As part of its network expansion program, Enagas undertook the installation of a submarine pipeline providing natural gas from the Spanish mainland to the Balearic Islands of Ibiza and Mallorca, integrating them into the Spanish gas system. This 20" nominal diameter pipeline was constructed in two distinct sections, one of 123 km between the mainland and Ibiza and another of 146 km between Ibiza and Mallorca.
Boskalis constructed the four landfalls of these pipeline sections at the three shore approach locations. Each shore approach posed highly different conditions:
- a sandy beach at Dénia,
- a rocky cliff at Ibiza and a shallow gravel and
- sandstone approach at Mallorca,
the latter further complicated by space restrictions onshore.
The landfall at Playa Les Deveses was characterized by a sandy seabed and beach and small dunes. A trench would provide protection for the pipeline along the shore approach.
At Punta de Cala Gració the shoreline consisted of a rocky cliff. To cover the height difference between the seabed and the cliff two micro tunnels had been drilled previously, into which 48" casing pipes of 150 m each had been installed.
The Mallorca landfall at San Juan de Dios featured a gravelly / rocky seabed and sandstone coastline with space onshore limited by an existing water plant and fish farm.