STM mills have multiple operating modes, the Kevitsa mill operated in the most sophisticated “P80 control mode”. This utilises the installed online particle size analyzer: the target P80 from the mill can be set by the operator. The mill operates in a closed loop control mode, and despite the feed size and feed rate fluctuating significantly, the control automatically varies the mill speed, in order to achieve the target P80. This produces very consistent grinding results minimising wasted energy on overgrinding.
Steep Product Particle Distribution
The mill produces a large amount of particles within the required product size range. The internal selective grinding mechanism minimises overgrinding of fine particles, minimising ultrafine particles, and produces large amounts of desired 20-40µm particles. The grinding performance achieves precise results on a single pass through the mill, allowing open circuit flowsheet, without any recirculating through the mill.
High Performance Recoveries
The impact of the HIGmillTM on the final copper grade and copper recovery is outstanding. Interesting is also that the finer grind resulted into less nickel reporting to the final copper concentrate product.
Not only did recovery and grade increase, but the finer grind resulted into less nickel reporting to the final copper concentrate product.