Alternative lifting specialist Lampson (Australia) Pty Ltd completed a jacking project in one of Australia’s coal mining hubs, the Hunter Valley, north west of Sydney in February this year.

The P&H 4100 face shovel required a major overhaul, and the lower works from the upper rotating structure had to be removed.

Lampson supplied the engineering and equipment for the project. The upper works, without the dipper arm, bucket or boom, weighed 630t.

The jacking of the machine from the lower works was completed in a cautious time of 30 minutes, with lowering completed in less than 10 minutes – a saving of over 20 hours compared with conventional jacking time, according to Lampson.

The jacks are in a unit of four cylinders called a “leg” and four legs were used simultaneously for this application. The legs were controlled by remote consoles that regulated the level of the jack legs automatically.

Laser distance measuring devices and hydraulic pressure sensors were mounted in the four legs to ensure that each were at the same elevation and shared the load correctly.

The maximum capacity of this arrangement was 1,200t. Lampson reckons this was the first time these jacks were used for this purpose.

Cranes could have completed the job but a number of key factors promoted the use of jacking. First, substantial fabrication would have been required to distribute the loads from lifting points when using cranes. Secondly, a number of smaller cranes would have been required to lift the 630t, or one large crane, with costs far more than those experienced using jacks.

Lampson (Australia) Pty Ltd is the Australian arm of Lampson International LLC, which has its headquarters is Kennewick, Washington, US.