KEW Foundries, Africa’s only manufacturer of large cast safety critical headgear sheave wheels, has developed its largest sheave wheel to date. The company has designed and begun manufacturing a 21,5 foot (6,5 metre diameter) sheave wheel for use as part of a cluster arrangement.
KEW Foundries recently secured a contract to supply two sets of 21,5 foot deflection clusters to a South African mining project house. The cluster consists of four sheave wheels mounted onto a single rotating shaft. The clusters will be used on one of the new platinum mines in the Phokeng area and are due for delivery in early 2009.
According to Jaime Goncalves, Technical Director, KEW Foundries, the larger diameter sheave wheels translate into a greater payload per winding cycle.
“In South African mining, there is a growing trend to use Koepe winders, using multiple ropes. The continuous ropes go down the shaft and are attached to both the conveyance and a counterweight arrangement.
“The winder is mounted over the centre line of the shaft, causing the rope to drop off-centre, either on the counterweight or conveyance compartment. The deflecting sheaves are mounted below the winder to deflect the rope back to the applicable compartment centre line,” says Goncalves.
Conventional winding systems offer a payload of up to 15,000 kilograms, while the Koepe system offers mining operations a payload of as much as 45,000 kilograms.
With its extensive research and development capabilities, as well as manufacturing facilities, KEW Foundries customises sheave wheel designs according to the specific requirements of a client.
“The key aspect in the design of a deflection sheave wheel used as part of a Koepe arrangement is the inertia, which the cluster sheave wheels contribute to the overall mechanical system. This is where cast iron or SG iron, as the material of choice in the manufacturing of these types of sheave wheels, plays an important role.
“Cast iron and SG iron offer the designer the flexibility to alter existing or develop new designs to optimally suit specific customer requirements,” says Goncalves.
The company supplies its sheave wheels to mines and mining houses throughout South Africa, as well as the rest of the continent, and has secured deals in countries such as China, Australia, Brazil, Canada and Sweden.
Goncalves notes that as a result of the company’s extensive experience in the industry and its relationships with mining houses, KEW Foundries has developed a “best of specification”.
“We have taken the best requirements of the mining house specifications to produce sheave wheels and related equipment that meets and often exceeds our clients’ requirements. The KEW specification has been adopted by a number of mines that were without a detailed specification.
“The 6,5 metre sheave wheel has met with great success over the past year and we are using this positive feedback to expand our offering by developing a sheave wheel with an outside diameter measuring 7,1 metres,” concludes Goncalves.