Condra ramps up overhead crane production to meet African mining demand
AN unusually high demand for very large overhead cranes from mining companies across Africa is keeping Condra’s Johannesburg manufacturing facility exceptionally busy, with the company introducing additional shifts. Condra is currently manufacturing six 50-ton cranes for a mine in Zambia and a 5-ton crane for a Namibian mine. Three of the cranes have box-girders of more than 30 metres long.
Large cranes such as these present different manufacturing challenges because of their girder dimensions. Two of the 50-ton cranes have spans of 34 metres, and a third, high-lift, 5-ton crane spans 35 metres. Condra is simultaneously completing manufacture of a further four 50-ton cranes with spans of around 20 metres. In addition to their length, box girders for 34-metre spans stand two metres high and measure just under one metre wide.
A Condra spokesperson explains that these cranes are particularly large, long and heavy fabrications to manage. “Manufacture involves intricate welding and very careful jigging to incorporate the correct camber to counter the girders’ natural tendency to sag under load. Girders this long are also quite delicate to manoeuvre on the shop floor. They require resource and workflow planning, and tie up use of our factory cranes,” he said.
“End-carriage design has been important to ensure crane longevity, because the wheels must accommodate continuously changing stresses imposed by the girders as they flex under different loads. Our design team paid attention to both camber and end-carriage design to ensure durability. Condra cranes are known for their low overall lifetime cost,” said the spokesman.
Also under manufacture for Namibian mines are three single-girder overhead cranes, two portal cranes and a jib crane. The company behind these orders, with which Condra has a long association, is an engineering and project management consultancy with worldwide representation. It has additionally ordered 18 electric hoists with capacities ranging from two to 25 tons, as well as four chain blocks.
In the Northern Cape, Condra is currently commissioning two substantial cranes at Gamsberg Phase II, where the same consultancy contributed to metallurgy and process plant design; one is a 40/5-ton crane with a 22-metre span, the other an 80/20-ton machine with an 18-metre span. In addition, Condra has delivered two more cranes at the same site for installation as structural steelwork progresses. Gamsberg Phase II is an expansion of the open-cast zinc mine near the town of Aggeneys.
Condra anticipates further orders from southern and east Africa, notably Tanzania and Mozambique, where a marketing drive is currently under way.
Further information, contact: Marc Kleiner (MD)
Tel: +27 11 776 6000
E-mail: sales@condra.co.za
