HUMBERSIDE, UK February 26, 2018. Contractors for the UK power utility National Grid have begun a 12-month excavation of a five kilometers tunnel under the River Humber using a German-built boring machine delivered to the site by heavylift contractors Collett & Sons.

National Grid awarded the £100 million tunnel contract for a replacement gas pipeline to a joint venture of Skanska, PORR Bau GmbH and A. Hak.

When installed next year it will be the world's longest gas pipeline in a tunnel inserted in a single string.

The boring machine, named 'Mary', was manufactured in Baden-Wurttemberg, Germany and Fracht AG was responsible for delivering the 215 tons consignment to Rotterdam for onward shipment to the Port of Immingham.

Collett partnered with Fracht UK Projects to collect the disassembled machine, consisting of a 30-tonnes Cutter Head, 70-tonnes Shield, 95-tonnes Machine Can and 20-tonnes Tail Shield, and transport it 27 miles from Immingham to the National Grid site in Goxhill, North Lincolnshire.

After being reassembled in January, the machine has now begun boring a 3.65 meters diameter tunnel 35 meters below the River Humber.

Collett lead Project Manager Steve Ellison commented: "We've been planning this for months and we expect to see the machine emerge on the other side of the river [in] around a year."