All offshore works for the installation of 2 x 1.2m diameter intake lines and 1 x 1.2m diameter outfall line Desalination plant AREVA Trekkopje Uranium Mine now known as the Erongo Desalination Plant
Short Description
The works included:
Survey and preparation of area to 900ton Caisson 1,5km off shore
The placing of the caisson and final positioning. This required a re-float
The grouting of the Caisson to the sea bead
Installation of pulling wire from shore to the caisson pre-installed sheave wheel and joining of the wire
Shore Crossing of the line
Span correction under pipelines
Monitoring of pipe pull
Installation of intake screen
Taking of metrologies and installation of 12 spool pieces
Closing of anulas where spools penetrate the intake chamber
Opening of diffuser ports
Continuous maintenance on the screen as well as intake and outfall lines
Deepening and Placing of Scour ProtectionQuay Berth 1 – 3 Port of Walvisbay
CLIENT: STEFANUTTI STOCKS MARINE (ANDREW PIRRIE)
Quay repair Berth 1 – 3 Port of Walvis Bay (Completed 9 December 2011)
Short Description
Walvis Bay is the principal port of Namibia and is situated on the west coast of southern Africa. The port has a concrete quay of 1400 m and the channel and waters alongside berths 1, 2 and 3 have been dredged to 12.8 m, with berth 4 deepened to 10.6 m.
As Namibia's largest commercial port, it receives approximately 3000 vessel calls each year and handles about 5 million tons of cargo. It is a sheltered deep-water harbor benefiting from a temperate climate. In order to deal with even higher levels of throughput, Namport has steadily improved its cargo-handling facilities.
Covering an area of 3.2 hectares, the new terminal is located at berths 1, 2 and 3. In order to make turnarounds quicker and more efficient for vehicle traffic, the new container terminal has its own dedicated entrance, separate from the main general port entrance.
The project engineer WML Coast (Pvt) Ltd. and Stefanutti Stocks Marine relied on HYDROTEX® Articulating Block (AB) concrete mattresses for scour protection of the berths.
B-4 Was sub contracted to do all subsea and marine related work
The works included:
Preparing and installing an articulating grout mattress system to prevent scouring of revetment and sea bed.
Developing of revetment and monitoring of levels prior to installation of the mattresses
Precise placing of mattresses and filling with cement using tremie method.
Cutting of steel tubular piles on the sea bed.
Repair of revetment collapse under existing structure – Berth 4
Installation of HELIFLEX Anchoring system and then attaching inter linking pontoon system to the anchoring lay out.
Short Description
The works entailed the marking of the anchor positions and then drilling in the Helix anchors. A total of 240 anchors was then installed. 20% of these anchors where then load tested. The pontoons where then placed in water and towed to the installation site where the Seaflex anchors was joined and the connectors for the pontoons where installed.
Instalation and Removal of Link Span Mooring System Port of Walvisbay
CLIENT: Shoreline Construction & NAMPORT - ZEROMSKI LOUW
The works entailed the installation of a link span mooring system to allow the RORO vessels to moor in a Meditiraion fashion. The mooring blocks weighing 35 to each had to be placed in shallow water posing a challenge. A purpose made frame was designed by B-4 for this purpose. Each link consisted of 4 blocks with piggy back chains and then to the main stud link chain. The blocks where then air jetted to sea bed level. The buoys was then attached.
The system had to be removed again to crate room for a new port extension. B-4 was then asked to remove it after other companies where unsuccessful.
Maintenance on the Erongo Desalination Plant.
The plant is managed by Avenge Water
Continual maintenance is done on the intake and outfall lines as well as the intake screen.
Maintenance consist of:
1. Replacing of depleted anodes
2. Cleaning of intake screen
3. Clearing of sediment in the intake chambers by means of airlift
4. Replacing holding down chains on the screen as they wear
5. NDT on spools
JETTY REPAIRS
Installation of Floating Jetties
Various Jetty repairs have been done with works such as concrete pile repairs,wooden pile repairs, soffit repairs and concrete sheet wall repairs.
In the Port of Walvisbay the sheet wall had breeches and back fill was seeping through. B-4 was tasked to do a complete inspection and repair of the wall.
The tanker berth at Walvisbay was also repaired and extending its life span until completion of the new Bulk oil storage facility is completed.
B-4 is a registered applicator for SIKA and we do the following using their products:
1. Grout repairs
2. Crack Injections
3. Other advanced concrete repair methods
B-4 have also installed floating jetties doing the pre assessment , design and construction.
Concrete Cutting
Concrete cutting using diamond wire to remove old structures. This can be done subsea as well as in the dry.
B-4 had cut approximately 1300m2of heavily reinforced concrete at the New Port extension in the port of Walvisbay for China Harbour Engineering Company.
We have since taken on smaller projects such as the Mehr am Platz Mall located in Swakopmund having cut approximately 200m2. This is done in public with minimal disruption.
NDT & INTERNAL PIPELINE INSPECTION
NDT on Namport Channel Marker Buoys and other steel structures
Internal Pipe Inspection Using Divers or ROV’s
Inspections on structures are required from time to time. B-4 uses innovative ideas to accomplish this. We have gone as far as custom building a Robot to inspect a high-pressure pipeline at the Erongo desalination plant.
SALVAGE WORKS
B-4 have done various Salvage operations along the coast of Namibia.
These operations are always unique in nature and innovative ideas have been used to complete such works cost effectively.
SHIPS HUSBANDRY
Ships husbandry includes the following:
Cleaning of through hull intakes, blanking of intakes, propeller polish, replacing of sacrificial anodes, class surveys, crack arrests, welding, propeller cropping and removal of foul from propulsion systems.