The construction of Queensland’s first liquefied natural gas (LNG) plants on Curtis Island near Gladstone, required many technical and complex crane lifts, writes Mat Ovenden.
As part of Queensland’s coal seam gas (CSG) boom, the State’s three LNG plants are currently being built side-by-side on Curtis Island in Gladstone Harbour. Project leader, Bechtel, is concurrently building all three operations. The massive project is currently employing more than 10,000 construction workers with 166 cranes punctuating the Gladstone skyline.
In April of this year, the project team completed one of the heaviest dual crane lifts seen across all three Curtis Island LNG Projects, as the project safely lifted and set a Carbon Dioxide (CO2) Absorber on its foundation.
The CO2 Absorber, which weighs almost 680 tonnes – equivalent to four single storey houses -required two cranes to move the cylindrical piece from a horizontal to vertical position, before precisely placing it on its foundation.
Rigging Superintendent, Warren Achilles, said the lift was one of the most technical on the project so far and tested the expertise of everyone involved.
“Lifting such a big piece of equipment is challenging because the absorber has to sit exactly on its pre-constructed foundation – there is no margin for error. The team worked hard to ensure it fitted perfectly, and most importantly was done safely.”
“The massive project is currently employing more than 10,000 construction workers with 166 cranes punctuating the Gladstone skyline.”
The team used a 1200-tonne Demag CC6800 and CC2800 crane to ‘top and tail’ the CO2 Absorber. The CC6800 lifted the load using two 400-tonne slings attached to two bollards on the side of the absorber, while the smaller CC2800 crane picked it up from the other end, gradually walking it down a 60 metre timber crane pad until it was vertically suspended in the air.
Preparation for the lift began months before the event.
As one of the largest cranes in Australia, the CC6800 took almost three weeks to assemble in readiness for the lift, with 400 tonnes of super lift counterweight to go with it.
Assembling the crane itself involved bringing over approximately 70 truckloads of parts and pieces, with the heaviest piece weighing 80 tonnes alone.
“We actually built the big crane using another big crane. A 600 tonne crane put the 1200 crane together,” Achilles said, “The lift was the easy bit. The hardest bit about our job is setting it up and making sure it all goes to plan, following the rigging drawings that we‘re working to.”
A short video documenting the complexity and enormity of the dual crane lift can be accessed on Queensland Mining and Energy Bulletin’s website: www.qmeb.com.au.
Curtis Island’s Biggest Crane
There are only two Demag CC 6800 Lattice Boom Crawlers operating on Curtis Island and they are by far the biggest. Both cranes are powered by twin diesel engines and can be configured to a 1680 tonne lifting capacity and a maximum boom length of 96 metres, and up to 210 metre with luffing fly job extension attached.
This crane offers a variable superlift radius and main boom offsets for SW and SWSL luffing jib configuration. The Demag CC 6800 also incorporates Demag‘s IC-1 LCD touchscreen crane control system, Quadro-Drive, and hydraulic assisted boom section pinning.
Demag CC 6800 Lattice Boom Crawler
FAST FACTS
- Known as the 6800 this crane has the capacity to lift 1200 tonnes
- Sourced from the Netherlands as there is only two of its kind in Australia
- Once finished on this job this crane will have lifted an estimated total of 6000 tonnes
- It takes 140 truckloads to mobilise to site and two to three weeks to assemble
- Maximum main boom length of 96m and with extension is 210m.
Where the jobs are
There are currently 10,000 people working on the LNG projects on Curtis Island with that number expected to hold through to mid 2014.
The projects are now predominantly out of their civil phases, and well into the structural and mechanical phases. This is where most future recruitment will now be concentrated.
Bechtel is currently looking for a range of roles such as:
- special class welders
- instrumental
- pipefitters
- riggers
- electricians
More information on how to apply for these positions is available at: craftjobs.becpsn.com.
Three roof raises in three weeks
Three roof raises across three projects in three consecutive weeks is all part of doing business on Curtis Island.
As the LNG plants on Curtis Island continue to take shape, some of the most visual elements were completed in June across the Australia-Pacific LNG, GLNG and Queensland Curtis LNG projects, with three of the six LNG tanks successfully capped with the raising of their roofs.
And this is not your average roof. Each roof, constructed at ground level on the inside of the tank and weighing in at about 900 tonnes, is raised on a cushion of air some 38 metres off the ground to the top of the tank wall where it is wedged and welded into place.
The air is forced into the sealed tank cavity via a series of fans, using volume to force the roof to rise.
“The engineering is extremely simple. These are among the heaviest lifts we have on these projects, but this simple and very safe solution to tank roof construction means most of the work is done on the ground and no cranes are needed to successfully raise these roofs,” Bechtel Gladstone General Manager Kevin Berg said.
“Visually, these roof raises are significant. It’s a great sign of the progress being made across all three sites.”
Vice President GLNG Downstream, Rod Duke, said the electric fans used to lift the 850-tonne roof, used about the same pressure it takes to blow bubbles through a straw in a glass of water.
“We used air to raise this huge roof, around 40 metres inside the outer concrete walls of the LNG tank,” Mr Duke said.
“Construction now starts to build the inner nickel steel tank that will hold the LNG at minus 162 degrees centigrade.”
The steel roof will be covered by two concrete layers and weigh a total of 7725 tonnes.
FAST FACTS
- Over 2hrs: the time taken to raise the roof
- 79 metres: roof diameter
- 200,000m³: quantity of air needed to raise the roof
- 7725 tonne: total weight of the roof after all concreting and fixtures are complete
- 30 months: construction time
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