trenchless works, being a charitable work it was the lowest priced option available and as the duct was only to act as a cable pathway it did not need to meet any particularly heavy duty requirements. Ultimately the job continued to a conclusion and final success.

The main difficulty of the project, it was thought, was the fact that the old pipe was blocked with silt and other detritus. This meant that the usual simple method of passing the pipe burst cable through the old pipe was not possible. After careful application and experience of the operators, a rod was eventually pushed through the blocked old pipe so that it was subsequently possible to pass the burster rope through.

This in itself proved difficult due to the rope being of a larger diameter than the placement rod. It appeared that the rope was catching on something immediately outside the building. A quick investigation using a small pit proved that the old duct had completely collapsed at this point literally just below the surface slab. After clearing this collapse, the job went ahead smoothly to completion of the installation of the new pipe.

Works to reconnect the link through the new duct are expected shortly and everyone involved in the project from the Trust team to the U Mole and its operators are all are looking forward to seeing the river level gauge re-commissioned and working as it has for more than 100 years.

Subsequent to the duct replacement works K.S.G. Hinde, Chairman of the Stretham Engine Trust commented in a letter to U Mole saying: “We are very grateful indeed for the sterling work carried out by you and your men in laying the duct under the roadway at the Engine to serve the river level gauge. This proved to be a considerable exercise and your work is much appreciated. For a trust that subsists entirely on takings at the Engine and donations, without any grant aid, this would have been a severe strain on our resources. As far as can be traced, these gauges are unique to this plant and were almost certainly installed over 100 years ago. As well as yourself, please express our particular thanks to your two men who worked so hard.”

For U Mole Russell Fair said in answer to the question asked earlier: “It is vital to the history of the area to see how and why it became such an important farming landscape and how mills like this achieved that. As the Stretham Engine is the only surviving and probably best example of just how much effort and skill was put into creating this landscape, we felt that it was important to ensure its continuation without a heavy financial burden on the Trust. As engineers ourselves we see just how innovative this set up was for its time and how keeping it at its best is so desirable. Given the history behind the site, the cost to our company of completing the works free of charge to the Trust was minimal and we were very happy that we could help preserve such an important historic site.”


The PB30 compact pipe bursting system has been specifically designed for the replacement of small diameter sewer laterals and ducts with minimum surface disruption and disturbance to the client. Producing up to 28 tons of pull back on a special compact cable the PB30 can be broken into several easily manageable components to ease transport/assembly in difficult access locations and even man-holes.
The use of the compact cable together with the compact bursting heads with integral pipe towing head enable the PB30 to burst in-line bends up to and including 45 degrees with no problem. Hydraulic power can be provided by an independent power pack or even from the hydraulics on a mini excavator.


U Mole, a part of Vp plc’s Groundforce division, is the direct factory United Kingdom and Ireland distributor for Earth Tool equipment offering the company’s full range of products for trenchless installation and pipeline replacement. This range includes impact moles (earth piercing tools), pipe ramming hammers, twin capstan winches, static rod pipe bursting systems and the portable cable-based, hydraulic pipe burster range.

U Mole also supplies a full and extensive range of trenchless and limited dig equipment including: Suction/vacuum excavation systems (including MTS systems alongside Vac-Tron systems) and surface coring equipment for the ‘Keyhole’ excavation of utilities and services with minimum disruption to the local area and minimum damage to the buried service. Other trenchless related equipment available includes the market leading Robbins SBU equipment, Pipe to Site coiled pipe trailer range, pipe fusion systems, Reed Tools and a complete range of accessories such as Cobra flexible rodding, towing heads, cable socks, pipe pigs, swivels, breakaway connectors etc.

This article was submitted by U Mole, part of Vp Plc., Cambs, United Kingdom.

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