The double-girder crane is the final part of Sishen’s ore spillage recovery chain, using a 0.5m3 clamshell grab to transfer dumps of ore recovered into railway cars after being spilt by the conveyor system.

The crane is relatively small, says Condra, with a capacity of 1.5t and span of 7.2m, and a fairly standard lifting height of 5.7m. It offers a cross-travel speed of 16m/min for the 7.2m end-to-end travel distance, with long-travel speed of 32m/min over a gantry length of 20m, and hoist speed of 6.2m/min.

The manufacturer had previously produced much bigger grabbing cranes for various applications, including the 25t, 30m-span machine for a cement factory in Mozambique, but this project required very high operational precision, and therefore low-tolerance engineering of the crane clamshell grab, to enable it to move smoothly in and out of the railway cars.

A spokesman for Condra said: “For a grabbing crane this is a very confined area in which to work. Spans and lifting heights are usually much larger.

“There was also the design requirement to be able to dismantle the crane beyond the normal requirement of transporting an abnormal load by road, because shipping was scheduled to take place in the second half of December during the road network embargo on abnormal loads which allows free flow of peak seasonal holiday traffic.”

The crane incorporates features including variable frequency drives throughout, a radio remote control with optional pendant control, downlights, four red-and-green proxy lights to indicate movement clearance on the gantry and grab, and a digital scale monitor on the remote control to show continuous grab load measurements. There is also a second, larger digital scale read-out on the crane itself.