COVER STORY
Super-span maintenance crane for platinum concentrator Condra has followed deliveries of customised cranes for injection-moulding and shipboard maintenance applications with a third overhead machine of unusual design, this one sporting an exceptionally wide span of no less than 35 metres. A span of this magnitude is more than double the average of fifteen metres, and approaches the manufacturer’s record of 42 metres. Not only is Condra’s newly completed crane unusually wide, but it is also large from an overall perspective, with box girders the height of an average man, and a 20 ton two-speed hoist mounted
on a seven metre-wide crab with a wheel base of six metres. A working platform of opengrid walkway and solid-forge handrail runs the full length of the machine. The crane will be delivered to a platinum concentrator for maintenance duty. Weighing in at 33,3 tons, it has a lifting height of 18,7 metres and is controlled remotely by
radio. There is a pendant back up. During the crane’s design phase, the very large size of this machine dictated careful consideration of wind loading. Condra’s engineers included the company’s patented storm brake to counter wind forces anticipated at the installation site. The storm brake is activated by anemometers in two stages, the first sounding a siren when the wind speed reaches 30 km/h, and the second automatically engaging the brake at a wind speed of 50 km/h. At this point, any crane operation is de-activated and the machine automatically secured against all movement. Condra completed final assembly, alignment and testing of the concentrator maintenance crane in the last week of March. No less than 260m2 of factory floor space was set aside for this phase of manufacture. Transport to site will require three specialised vehicles: two horse-and-dolly movers for the two box-girders, and one flat-bed trailer to be loaded with the hoist, crab, end-carriages, bottom-block, panels and ancillary equipment. Installation and commissioning at the concentrator will be undertaken by an independent contractor with Condra engineers in support.
Condra's factory - hoist (yellow) nearing completion, overhead crane above it 4
Lifting Africa - Mar/Apr 2021
Johannesburg-based Condra boasts a manufacturing pedigree going back more than 50 years. The company claims the highest
