The andersite rock found at AfriSam’s Eikenhof Quarry is one of the hardest and most abrasive aggregate materials found anywhere. Its strength and resistance to wear is what makes Eikenhof’s andersite a commodity that is sought after by the asphalt industry. It is also what makes it extremely challenging to work with. Andersite is difficult to crush, says Eikenhof works manager, Yedwa Christopher Mgxekwa.
In addition to being hard to crush, it is also hard on crushers. “Andersite has a high crushing value compared with other aggregate commodities,” Yedwa explains. “It is also abrasive, so it is extremely tough on the machines that handle it.”
Equipment longevity was a problem at Eikenhof Quarry before AfriSam turned to Osborn for a solution. Yedwa says that the quarry’s jaw crushers used to last only five years.
In 2008, Osborn supplied the quarry with a new 47×60 jaw crusher. This was, however, no standard jaw crusher, but a machine that was customised by Osborn, in collaboration with AfriSam, to tackle Eikenhof’s challenging andersite rock.
An analysis led to specific modifications of the standard 50×60 crusher, including moving in the back wall of the crusher, to offer a better crushed product.
Other modifications that were undertaken by Osborn in order meet Eikenhof’s needs included modifying the unit’s standard spoke type flywheel to a solid disc type flywheel. This was done to minimise the risk of Eikenhof’s hard andersite breaking the standard flywheels.
Osborn’s design interventions have extended the lifespan of Eikenhof’s jaw crusher from the previous five years to eight to 10 years.
Osborn Engineered Products
Charisse Fallows
Tel: (011) 820-7600, www.osborn.co.za
