More Cranes for Grootgeluk

Exxaro has again chosen Condra to manufacture high-lift overhead travelling cranes for vehicle workshops at its Grootegeluk Coal Mine, near Lephalale in Limpopo Province. Orders for three cranes placed late last year bring to six the number of these machines supplied by Johannesburg-based Condra since mid-2016, with a total combined order value of some R10-million.   The first of the new orders, for two cranes, was secured by authorised Condra distributor H&H Specialised Services in November of last year.  A third crane was ordered in December and a further order for a fourth machine is expected soon. H&H Specialised Services will supply staff and technical expertise to install and commission all new cranes, the first two of which have already been delivered.  Both are 50-ton double-girder electric overhead travelling cranes with standard two‑speed hoists, and both have spans of 18,4 metres. The third crane, delivered in mid-April of 2018, is an 18,4-metre span 50/20-ton machine featuring variable‑frequency drives on the main lift, long travel and cross travel to facilitate precise positioning of very heavy loads. The auxiliary hoist on this machine has a standard two-speed option, while lift heights of the main and auxiliary hoists are 16 metres and 17 metres respectively, similar to those of the first two cranes.   Design of all three machines was described by a Condra spokesman as “standard”, although they feature live-axle drives across their design in place of the more common ring-gear configuration, part of Condra’s mandate to keep maintenance costs to a minimum. Other non-standard elements of the Exxaro contract include special LED lighting, limit switches on the long-travels and cross-travels, and armoured cable on all wiring. The Condra spokesman said that manufacture of all three machines had been straightforward except for painting, which took twice as long as the usual seven days because of heavy rains experienced during this final phase of manufacture. All cranes were nevertheless delivered on schedule.   Condra is in constant pursuit of lower machine maintenance costs, one result of which is the live-axle drives incorporated in the Exxaro cranes. Gearboxes across the hoist range were up-rated some years ago to deliver additional power, and the company today uses a 36B case-hardened material on most pinions.  This material, though expensive, is beneficial in extending crane lifespan. Additionally, hoists are fitted wherever possible with high tensile-strength ropes to reduce rope diameter and enable a reduction in drum diameter and a smaller gearbox and motor. All these factors all help the customer to contain costs.