Shore End Survey Completion

View of the coral ledge where the cable will land in Madang

From the beaches to each of the Cable Landing Stations in Madang, Guam and Sydney, the shore end surveys scrutinize the beach environments where PIPE’s cable will land.

Engineers have been performing periodic inspections at each of the landing sites to assess changes in environmental conditions such as beach erosion and other external hazards.  The inspections form part of local government permitting requirements.

Where possible, shore end engineers perform their inspections following earthquakes or wild weather to determine any impacts to the integrity of the cable system or changes in the seabed.

Our engineers have been comparing the as-built records against actual inspection data to identify any discrepancies and update changes in shore end cables. Common changes needed to the original drawings are new cable crossings, changes in burial depth due to sand migration, and new cables in shared manholes.

The following are extracts from each of the survey reports.

Extract from the Madang Report:

There are no charted obstructions to the landfall except coral reefs and beach rocks in the vicinity of the area. The area immediately in front of the landfall point is shown on the Admiralty charts as “UNSURVEYED” (approximately up to the 100 meter contour, which is approximately 300 metres offshore).

Extract from the Guam Report:

Minor beach deposits, reef limestone, and alluvium of Holocene age occur along the coastline. These deposits cover a small percentage of the surface of Guam, and may be as much as 70m thick at the mouths of some rivers. The beach deposits are composed of poorly consolidated sediments, mostly calcareous sand and gravel thrown onto beaches by waves but some deposits of volcanic sand can be found where streams drain volcanic uplands. Reef limestone up to 4m thick also occurs locally. Deposits of alluvial clay fill stream valleys and cover the inner parts of coastal lowlands.

Extract from the Sydney Report:

The proposed landfall is situated on a high energy ocean beach in a wide east facing bay. The seabed slopes away relatively sharply to approximately 18 m, approximately 0. 5 nm from shore. The seabed up to this contour is mostly fine to medium grained golden colored sand with 10% to 60% shell. Some reef rock is exposed close to shore towards the northern end of the bay. Due east of the bay, between the 20 and 40 m contour (0.5-1.5 nm from shore) is an expanse of exposed reef rock. There are at least three sandy (medium to coarse grained orange sand with 40% shell) channels. The rocky promontory of Long Reef continues underwater eastwards beyond 3 nm from the coast. The gradient of the seabed beyond the band of exposed reef rock becomes gentler, obtaining a water depth of 50 m at 3 nm from the shore. The seabed composition is coarse sand continuing eastward, gradually blending into fine grained grey colored sand with 5% to 20% mud and 30% to 40% shell.

3 comments – Latest by:
  • PIPE International
    Jesse The PIPE team take loads of photos throughout the progress of the project. Visit the Photo Gallery for pics ...
  • Nick Koopalethes
    How will you secure the cable to the coral in Madang? I assume it will be double armoured close to ...

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Construction at Madang CLS

Back in June, construction began on our new cable landing facility in Madang. An expansion of an existing building, the works are expected to be completed by the end of August this year.

The Madang Cable Landing Station Outside Plant (OSP) survey was completed in the week 8th – 12th July.  The outcome of the OSP survey schedule will be developed along with the Guam and Sydney survey reports.

PIPE’s Environmental Plan, Madang’s local planning and construction laws are all being observed during assembly of the structure.  PIPE and its partners will closely monitor the works for compliance as well as any environmental impacts.

Madang CLS is expected to be operational by April/May 2009 functioning as a landing point for the PPC-1 cable.

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  • Robert
    Windows?????? BTW.. great BLOG.. interesting read. I'm surprised how far along everything is before the cable pull begins.

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MegaForce to Demobilise

Having completed the surveying tasks appointed to her, the Megaforce and her crew will demobilise in Sydney this week and end their journey with the PPC-1 project.

The above photo was taken from the Gelendzhik prior to her demobilisation last week.

PIPE would like to thank the owners and crew of the Megaforce and wish them well in their future sailing opportunities.

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Seabed Sampling

Picture courtesy of EGS 

Seabed Sampling provides the researchers with soil analysis and data which will assist with the rollout of the cable.  The analysis will identify, amongst other properties, the soil density which is useful in areas where the cable is to be buried.

Sampling by Divers

The divers will collect samples of seabed sediment, at intervals of 25m along the survey centreline, at the same locations as the steel bar probes.

Sampling by Inshore Vessel

A Stainless Steel Grab Sampler tool will be used the ‘grab’ samples of seabed sediment and will be collected at intervals of 500m from the safe inshore working limit to the 20m water depth contour. There is less than 5 kilometres between the 20m depth contour and the shallowest sample of the offshore vessel planned at 50m water depth

Sampling by Offshore Vessel

The shallowest sample of the offshore survey vessel will be at the 50m water depth contour, both a gravity core and a CPT. From there, there will be CPTs at intervals of 5km and gravity cores at intervals of 10km to the end of burial.

