Mining Mirror May 2017 - Page 28

Completed Kwatani double-deck screen with gearboxes and motor being put to the test. The importance of maintenance “A proper maintenance regime will prolong the life of a vibrating machine significantly,” says Mayhew-Ridgers. “We’ve had exciter gearboxes running for 15 years because the operators regularly changed oil, and regularly exchanged the breather and checked magnetic plugs, while there has been another case where unbalanced motors lasted for less than a year due to a complete lack of maintenance, as they were still running with the original grease.” To prevent downtime, the unbalanced motor must be properly sealed; weights need to be aligned; nuts and bolts have to be properly tightened according to the correct torque value; and the bearings greased according to the OEM maintenance manual. [26] MINING MIRROR MAY 2017 “Lining protection of the vibrating screen is probably the biggest culprit of machine wear. If the maintenance team doesn’t replace the side liner, particularly where the material flows in, the material rubs on the side and starts eating through the steel plate,” says Mayhew-Ridgers. In addition, the feed area on a vibrating screen is subject to a great amount of impact by the processed ore. Consequently, the feed chute to the vibrating screen is an important and integral part of a successful screening installation. They need to be correctly designed in unison with impact absorption and optimal distribution in mind. Impact screen panels in this area should be of a robust design so that they can survive the arduous conditions prevalent in this part of the screen, which is often the cause of screen damage. Screen media Mining in focus When it comes to the screen media that are fitted onto the screen decks, traditional products such as woven wire cloth have been used for years with great success. However, according to Steve Fair, media manager at German company Haver & Boecker, it is worthwhile for operations experiencing high wear and frequent screen changeouts to look into engineered screen media. “The difference between using ‘good enough’ screen media instead of the optimal screen media for the application can be unwanted downtime and expense,” says Fair. Fair gives the following advice when installing screen media. First, look at all aspects of a mining operation and any challenges to increasing production rates and profitability. Second, look at the