Mining Mirror October 2018 | Page 35

Cradle to grave Grinding ball design optimises SAG milling Sino Grinding delivers grinding media that works effectively with a processing plant’s ore characteristics, milling method, and other objectives. The sheer size and scale of new ore processing operations, with their associated desire to substantially increase product throughput, means that primary SAG mills have grown to larger capacities. According to Paul Peng, CEO and chief metallurgist at Sino Grinding Industries (SGI), it is critical that grinding media is designed and manufactured to cope with this increased demand. “A primary influence on maximised performance is the longevity and overall health of the grinding media,” says Peng. “There are standards of steel manufacturing for specific applications and each end use is covered by an ISO, AS, JIS, or other basic chemistry design. However, with grinding media, there is not one specific standard that provides a basic grade for steel grinding media. Sino Grinding therefore went back to the drawing board to define the purpose of all media it produces,” says Peng. Sino Grinding determined that any SAG grinding balls it produced would need to withstand high levels of impact and should possess superior abrasion resistance. The current product range includes seven distinct types and grades of forged steel SAG grinding media, in sizes ranging from 90mm to 155mm. Each grade has variations in chemistry, physical characteristics, and efficiencies to suit the various grinding and impact environments of mills. “The key to ensure grinding balls will perform optimally is to dispense with the assumption that a single ball design can work well for all sites. One needs to factor in variations such as mill size, ore type, and characteristics; final grind targets; and milling work practices,” says Pieter Theunissen, Sino Grinding’s marketing manager for Africa, Europe, and Middle East. OCTOBER 2018 MINING MIRROR [33]