Skip navigation

News Detail

AT Processing

AT Processing – 27-05-2019 The ongoing trend to increase output tonnages in the global mining industry while maintaining efficiencies means that screening machines are becoming larger and heavier.

The ongoing trend to increase output tonnages in the global mining industry while maintaining efficiencies means that screening machines are becoming larger and heavier.


South African-based manufacturer Kwatani has, over the past more than 42 years, built some of the strongest, most robust, biggest and heaviest vibrating screens for the mining sector across the African continent and beyond. These fit-for-purpose screening machines are installed across a wide spread of commodity sectors including coal, iron ore and other heavy metals.


Kwatani’s ‘engineered for tonnage’ philosophy is underpinned by the strength of its in-house engineering capability and manufacturing facility. This has allowed the company to design, engineer and produce some of the world’s largest and most rugged screens. Recognising the value of innovation and technology, the company probably employs the highest percentage of tertiary-qualified technical staff in this industry segment.


The in-house expertise extends to designing screening machines for the 4th Industrial Revolution where technology is fusing the physical world with the digital world. This includes the incorporation of modern electronics linked to leading-edge digital functionality, while still ensuring a screening machine is robust and capable of meeting the output tonnage requirements of a specific application.


Kwatani’s extensive experience includes both mechanical and metallurgical expertise. This allows company engineers to understand how its equipment can help optimise upstream and downstream processes within a plant. Leveraging this information facilitates the customisation of large and cost effective equipment that will perform reliably over the machine lifespan.


Service technicians and mechanical engineers work closely with customers on-site analysing data and testing concepts to improve performance and lifespan. Kwatani invests heavily in its own research and development, not just through monitoring the equipment but in conducting innovative testing for continuous product improvement. The company’s R&D leads to expert reports being published in peer-reviewed forums, thereby sharing valuable insights with industry.


One of the widest screens manufactured to date is successfully operating in a coal processing plant in South Africa. The screen has a width of 4.3 metres and is 8.5 metres long. The cross members and side plates beneath the screen deck are rubber-lined to protect the screen against water and corrosive materials, increasing the lifespan of the machine. The massive machine is driven by two large gearboxes that deliver a centrifugal force of more than 460 kN each to provide the vibration necessary for efficient screening.


Kwatani has successfully custom-engineered and manufactured about 1 000 of its robust vibrating screens and feeders for the iron-ore sector in South Africa to date, while more than 15 000 units have been shipped into 35 countries globally.


The heaviest scalping screen manufactured by Kwatani for the iron ore sector measures 3.7 metres by 10 metres. It is driven by three of the largest exciter gearboxes in the Kwatani range, generating a centrifugal force of more than 2 MN. While this is not the largest screen the company has manufactured, it is the heaviest, weighing in at 54 t. The scalping screen handles variable ROM ore conditions with a maximum continuous feed load of 7 000 tph of iron ore.


The screen deck was engineered to withstand the gruelling pounding of feed tumbling from great heights onto the screen deck. Boulders can measure between 400 mm and 800 mm and the screen deck will lift and fall by 12 mm to 14 mm about 800 times a minute, requiring a robust screen that offered extended wear life.


Kwatani also designed special steel-reinforced rubber screen panels for this scalping screen, facilitating panel resilience and absorption of the centrifugal forces placed on the screen and on the screen deck, during operation. The rubber panels engineered by Kwatani are designed in harmony with the screen because it is such an integral part of the unit.