Oil pipeline made safe for centuries

Lanes Group makes oil pipeline hidden beneath Welsh countryside safe for centuries

The industrial services division of Lanes Group has decommissioned a pipeline that once allowed crude oil to be pumped from North Wales more than 80 miles to one of the UK’s main refineries.

Nearly 8 million litres of water and oil residue have been removed from two three-mile-long pipes in North Wales, while sections under roads have been filled with concrete.

The challenging project was needed to make the redundant buried pipeline safe, with a design life that stretches centuries into the future.

Given the route of the pipeline through ecologically sensitive areas in one of Wales’ most important tourist spots, completing the work safely with no risk to the environment was of paramount importance.

Impressive scope of capabilities

Project management specialist Arcadis appointed Lanes Group to decommission the two 40-inch internal diameter pipes, which were installed in the late 1960s and operational until the 1990s.

Arcadis Principal Consultant Daniel Wood said: "I was impressed by Lane Group's diligence throughout the project and the ownership the team took with the project.

“The company promoted health and safety, and this really showed in the attitudes of contractors on the site and in the safe delivery of the pipeline decommissioning, despite the numerous unknowns to contend with.”

Lanes Group Business Development Director Colin Mackay said: “Delivery of this decommissioning programme demonstrates the impressive scope of Lanes Group’s service capabilities.

“As the principal contractor, we had the capability to bring together a multi-disciplinary team of supply chain partners to deliver a project that has taken over two years to complete.

“In all aspects of the project, including safe and sustainable delivery, rigorous cost control and stakeholder engagement, our team demonstrated exemplar standards.”

The project has been submitted to the owner of the pipeline, for a sustainability award for Lanes Group’s development of a local supplier network that has minimised carbon emissions.

Minimising costs and carbon footprint

The two pipes formed part of a 79-mile-long pipeline that took crude oil from oil tankers moored off the North Wales coast to a refinery at Ellesmere Port, in Cheshire.

They carried the oil from where it came ashore to an inland holding station. From there, it was pumped along four narrower pipes to the refinery.

The pipeline was needed because oil tankers had become too large to dock directly at the refinery, located in the Mersey estuary.

Phil Bache, National Technical Manager at Lanes Group, who led the project, said: “We’ve had a number of big challenges to contend with. For example there have been no technical plans. “We’ve had to respond to what we’ve discovered as we’ve progressed the project, which was one reason why we knew it would be beneficial to build a local supplier network.

“Our engineering, scaffolding, civils and demolition partners were all from North Wales. It’s allowed us to respond more flexibly to our operational challenges, helping us to meet project deadlines.

“It has also controlled costs and eliminated 8,000kgCO2e of transport emissions. During the project, we also used a jet vac tanker, a CCTV surveying unit and an articulated tanker from our own Chester depot, which is just inside Wales at Flint.

“Our decommissioning work has made the redundant pipeline safe for future generations. For example, sections under road crossings have a predicted design life of 600 years.”

Pigging clears contaminated water

After months of planning, Phil Bache and his team launched the project’s operational phase in July 2023 by pressure testing both pipes with nitrogen.

This led to one of the pipes being excavated to a depth of four metres so a weld cap could be fitted. The pipe was tested again, and approved for dewatering.

The water removal, treatment and disposal process was carried out during July and August 2025, first for one pipe, then the second.

Key to the process was a technique known as pigging. The pig, a cylinder of polythene-coated plastic foam, was inserted through a specialist launcher into the inland ends of both pipes.

Compressed air then forced the pig through the pipe at a speed of just over one metre per minute. This pushed the water into two giant inflatable rubber bags set up at the other end of the pipes.

Each of the bags, located within protective bunds, could hold up to two million litres of water. Each was 56m long, 26m wide and 1.6m high when full.

The water was found to contain less than 5% oil residues. It was fed through a carbon sand filter to remove these contaminants and other impurities.

The treated water could then be sent for disposal via a standard 1-inch supply pipe to a nearby water treatment plant operated by Dwr Cymru Welsh Water at a rate of 170,000 litres per day.

Road crossings reinforced along route

Lanes Group’s team continuously monitored the treatment process, regularly sending water samples to be laboratory tested, in accordance with Welsh Water requirements. The water company also carried out its own testing.

A total of 7.7 million litres of water were treated and disposed of. Around 10 tonnes of waste material left by the process was taken to a specialist waste site for safe disposal.

In the final phase of the decommissioning programme, completed at the end of October 2025, work has been done to reinforce the pipes at five road crossings.

Excavations have been carried out either side of the roads, the pipe cut into, and steel plates welded into place to seal off 55m sections.

These sections were then filled with concrete to eliminate the risk of the pipes collapsing, creating a void, into which the roadways could sink.