A typical Condra overhead crane

A typical Condra overhead crane

Condra recently completed the final crane of a four-unit order worth some R6 million for Impala Platinum’s Number 17 shaft. The three machines previously delivered comprised workshop cranes, two of them 60 tonners and the third a 40 tonne unit. All have spans of over 20 metres.

The fourth crane is a 30 tonne, very high lift maintenance machine designed with a 14 metre span to service the mine’s headgear. Lift height of this crane is 81 metres, or more than three times the 25 metre lift classified by international standards as ‘very high’.

Condra is acknowledged as South Africa’s market leader in very high lift applications, a niche in which the company’s K-Series hoists have proved dependable, durable and robust under conditions of increased mechanical strain.

Hoists for all four of Impala Number 17’s cranes were drawn from the K-Series, where modular design permits rapid modification to the specific requirement of any high-lift application.

K-Series motor reliability in the highlift role is enhanced by the use of silumin motor cores, while variable speed control levels on the drives have been developed to enable precise load positioning even on lifts greater than 100 metres.

Condra can provide high-lift hoist speeds of between zero and 18 metres per minute, and travel speeds of between zero and 100 metres per minute, depending on requirement.

Commenting on the order for Impala Platinum, a spokesman for Condra pointed to the headgear maintenance crane as continuing a trend by mining companies towards replacing the traditional chain block and tackle with a dedicated unit.

The spokesman explained that the higher cost of a headgear maintenance crane is quickly repaid by reduced production losses when maintenance has to be carried out, because mine downtime is reduced.

Condra supplied its first dedicated headgear maintenance crane to the mines some ten years ago.