The Guardian: October 20, 2006
Giles Tremlett in Madrid
· Spain and Morocco set up engineering study project
· Major hurdles, but service could be running by 2025
The Strait of Gibraltar, linking Europe and Africa.
The excavation of a tunnel joining Europe and Africa deep below the Strait of Gibraltar could start as early as next year after Spain and Morocco commissioned preliminary engineering studies.
Veteran Swiss tunnel engineer Giovanni Lombardi has been called in by the governments of both countries to draw up a project outlining how work could proceed towards creating the only direct physical link between the two continents.
Exploratory tunnelling could start after his report, which will be based on recent detailed studies of the geological patterns under the strait, is handed in next year. "We are just beginning the work, but I would say this is more difficult than the Channel tunnel," Mr Lombardi told the Guardian yesterday.
"The main difference is the depth of the sea but the geological conditions are also different."
Actual construction of the 25-mile twin rail tunnel could take 15 years from when preliminary studies and the exploration tunnels were finished, Mr Giovanni said.
Spanish engineers involved in the project have said that if no major geological or technical problems arise rail passengers could be travelling to and from Africa by 2025.
It would be a twin rail tunnel with a service tunnel between and is projected to carry 9m passengers in the first year, rising to 11m after 10 years. It could also carry 8m tonnes of goods in 2025.
A final decision on whether the tunnel will be excavated, however, depends on both financing and political will. The border between Morocco and oil-rich Algeria is currently closed, for example, thereby reducing potential traffic.
There are no costings for the tunnel as yet, but estimates made several years ago put the minimum price at more than €5bn (£3.36bn). The 31 mile Channel Tunnel, although relatively easier to build, eventually cost £10bn.
If the tunnel to Africa was linked to the existing high speed rail line at the southern Spanish city of Seville the travel time between Madrid and Tangier could be as low as four hours.
Spain first began studying the idea of a transcontinental tunnel in the 1970s. A joint Spanish-Moroccan body was founded in 1991, inspired by the building of the Channel Tunnel, to start surveying the seabed under the strait.
Those studies have been hampered, however, by sea conditions in the strait.
Engineers have had to invent new boring methods in order to cope with the fierce underwater currents at a point where the Atlantic Ocean meets the Mediterranean Sea.
They have already decided that the tunnel cannot cross the narrowest part of the strait because, at 900 metres, it is too deep.
A rail tunnel at that point, between Spain's Punta Canales and Morocco's Cirea Point, would have to start many miles inland so that the gradient would not be too difficult for trains to climb.
The current proposed route for the new tunnel lies to the west, where the seabed is, at 300 metres, relatively shallow.
Even that is much deeper, however, than the Channel Tunnel where the sea bed lies just 50 metres below the waves. As a result, the gently sloping tunnels will emerge at least three miles inland from the coast on either side.
They will cross the African coastline under the area around Malabata Point, near Tangier, and reach European soil somewhere under Spain's Punta Paloma.
The strong currents and depth mean that bridges have been ruled out as a way of connecting the two continents.
Some engineers, however, favour the idea of building a huge barrage that would also control water flow into and out of the Mediterranean.
The geological layers under the Strait of Gibraltar are horizontal, meaning the tunnel has to cross through many different rock strata. "That is quite a complex geological situation," said Mr Lombardi.
Underwater clay deposits that have recently been discovered near the Moroccan coast have further complicated the project.
Mr Lombardi said he would also have to take into account a history of earthquakes in the region, including the 1960 quake in the Moroccan city of Agadir and the 1755 quake centred near Lisbon, Portugal.
Mr Lombardi, aged 80, has built many tunnels in Switzerland and was recently called in to redesign the Mont Blanc tunnel after 41 people died in a fire there in 1999.
See also:
Swiss plan tunnel under Strait of Gibraltar
swissinfo: September 30, 2006
Looking to Africa: the tunnel would be buried under the Strait of Gibraltar
The Swiss Lombardi engineering firm has won the contract to design a railway tunnel between Europe and Africa running under the Strait of Gibraltar.
The company, one of 14 competing for the job, has one year to draw up the plans for one of the most complex projects of its kind ever, on the cards for over a quarter of a century.
A Spanish-Moroccan committee has been considering various options since 1980, not surprising since the difficulties faced by potential builders are a huge challenge. It was only in 2004 that the two countries' governments decided to go ahead.
A bridge was ruled out because of the depth of the strait. It would be impossible to build supporting pillars in 300 metres of water.
A floating bridge was also not an option because of the number of ships passing through the Gibraltar bottleneck. An underwater tunnel made out of prefabricated elements was considered unfeasible as well as the sea bottom is unstable and currents too strong.
If the project goes ahead, it will be a close cousin of the Eurotunnel that runs under the Channel between France and Britain. Running at depths of up to 600 metres, it will connect Tarifa in Spain to Tangiers in Morocco.
Giovanni Lombardi, the 80-year-old head of the engineering firm, says the planned 40-kilometre tunnel is not the shortest way of connecting the two continents, but simply the best. He adds though that it is just feasible.
Planning for the project will be difficult. Just figuring out the configuration of the seabed will be a challenge.
Ships sent out to prospect its geology had to give up after a week's work as they were unable to stay in a stable position because of the strong currents washing through the strait.
Public backing
Two publicly owned companies in Spain and Morocco are financing the project. Lombardi reckons it will cost up to €5 billion (SFr7.9 billion) to complete it, but cannot be more precise at this stage.
Preliminary studies should be finished by 2008. A 4.8-metre-wide service tunnel will be built first.
This tube should help the engineers figure how much water might leak into the tunnel. "In the old Gotthard rail tunnel under the Alps, 200 litres of water filter through every second," said Lombardi.
The pressure on the tunnel will be huge, approximately 500 tons per square metre, so powerful pumps will be needed to avoid it filling up with water.
Another problem is the risk of earthquakes in an active seismological zone. In 1755, an earthquake caused huge damage in the area and killed 50,000 people in the Portuguese capital Lisbon.
Comparatively speaking, building the Eurotunnel was much easier reckons Lombardi, who also worked on the Channel project. "Eurotunnel didn't go as deep, water pressure was lower and the rock was more solid," he added.
The Gibraltar project is Lombardi's biggest challenge so far, but he is confident he can overcome all the obstacles in his path. "If you aren't optimistic, you never achieve anything," he said.
