InfraStructures - October 2005 - World Record Lift Succeeds With Pinpoint Precision

World Record Lift Succeeds With Pinpoint Precision

Irene Kremer, Enerpac B.V.
Special Collaboration

One of the world's largest precision lifting applications of land-based equipment has been successfully completed in Australia. G&S Engineering Services in Queensland used an Enerpac synchronous hydraulic lifting system to lift, within tolerances of 0,5 mm, a huge mining dragline weighing more than 3500 t.

Draglines are probably the largest land-based equipment moving across the earth, typically ranging in size from 2500 to 6500 t. Throughout Australia, they "walk" across the surface of the land, progressing a few feet at a time as they stop to scoop huge masses of earth to expose resources being mined. The Enerpac PLC-controlled hydraulic system used eighty 100-t capacity hydraulic cylinders to lift the dragline at the Curragh coal mine in the Bowen Basin so that necessary maintenance could be done on the bearing surfaces on which it swivels.

The system also tilted the huge suspended weight as to simulate different loads on the structure. The bearing surfaces could then be precisely machined to accommodate different loads and maximize the lifespan of the bearing surfaces.

The cylinders, controlled in groups of four around the perimeter of the dragline's base, lifted it 10 mm at a time for optimum precision and control. They raised it a total of 200 mm to allow machining between the upper and lower rails on which a bearing is placed. The system simulated actual loading on the dragline to maximize and accurately predict the life of the bearing.

Pinpoint accuracy
The synchronous system provided pinpoint accuracy by minimizing the difference between leading and lagging lifting points, ensuring optimum safety and stability throughout the entire lift. In addition to great safety and stability, the high-pressure (700 bars) cylinders used offered great weight and space savings compared with the much larger lower-pressure types of hydraulic cylinders previously used.

On-site the benefits of these smaller and lighter cylinders translate into more space under and around the job, permitting G&S Engineering Services to employ uninterrupted use of the latest laser-guided machining systems when they are machining the upper rail on which the dragline rotates. The precision achieved by Enerpac's synchronous system is so great that it can be used to safely tilt massive objects during lifting to enable exact aligning of upper and lower bearing surfaces.

Not Only For the Mining Industry
The size and control of the lift is significant not only for safe and precise lifting of heavy mining equipment, but also for precision lifts across a wide variety of applications. Applications such as building and construction (building lifts), civil engineering (bridge lifts), energy (turbine lifts), heavy manufacturing and primary processing (servicing and positioning of plant) and resources and petroleum (building of onshore and offshore rigs). New lifting technologies can replace traditional manual alignment and synchronization of lifts - saving time and money while increasing safety.

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