In an industry first, bulk materials handling and minerals processing specialist Osborn Engineered Products SA secured an order from Randgold Resources for mobile, track-mounted crushers to be used underground at the Loulo gold mine in West Africa.
Osborn Track 3042 mobile jaw crusher
Following the success of an Osborn Track 3042 mobile jaw crusher supplied to Randgold in an earlier order, Osborn has supplied a further three units. “One is for surface use, while two of the new units are for underground use, and one of these was recently commissioned,” reports marketing director Martin Botha. “To our knowledge, this is the first wholly South African designed and built mobile track mounted jaw crusher being used underground in Africa,” he notes.
These Osborn Track 3042 units have been modified for electric operation. Botha elaborates: “The electric version of this robust track mounted crusher is ideally suited for an application like Randgold’s, where the machine can be driven underground, then simply plugged in and operated. This is a cleanrunning machine with all the advantages of a mobile crusher ,” he stresses.
“This electric unit is also perfect for installations where diesel is expensive, but where mobility is essential. Just drive it to site, plug it in and run it. The ‘tier 3’ engine on the unit boasts emission control features that comply with strict European standards,” Botha adds.
Osborn secured this substantial order based on the quality and features of its exceptional machine, as well as the successful operation of other Osborn equipment supplied to long-standing customer Randgold Resources. “Over the years, we have supplied various machines to Randgold Resources, including apron feeders, crushers and vibrating grizzly feeders,” Botha notes.
Osborn Track 3042 units
These Osborn Track 3042 units were custom designed to meet Randgold’s underground requirements, one of which being that the machines should be able to track and turn in the narrow confines of the decline until reaching the ore passes. Fed by LHDs, the Osborn Obex 4212 Vibrating Grizzly feeders on the mobiles feed the -600mm +150mm material through their Osborn Telsmith 4230 jaw crushers at a rate of up to 300tph. These units are designed to straddle the ore passes into which the crushed material passes, thus negating the need for the standard 1050 discharge conveyor .
This unit will also be available in a 2540 jaw crusher size, enabling customers to choose the model best suited to their needs. “Customers like Randgold Resources recognise the benefits of this track unit being locally designed and manufactured,” Botha notes. “The spares, backup service and support of a South African manufacturer is a significant benefit, with clients being assured that spares and service from Osborn’s trained staff are readily available.
In addition, this mobile crusher features standard machines and components in order to fit in with Osborn’s standard product offering to ensure that parts are readily available and supported in the African and world market.”
The Osborn Telsmith 3042 Jaw Crusher
The Osborn Telsmith 3042 Jaw Crusher used on the mobile is one of the most widely used in Southern Africa for primary crushing, explains Botha. It boasts a rugged frame and optimised toggle seat and nip angle. The crusher handles up to 610 mm feed size and can be set to a 65 mm minimum closed side setting. (This is controlled by the feed size.)
On units where the Osborn track discharge conveyor is included, it features an impact bed, to minimise belt damage, head adjustment for ease of maintenance and a low-maintenance electric drum motor.
A further benefit is that the conveyor is completely removable for service as well as for access to the bottom area of the track unit and jaw crusher. Outstanding features of the 4212 Osborn Obex vibrating grizzly feeder on the mobile unit include a low-maintenance variable speed electric drive and a hard-wearing steel bin.
Hydraulics on the Osborn Track 3042 have been minimised to reduce maintenance. Its hydraulic system has also been sized for a 45 °C ambient temperature and it has no heat-inducing flow control valves. The unit’s tracks have a 500-mm-wide shoe. Its speed range is from 0,3 km/h to 0,8 km/h.