Yantlett to Stoke Pipeline

Yantlett to Stoke

1550m pipeline

Project and Site Management

The installation of 1550m of 200mm dia. pipeline as part of OPA's Thames to Grain (T/G) 109km re-lay. Due to various topographical influences the first 800m was by HDD with remainder as open cut, lower and lay.

The Project

The initial 800m was by HDD due to the sensitivity of the route's proximity to the LNG Terminal, numerous parties' landownership issues combined with the myriad of known utilities that have been concentrated in front of the Terminal for some decades. The surface features of Medway one side, Thames on the other with Terminal, road and railway all in a narrow strip of land meant that appropriate levels of caution for any excavation technique were always going to be required.

The selection of HDD minimised the exposure to the pipeline to the near surface services, etc and the designed running depth placed it (6m below the seawall) 19m from surface for some 300m of the 800m drill.

The remainder of the planned route to Stoke pumping station, initially, appeared mostly constrained by time. The requirement was to clear of the marshes by a set date for the wintering birds. However the discovery of several previously unknown services, some of the significant in size, tightened this programme further.

The burying of the pipe occurred without detriment to the birds and with a commendation from the Environmental Inspector on the attention to detail of the re-instatement.


SDL's team is now well versed in a thoughtful, considerate approach to the constraints that arise from spread working adjacent to SSSI land owned by Network rail whilst drilling under a NG Terminal of strategic importance. The anticipated hazards were addressed proactively by deploying SDL's pre-established Environmental Management System. This was tailored to the site specific risks and strengthened, as required, with the inclusion of on site Ecological and Environmental staff.

The inherent risks of HDD impinging on the ecology were minimised by providing standby resources to deal with any event in the most timely manner.

Project Management

As the Main Contractor, SDL managed all aspects of the construction design and its implementation either by themselves or by supervision of specialist subcontractors. The final product differed to the simplistic initial concept, largely due to the latent challenges that emerged as construction progressed. Time was taken to understand each and every affected organisation, or individual, so a liaison can be established to boost confidence that the works would be carried out with minimal impact, even above and beyond the specified requirements.

Project Summary

  • Full Project and Site Management.
  • 800m of 12.25" HDD.
  • 750m of Mainline Opencut lower and lay.
  • Adapting to the many previously unknown services and structures, active and disused that were revealed.
  • Environmental Issues from hazardous chemicals likely to be present.
  • Ecological Issues from SSSI areas, Water Voles, protected habitats and wintering birds.

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Designed at B&W studio