Nearshore and onshore geophysical, UXO and geotechnical campains at the Biscay Gulf.

The services consists of integrated nearshore and (as applicable) onshore surveys: UXO, geophysical and geotechnical to be performed at various locations of Biscay Gulf mainly in water depths ranging between 0 and approximately 20 m LAT and mainly in French waters, with a possible option area at around 100 m LAT.

The purposes of the geophysical and geotechnical investigations are the determination of the detailed seabed conditions and stratigraphy with detailed characterization of the materials in the surface and sub-surface soil layers in which the submarine cable installation will be executed.

The geophysical investigation shall include both surface and sub-surface survey (sub-bottom profiling).

The purpose of the UXO survey is to ensure an As Low As Reasonably Practicable (ALARP) UXO risk at each anticipated geotechnical location to be investigated during the subsequent Geotechnical Survey. Nominal clearance boxes of 50 x 50 m are anticipated at each geotechnical location.

The geotechnical investigation shall consist in CPTs, vibro cores, bored holes and similar.

At landfall sites, deep geotechnical ground truthing shall be performed onshore and nearshore to characterize the materials which would be drilled cable installation works by the means of Horizontal Directional Drilling (or equivalent trenchless technique). Both surface drilling (with or without piggyback seabed frame) from a stable and waves uncoupled platform such as dynamic positioned vessel, jack-up or heave suitable wave — compensated rig, and remotely operated drilling can be considered.

It includes the collections of quality samples of soil and rock from onshore and nearshore locations, to be tested for the determination of physical and mechanical properties and to support the interpretation of the geophysical data.