Capital Equipment News December 2018

Osborn grizzly feeder for Guinea gold mine

8mm on the sides. Grizzly bars are installed individually, with half bars on the sides (or complete cartridge), held down with hex bolts,” he adds. The unit features a fully fabricated 350 WA steel main frame assembled with tough huck bolts.

Osborn has supplied its GBEX 2 000 mm x 4 400 mm vibrating grizzly feeder to NordGold’s Lefa gold mine, which is situated some 700 km north east of Conakry, the capital of the Republic of Guinea. The order for a vibrating grizzly feeder that will be employed at the Russian-owned gold mine reflects the global reputation of the high-quality machines manufactured in South Africa by Osborn, comments area manager, Joe Sequeira. The unit features a fully fabricated 350 WA steel main frame assembled with tough huck bolts, and an exciter drive Innovation is at the heart of the “green” revolution that focuses on mitigating the environmental impacts associated with mining, by reducing greenhouse gases, ecological footprints, chemical use and potentially harmful X-ray or nuclear emissions. The focus spans the exploration phases all the way through to processing, and even includes the types of measurement and control techniques that are now being deployed inside concentrator plants. While safer and eco-friendlier, these instruments, importantly, have also helped mines lower operating costs and increase their efficiencies, by sidestepping the onerous regulatory requirements associated with the use of traditional technologies, such as X-ray-based sources and nuclear densitometers.

beam that is stress relieved. “Each of its two UG40 exciter drives boasts sturdy, soundproof cast metal housings and two synchronised shafts with gears mounted on swivel joint, heavy duty roller bearings. Lubrication is achieved by a combination of oil bath and oil mist (splash), while the eccentric weights attached to both ends of the shaft can be adjusted by adding or removing steel or lead weights and steel plates,” says Sequeira. “Coil spring vibration isolation is used, and the drives have pan liner support frame crossbeams. Wear liners on the pan area are VRN 200; 10 mm on the bottom and Nuclear densitometers, for example, emit low radiation levels of typically 10 microSieverts per hour, which is similar to that of medical X-rays, and thus, the use thereof is restricted globally and governed by strict health and safety standards. Restrictions include, for example, handlers requiring special mandatory training and having to undergo regular testing and skills development, while in some instances, designated radiology safety officers need to be appointed in areas where the technology is being used. An example of a “greener” option is Rhosonics’ slurry-density meter, an ultrasonic system that measures the acoustic impedance of slurry in both dredging and mineral-processing applications. Blue Cube Systems, a leading technology company that specialises in real-time in-line instrumentation for mineral

• Osborn vibrating grizzly feeders available in single or stepped deck configurations • They have a minimum grizzly length of 1,2 to 3,6 m • Widths are from 900 through to 3 000 mm

‘Green’ measurement technologies break traditional barriers

processing, has also responded to the clarion call for more environmentally friendly alternative measurement and control technologies. Its popular solution is based on diffuse- reflective spectroscopy, a tried and tested technology, which has also been used safely in agricultural and pharmaceutical industries. Diffuse-reflective spectroscopy studies reflected and scattered light, which is a function of, among other factors, particle size and the vibrational characteristics of all the molecules and crystals in the surface chemometric methods calibrate the optical spectra, including characteristic changes. Among these are the grade and percentage of solids that occur in a complex colour change. b material that is being scanned. Blue Cube Systems’ propriety

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