HDD bores on the "Cool Coast" of Spitzbergen
The Norwegians generally call Spitzbergen the "Cool Coast" or Svalbard, one of Norway's own island groups in the North Atlantic. As there are no constructed paths between the towns on Spitzbergen, the supply is usually provided by air or by ship during the ice-free period.
Ny-Ålesund on Spitzbergen is a centre for international arctic scientific research and environmental monitoring and reputedly one of the most northern settlements in the world. 180 international scientists of all disciplines work in this unique environment, exploring the Arctic, the oceans and the climate developments. The research centre is connected to a network of scientists in Norway, Japan, Italy, France, England and Germany.
The Norwegian Mapping Authority (NMA) is based in Ny-Ålesund since 1992 and operates a VLBI antenna there which is part of a global VLBI-antenna network for distributing the interferometric measuring results. Transferring all the scientific data requires a large broadband and because the capacity limits of the the aerial close to the airfield of 155 Megabit/s had already been reached shortly two new aerials with a broadband of 10 Gigabit/s are to be taken into operation.
For distribution of the data the NMA wants to connect two underwater glass fibre cables. The main line from the Norwegian mainland to Spitzbergen has already been ploughed into the seabed and ends at the town Longyearbyen. From there the sea service line will be installed in the coming year towards Ny-Alesund which is 100 sea miles away.
For the data transmission and the connection to the sea service line two bores in Ny-Alesund of
202 m and 110 m lengths and in Longyearbyen two bores of 79 m and 76 m length are necessary.
HD-PE protection pipes OD 110 x 15,4 mm are to be installed in order to retain the glass fibre cable. Divers will later connect the cable to the sea service line.
The Trondheim based client Uninett AS, which operates and develops the Norwegian national research and education network, contracted the company Entreprenørservice AS from Bærum west of Oslo for installing the HD-PE pipes. Entreprenørservice specialises in non-standard underground constructions including HDD bores, the laying of foundations and the sanitation of tunnels and concrete constructions.
Work started at the beginning of September 2013. The machine applied by Entreprenørservice AS was a GRUNDODRILL 15XP. A marine ship from Seaworks AS in Harstad was hired especially to transport the GRUNDODRILL 15XP and the necessary equipment. The sea journey was approximately 600 sea miles from the Norwegian main land through the Barent sea to the target town of Ny-Alesund. The ship with a special loading ramp allows for a landing and unloading of the GRUNDODRILL directly on the coast, where it was to be applied.
The Bentonite mixing system remained on board, as the bores were carried out close to the ship. From there the GRUNDODRILL was supplied with the necessary drilling fluid.
Site manager Hans Flaten reports: "After the setting up process, we were quickly able to start the first bore from the coast into the sea. Due to rough pebbled and sandy soils we chose the HDH rock drilling bore head. Initially we wanted to carry out the detection with a standard walk-over system. Due to the bore depth of over 20 m and the high salty contents of the sea it did not work and we lost the signal after approximately 14 m depth. Thus we decided to carry out a cable guided bore, which was more time consuming for us.
Even in mid-summer the average temperatures there are only + 6°, while in Winter the temperatures are usually below - 25 °C. Hence Spitzbergen's coasts are very rarely completely free from ice and time and again smaller and larger sheets of floating ice had to expected. When the bore head exited in the target area and during the pipe installation great attention had to be paid not to collide with any floating ice which could have caused damages.
It all went to plan. The pilot bores were carried out without any problems and PE protection pipes were pulled in.
Within one week the pipes had been installed. The bore rig was loaded and transported to Longyearbyen. With the bore experiences from Ny-Ålesund on board, the bore processes in Longyearbyen were smoothly completed with great routine.
Besides being a logistical and technical challenge this jobsite close to the North pole also was, as far as we know, the most northern application of an HDD rig.