Skanska has secured from Norsk Hydro the contract for the construction and civil engineering work for the on-shore terminal for the new Ormen Lange gas field in Nyhamna near Kristiansund. The gas field is located at a depth of 800-1,100 m under the Norwegian Sea, about 100 km from the coast. The contract is valued at NOK1 billion. The contract also includes an option to supply concrete. The assignment includes in particular two seawater tunnels with a total length of 2.4 km and two caverns.The project consists of two separate tunnel systems. The first is the seawater intake/outlet system and the second is the storage caverns with subsequent tunnels. The seawater tunnels consist of an entrance tunnel of approx. 220 m. The seawater intake tunnel has a length of 1,250 m and a cross section of 25 sq m. With respect to the intake tunnel, an intake shaft of 34,000 cu m will be excavated. A shaft for back up firewater is also to be excavated. These shafts are partly to be excavated from the surface. With respect to the firewater shaft, a 70 m-long 2 m-diameter shaft will be drilled with raise boring equipment. The intake tunnel will be driven 80 m below sea level.From the intake tunnel a 900 m-long outlet tunnel with a 20 sq m cross section will be excavated. A underground weir box shaft of approx. 2,800 cu m is to be excavated in connection to the outlet tunnel. A 55 m-long 1 m-diameter shaft will be drilled with raise boring equipment. The outlet tunnel will be driven 40 m below sea level. Drill/blast with a three-boom drilling jumbo. Removal of excavated rock as load-and-carry to niches and further transportation by trucks. The seawater tunnels will be supported with rock bolts and steel fibre reinforced shotcrete.The storage caverns consist of an entrance tunnel with a 350 m-long 60 sq m cross section. From this cavern, two 250 m-long 30 sq m cross section tunnels will be excavated above the caverns, for drilling water infiltration boreholes. The access tunnel divides in two tunnels with a total length of 700 m featuring a 60 sq m cross section, to access to the top heading and bottom of the caverns. The condensate storage cavern is 269 m-long 21 m-wide and 33 m-high. In addition a 13 m-deep pumping shaft will be excavated from the bottom of the cavern. The off spec cavern is 95 m-long with the same width and height as the condensate cavern. The caverns will be built by excavating a top heading, two intermediate benches and a bottom bench. In the tunnels, the top heading and the first intermediate bench will be excavated by means of three-boom jumbos and the last two benches by ordinary blasting. A maximum of three jumbos will be involved. Wheel loaders and trucks will be used for the mucking-out.From the roof of the caverns, 12 vertical shafts, with a total length of 760 m and diameters ranging from 0.66 m to 3.72 m, will be drilled by raise boring. The roofs of the caverns will be supported by rock bolts and a steel fibre reinforced shotcrete layer. The groundwater level around the caverns will be controlled by cement injections and a waterstop liner. The geology in the area mostly consists of fairly good gneiss. The cost for the underground works including the shafts and concreting accounts for approx. 30% of the contract value. Approximately 12 wheel loaders, 25 diggers and 31 dumper trucks will be at work at the construction site at Nyhamna. Work will commence in April and is scheduled for completion in December 2006. Visit www.ormenlange.com and www.skanska.com 15/04.Skanska progressing on schedule with Ormen Lange storage caverns and associated shafts and access, together with two 25 sq m section seawater tunnels, 1.0 km and 1.4 km-long, from which probeholes have located the seabed and advance is now cautious under cover of grouting. The seabed will be pierced at 40 m and 80 m respectively in July, 2005. Roof of large condensate cavern has been fully excavated at 125 sq m section using Atlas Copco Rocket Boomer XL3 C with Dyno Nobel SSE explosives and supported with rockbolts and shotcrete. 11 m-deep benches are being drilled in both caverns using Atlas Copco ROC D7 surface crawlers. Visit www.ormenlange.com, www.dynonobel.com and www.atlascopco.com 20/05.