Marine UXO Survey including Reconnaissance of Anomalies and Detonation of Found UXO

Menge oder Umfang

The planned DolWin3 offshore submarine cable connection is a DC power transmission link of approximately 42 km. The starting point will be KP 43 north of the island of Borkum, Germany. The route is within the German EEZ and the final destination is the planned substation DolWin Gamma at approximately KP83. The route provides a wide variety of morphological features and water depths between -1.5 m to 40 m relative to lowest astronomical tide (LAT). The entire scope of the clearance works encompasses geophysical survey, UXO identification, removal (if deemed possible) and detonation (if required).— Geophysical survey to identify potential UXO objects within the prescribed surveyed corridor. Contractor will host a “route” working group meeting to conduct re-routing as far as possible to avoid potential UXO objects within certain constraints in order to issue a final route position list, a final potential UXO object list and a route clearance certificate.— Positive visual identification of the final potential list of UXO objects resulting from the re-routing exercise between KP43 and the Platform site.— Where required, disposal to shore of any actual UXO objects if safe to transport or detonation on site if unsafe to do so. Issuance of final target clearance certificate(s) for all objects inspected and removed. Provide assistance with securing final approvals from the authorities for the subsequent cable installation works.The works will pass the following phases:Geophysical survey:The geophysical survey will commence with full systems tests and calibrations in port and offshore, and a surrogate item trial on site in order to prove the survey spread. Only when these tests are completed and approved shall the geophysical route survey be conducted within a corridor centred on the cable route, acquiring multibeam bathymetry, sidescan sonar, sub-bottom profiler and magnetic gradiometer data. During the survey, all data shall be processed on site and delivered to the Contracting Entity within 24 hours of completion of acquisition so that decisions regarding data quality, gaps, re-work and development can be made on site as soon as possible after acquisition. If this cannot be achieved offshore then an onshore data processing facility shall be set up as close to the site as possible to facilitate data transfer to shore and access to the Contracting Entity.Upon completion of the geophysical survey and prior to the submission of the draft final report, Contractor will host a route working group meeting at its premises in order to review the geophysical data and agree with Contracting Entity and its UXO Consultant (third party). The outcome of this meeting shall be a final route position list for installation that avoids as many potential UXO objects as possible, a final potential UXO object list for subsequent detailed identification and a route clearance certificate.The following submissions will be required as a minimum:— Mobilization report of all tests, calibrations and the surrogate item trial (SIT). Mobilization shall be complete when all activities are approved by the Contracting Entity.— Daily progress reports to be issued each morning for the previous day's work of an agreed format and content.— Preliminary processed bathymetric, seafloor imagery, geological profiles and magnetic data within 24 hours of acquisition.— A field operations report shall be issued on completion of completion of the survey at sea, containing as a minimum the preliminary processed survey results and conclusions.— A complete draft final report including the method statements, results, conclusions and data (raw and processed) shall be delivered in German and English within the specified time after completion the survey at sea.— Final submissions in German and English shall be within the specified time after receipt of final comments from the Contracting Entity on the draft final submission.- Visual identification and disposal operations:The phase will only commence with full systems tests and calibrations in port and offshore, and a surrogate item trial on site in order to prove the working spread. Only when these are completed and approved shall the identification works commence. All objects given in the final potential UXO object list that cannot be avoided by re-routing shall be inspected as visually by diver and/or ROV in order to determine if the object is actual UXO or not. This may require de-burying of the object to a depth equal to the proposed cable depth of burial. Non-UXO items may need to be recovered if stipulated by the authorities. The Contractor will issue clearance certificate for all objects inspected and identified stating the precise nature of the object if any is found.The following submissions will be required as a minimum:— Mobilisation report of all tests, calibrations and the surrogate item trial (SIT). Mobilisation shall be complete when all activities are approved by the Contracting Entity.— Daily progress reports to be issued each morning for the previous day's work of an agreed format and content.— Target search reports and original clearance certificates within 24 hours of inspection and identification.— A field operations report shall be issued on completion of completion of the survey at sea, containing as a minimum the inspection results, clearance certificates and conclusions.— A complete draft final report including all method statements, results, signed clearance certificates, conclusions and data (raw and processed) shall be delivered in German and English within the specified time after completion the survey at sea.— Final submissions in German and English shall be within the specified time after receipt of final comments from the Contracting Entity on the draft final submission.Disposal Operations:If conducted from a separate vessel spread to the visual identification works then this phase will only commence with full systems tests and calibrations in port and offshore, and if required, a surrogate item trial on site in order to prove the working spread. Only when these are completed and approved shall the disposal works commence. Once a potential UXO target is positively identified as hazardous UXO that cannot be avoided, the Contractor's EOD Manager shall decide whether or not the UXO item can be safely recovered and transported to shore or if has to be detonated on-site. All applicable rules, guidelines, mitigation measures and ordinances will be followed, and appropriate communications with the relevant authorities (BSH, KMB, etc.) will be made. Final detonation will only take place when all regulatory permissions and clearances from the authorities, marine coordination centre and BSH are in place. The Contractor will issue clearance certificate for all actual objects cleared.The following submissions will be required as a minimum:— Daily progress reports to be issued each morning for the previous day's work of an agreed format and content.— Target disposal reports and original signed clearance certificates within 24 hours of disposal. If conducted from a separate vessel spread to the visual identification works, then the following reports will also be required:— Mobilisation report of all tests, calibrations and the surrogate item trial (SIT). Mobilisation shall be complete when all activities are approved by the Contracting Entity.— A field operations report shall be issued on completion of completion of the survey at sea, containing as a minimum the inspection results, clearance certificates and conclusions.— A complete draft final report including all method statements, results, signed clearance certificates, conclusions and data (raw and processed) shall be delivered in German and English within the specified time after completion the survey at sea.— Final submissions in German and English shall be within the specified time after receipt of final comments from the Contracting Entity on the draft final submission.[mentioned route details and periods are up to further clarification].