How to Use Bond equation to calculate work indices from operating data

The Bond equation can be and is used to calculate work indices from operating data. To distinguish this from the work index (W_i) obtained from grindability test, the work index calculated from operating data is designated as W_io

When accurate 1) mill feed rate, 2) mill power, 3) feed size analysis, 4) product size analysis data are available, using the Bond Equation as shown, W_io is simple to calculate.

In using this Bond Work Index equation, the feed is the feed to the grinding circuit and the product is the product from the circuit. In a closed circuit operation, do not use the feed into and discharge from the mill as is done with an open circuit mill. The work index is bases upon the work done, in going from the circuit feed to the circuit product.

Calculate the Operating Work Index.