Two tunnellers have helped Scottish Water progress a major new sewer beneath Edinburgh, by hand digging 90t of debris.
The 100-year-old sewer is currently being upgraded, and a challenging section required a more hands-on approach.
Gerard Boyce and Thomas Peoples of ASG Tunnelling & Civil Engineering Services used tools to dig their way through a 20m stretch to avoid damaging a complex web of services.
Working over a two-week period in a trench, the two men shovelled between 6t and 9t of earth a day for the new 1.2M diameter pipe.
The two tunnellers used gas detectors, laser technology and hydraulic drills to cut the rock face whilst the earth was then shovelled by hand into a traditional cart on rails, which was then lifted by crane to the surface.
ASG Tunnelling & Civil Engineering managing director of services John Doherty said: “We are one of the few remaining family run firms that have the knowledge and experience to take on these hand tunnelling projects.
“I’m extremely proud of hand tunnellers Gerard and Thomas who have completed this work in challenging conditions due to the confined space underground and the sheer number of utilities we encountered and had to work around to get the section completed.”
Scottish Water has previously used ASG to precisely hand excavate sections of tunnel where tunnel boring machines are not appropriate for the terrain conditions.
Scottish Water’s corporate affairs regional manager Scott Fraser added: “The original sewer was built by Victorian engineers using old-fashioned methods.
“Whilst we’re using a range of high-tech solutions to help progress this vital work to upgrade the sewer at Haymarket, we’ve had to use those same basic tunnelling techniques as the Victorians to clear this particular section.
“The £2.5M work at Haymarket is one of our most high profile projects due to its busy location and the small, challenging work site. This unique environment means we are using traditional techniques combined with modern technology, to efficiently tunnel under a section of road with a large number of vital utilities, which if damaged could impact local residents and businesses.”