Project Detail

This job was unique in that it had not just one challenging aspect, but many different strands ranging from engineering difficulty to community relations. The ground conditions comprised schist where specialist rock tooling was required to cut through this abrasive formation. The topography of the site pushed the boundaries of design due to the significant changes in elevation and steep banks between the River Foyle. The exit site was in a housing development where early engagement with the local community contributed to the success of the works.

The HDD also crossed under the Derry – Coleraine railway line at a depth of 16m. Pipe welding was undertaken in the grounds of Thornhill College, the school remained fully functional throughout with no disruption. The stringing of the pipe for welding and installation required exceptional planning and execution. Due to the depth of the HDD, 25m under the riverbed an SDR of 7.4 was selected for the 355mm pipe which equates to a 48mm wall thickness. The HDD was undertaken using McCormack Drilling’s 200t American Augers DD440t rig with the pilot bore being completed using Brown line’s gyro steering system.

Year 11 GCSE Construction class from St Colm’s High School, Draperstown were invited to visit the site and experience a live specialist construction site. They provided pupils the opportunity to see some of the equipment being used to bring gas beneath the River Foyle. Students were also given the opportunity to ask questions about potential future careers in engineering and what subject choices they should make if they want to pursue a career in a Science, Technology, Engineering or Maths (STEM) role.