Mining giant Anglo American’s 73%-owned Kriel colliery, situated 45 km south of eMalahleni, in Mpumalanga, will become the first operation in Africa to adopt a 250 kW Rulmeca motorised pulley, which is the largest in the world and exclusively available in the local market through conveyor equipment manufacturer Melco.

The Rulmeca motorised pulley 1000HD, which will be fitted in the first half of this year, is a compact and efficient conveyor drive of Rulmeca’s power class. The shaft-integrated motor gear unit is completely enclosed in the drive drum body (pulley), providing increased protection in harsh environments.

“This reduces the inertial mass of rotating parts to an absolute minimum,” explains Rulmeca Germany research and development manager Hans-Hendrik Huenicke.

“By enclosing all the drive components within the pulley shell, the unit becomes considerably more compact and efficient. An added safety feature of the Rulmeca motorised pulley is the fact that all electromechanical components are sealed to IP66/67 standards within the steel pulley shell, thereby increasing reliability and operator safety, while minimising drive size and reducing noise,” he adds.

The Rulmeca motorised pulley 1000HD produces 50 000 Nm nominal torque at 30 t belt tension and 2.5 m/s belt speed, with a diameter of 1 000 mm and width of 1 500 mm. The technology’s efficiency class is IE3 and is protected with IP66/67, which is enclosed in the rotating drum body.

“The technology can be configured to meet a customer’s requirements. The machine can be ordered in a drum width from 1 500 mm to 2 500 mm. Its size is about three times smaller than a con- ventional drive unit, with its mass not exceeding 5.5 t,” notes Huenicke.

He highlights that the Rulmeca motor- ised pulley has a low rotating mass of inertia and is highly efficient because of its integrated design, which results in energy savings.

“No comparable machine in that power class is available on the market and Rulmeca is the only manufacturer of those kind of drive units. It offers the materials handling industry a compact, high-performance power drive solution of outstanding quality, which is unique in the world,” he notes.

Huenicke explains that the pulley was developed in 2008 by Rulmeca Germany in Aschersleben/Sachsen-Anhalt – a traditional German machine manufacturing area. Rulmeca Germany has been producing motorised pulleys in all sizes since 1956.

Melco product manager Bryan Krynauw states that Melco first presented the 250 kW Rulmeca motorised pulley to the local market at the 2012 Electra Mining Africa exhibition in September 2012, which was received with positive feedback.

“This is the next step of advancement in African mining and the Kriel colliery has identified the benefits that the pulley offers in terms of improving productivity and efficiency.”

Other Installations

The 250 kW Rulmeca motorised pulley was installed in early 2011 at the Hunterston deep-water terminal, in the west of Scotland, which is one of the UK’s foremost facilities for coal imports. The operator, Clydeport, moves 3 000 t/h of coal across 27 conveyors on a 24/7 basis and Peel Ports’ group engineering manager Peter Little notes that performance has been dramatically improved.

“In addition to increasing the throughput, the 250 kW Rulmeca motorised pulley requires no maintenance measures, which further increases productivity”, he adds.

Krynauw adds that only the shell of the motorised pulley moved during installation, which made it a safe design for any application. “The compact design of the motorised pulley also enables a more cost-effective and efficient installation process when compared with standard pulleys,” he continues.

Krynauw is confident that Melco will obtain significant market share in the African mining sector through its range of Rulmeca motorised pulleys.

“As investment in African mining projects continues to rapidly increase, mining houses will consider investing higher amounts of capital into more efficient machinery.

“This change of mindset is sure to change the way materials are conveyed in Africa and I am confident that, as one of the largest suppliers of idlers and rollers on the continent, Melco can expand its market share across all mining sectors in Southern, East and West Africa in 2013,” he concludes.