Industrial validation of the functional performance equation for ball milling and pebble milling circuits

The “functional performance equation for ball milling” was first presented in 1988. It has now been used successfully in a substantial number of mineral- processing plants. This powerful, yet simple, tool provides a new level of understanding of closed circuit grinding. It shows how grinding circuit efficiency is really comprised of two distinct efficiencies. It demonstrates how circuit production rate is a factor of these two efficiencies, energy input and the grindability of the ore. And it links circuit performance to design and operating variables that can be manipulated. Thus, it provides an effective strategy for making plant improvements. This paper covers the derivation and industrial validation of this equation. As part of a grinding process engineering system that also incorporates suitable metrics and process control, all operators can use this tool to improve and manage the performance of their grinding operations with clarity and confidence.