## Equipment Sizing: Crusher or Grinding Mill

UNTIL THE THIRD THEORY OF COMMINUTION of “Work Index” **method of determining crushing and grinding mill** size was introduced, there was no way of accurately figuring the most applicable, most economical **size of crushing and grinding mill**.

Naturally, with little or no factual operating data correlated in useful form, it was easy enough, even for the most experienced, to arrive at an incorrect size of crusher or grinding mill, especially when a slightly smaller unit carried an advantage in initial investment.

The “Work Index” method, frequently referred to as the Bond* method, is based on extensive field operating data and equally extensive laboratory data covering wide varieties of materials, ranges of reduction sizes and types of equipment. The correlation of all this factual material enabled the establishment of a consistent common factor, known as the Work Index, for accurately determining crushing and grinding mill sizes.

The Work Index is actually the total work input in kwhr/short ton required to reduce from theoretically infinite particle size to 80% passing 100 microns, or to approximately 67% passing 200 mesh.

Knowing the Work Index, one has but to apply the proper given equation to determine the power input required. The calculated power input in turn enables you to ….Read more