Client: Seymour CEC. Ultimate Client The Coal Authority.

Location: Horden, County Durham

Project Summary:

This scheme involved the survey and detailed design for the construction of a replacement culvert, embankment and access track. The existing site, which provides critical access for the Coal Authority, was in a state of disrepair and was putting the integrity of the access track at risk due to subsidence. After working together with multiple agencies, our team was able to develop several innovative ways to make the site safe and functional.

Original planning had suggested using a box culvert but, with the site having such restricted access, the design was revised to incorporate a pipe culvert arrangement; this ensured risks to the adjacent Network Rail line were negated due to the use of smaller lifting equipment. In order to maintain watercourse flows during construction, we were able to utilise the existing culvert whilst the proposed culvert was built “off­ line”. We were then able to leave the existing culvert in-situ and included a removable cap; should any future works be required this could be used to divert flow from the main culvert.

Maintaining the integrity of the site was at the forefront of the Lynas Engineers team and so continued to work on ways to lessen the impact on the environment. As the site is located within a Site of Significant Scientific Interest (SSSI) we designed downstream stone gabion areas which help provide benefits to water quality whilst maintaining the rural and ecological aesthetics, treated timber was used and earthworks graded throughout to complement the surroundings.

We assisted the Seymour Civil Engineering team throughout the entire construction process including the design of the temporary access route which significantly limited impact upon the rural area and to ensure materials, specifications, and working methods were in keeping with national guidelines and standards.

Challenges:

Being able to access all parts of the site safely and completing a comprehensive

recommendation during peak access times in a busy site.

Successes:

Completing all design works to an exceptionally high standard using innovative solutions.

Providing a robust design and assistance throughout construction – on time, under budget and with all stakeholders satisfied