Source: International Dredging & Port Construction
Principal particulars of the “COOLJARLOO I”
|Digging depth||max 25 m, min 4.6 m|
|Dredge pump||Ellicott® 24 in.|
|Pump horsepower||2,000 HP (1491 KW)|
|Dry weight||approx 2,700 tons|
|Shore power supply||22,000V/3-ph/6047|
|Suction pipe diameter||23.52 in.|
|Discharge pipe diameter||23.62 in.|
|Total installed power||4,100 hp (3057 KW)|
Ellicott® International of Baltimore, Maryland, completed a turnkey project to design and build what is believed to be the world’s largest ever mineral sand mining dredger.
Christened “COOLJARLOO I”, the bucketwheel dredger was built for heavy minerals mining in Western Australia. And with an overall length of 195 ft and a breadth of 52 ft, operating a 160-inch diameter dual wheel excavator, the dredger is the largest of any type in Australia.
The contract for the dredger was awarded to Ellicott® by the Cooljarloo joint venture made up of Minproc Chemicals Pty. Ltd. and KMCC Western Australia Pty., Ltd., a subsidiary of Kerr-McGee.
The dredger was designed for the joint venture’s A$ 400m Cooljarloo development, which is the world’s first integrated project to turn raw titanium minerals into paint pigment.
The heavy mineral sand deposit, which is located 140 kilometers north of Perth, contains all the necessary ingredients, the main components being ilmenite, zircon and rutile. There are also viable quantities of leucozene and monazite and the whole project is expected to generate annual exports worth A$200m.
The joint venture awarded the contract to Ellicott® after a worldwide tour of manufacturers and existing plant, on the basis of price and a delivery time of 11 months. In fact, the dredger was completed in less than 11 months from project start-up which, according to the joint venture partner Minproc, was “a record time for a project of this size and complexity.”
The early delivery was made possible, according to Ellicott®, because of its philosophy of “single responsibility” project management.
The design and construction of “COOLJARLOO I” machinery was completed in the United States, and the structural steel work in Singapore. All the components were shipped to Australia for field assembly at the site.
The “COOLJARLOO I” has the first electric line-shaft-driven dual wheel excavator. The entire dredger is DC electric with the exception of the spuds which are handled by hydraulic cylinders.
Its 900 HP patented dual wheel excavator has a 160-inch diameter which weighs approximately 100 metric tons. This hydraulically driven rotating bucketwheel has a roller bearing supported drive shaft, fabricated steel receiving hopper suction pipe, and structural supports for attaching the module to the dredge ladder.
The dual wheel consists of two heavy steel sections of eight bottomless buckets which form an integral unit and achieve a positive feed. This assembly is fabricated in sections to facilitate replacement without dismantling other components of the module.
The dual wheel is driven by slow speed, high torque, radial piston, hydraulic motors through an Ellicott® gearbox to the drive shaft mounted in sealed anti-friction bearings. The drive is designed with a high service factor to provide the ruggedness necessary to withstand the rigors of underwater excavation.
The receiving hopper, which is mounted inside the rotating excavating wheel halves, is of welded steel construction with replaceable wearing plates welded or bolted in place in the areas that are subject to abrasion.
The dual wheel operates with equal efficiency on both starboard and port swings, significantly increasing the effective digging time and dredge efficiency. Materials excavated are passed through the buckets into the hopper to the intake, thus to the suction pipe, maximizing the percentage of solids to the dredge pump.
Reprinted from International Dredging & Port Construction