Simple Approach to Estimation of the Work Index

Synopsis
The work index of the mill feed of any mineral processing
plant , determined according to the procedure prescribed by F. C. Bond in 1961 , is still considered useful for estimation of the required size and power of a mill, espe-cially in the preliminary phases of a feasibility study. The index, however, is no longer considered very important from economic or operational points of view. Moreover, sci-entific and technological advances in the design , oper-ation and control of comminution circuits have rendered very precise determination of the work index unnecessary . It is, therefore , considered logical to develop a simple method of obtaining a fair estimate of the index that does not require special equipment and experimental procedures.

An approach is presented that is based on a statistical
analysis of data accumulated over four decades of
experimental determination of the work indices of a large number of ores, minerals and rocks. A simple model has been developed that correlates the work index of a mate-rial and the parameters of the Rosin-Rammler size distr-ibution of an experimental feed passing 6 mesh (-3327 gm). All that is needed is to crush a sample of the mill feed to -3327 pm, determine e size-distribution parameters from sieve analysis with the aid of a computer and compute the work index irons the correlation model.