The vessel will use two (2) x 3m gravity corers, two (2) Grab Samplers and a Full Tool kit to perform the sampling

10 comments – Latest by:
  • Tim
    Tim, We use optical repeaters at regular intervals along the cable to amplify the signal.
  • Tim
    Considering the long distances, how do you overcome signal degradation and the need for repeating it?

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Survey Demobilisation – Farewell Gelendzhik!

On Monday 23rd June, the Gelendzhik underwent demobilisation in Sydney.  The demobilisation signifies the completion of the scheduled operations in the survey area, off the Australian Coast for the vessel.

The survey operations completed by the vessel will now be reviewed by the PIPE team.

We would like to thank the Gelendzhik for the journey they have taken us on and wish the crew safe sailing.

The vessel will now sail north for further surveying around Guam.

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Diver Swim Surveys

Photo courtesy of undersea.com.au

As part of the Sydney inshore survey, the dive team will swim five ”traverses” of the survey area to visually inspect the seabed in detail.  The dive team does this to ensure that the marine limit of the landfall topographic survey and the inshore limit of the inshore survey vessel overlap.

The centre traverse will be conducted along the middle of the survey corridor.  The divers will also traverse each side of the corridor at approximately 100 metres from the middle and also approximately 200 metres from the middle.  Each traverse will be marked with a diver’s rope annotated at intervals of 25m.

In addition, the divers will investigate, photograph and identify any obstructions along the route that is within safe diving limits.

2 comments – Latest by:
  • Matt Whitlock
    Stuart, Thank you for your comment. At the moment we are not planning to release the data in this fashion.
  • Stuart
    Are you guys able to publish a lat/long position listing of the proposed route for your cable. Would be cool ...

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Survey Operations Update

On Tuesday, the wind abated enough for the Megaforce to attempt to resume inshore operations. The crew deployed the equipment, ready to resume surveying; however the information was still poor with the records affected by the large sea swell conditions.

The Gelendzhik is a much larger vessel with a comparable platform and so was able to continue with the scheduled operations.  They had to work very slowly to ensure the quality of the data, however are expecting a clearer window over the next couple of days to begin the more sensitive part of the operations. The photo above shows the crew preparing the Cone Penetration Testing (CPT) Rig for deployment.

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Weather update for the Gelendzhik and the Megaforce

Over the weekend both the Gelendzhik and the Megaforce were on standby due to bad weather. Both vessels are anchored within 30kms of the Sydney region. The above satellite image from the Australian Bureau of Meterology was taken on Sunday.

The Gelendzhik was experiencing gale force Beaufort 9 conditions up to 45 knots with a heavy, south-westerly swell.  The winds have caused minor damage to the on board antennae, and communications have been limited to satellite phone.  The crew had a weekend forecast of 50-55 knot winds with  rough to high seas.  We are waiting for the reports from yesterday’s activities.

The Megaforce is also anchored, riding out the poor weather conditions, with 30-40 knot winds in a 2-3 metre swell.  Our survey representative, Martin Blakely, reports that conditions are clearing and they hope to resume survey activities tomorrow.

The schedule for the survey takes into account delays due to poor weather conditions, and as such the survey is still considered to be running on schedule.

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Inshore Survey Vessel – MV Megaforce

This is the “MV Megaforce”, the vessel conducting the inshore survey. There are 5 officers on board and the vessel is currently surveying in 50 metre water depth.  In addition to the magnetometer survey the crew will also conduct a diver site survey, landing site survey and landfall survey. The inshore survey is due for completion in approximately 10 days, but may experience delays due to weather.  The Gelendzhik, which is currently conducting the offshore survey, has already been delayed due to poor weather.

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Sea SPY Towed Magnetometer

Photo courtesy of Marine Magnetics

Sometimes it is possible to map the location of existing cables using the side scan sonar records. This can either be by direct detection of a cable exposed on the seabed, or from the disturbed seabed trench of a buried cable. Where the cable is detected by side scan sonar then no further survey effort is required. But where the existing cables cannot be mapped reliably for distances of 500m or more along their length, the magnetometer survey will be used. The magnetometer on board the inshore survey vessel is a Sea SPY Towed Magnetometer by Marine Magnetics. This model is an interchangeable, modular design consisting of an FSK transceiver, a tow cable, and at least one fish that contains an electronics module and an Overhauser sensor.  The Sea SPY is capable of depth rating up to 6000m (9000psi) and is fitted with GPS logging software. More information can be found on the Marine Magnetics website.

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  • Graham
    What are the magnetic variations, and at what point does it become a problem?

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